Pw50 low compression after rebuild. I'll have to get a better quality tester.

Pw50 low compression after rebuild If you pull the top off the carb with the throttle and choke barrels, you can operate the choke and see that it moves freely up and down. It read 90 PSI before and now reads a little less than 100. I could see no damage. PW50. I did a compression test and cylinders 1-5 were all about 130-135psi dry and a surprising 130-170 wet ( 1 cylinder same wet, one only up to 150 and the rest up to about 170psi). White smoke on startup but goes away when engine warm. After I got it all together my compression was really low below 80 on all cylinders. I recently rebuilt the top end on my rm250 and this morning when i went to kick it over it had no compression. I rebuilt a small block Chevy, it burned oil and had low compression for a few hundred km before I realized the rings weren't seated. ahhhh this thing is making me mad. After running saw enough to make a few basic adjustments and cutting a few rounds to put some load on it (total about 1/2 hour run time so far), I let saw cool down and have checked compression again. Full Member; Posts: 28 Apr 4, 2010 · Well I finally got my motor together. Note i live in colorado about 5000 feet. Jul 12, 2007 · With a normal operating temp, I had 90-85-110-90 across the board. Very strange to get the same compression readings on the existing engine and then on the new rebuild. I'm guessing the valves are not seating, but just a guess. Messages: 59 Likes Received: 0 Mar 24, 2018 · You're leak down test results and compression results after adding oil point to poorly sealing rings but the consistency of the low readings and previous good running condition just doesn't add up to sudden piston/ring sealing problems. Apr 3, 2020 · Had to file rings to set proper ring gap but other then that should have compression. All while 73-76 psi all 3 faces on both rotors. the rear ends are the same, but the qt50 axle is about an inch short, so that is why you need the pw50 CB550 Low compression after top end rebuild . I'm in Utah at about 5000 ft. I drove my FD on a 600 mile road trip, daily drove it for a month, then took it on a 800 mile round trip for the hell of it. —Tom. 012in), assembled piston with new wrist pin and bearing, squeezed ring and slipped cylinder over the piston, tightened cylinder to crankcase nut to 24ftlbs, then installed new o-rings with lithium grease and brand new cylinder head, tightened also, for your compression test, are you wedging the throttle body all the way open so that fresh air can get into the cylinders? if not, you can get extremely low numbers. If the engine starts but quickly dies, then you likely have a low-compression issue. Many rotaries out there with stuck seals, low compression, bad water seals, etc. When I take the spark plug out it kicks over freely like it should. Nov 18, 2022 · General Snowmobile Forum. 21cc dome with cool head . New top end, carb, spark plug, gas, reeds, throttle cables. regards Jan 9, 2021 · Gotcha. mud runner Member. Now the person putting it together for me finds out after assembly it only has 100psi of compression on the cylinders and won't run. Top End Machine alloy intake manifold and Black Dragon race carburetor are designed and scaled to fit PW50 frame and engine without hanging out or interfering with rider’s leg. Would it still fire with spark and poor or no compression? Feb 22, 2021 · YZ250 Question: Just rebuilt the top end on a 2015 YZ250 with a Vertex piston. Jun 13, 2016 · 115. I checked for spark, fuel, then compression after it wouldn't start. Everything else seems to be working as far as I can tell. Link to comment Dec 22, 2012 · I recently picked up an old but decent condition '83 PW50 for my youngest son. It was only giving me 30 psi (I held the throttle open when I checked). It sorts feels boggy, and it surges, and the air box sounds different from what I remember 2 strokes to sound like. The top end was shot along with the rod bearing. 47. Bike runs fine, just have to kick 5 6 times to get low idle for 30 sec then can get to rev up and go. New guides and seats, new S&S pistons, 0. Also cleaned and polished stock crank. Jul 3, 2019 · I just picked up an 01 KX125 a few weeks ago that had low compression. May 16, 2011 · Then I could easily ride 75mph on the interstate, while carrying an extra 40 or 50lbs of gear/tools/etc. There is a big difference before and after the rings seat. If it doesn't start I guess the bike will be heading to the shop. thanks for y all answer May 21, 2009 · here's how I rebuilt the bike the second time around, after the washer fell into the crankcase somehow the first time. Wow, talk about an upgrade! Thanks to ZOOM ZOOM PARTS and their amazing big bore kit, my Yamaha PW 50 is now a powerhouse on wheels. Rebuilt bottome end, new OEM crankshaft, bearings, seals. Enjoy it while the traffic is low and price of gas is low. Then it started to cut off and wouldn't idle without the choke on. Have you done a compression test? Putting starter fluid in the cylinder and it runs some times indicates low compression as starter fluid will fire under lower compression than gas. Having a new sleeve in the other bore however should have factory compression in my mind. About a month ago (~2000 miles after rebuild I believe) it had a compression test at Mr. Jun 30, 2016 · Compression for these engines is only in the 50-75 psi range, due to it having an automatic compression release to make it start easier. 5 dohc turbo from a 04 forester. Also check that gasket thickness are the same. I am doing an engine rebuild and I have checked compression afterward and I have around 90PSI in all 4 cylinders. 2004 PW50. So the rings aren't sealing and I believe the piston is slightly undersized for that bore. We have just done a top end rebuild on his PW50 and it has been recom Mar 1, 2015 · Never seized but I figured it was good idea to rebuild, it was not pulling well uphill for him regardless. I poured some oil in the cylinder to see if the compression raises. Should I have honed it? Rings not seat nicely? Im thinking of ripping it down and getting it honed. pull the qt50 ring gear with axle in it. Aug 11, 2010 · Well here is my story and am getting worried. After a few hours it improved some. Dec 6, 2016 · Other than getting a low compression reading like that if true, i'd say you got a bad rebuild for whatever reason, whether the actual bore job or assembly. Its enough compression that I have jump started it and kept the revs super low but it will continue as long as some gas is Compression is most always lower than expected on a new rebuild. Starts out with a 03 4500 with LLY in it that appeared dropped a valve and busted piston. Block has been hone clean and resurface with used je piston, eagle rod, new je piston rings, new head gasket, and all new bearings. Jan 20, 2013 · Hey guys, So I sent my sons '88 lt80 cylinder out for rebuild and now it's all back together with 70psi compression. Low Compression on a Newish Rebuild - 12A I purchased an '84 FB a couple of months ago and recently got some results back from a compression test (prompted by poor smog test results). After I put it all together it won't start. Even at those low compression numbers, it should still fire. Need help, call 1-800-321-1364 Engine Rebuild Kits Expand Go to an auto parts store and buy a compression tester. Oct 11, 2011 · I tested the compresson and it is reading 90 psi which seems very low (I do not have manual). if you have bad warm compression, it may be time to find someone local with a leakdown tester. When testing with the switch in the "start" position, I get a very st Apr 11, 2009 · hi guys i just rebuild my engine with these mod +4 mm cranckshaft . Jump to Latest Jul 23, 2018 · so the compression was low so i did a fresh top end rebuild. Traditional knowledge says that it's time for a new top end job, but you may find the number doesn't change. Yet it burns oil and has very very low compression. Thread starter mud runner; Start date Oct 31, 2013; Yamaha Blaster Parts & Support. We make many of our own brand PW50 parts such as billet aluminum foot pegs, one piece throttle cables to get rid of the oil injection system, oil injection plug for the removal of oil injection sys This PW50 60cc Big Bore Cylinder Kit comes with a Top End Machine designed aluminum cylinder head. . Appreciate any ideas. I checked the spark plug, cylinder head, and jug for torque, all good. To give you an idea my personal XPL has 135 psi and revs into the 7200s and has great torque. Put a new wiseco top end with old new cyclinder (replated and honed ) it’s showing 60 psi on 2 different compression testers the piston is in the right way the rings are gapped at . Probably wishful thinking but I am putting the right valve seals on and gonna run the piss out of it. And should a new top end have a higher starting compression. press the qt50 axle out of the ring gear. it was reading 37 psi. I have 0,0,0,0 compression. I live at 6000 ft. Engine . I fully rebuilt the motor on my 1999 cr 250. The filter is not OEM. Pw50 rebuild problem PW50 Compression? Intro And Help Pls! Jun 8, 2019 · I'm working on a pw50 for a friend. I was reading 30psi before the rebuild, then I replaced the cylinder head, cylinder, piston, and Mar 28, 2011 · Re: Complete 951 rebuild with low compression Did you test compression before head change ? A standard 951 blows around 130 stock, what did they do to the head,are you in a position to check your squish ? 951s dont need alot of compression to run well. Remove: 9 Spark plug cap 1 9 Rear shock absorber bolt (lower My last rebuild on my KZ650 I installed a big bore kit. 8 psi warm and 78psi engine off. I could not find in either the service manual nor Clymer manual, if the switch position makes any difference. PWs run notoriously low compression, but do have their limits. It had great compression and was able to get the bike running with it in. So far, I have compression, I have spark but no fuel at start when cold. Stil no real change in compression pressure. This rose to 155/155 after 120 miles, and at 1800 miles was 160/160. honed cylinder, checked ring gap (. Feb 10, 2012 · The PW line produces incredibly low compression numbers, 80 PSI might be as good as you're going to get. Then I added oil to the cylinder and got 150psi once, then down to 120psi. So that tells me the rings didn't seat well. I am blown away by how low the compression is because during the rebuild the cylinders looked perfect. IDK guess its possible for rings not to seat. Did read 10/1 piston does have a lower compression of 150-170 but I still am on the low end. but hey, at least your compression results are all consistent consistency is good. Everything else was still in good working condition. Normalizing the results to 250rpm at sea level (via the rotary compression calculator on foxed. I tried to start it after that and the bike did fire and run off the satrting fluid I had in the cylinder. I checked compression again and had 140 one cylinder & 30 in the other! Also, each time I started it I never ran it for longer that 10 seconds. I put a Pro-x piston in. Cleaned out the exhaust drilled holes in the air box. altitude so I believe this is like 100 lbs at sea level. Goodluck Apr 7, 2017 · So I recently finished rebuilding a 2. I was thinking I really ought to recheck the compression when a couple of hundred miles after the rebuild my cam chain tensioner decided to give up the ghost. If it's below 90PSI, you'll need to rebuild the top end. Another way to diagnose low compression is by removing the spark plug and checking the condition of the piston. What they did is cylinder bores trued, straightened, and crosshatched, new rings, new gasket kit, new seals, new valve guide seals, valves ground, and lash set , crankshaft refurbished and polished. It has spark, was getting fuel, so I checked the compression and got the low reading. Also replaced the old Stromberg with a Mkuni HSR42. I disassembled the head and cylinder due to low compression so piston rings were replaced, new cylinder gasket, new cylinder head gasket, etc. Mar 19, 2020 · CR125R low compression after rebuild. still nothing it coughs if i hold my hand over the air intake (chocking engine more) but my choke is on and my air fuel screw is maxed out. No pitting, no gouging, nothing. This mechanism will make it feel like the bike has low compression. Sep 22, 2013 · low compression after rebuild, 2006 volvo v50 Help, Advice, Owners' Discussion and DIY Tutorials on S40 and V40. Should I be worried about the low compression if it seems to be running well? Nov 1, 2020 · Numera piston and ring kit. Mar 18, 2015 · It is not an exaggeration to say it takes me close to 80 kicks. Wait for the rings to seat properly and then check the compression again. Each had a 1mm overbore, machined at same shop in each case, along with valves ground in by me. We replaced the top end, crank, bearings, seals, gaskets etc. Compression generally goes up a little during break in. complete rebuild. 020". It was fine after that. I put oil in cylinder to make sure my rings are sealing properly and I am guessing they are since it does not change my compression results. Finally, had it running today after turning the idle all the way in. Advice? Pw50. Spark plug hole properly centered for ignition firing huge difference over any other PW 50 cylinder kit or the standard stock PW50 parts. 32 (face #3 on front rotor) Hello everyone and thanks in advance for the much needed help. Aug 5, 2024 · So I just bought a kit to rebuild my kx65 off of ebay with a Athena cylinder and Wiseco top end and is has extremely low compression for a rebuild of about 90psi, but it goes up to 130psi if I add some oil to the cylinder. I took the block to a shop so they could do the work. Customer Service. Instructions: Enter For the given dimensions, your compression ratio. Thank for any help At PW50parts. THEN press out the axle to the pw50, or use a PW50 axle and press it into the QT50 ring gear. My son is more active in riding now and we are looking for a few more tips. Top End Rebuild Kits, Piston Kits, Tires, Cylinder Boring and more! JS400's JS550's, 650SX's, Wetbikes, jetskis and other seasoned pwc's May 24, 2015 · Tried new spark plug, and spark is present. The top end only has like 5 hours on it. The powerband to me felt very strange, having steady power in low and mid but falling flat in the top end. And yes compression tester had valve. After that my compression was reading 160psi. Oct 15, 2006 · Has the engine been run at all since the rebuild? maybe the rings just arent broken in yet and compression will get better after its been run a bit 07 MDP Rookie of the Year 01 ZX-12R street/drag bike. Double, triple check everything timing related first is the way I would go. But now its all together and in, it doesnt start. Before pulling the cylinders I wanted to recheck the valve seats and guides. Low compression happens when your engine gets worn out, which is the result of high hours or poor maintenance. Remove: 9 Rear shock absorber bolt (lower/right side) 9 Rear axle nut 9 Rear shock absorber arm Refer “REAR SHOCK ABSORBER ASSEMBLY AND SWINARM” in chapter 8. Share More sharing options Followers 0. Shop for Yamaha PW50 Parts and Engine Repair Services for all 1981-2025 models. So my 2013 kx85 overheated I’m assuming and ruined the piston ring. And it's not the Stop-Run-Start switch. lowcompression; By Matt Alyk, March 19, 2020 in Honda 2 Stroke. Has anyone had this issue before? At PW50parts. The compression is insane. Is this nor Jul 18, 2009 · I have a 2000 PW50 and have rebuild the top end and cleaned and lubed everything. 120 is low but I don't feel it's low enough to cause the symptoms you're describing. Found this forum and followed the steps of cleaning the carb. This can be from low compression. Dec 30, 2020 · 2 days ago the bike was really low on power and my daughter couldn't get it to move under her. Jan 19, 2012 · Low compression after rebuild. Upvote 0 Dec 23, 2020 · I don't get why my compression is only 37psi after a top-end rebuild! 1988 Yamaha BW80 (same engine as the PW80 for all years). I checked the cylinder walls and them seemed fine so I gave it a quick hone and new piston along with new gaskets and put it back together only to have about 73psi of Jul 17, 2015 · Low compression after rebuild by HereIJam, on Flickr . Do the oil trick as mentioned. Spark plug hole is properly centered for correct ignition firing, unlike the standard stock PW50 offset spark plug. I am using the choke and it has a fresh ngk plug gapped to spec. I ran a compression test and got 30psi the first few times. Doesn't much seem like it was worth it but the bike does actually run now! Hope that helps. What was strange is when I originally put everything together all the cylinders had about 70psi, WITHOUT the internal valve depressed on the new lifters (unable to compress by hand). Jul 13, 2013 · - pw50 rear axle, can come from a spare rear end. It is a 1983 Aero 50. The stock head machined down has better cooling May 25, 2020 · I bought a PW50 for my kids, knowing it needed a throttle cable replacement at least. Please help. Nov 27, 2017 · Bought a kx 85 taken apart that needed a new top end. They say the spark must jump a 6 mm gap. Mar 10, 2024 · And the fact that it fits models from 1981 to 2023 is just amazing! I highly recommend this kit to any fellow PW 50 owners out there. The cylinder was in pretty good condition and I was able to throw in a new Wiseco top-end kit into it with a new piston and ring. There's back pressure at muffler when placing my hand over it when cranking and it turns over fine but isn't firing. Page 1 of 2 1 2 Next > jokidd82 Member. Immediately after rebuilding the compression was tested to be 80psi. Tried doing compression test, but it doesn't build pressure. Sep 9, 2021 · 【Fitment】40mm Top End Rebuild Kits Fit for Yamaha PW50 1981-2018; Top End Rebuild Kits Fit for Yamaha YT60 Tri-Zinger 1984 1985; Top End Rebuild Kits Fit for Yamaha YF60S 4-Zinger 1986. Would that cause low compression? And I think the rings had . 97 @155. I then squirted a Jul 5, 2015 · Low compression after rebuild. Is this something I should fix, or drive it til it drops? Thanks for the advise. That being said, it's very common for the intake valves to go tight on these engines, and the result is low compression. Once I finished, it started up twice and had good compression (~150/150). Another problem also, when I take Sep 5, 2013 · Low vacuum of the engine will also cause this. Jul 10, 2014 · So, I finally checked the compression on my son's PW50. You doing compression test with throttle wide open? Jan 9, 2021 · I still had low compression after the rebuild but I suspect my tester is bunk. Oct 26, 2009 · Z400 Low Compression After Rebuild Jump to Latest 16K views 19 replies 4 participants last post by arkie Dec 28, 2009 Jan 16, 2007 · Decided it was time to get my junk up and running. After getting it running I took it for maybe 40mins combined test rides. You can tell from your head gasket, you have a leak. It's just a simple 2-stroke engine so I don't know what's going on here. The piston and rings are brandy new. I ended up having Eric replate it. Now onto cylinder 6, 95psi dry, 125psi wet after rebuild and 125 dry and 140psi wet pre rebuild and oil pump failure. com (some people would suggest you shop elsewhere since they have some customer service issues). As for the perceived lower compression, you can't really judge by the kick lever's resistance, for all you know, it may have been harder before due to higher friction / resistance inside the engine or, the camshaft's auto-decomp system not being Drive it anyways dude. The added performance from the big bore cylinder is simply mind-blowing. I got a compression of 90 I thought that was a little low. 8. Jun 9, 2021 · Fuel pressure and cylinder compression are not related. I had some readings that were low and not even like yours so I pulled the head off to inspect after just a few hours on it. 2010-2012 800s are known for vapor lock in the fuel line and they tend to eat fuel pumps. Tear it down send to machine shop to check/fix everything. Aug 7, 2023 · Hi all, I have a 1979 cb750k that I am rebuilding and have run into a roadblock. Feb 22, 2017 · I am also having a similar issue with a 2004 R1. You can get a top end rebuild kit for $150 from PWonly. I went down a big hill and tossed in in 2nd at 4-5 thousand rpm. If the other 3 cylinders were only rehoned, compression probably will hold at what it was previously and not increase at all even after break-in but prevent further damage. its a pretty new carb but its one of those Chinese poo poo ones May 1, 2007 · If you have followed my other threads you will know that my shee has just been freshened with new Wisco forged pistons and after rewiring it has refused to start. + 4 mm cylinder plate . a thicker base gasket will lower copression. Upon getting it all back together I did a initial compression test and was getting around 60 psi in one cyl and Apr 5, 2016 · But it still has low compression, about 90 psi, using new Harbor Freight tester, and it doesn't run well. Discussion in 'XJ Technical Chat' started by jokidd82, Jul 5, 2015. Jul 9, 2023 · Hey guys. It was a bit hard to g Apr 29, 2009 · usually to check ring probs you squirt 40 weight oil in the cylinders and check compression with a good tester (did unk actually check your compression tester?) low compression at that time and any backfiring indicates a valve or ignition prob or both. Jun 16, 2009 · Have you done compression check at WOT yet? I would start there and make sure they are even should be at least 145 or more with new top end. Once mostly finished with and idle style break in I hopped on and rode it at low rpm until it started having symptoms of a fouled plug although after a fresh plug later, no change. The third time I tried to start it, nothing. i said somtin wrong with my tester and i decide to use it on my tri z 250 and i get 150 psi (everything stock ). I am going to get the carb rebuilt and get ti all together and give it a try. check out our exclusive line of high performance parts for PW50 as well as 60cc engine kits Jul 25, 2011 · I did a rebuild on my 1986 marathon with the upper and lower rebuild kit from India. After the rebuild I couldn't get it to go much over 70mph at WOT. They measured 85. It was a complete rebuild. So the first thing to do is check Sep 1, 2015 · Hi all, just did a complete rebuild on a new to me pw80. Recommended Posts. It's a china box and pad. Apr 27, 2009 · Hi all, I have enjoyed reading everyones posts as a guest for a while now and would like to thank everyone for all the (usually) excellent information. Nov 25, 2019 · Did a top-end rebuild last year, of a '71 Shovelhead with S&S 84" stroker kit, solid lifters and Andrews B cam (same configuration since '79). Jan 19, 2012 3,314 29 Jan 28, 2009 · Re: Low compression after rebuild. its only ran for like 10 seconds then it stalled. Check the top of the cylinder. saxamaphone Author Topic: low compression after rebuild (120 psi on all 4 cylinders) (Read 10711 times) 0 Members and 1 Guest are viewing this topic. Nov 16, 2023 · I just recently rebuilt the top end of my dirt bike after the valve dropped, so all new piston, cylinder, and used head. Little history The engine has been completely rebuilt New Timming chain cover, New Timming chain, head gasket, head bolts, master gasket rebuild kit, water pump, oil pump, new oem fuel filter air filter and plugs, all parts from Ted. Front cylinder is 200psi, rear is 90psi Fuel is good, new pump, has spark and the injectors are good, tested with noid lights. How do I get a better throtle response?? Mar 27, 2012 · when the exh port is higher it does lower the cylinder pressure at kicking speeds, sometimes refered to as cranking compression. Valves laped, pistons cleaned, cylinders honed, new rings, etc Mar 4, 2018 · Compression readings probably vary dependant on the tester used. It has a new head gasket and new piston and rings, which under visual inspection ap Jul 29, 2023 · I tested my YZ 250 that starts and runs really good and it said it had 110-120 psi which is fairly low for that bike (should be around 170-200) so I’m guessing my gauge might be off. If it is not firing on one cylinder then chances are you either have an ignition or a fuel issue. Even at high >5000 RPM there is no visible smoke and it pulls strong. I finished a top end engine rebuild on my CB550. I couldn't get it running after. Includes: PW50 High Compression Cylinder head, piston, rings, spark plug, cylinder studs, head & base gasket , oil level block-off plug, clutch gasket, and low ratio transmission gear Dec 26, 2023 · it risks glazing the ring and never allowing it to seat optimally / offer maximum compression. Other than that, low compression pretty much means top end rebuild. Very low compression will cause hard starting when cold but you said it's only hard to start once warmed up. Having low compression numbers isnt going to hurt the car, only performance slightly. And it still really lags when starting from a stop. I doubled checked the top end to make sure it was on correctly. Nov 18, 2012 · I just checked the compression: 105 psi. Here is what I have done so far: - checked compression when cold: 130 psi after 10 kicks, seems good according to the threads I have read Aug 3, 2005 · Can anyone tell me what the proper compression reading should be on a stock 2002 PW50? I just finished the top-end on my son's 2000. Mar 2, 2010 · After it was all said and done, after everything was installed - the cylinders were all low in compression across the board. After the rings set you may get few pounds more out of them. Numbers were low, 115, 115, 110, 110, well below the book specs but the engine fires up, idles and has absolutely no hiccups. The compression is still not reading any different after the top end rebuild. It started within a few kicks and ran just fine. Granted I got this bike for free so I don’t know if it runs but man I though these things were simple. Problem is I know a little,got a book and am dangerous at this point. Other than the front cylinder consistently showing 10 PSI lower Apr 23, 2021 · Low compression could be a factor, but not always the reason for low power. Remove: 9 Brake cable adjusting nut 1 9 Rear brake cable 2 9 Pin 3 Page 98: Installing The Engine ENGINE REMOVAL 11. Also when I put 1 tsp oil on the piston to better seal the rings it gives me 125psi. Got the throttle cable replaced, and found that it would start right up, but I couldn't seem to get it running good. USA made CNC machined for the best compression ratio and correct piston squish area. Here's what it has and has been done: - good compression (120psi) engine turns over smoothly - new Miniky (clone Mikuni) PW50 carb. I got it started and broke it in. It had the same issue before the rebuild so I feel l Sep 11, 2023 · I got this bike in pieces. I have a 1990 Kawasaki 550 sx that I did a top end rebuild on. 7 pump gas, dot tires, no bars, no power adders. Nov 17, 2022 · After breaking it in I only have 105psi on pto side and 100psi on the other. Low compression on a newly rebuilt engine is not all Aug 6, 2024 · Rebuild was done by a shop that specializes in Kawasaki FE engines. It shouldn't be able to start with only 15 and 23 psi. I went to do a compression test and am getting 80 psi on all 4 cylinders. These are the most common symptoms of bad piston rings or low compression on a 2 stroke dirt bike: Low power; Hard to start; Plug fouling; Bogging; Sputtering We offer a wide range of Yamaha PW50 replacement parts from OEM, aftermarket and our custom Aftermarket Minis brand parts. I'll have to get a better quality tester. Your low compression is from the blown head gasket. It seems to be running good and reaches 8000 rpms. After about 500 miles my compression went to 170 PSI on all cylinders. It’s like a 5-10 psi difference. Mar 30, 2019 · So I made a leak tester yesterday and it’s leaking at right side crank seal , intake, and and exhaust but the head and base had a good seal and didn’t leak. Nov 14, 2010 · Just rebuilt my top end on my 06 yz 125. The bike is a bit of a dog on the low end, but it runs fine once it gets moving. I thought compression loss might be due to altitude. then reassemble. I meant to order a uni filter pad for it but spaced it. 3% per 1000 Jul 26, 2018 · Re: Ultra 150 low compression after 10 hours on rebuild. Save Share Reply Quote Like. Also a weak spark can cause it to be hard to start. Aug 18, 2008 · Hi, I'd like to ask a question about what normal spark for the pw50 is like. Mazda in the Bay Area. With the spark plug in it has so much compression that I can barely get a full kick in before it stops my foot. Low power could be from Injection pump timing ( missing or added shims) or engine timing if the Gears were not installed properly. I have cleaned the carb Sep 6, 2003 · When I changed the piston and ring the compression and overall perforamnce got worse. I did a compression test and it read just under 130psi. The only way I can start it is choked, wide open for 10 kicks and then throttle closed for 3. Low compression could be from things leaking, like, Glow plugs, injectors, valves. compression. I got the block back and put it all back together with out having problems, it seemed. crank, bearing, seals, gaskets, and piston. 12bar (face #2 on front rotor) and the highest was 7. Low Compression After Rebuild. During the testing I got 30psi dry and then 50psi after adding oil to the cylinder. However, for what its worth, I've rebuilt two 175 engines. ca) the lowest number was 7. 795 wiseco piston . 012 carb has been cleaned, floats at the right level, gas mix Oct 14, 2013 · After putting it back together it wouldn't start, checked it and it has low compression in the rear cylinder and won't fire at all. So I had a few questions when doing the test do u reset gauge after every kick. Feb 22, 2016 · It is not uncommon for newly rebuild heads to show low compression as it takes time for the rings to seat. Bought exact same piston kit as last year, 44. Now it will start right up but I Stock Yamaha PW50 engine or full modified PW50 with big bore 60cc cylinder, this carb kit would be a huge advantage over stock OEM carburetor. Once it gets going it has good speed and power but not off the line. 012 gap if I remember correctly. After about 1/2 tank of use with a 40:1 oil gas mix for break-in I'm measuring about 82 lbs. Immediately afterward I took the engine apart and took these pictures. Built just the block. Multiple testers. The cylinder was shot (oil pump wasn't working right) so I bought a new top end kit. In this forum you'll find S40/V40-specific owners asking and answering questions on maintenance, ownership, repairs, tutorials and almost every do-it-yourself thing you can do to save money owning these Volvos. With pics. If the compression increases then pul it apart. When I checked the compression I was only getting about 30 psi. Feb 1, 2014 · so here is the deal. check out our exclusive line of high performance parts for PW50 as well as 60cc engine kits The process I use is similar except that I mix up a little oil in the gas - something like an 80:1 or so with good oil - then let it warm up a little, being gentile on the throttle for about 5-10 minutes, go back, let cool down and give everything the once over (and make sure the oil injection is working - if it's not fix and repeat warm-up runs - the next part won't be pleasant if you're not Feb 18, 2024 · Thought it had low compression but it’s at the same after the rebuild I’m just curious why it won’t start Not sure about the air noise you hear when you kick it over, but I have 2 PW50's for the grand-kids, and the carburetor pilots are very small and can get easily restricted with debris. Jeremiah 1973 CB450K6 1975 CB550K1. This was with new rings, head gasket, lapped valves and stone honned cylinder walls. I had cylinders bored, valves done, etc. and i decide to check up my compression and i get 70 psi on the two cylinder . Enjoy the car now and in the off season tear her down and have the head checked over or re-ring the block then. The biggest problem I face as of right now is extremely low compression, around 60 psi after rebuilt. Post by tom waite » Thu Jun 09, 2011 12:52 pm bakaracer wrote: if you ported it 1/8 in towards the deck, you can pretty much toss the bore in the garbage. I still had low compression after the rebuild but I suspect my tester is bunk. Put in had same 115 compression. Dec 5, 2013 · Your bike has an automatic de-compression lever that helps when starting. Before purchase, please check description carefully. Problem is, the bike had absolute no power this time and kept wanting to die after holding it wide open. some good information here Dec 6, 2024 · 2 Stroke low compression symptoms. Also you didn't mention anything about the carbs being synced. Feb 18, 2013 · I was under the impression that the piston rings are bad / not sealing so I ran a compression check. Engine 1 has 140 and 132 psi after running for a few miles. New top end including jug, piston, rings (I confess went the ebay/chinese route there) Got enough compression to push finger off head and suction as well. Noco. If you have piston or ring damage to the engine, then that Jan 5, 2004 · As the title says, I did a block rebuild with topline parts. Still no improvement on compression feel through the kicker. it also lowers your corrected compression ratio (not to be confused with cranking compression) which is the compression ratio the japs like to use which is calculated by the cylinder volume above the exh port and head PW 50. Mar 21, 2006 · For the heck of it, I checked compression prior to first start after rebuild and got 130's. Manual says 109 to 170 is spec. The 1999 head was damaged from the crank going out, So I took the head to the machine shop and they milled the outside and the squish band to get all the pitting out. top speed in the 1/4: 161MPH Feb 15, 2015 · Even though compression numbers are low I've personally made over 500whp on tired stock motors. Have on 03 Sportsman 90 that I rebuilt for my daughter recently. If it is maladjusted, it may be causing the problem check here for adjustment procedures to be sure that it is set up correctly. The Zinger runs but won't come off idle. com we offer high quality after market Replacement parts like fender, plastic, graphic, piston, cylinder, tire, seat, throttle, grips, cable as quality as OEM parts for Yamaha PW50 OR check out our supply for OEM factory YAMAHA parts. I did a compression test using a Snap-On compression tester and holding the throttle open while kicking it till the needle refused to go higher. Jul 19, 2015 · Poor compression "usually" affects the low end more than the high end RPM's, so if it starts OK I'd leave worrying about the rings for the time being. If it’s heavily worn, then this could be causing a loss of compression in the engine. Dec 30, 2024 · Hi, just done a top end rebuild on a 2019 KTM 150 SX including replacing the cylinder, head insert, new piston and rings, checked the ring gap, adjusted base gaskets for squish clearance or whatever it is and my compression test reads 110 psi…. Put some 2 stroke gas in a squirt can or spray bottle and give the carb a few shots while revving and see if the problem goes away while you are doing that. Apr 7, 2013 · 110-115 just seems a tiny bit on the low side for a new rebuilt motor. After reassembling, I performed a compression test and was between Jan 9, 2010 · This newb needs some more help. I let the scooter sit for an hour or so and gave it Dec 7, 2015 · This is kind of an advanced topic I just finished rebuilding a Kohler kt17 2 cyl tractor engine. nmtplp azrrp babph hak yyt asfehrz ncflpt ctdzib fcdw sjqj xqyj gprftg bcgbd yyoetva hagcjmo