Yamaha xs650 Cam timing out 1 tooth !?

[@damo690]

This has been a great help. Thank you. I'm working on a Honda cd175 and it's been one fiasco after another. The cam sprocket was changed at some time in it's life and there was no 0 timing mark to time it off. It's a 360 cycle engine which means both pustons are at tdc at the same time luckily. I tried to start it last week and it ran like shit and stopped and wouldn't go again. I'm pretty sure it's the cam timing. I can now check tonight. I hope I haven't damaged any valves or anything. It turned over by hand on the bench with no issues.

[@CenterStandMechanX]

@damo690 Thank you. Ya timing can be a pain. Have you checked the Woodruff key on the flywheel? That can mess with your ignition timing. I've found them sheared right in half or just partially sheared. Enough to throw ignition timing off. It can happen from stalling the engine a lot or I've seen it happen when there way to much gas flooding into the engine and so much that when the piston comes around it hydro locks at top dead center causing the Woodruff key to shear off. As far as valve timing goes check the compression. If you have lots like over 100 it should run and valve timing can't be to far off. When my engine was off one tooth it would pop out the exhaust really badly

[@serge8400]

Thank you mate, I have the same problem on my 1974Tx 650. I inherited the timing problem when I bought the bike a month ago. Tried with new points but same results or similar. Compression is also down, but that is another issue. It looks like the engine will have to come out anyway. Also have the first gear jumping out often. All other gears are ok. I have been able to ride the bike ok, but not a lot of power there, and difficult start on first cold start. Again thanks for your video Serge, 🎉from New Zealand, Nelson

[@CenterStandMechanX]

You welcome Serge! I appreciate the positive feedback. Ya these bikes can be a pain to sort out but once you do it will be so worth it. I'm hoping to do a proper engine rebuild on a different xs650 engine. Most likely this winter I'm thinking. Looking forward to it. I really enjoyed working on this one even though it was a bit problematic. I learned a lot from the first one and should be better next time. Cheers!

[@serge8400]

@@CenterStandMechanX i look forward to your Yam 650 re- build. I will follow your steps. You are doing a good job for the rest of us… thanks. Serge

[@benspeedschannel888]

It’s sounding lovely now, I’ve found quite often that timing marks can be a little bit hit and miss like that where it could be one or the other tooth. Thinking about it it’s probably harder to get it right with an old chain that’s stretched a bit. You’re on the right track now, onwards and upwards 👍👍😎😎

[@CenterStandMechanX]

Yeah the chain is probably stretched out a bit .I was trying to get this done without buying a whole bunch of new stuff but next time it will be all new stuff. This is a good learning experience for me and glad to have it. I really enjoyed working on this engine and would like to do it again only better

[@benspeedschannel888]

@@CenterStandMechanX it’s one of those things that the more you do it the better at it you’ll get, you’ve definitely got plenty of talent with engines for sure 👍

[@CenterStandMechanX]

Thanks Benspeed I appreciate that. You sound like you know your way around this stuff too. Definitely gets faster and better the more times you do it. I was thinking about it the other day if guys raced these bikes or not. I'm not well versed in the history of them. Was wondering if guys didn't like using these because you got to take the engine out to do any real work to them or not. Maybe it's not a big deal just something I was thinking about. Like would they choose to race something different cuse it was easier to work on.

[@ronberam3686]

Thanks! Helpful.

[@CenterStandMechanX]

@ronberam3686 Awesome! I'm glad I could help. Cheers!

[@maxgood4361]

Could the tensioner cause this, sorry that this occurred but this was a good lesson for us working on our project bikes. Thank You.

[@CenterStandMechanX]

Hi ! No, I don't think so. It was adjusted tight like it should have been before I took it apart. Trust me, I would have loved that to be the issue. Would have been a lot easier than taking the engine back out and apart. It's hard to see it on the video, but when I got it all put back together, it ran a whole lot better

[@serge8400]

By the way, I have a temporary solution for the timing tooth-out problem. I have put the electrical timing problem aside by grinding a bit on the point main plate to be able to adjust the point right in sync with the piston position. Ignoring the cam valve error at around 10 degrees, still give me an appreciated improvement on motor performance and smoothness. Soon I will be able to deal with the REAL problem, and take the engine out of the frame. The first gear jumping out when on a bumpy dirt road is still a mystery. Any suggestions on this from anybody reading this? Serge. NZ.

[@serge8400]

Ps: correction …error valve timing error OF around 10 degrees. [ in my case opening / closing a bit too early.] Serge NZ

[@CenterStandMechanX]

@serge8400 I tried messing with the points plate too and couldn't get the points to fire correctly even with the few extra degrees. This is where I stopped myself from doing more crazy things and looked into the cam being out. It's was one of those inconvenient truths that I didn't want to have to go there but in the end it made all the difference. Before I retimed the cam properly the engine was backfiring a lot preventing it from revenge up untill it got past a certain rpm then it was more responsive. This might have been from the centrifugal advanced kicking in and alowing it to run better in a way. Skipping one tooth made all the difference. As far as jumping out of first gear. Not sure. Have a look at your drain plug magnet for metal chunks or the remnants of a small cotter pin or pins. You can also take the clutch cover off ,take the plugs out and spin it over with a 1/2 drill and run it through the gears and look for problems while you shift through the gears. Get one of them bore scope cameras and look down it to the transmission and see how everything is shifting. Cheers

[@Stuckin330]

These marks on these bike arnt really perfect when they line up. I did a 650 and found that out . Even with a new chain it’s not perfect . So when you time it you time it with the marks that are the closest to the spot you need . And youl kno when you see it

[@CenterStandMechanX]

@Stuckin330 ya I found them to be a bit hard to be sure . I think It would be good idea to rig up a way to start the engine before installing it into the bike. Just to make sure everything checks out before going through all the work of putting the engine in the bike and then having to take it out again just to skip 1 tooth on the cam and put it all back in again. It messes with you because not always convinced it's the problem while doing it. Lol

[@deltabluesdavidraye]

So the valve cover cannot be removed with the engine in the frame?

[@CenterStandMechanX]

@deltabluesdavidraye yeah that's right unfortunately. The head bolts protrude out of the engine case to High for the valve cover and head to clear the frame. Valve cover is fairly thick and there's not enough clearance to remove it while the engine is in the frame. Makes doing any of this type of work a little more involved. Cheers!

[@ChrisArmstrong-qn1ob]

Nice vid mate 🛠👍

[@CenterStandMechanX]

@@ChrisArmstrong-qn1ob thank you! Much appreciated. Cheers!!