June 23, 20188 yr Author 5 minutes ago, section swept said: The reed valves should be closed with no gaps that you can see daylight through. Initially remove reed valve and ensure it’s not bent or distorted. Refit carefully to the block. Have you made sure the throttle slide can move freely up and down? By the sound of the engine and the age I would be looking to change those crankcase oil seals anyway, lube the lips of the new ones with either 2T oil or silicon grease sparingly if you will. While you’re in there you can check the main bearings for excess carbon which does get in and cause frictional losses and eventually failure. From the sound of the engine on the video it is ok ? mechanically, but it’s easy to make sweeping statements. By doing the work you will become more confident in the bike and know your way around so if it stops miles from anywhere you may have a chance of fixing it.? Cool, I'll order some new reeds. There is quite a bit of light showing through. Then, if still no joy, I'll address the crank seals. Do you know what thread pitch I need for the flywheel puller? I'm loving working on it so far. So simple! :-)
June 23, 20188 yr You may find that with the crankshaft nut released and a bit of gentle wiggling and inertia persuasion that the flywheel may come lose. The best method though is to use the correct tool. I don’t know the thread size but I’m sure you can get a puller for about £10-15 which is a good investment.
June 23, 20188 yr Author 16 minutes ago, section swept said: You may find that with the crankshaft nut released and a bit of gentle wiggling and inertia persuasion that the flywheel may come lose. The best method though is to use the correct tool. I don’t know the thread size but I’m sure you can get a puller for about £10-15 which is a good investment. I have a few sizes so will see how I get on. Probably have to buy one though!
June 24, 20188 yr Author 22 hours ago, Nebulous said: Refer to my earlier post on page 1 for the puller-size. Very common size anyway. If the crankshaft has any waggle on it - then it isn’t worth putting new seals in until the bearings are done as well. Hopefully it will be ok though. Pay attention to that little woodruff-key - don’t lose it! Thanks again Nebulous for your help! Your 4t sounds like a bit of a pain. Are the valves shim under bucket type? Or tappets with lock nuts? I noticed that the Sherco guide says to run 80:1 two stroke mix. Im not one to go against manufacturer's instructions but would have thought it would be more like 50:1. What do you all run? Thanks
June 24, 20188 yr Author Thank you both! Tappets are way easier, you won't have a problem. Finding TDC compression isn't hard either. Select top gear, rotate the back wheel forward until you see the exhaust valves open and close. Keep going til the inlets open and close, then put a drinking straw or a pen in the spark plug hole and rotate the back wheel until the straw rises to it's highest point. If you miss it and the straw starts to go back down, no biggie. You can rotate the wheel backwards to bring the straw back to the highest point but generally I just go around again. Edit: once you've found TDC you generally don't need to do anything to lock the crank in place. You can if you want, but nothing is gonna move really. The crank will stay in that position, it isn't under any strain to find a different position. Edited June 24, 20188 yr by mlcjot
June 24, 20188 yr Be careful turning that engine back against its normal direction of rotation (dor) some cam chain tensioners will break if you do this, better to go round again in the normal dor.?k
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