rebuild timing/stroke/flywheel? , please help!

[maxamillion]

I just put my new 406 piston in my 400ex. Everything has gone fine until now. The head is on and i was begining to put the piston at TDC so i could install the cam correctly. I started turning the flywheel counter clockwise and it was very hard, so hard the 17mm flywheel bolt actually came loose! Now when i turn the flywheel counter clockwise, the bolt just turns instead of the flywheel. Besides that....how do i know when the piston is at TDC with no cam installed? I usually look at the cam lobes and when they are facing down i know its at TDC.

Thanks in advance,
Max

[Crazy400EX]

Tighted the bolt back down......when i did this i put something firm but soft between the gears behind the flywheel. Then try again. It takes time. I dont know if i was clear enought but i just got odne doing the same thing.

[maxamillion]

hmm..so say i get the flywheel bolt tightened again, how do ino if im on the compression stroke to get the piston at TDC without the cam being installed? thanks

[Crazy400EX]

the two lines going horizonally with the line touching them going verticle will be lined up with the line on the flywheel cover( the little one that you take off witht he allen wrench. Then you install your cam with the lobes down and the marks even with the engine. I dont do good explaining this so ask questions.

[TC426EX]

Tighten that flywheel bolt up man. Should not be coming loose when cranking by hand, it will be under alot of stress when its together. Use a quick blast with an air ratchet/impact socket if you have access to it. Otherwise youll have to use a strap wrench to hold the flywheel (if you dont have a flywheel holder) and tighten the bolt down as much as possible.

Once thats done you spin the flywheel around until you see the "T" mark on the flywheel line up in the small hole (when the smaller allen cap is removed).

Keep slack in the chain, and make sure your tensioner is removed. Its kind of a chore to get the chain lined up on the cam teeth how you need it with the bearing assemby on, so I did the following. I put the bearing race for that side off to the side and put the chain on the teeth, pulling it tight to check and make sure the lines lined up flush with the top surface of the head. Remember, the lobes should be DOWN and the vertical line on the sprocket should be UP. Then I slid the bearing onto the end of the cam and moved it into place in its groove. Some people say not to use assembly lube when doing this, but I always use red assembly lube on all the journals

You can tell its on the compression stroke easily when you have the stock cam or a cam that uses the stock decompression mechanism because you will hear it click when you turn it over on that stroke (if you put a spark plug in it) Thats because on the compression stroke when youre first starting it up it opens one of the exhaust valves a slight bit to release some compression so the starter can turn the engine over easier.

Hope this rambling response helped some, if not just ask more questions and Ill try to be more clear

[maxamillion]

i appreciate the responses and the impact wrench is a great idea. I understand the T mark alignment on the flywheel. But its possible to have the T mark lined up on the decompression stroke as well as the compression stroke, correct? I guess im missing something simple here. I dont understand how i can tell which stroke (decompression or compression) the T mark is lined up on because there is no cam lobes to look at and no "click" sound from the decrompressor to listen for. I think im making this harder than it should be but i dont want to get it all back together and have to tear it back down again.

Thanks

[Crazy400EX]

turn it counterclockwise until you get to the t........then your there

[TC426EX]

To hear the "click" you have to have the rocker cover on with at least a few bolts in it so the valves open and close... Otherwise without the rocker cover on, the cam just spins in the middle and doesnt impact the valves in any way

[maxamillion]

I got everything put back together and it turned over fine but wouldnt fire. I thought my timing was off 180 degrees, but then i realized my gas wasnt turned on. :D After that it started right up and ran awesome! thanks for the help.

[Crazy400EX]

Glad we could help! (i dont know how much i helped but.....)