how to make sure timing is correct?

[bens250ex]

tore the engine completly down to check everything and get the valves checked and so forth. put in a new timing chain i had to roatate the engine a couple times while pulling the clutch. i put the engine back to top dead center (i think) what mark equals top dead center on stock flywheel? i am using a crf450 timing chain as well seemed kinda tight to me was anyone eleses tight? also have a stage 2 hot cam anyone have a link to any picks of what the cam should look like at tdc?

[hjsmith00843]

did you take the tensioner out before trying to set the timing.

[bens250ex]

yea the tensioner was out

[honda400ex2003]

The T is what is TDC on the flywheel and it lines up with the mark on the cover or there is a ^ on the block too you can use if the cover is off. then the cam has a line on both sides and would have the lobes on the cam down to have it at TDC also. this can be confusing but if needed you can check it with the cover. the lobes would be down into the head when correct not out. lol. I hope this is helpful and i did not confuse you lol. do all of this with the tensioner out and you should be good to go. steve

[honda400ex2003]

this has some pics and stuff in it too.

http://www.atvriders.com/articles/valveadjustment400ex.html

steve

[F-16Guy]

Originally posted by bens250ex
...also have a stage 2 hot cam anyone have a link to any picks of what the cam should look like at tdc?
Line up the timing mark on the flywheel (the little line next to the "T") with the notch in the inspection port. Next, coat the cam in assembly lube and lay it in the head. Make sure the cam bearing with the seal is on the right side and that the seal is facing out (very critical!). The lobes on the cam should be pointing down. There are three lines on the cam gear. Two of the lines should be parallel with the gasket surface, and the third should be pointing up. I find it easier to install the cam without the gear, and then put the chain on the gear and bolt the gear to the cam.

The 450R chain is the same length, so it shouldn't be any tighter length wise. Each link has an extra plate vs. the 400ex chain, so it's a little thicker, but it shouldn't cause any problems. I installed one on a rebuild for a friend and it worked fine.

[Pipeless416]

sounds like you got the answer you were looking for on the timing. as far as the tension of the chain, did you reset the tensioner when you were installing it? if not, take off the phillips head cap on it and find a small flat head to turn the screw under that counter clockwise. once you have it all the way turned and backed off, let go of the screw and it should snap back to the correct tension.

[bens250ex]

well see i should know how to do this i have done it several times before but i forgot it been awhile lol.


F-16 as far as the cam bearing i did not know that but i believe thats how i have it right now but which right side are you talking about? right side from back or right side from front? the cam has already been in i just put some oil on it for lubrication.

[F-16Guy]

Originally posted by bens250ex
F-16 as far as the cam bearing i did not know that but i believe thats how i have it right now but which right side are you talking about? right side from back or right side from front? the cam has already been in i just put some oil on it for lubrication.
It has to be on the quad's right side (brake pedal side) facing out. If it's not on the right side and/or the seal isn't facing out, you won't have any oil pressure to the cam and you'll trash the valve train.

When that bearing is properly installed, oil flows up through the passage in the side of the cylinder and the sealed bearing forces it to pool up in the little reservoir cast into the right side of the head/rocker cover at the right end of the cam. Once that reservoir fills up, the pressurized oil is then forced into the end of the cam (the cam is hollow) and through the cam journals to lubricate the valve train.

If it's not right, or you're not 100% sure, take the cover back off and check it. If you don't and it's wrong -- kaboom!

[bens250ex]

i still got the cover off so its no big deal i still have to check the timing.

[CJM]

Just wondering:

So what your saying is the sealed end of the bearing faces out towards the brake pedal?

[F-16Guy]

Yes, the rubber seal on the right side cam bearing should face to the right, toward the outside of the engine.

[CJM]

I figured as much, but wanted to be sure.

Thanks :)