timing issues

[sweet t-rex 400]

how do you set the timing...i got the two lines level with the head and the lobes pointing down...is that right...mark on the "t" on side case...please help im going nuts

[Stickman400]

That sounds right. There should be 2 big lines and 1 short line on your cam sprocket. The short line goes straight up after you line the other 2 lines up with the cylinder head surface. Also lobes down and piston is at TDC, or the t is showing in the little crankshaft plug hole, same thing.

[sweet t-rex 400]

did all that and still wont fire...it will fire every now and then for a second then stall out...i have no idea and spent two full days trying to figure it out...

[hocman123]

well it sounds like the timeing is good so what else happened did u just replace the chain or did it stop runing one day and u think it is was a timing problem, did u install a after market cam?

most importantly did u adjust the valves i would be willing to bet that is ur problem

[CJM]

Yep, valves probably need adjustment.

.004in intake and .005in exhaust.

The way to adjust them goes like this:
1. Put flywheel to T mark.

2. Remove valve cover caps (24mm socket or an adjustable wrench-use a socket tho if you can help it)

3. Grab rockers, they should have play int hem and be able to move.

4. Follow the rest at this link. http://www.atvriders.com/articles/valveadjustment400ex.html

As noted the specs should be close if not dead on. Its really easy to do, all you need is feeler gauges, a 10mm wrench and a flathead. Adjust them till its tight but enough to move the feeler around.