tdc?

[rob_990]

since the sparks key advances the timing how would i find tdc so i can start taking apart my motor?

[F-16Guy]

Put something long and skinny (screwdriver, brazing rod, etc.) in the plug hole and turn it over slowly until you get to the top of the stroke.

[puTTs]

On the left side of the bike. There's a plug on top of the left case, just above the stator/flywheel. Take the plug out, look down the hole, spin the engine over untill the slash mark with the "T" next to it shows.

[honda400ex2003]

I think it will be the same as usual since it is not moving the cam or anything it just moves the flywheel i think. that is what makes the timing advance. The flywheel hits the magneto inside it a bit faster. I could be wrong though. I have never actually read too much about how it really works and the details of it. I am just going off of some thoughts li have had here the last few minutes while replying to other threads. steve

[puTTs]

"The flywheel hits the magneto inside it a bit faster."

It hits it at the same speed, but 6 degrees before where it used to hit. :)

[honda400ex2003]

alright so it does not change anything with the crank as you and i thought. thanks for the info on the key. I should read some more about it but there are many others on here that know so much that i dont have to know about that too. LOL, steve

[puTTs]

The sooner you light the fuel off the sooner the combustion starts, giving you more time to extract the power from the explosion. On higher end fuel injected cars you have a "knock sensor". The computer advances the timing just to point of pre-detonation then backs the timing off just a hair to get optimum performance all the time. From the factory our bikes are very relaxed on timing. This keeps things running cooler and keeps the amount of spark knock engine damage going back on Honda minimal. But playing it safe does make performance suffer, that's why there is the sparks key.

[rob_990]

well i aligned it up and just marked the gear/chain with a sharpie.when i got to my valves they were fine i kept getting deeper until i found the problem.the wrist pin for the piston rocks a little bit and it was causeing half the piston to hit the valves.

Now i need a new rod!!!!!!!!!!!!!!!!!!!