How much compression should I have?

OK, another dumb questions - sorry. I went to do a quick ride my 05' WR450 today and I noticed that after a few kicks while trying to start it it seemed to lose some compression and became fairly easy to kick through. Not easy like the spark plug was off but I could kick and pass through TDC without too much resistance (ie. I didn't need to do the ritual - I just kept kicking). Once it started it seemed to run fine considering it is still all bottled up. Is this something that is normal? I've only got about three hours on it so far so could it be the piston starting to get in groove with the cylinder? I could still easily tell where TDC was and it held me up once or twice but for the most part it just didn't seem to resist me like it did before. I'd say it was a still a little harder than a 250 2-stroke to kick but not too much harder. Just how hard should my bike be to kick in terms of resistance? Any thoughts on this? Am I just being paranoid again? It sure is a fun bike. :cry: Thanks.

Matt

Sounds like the auto-decomp exhaust cam doing it's job to me... :cry:

try using the electric start and see the behavior is like. or keep kicking it until your leg is about to fall off. good luck!

Thanks for the input. I don't even know what the-auto decomp exhaust cam is but it's nice to hear it's doing it's job and my bike isn't acting strange. wantmorepower, as far as electric start, it doesn't work until the bike's warmed up - I just end up draining the battery if I try using it on a cold start. My mechanic told me that once I do the mods and rejet the bike it should work better - right now it's quite lean and all plugged up which is making it run and start not so well. However it's not too difficult to kick start initially so I'm not complaining - yet. My question was more about how easy it is to kick now compared to when it was new and if that signifies a problem. I was worried that it was losing pressure somewhere but it sounds like it is doing what it's supposed to do. Maybe I am just getting used to kicking the bike but it sure seemed to kick over easy today. If anyone has anything else to add feel free, otherwise I'll just assume everything is ok. Thanks again.

Matt

the autodecomp cam prevents the exhaust valve (only 1 I believe) from fully closing at cranking speed. Sounds like you have a PJ/fuel screw problem because the e start should work hot or cold. Make sure u dont touch that throttle!

the autodecomp cam prevents the exhaust valve (only 1 I believe) from fully closing at cranking speed. Sounds like you have a PJ/fuel screw problem because the e start should work hot or cold. Make sure u dont touch that throttle!

I'm not too sure about that. I'd say it really depends on how cold it is. I've installed the JD Jet Kit, and a Zyp-Ty fuel screw, and last night I had to kick the crap out of the bike to get it started. (It was 19F outside). When I first installed the kit, in a heated garage (about 60F), it started up with the electric start no problem. Granted, 19F is a bit extreme to be starting a bike, but thats the weather I have here right now. =(

M.

Try this when it's cold:

1) Set the choke

2)Two quick half-throttle pumps on the throttle, then put your right hand on the brake resivoir so you don't touch the throttle again.

3) Kick or push the start button.

Should fire right up.

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