Jump to content
Sign in to follow this  

Motor mystery...gurus explain this because I'm stumped!

Recommended Posts

I posted awhile back about my R bogging at upper mid and beyond rpm. Turns out the timing chain was off by one tooth...but the bike had not been apart for 9 hrs (by my hour meter) since the last valve adjustment. Valves were still in spec so I scratched my head, reset the timing chain and put it back together. Problem solved, bike ran like a top again.

Now, after another 14 hours on the bike the symptoms re-occurred. I was at the track riding and pulled off for a rest. When I went to restart the bike it was tough to kick over, but started easily enough. On the first straight when I revved the bike it bogged up top. I brough the bike back home and took it apart. Again, the valves are in spec and the timing is one tooth off. Bike has not been apart since the last time I fixed it 14 hours ago. Timing chain seems plenty tight, but even if it wasn't, could it possibly skip a tooth?

I'm stumped and so is my friend at the dealership. He said he'd call Honda and quiz them on it. In the meantime, any motor gurus out there that want to take a stab at this one?

Share this post


Link to post
Share on other sites

thats why i hate the automatic adjustors,

i always jam them and make them manuel so there is no way they can slip,

i have see to many motors ( 450's) that will blow appart because the thing slips.

i had one customer on a 250 that complained of this happining ,

i locked his and he has had no more troubles !

Share this post


Link to post
Share on other sites

On the 250 I belive the timing gear is pressed on the cam. Try marking the cam and cam gear relationship to see if it is moving.

Share this post


Link to post
Share on other sites

Hey FourStroke...be sure and post what you find. I ran into a similar situation after installing a new crank not long back. I swear the timing was good when the motor went back into the frame. The bike started fine, and ran for about an hour before it starting missing at high rpm. It also became hard to kick, but started up and ran fine at idle. Turns out it was a tooth off too. We've run it for 4 or 5 weekends now with no more problems. I don't believe it had anything to do with the cam chain tensioner, and I had put a new cam chain on during the rebuild. As long as it doesn't show up again, I'll just chalk it up to "the unexplained" and go on.

Share this post


Link to post
Share on other sites
On the 250 I belive the timing gear is pressed on the cam. Try marking the cam and cam gear relationship to see if it is moving.

while this is good advice and i mark them all, i have only had trouble with the hot cams being off , i have not seen stock honda cams slip,

and the marks are on the gear and if the cam slipped you would not know unless your checking your cam timing every time, ( witch should always be done )

Share this post


Link to post
Share on other sites

if the gear was slipping on the cam it would still seem to be on the mark wouldnt it? What I mean is the timing marks are on the gear so if the cam was spinning inside the gear the marks would still be lined up and you wouldnt be able to tell ( other than performance ) that the cam timing was off. yeah no maybe ?

Share this post


Link to post
Share on other sites
while this is good advice and i mark them all, i have only had trouble with the hot cams being off , i have not seen stock honda cams slip,

and the marks are on the gear and if the cam slipped you would not know unless your checking your cam timing every time, ( witch should always be done )

yes thats what im saying ,---you would still see the marks lined up,

the only way to know is to mark the gear to the cam and keep record of where your cam timing in when its degreed in .,witch you should also do every time on any 4 stroke motor , bike car or truck !

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...