[C-Note jr.]

A little back ground on the bike first. Bought the bike roughly a month ago from an old friend who's the original owner. He had issues with it which involved him tearing the engine all the way down and due to health issues it sat for two years in boxes. Well, to make a long story short I assembled it piece by piece (which was a nightmare because small pieces were lost and nothing was organized) anyways, every internal in the engine is brand new with the exception of the stage one hot cam which only had about 10 hours on it prior. New crank, piston, head was totally redone at MCR with titanium intakes and stainless exhaust and 20 thousandths shaved from the head. Well, I got it all together fired it up and all was great for about 10-15 hours of ride time. Started great and decompressor worked exactly as it should. Outstanding bottom end from the cam, and still had great top end even. Was out riding it a little over a week ago and it started cutting out on me in higher revs (much sooner than the rev limiter kicking in) so I pulled around and shut it off not knowing what to think. Went to start it again and felt like I was going to break my foot trying to start it. Thought maybe valves were setting in and needed to be lashed again since they were new. Pulled the valve cover and checked the lash one day when I had a few minutes and lash was still excellent! I had to go right after that it else I would've checked cam timing next, but I guess my question is, has anybody ever had issues with their 450 jumping a tooth and retarding the cam possibly? Mind you, I've got a manual cam chain tensioner, but I always kept up on it to make sure my cam chain wasn't getting loose. Due to working long hours and being away from the bike I haven't had much chance to look more into it. Any ideas?

[JimDirt]

Welcome to the site !!

Usually if the chain is able to jump timing then it is worn out and loose , in good condition it should not be able to jump time even with the tensioner loose , you should have had to tip the tower to install the chain and it should have been fairly snug once the tower was torqued back down

So unless you had about 100 hard hours on it or so , then usually NO the chain should not be able to slip a tooth , if its hard to kick i would bet its something to do with the De-Compressor , not the timing , you did not mention if you were able to start it or not , , but i would check the entire De-Compressor system first

Hope that helped !

[C-Note jr.]

Sorry I forgot a few details there. The cam chain is new, only has about 10-15 hours on it and was brand new when rebuilt. I know it shouldn't, but it was literally the only thing I could think of that makes sense. Like I said, not only does it kick hard (and it doesn't start by the way) but it cuts out on the top end.i checked the clearances for the decompressor arm and that's still perfect as well. Didn't check the spring loaded centrifugal mechanism to see if it was still working properly though. I just think it didn't justify the top end loss so I didn't really look into it. Now I suppose it could be possible I have more than one issue. The decompressor could be one and I could be detonating although I was told I was safe running 93 with what's done to the engine. I broke it in on 110 and then dropped to a 110/93 mix and am now at just regular 93. So I suppose it's possible I could be detonating up top and my decompression mechanism stopped working at the same time.

[JimDirt]

The gas should be fine , but i would look into the De-Compressor and make sure nothing is binding or stuck

[C-Note jr.]

Alright. Well thanks for the insight! I have to have it done by Thursday since I've had plans to go up north. You think that would affect my top end at all though? That's the part that gets me. I agree 100% for starting, but just not sure how it could affect top end.

[JimDirt]

I guess the only thing i would think is its going to be a beast to start (you did not mention what compression the piston is) , , i am guessing you have a manual ?? , so i would look over the De-Compressor section , it will show you how to check it , if you don't have the manual , i can post up pics of the Factory Honda Service Manual , as i have that one as well as many other bikes/brands **Honda,Yamaha,Kawasaki,Suzuki,KTM**, on PDF (i have a 02 450R)

So just say so if you need pics and i can post them up tomorrow if need be , otherwise , check it over really good

I would also triple check your cam timing , if its off 1 tooth the De-Compressor will not function correctly as it would not be working in time with the valves , so make sure the 3 marks are aligned
(1) Cam sprocket marks
(2) Flywheel Timing Mark *small round plug ignition side*
(3) Balancer Shaft *large round plug clutch side*

[C-Note jr.]

I have an aftermarket clymer manual. As for the piston though it's just stock ratio at 13.1, like I said though, it's got about 20 thousandths shaved from the head. I'll check into all that though. I know my timing was accurate at one point though so we will see what happens I guess.