Timing Chain How Much Damage??

[Bob DowsettMember]

04 wr450f

Bike was still running on last ride but got progressively more gutless especially if u gave it a gutfull of throttle it would nearly stall and basically just had nothing

it would still start on the button and kicker but kicker was a bit harder

Has possibly been getting progressively worse over last few rides(power wise)
I thought my ability was just catching up to bike but no

Took it to mechanic he had a look

timing chain very tight on 1 side and must have jumped a tooth as couldn’t be timed properly

What other damage could have been done considering bike was still rideable and going but a bit more like a pw 50 than a 450

hoping there aren’t any bent valves or shit like that

keep it in plain english as i am no engine mechanic

[TrentMember]

Was it making any noise like the piston was colliding with the valves?

Could be any one or a combination of:

Bent valves
Damaged head
damaged piston
damaged bore

Good luck with it.

[Bob DowsettMember]

no noises that i can remmember nothing to make u think oh f*#k and stop maybe just bit throatier in the noise dept

originally thought it may have been a carby problem

[GregMember]

Well no noises eh? Thats good, please PM me the mechanic looking at it mate

It sounds strange that it would just jump a tooth with out you noticing it, as the engine would change its note and performance straight away like a light switch

Need more information Bob

TB

[MalMember]

What might of happened is the cam sprocket/s may have slipped on the cam shaft. They are only pressed on and occasionally do this.
My WR400 did it and the bike shop could not get it timed so he had another WR in the shop and measured the cam lobe postions and they were different. We set the cam lobes up to the same measurement as the standard WR and mine run perfectly and never moved again.

Just a though Bob and easy to check.

[GregMember]

Yes that’s it Mal, I was at Sutto’s the other day and they were talking about that and it makes far more sense then jumping teeth as I cant see how they can jump. I saw a DRZ break the spring on an auto tensioner whilst on the rev limiter and it still didnt jump a tooth. If I remember now they dont have witness marks either and you have to buy a new cam. It should only be one cam that has slipped.

Check your PM’s Bob

TB

[Bob DowsettMember]

The bike seem to be lacking performance just had no sting when u twist the throttle
on the last few rides that I have been on could be just in my dreams but after this incident it was most probably correct

as said previously i was blaming the carby blocked jet or something

we went up a couple of hills ok then about 5 mins later or so went to give it a bootful and it just groaned and nearly stalled kept riding for a while and rode it home i would have thought if anything was colliding in there that wasn’t supposed to be u would hear it ???

cam gear slipping on shaft does make sense as it was a gradual thing ???

but i’m no mechanic

Have taken bike to a few local bike shops in past to get valves done and checked and so on and asked them too have a look through it and have come up with nothing wrong but i am beginning to think that most of them either don’t give a shit or want u to rebuild it there and then

got a referral from a guy i know about a one man op that operates out of cowra and tunes race bikes

should we pull it right down and have a look or not
how long and how much$ would u expect to pull down look and reassemble

Bob

[dennis da menaceMember]

Bob wrote:

Quote:

The bike seem to be lacking performance just had no sting when u twist the throttle
on the last few rides that I have been on could be just in my dreams but after this incident it was most probably correct

as said previously i was blaming the carby blocked jet or something

we went up a couple of hills ok then about 5 mins later or so went to give it a bootful and it just groaned and nearly stalled kept riding for a while and rode it home i would have thought if anything was colliding in there that wasn’t supposed to be u would hear it ???

cam gear slipping on shaft does make sense as it was a gradual thing ???

but i’m no mechanic

Have taken bike to a few local bike shops in past to get valves done and checked and so on and asked them too have a look through it and have come up with nothing wrong but i am beginning to think that most of them either don’t give a shit or want u to rebuild it there and then

got a referral from a guy i know about a one man op that operates out of cowra and tunes race bikes

should we pull it right down and have a look or not
how long and how much$ would u expect to pull down look and reassemble

Bob

doesnt sound good bob,

whatever it is i hope its cheap and easy fixed

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