08 CRF450 engine problem. Help!

[CRF119]

Hey,

I have recently had a small problem with my 08 CRF450 engine locking solid. I am unsure what is happening inside i am going to pull the engine aprat this week.

Basicly what happens is i turn it off and sumtimes maybe 1 in 40 start attempts it just becomes impossible to kick over or tow start. (Kinda fun to drag around the padock like sled tho) and will stay that way till you rock it back and fourth.

When it runs it runs mint has more power then a standard 450 has a small rattle but im sure thats the timming chain which i am going to fit this week. I have been doing piston and rings every 50 hours

I have had the bike from new has done 140 hours.

Pulling the clutch in dosent help so im pretty sure its not gear box. I have done 20 hours of riding since i noticed it and im finnaly sick of it.

[cheese]

I remember something similar on a new EFI one... I think it was something to do with the auto decomp lever..???

[CRF119]

This feels like a mechanical stop, but ill have a look and see if hey share the same parts. Thanks

[Ride it till the red]

Hey,

I have recently had a small problem with my 08 CRF450 engine locking solid. I am unsure what is happening inside i am going to pull the engine aprat this week.

Basicly what happens is i turn it off and sumtimes maybe 1 in 40 start attempts it just becomes impossible to kick over or tow start. (Kinda fun to drag around the padock like sled tho) and will stay that way till you rock it back and fourth.

When it runs it runs mint has more power then a standard 450 has a small rattle but im sure thats the timming chain which i am going to fit this week. I have been doing piston and rings every 50 hours

I have had the bike from new has done 140 hours.

Pulling the clutch in dosent help so im pretty sure its not gear box. I have done 20 hours of riding since i noticed it and im finnaly sick of it.

Mates one did a similar thing except his was probably 1 in 10 times. Turned out to be a piece of second gear (I think it was second) that had snapped off and was rattling around and getting stuck places it shouldn't.

A possibility although you'd think something more would have happened during the last 20 hours if that were the case.

[socialites]

Hey,

I have recently had a small problem with my 08 CRF450 engine locking solid. I am unsure what is happening inside i am going to pull the engine aprat this week.

Basicly what happens is i turn it off and sumtimes maybe 1 in 40 start attempts it just becomes impossible to kick over or tow start. (Kinda fun to drag around the padock like sled tho) and will stay that way till you rock it back and fourth.

When it runs it runs mint has more power then a standard 450 has a small rattle but im sure thats the timming chain which i am going to fit this week. I have been doing piston and rings every 50 hours

I have had the bike from new has done 140 hours.

Pulling the clutch in dosent help so im pretty sure its not gear box. I have done 20 hours of riding since i noticed it and im finnaly sick of it.

Mate, take it from me, I can guarantee that your auto Decompressor shaft pin has either broken off completely, or alternatively bent beyond functionality, It is an easy fix and one that Honda should come to the party with, as its a known recall in the states and should be one here as well.

[scott411]

the CRF450 09 had a recall with the decompressor as above, never heard of the 08 having been recalled, and when the 09 one went it went completly, it was not only sumtimes,

sounds like something to do with the decompressor through

[dino3310]

yep another vote for the Decomp

[socialites]

the CRF450 09 had a recall with the decompressor as above, never heard of the 08 having been recalled, and when the 09 one went it went completly, it was not only sumtimes,

sounds like something to do with the decompressor through
You dead right scott, it was indeed the recall on the 09, not the 08, my opologies. However, I would still stake a bet on the fact that it is indeed the Decomp shaft playing up.

[CRF119]

Thanks for the input i will cheeck that before i put the whole bike down. I would have never guessed it could bend.

[7mmWSM]

dump the oils and see if you get any metals or metallic coming out. You'll soon know if its gearbox or not. It could be that the decomp is not adjusted properly. have you noticed if its jamming when hot and comes right when cold?

[7mmWSM]

also the knocking is more likely the cam tensioner rather than the chain but I would replace both myself and also inspect the bottom end for play

[CRF119]

I do oil change every 5 hours so oil is always inspected and nothing in it. Happens when cold and hot completly random its been doing it for 20 hours i havnt pulled it down as i havnt got a clue what the cause is yet. No big end play last piston was 30-40ish hours ago. If i get a chance to waterblast under the tank today it will finnaly get pulled apart to inspect decompression which isnt ajustable like the old CRF250s