Changing the cam chain tensioner on '03 CRF 450?

Rubblemaker

Member
Dec 28, 2004
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I understand the cam chain tensioner on '03 CRF 450's to be a weak link. It's been suggested that I replace it with the tensioner from the '04.

Has anyone changed one without removing the head? It looks to me like the two bolts on either side simply come out and the whole tensioner slips out of the housing.

Can anyone comment?

Thanks!
 

Rich Rohrich

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You can swap the tensioner without removing the head.

Bring the engine to TDC, retract the old tensioner spring with a small screwdriver unbolt the old tensioner, bolt the new tensioner in, and release the spring.
 

Rubblemaker

Member
Dec 28, 2004
5
0
Rich Rohrich said:
You can swap the tensioner without removing the head.

Bring the engine to TDC, retract the old tensioner spring with a small screwdriver unbolt the old tensioner, bolt the new tensioner in, and release the spring.

Rich, there is a considerable amount of travel left in the old tensioner. Am I to assume that that is an indication of the amount of stretch that has taken place in the cam chain? If so, I would imagine that the amount of travel remaining in the tensioner would be a way to determine the need to replace the cam chain.

Any thoughts on this?
 

Hick

Member
Aug 15, 2000
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I'll wait for Rich's thoughts on this, as I'm sure you will, but I don't think the two are related.


Unless I'm misunderstanding exactly what you mean when you say "there is a considerable amount of travel left in the old tensioner."


Seems like you are describing the amount the tensioner moves to full stop w/ it off the bike, or do you mean the travel it takes to take up slack in the chain w/ it on the motor?
 

Rich Rohrich

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Jul 27, 1999
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Rubblemaker said:
If so, I would imagine that the amount of travel remaining in the tensioner would be a way to determine the need to replace the cam chain.

Any thoughts on this?

It's more of an indication of the wear on the rubber guide and it's overall radius. :cool:
 

Rubblemaker

Member
Dec 28, 2004
5
0
Rich Rohrich said:
It's more of an indication of the wear on the rubber guide and it's overall radius. :cool:

So, if the plunger must be retracted 1/2" or more in order for the tensioner housing to mate with the cylinder, is it safe to conclude that the rubber guide is within wear tolerance? Simply, is there any way to use the tensioner as a measure of wear on any related parts so that you don't have to tear into the motor?
 

Rich Rohrich

Moderator / BioHazard
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Jul 27, 1999
22,838
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Rubblemaker said:
Simply, is there any way to use the tensioner as a measure of wear on any related parts so that you don't have to tear into the motor?

I don't think so.
 

tnrider

Sponsoring Member
Jun 8, 2003
576
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if we go to the dealer for a replacement part for our 03 bike - do we need to explicitly ask for an 04 part or did honda fix this problem in their replacement parts?
 

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