CRF150RB Question

[EdLennon]

Hi all,

I need some insight on my son's MX bike.

He son has a 2007 CRF150RB. Last time he was riding, there was some abnormal noise coming from what seemed to be the left (shifter) side of the engine around the cylinder. The ran normal, but I did not want to let him ride it fearing that something might come apart and create a big mess.

I tore the top end off and the first thing that I saw that was abnormal was the cam chain tensioner (the actual black plastic thingie that the puts tension on the cam chain) was worn, like frayed and split. So I figured that is where the noise is most likely coming from. The piston, rings, valves all appeared to be in very good condition.

My question is this: Do I have to split the cases to replace the cam chain tensioner? If so, what else should I do while I've got it apart? New cam chain?

Thanks for any insight from you guys!

Ed

 

[IndyMX]

No, you don't have to split the cases.. If it's the rear slider, you should be able to take that off without even pulling the head. It should have a bolt at the bottom under the flywheel that you'll have to remove, then you can slide it out thru the top of the engine. You shouldn't even have to remove the chain to replace this..

If you need to replace the front slider, you'll have to pull the head.

I was told a while back that the likelyhood of me ever needing to replace my timing chain was pretty low. That they tended to last a long time. And my bike is a 2004 CRF450.

Doubtful you need to replace his. But you can if you want.

My best guess, you need the rear slider, some lock-tite, an ignition cover gasket and oil..

http://www.bikebandit.com/houseofmotorcycles/2007-honda-motorcycle-crf150rb/o/m15658 Then click on Chain Tensioner..

 

[EdLennon]

Indy,

Thank you for the reply. I saw that diagram and part number 11 (bolt in bottom of tensioner) is what had me thinking uh oh, maybe the cases have to come apart.

Thanks for setting me straight on this one!

Ed

 

[Rich Rohrich]

Ed - Make sure you take a close look at the cam chain auto-tensioner mechanism itself. This is something you replace every year or two on the bigger CRFs when they are ridden hard and the design on the 150r appears to be essentially the same. It's cheap insurance to just toss it and get a new one.