top end troubles

3 replies to this topic
  • torkrat

Posted February 19, 2003 - 10:38 AM


Hi all

I've got a 01 650R that blew the countershaft oil seal and was ridden pretty hard for several
miles before the problem was noticed.

End Result - very loud knocking coming from the top end.

I pulled it apart and found that the intake rocker arms were worn down to the point of having
a very large amount of valve lash. The camshaft appears to be worn down as well, I also noticed
slight vertical wear marks on the piston and cylinder(no grooves, just shiny lines on the exhaust side)
The wrist pin also has a slight groove worn into the middle and con rod has slight wear marks as well.

Crank bearings felt ok (smooth while spinning by hand) and con rod bearings have no noticable up & down play.

I found only very small particles of metal while dumping the oil.

My question is, should I have the cases opened up and bearings inspected up close?

Does anyone know were in the Orange County area I could have engine work performed (other than the Honda dealer)

Also, I was thinking now might be a good time for some performance mods, cam ect.. does anybody have any thoughts
as to what works well in this bike (it currently has a full big gun pipe & edlebrock carb)

The bike is used as a Baja runner as well as SuperMotard.

Any help is very much appreciated.

Thanks in advance


  • XR/CRDave

Posted February 19, 2003 - 04:40 PM


How much oil leaked out while the bike was ran?

Although it is a drive for you in Orange County, I would take the bike down to Precision Concepts in El Cajon, just east of San Diego. They do lots of work for team honda, they did some mods to my 95 600 motor after Glamis sand killed it. It ran awesome after they got done w/ it, porting polish and top end work. I would go w/ a cam and porting on the 650 if something happened to my 650 like yours.

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  • torkrat

Posted February 19, 2003 - 06:03 PM


I would say I lost more than a quart and a half of oil. I was running at a pretty high speed through deep sand at the time and unfortunately didn't notice until I let off.

Thanks for the tip on Precision Concepts, i'll give them a call.

  • ossagp1

Posted February 21, 2003 - 08:43 PM


I was just looking for my listing of Megacycle cams for the xr650. Since you need hard faced rockers to go with their cam, now would be a good time. I have had really good luck with their hardfacing and they have lots of available grinds.

What you describe on your wrist pin and con rod small end could have been from previous 'wear'. Since I do all my own work, I would probably end up changing the rod. Especially if I was going to go up on compression and go for a cam with more lift/duration etc.

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