87 XR600 Camshaft Broke in Half

[mripka2]

Hello all,

 

Recently while riding my XR600 I suddenly experienced a severe decline in power. I thought maybe one of my jets may have been clogged so I took the carbs off and cleaned them to no avail. I then threw a new plug in just to be sure it wasn't that before I went any further and that didn't help either. Yesterday I decided I would pop the inspection caps off of the valve cover and noticed that the two valves on the left side weren't moving at all. Low and behold after I did some further investigation I found that I had completely snapped my cam in half while riding . So now the engine is ripped out of the bike however the cam for 87 and back xr600s is now discontinued and I could not find one anywhere. I then read about a few people who have modified their valve covers to fit 88+ rockers and an 88+ cam in it. I would love to go this route and throw a Hot Cam in it however I was wondering if anybody else has done this before and can confirm that its doable. I attached a picture of the hell I found when I pulled my valve cover off for your enjoyment lol

 

 

[Horri]

Nice..I'd have to say I don't know much about swapping in other rockers etc..Can't say I've read much about it here.

What I am sort of shocked about is that the Indians or Chinese haven't whacked out a run of twin carb cams..Plenty 

of the things are still running around..would have thought it would be viable in the long term to do a run of them. You

could pretty much charge what you like within reason..$250 would be bearable for the desperate owner..

Edited April 27, 2014 by Horri

[heart_of_darkness]

I've seen a similar dual overhead cam conversion, which seemed to be due to oil starvation.  Your cylinder head's center cam journal toast, and when you remove the cylinder head you'll probably find that at least two of the valves have hit the piston.  It may be cheaper to get a complete single carb style top end and to do that conversion.

[bork]

Whats the little Oring from , in pic? How do the lobes look?  lack of lube indicators?

[mripka2]

@Bork That Little O Ring Is A Copper Seal From one of the oil lines that fell in during disassembly so it's not A problem. Seems to have had plenty of oil. Lobes on the cam look okay. I have no idea why it split. No signs of jumped time or piston hitting valves either.

[ThumpNRed]

The newer cams have the auto decomp on them. Do we know that there are any other physical differences? A Hotcam doesn't have the auto decomp on it, so one may drop in if the journals are the same. I can't believe that someone doesnt have a dual carb and single carb head and/or valve that they can measure.

[valvesrule]

ThumpNRed, on 08 May 2014 - 11:49 AM, said:ThumpNRed, on 08 May 2014 - 11:49 AM, said:

The newer cams have the auto decomp on them. Do we know that there are any other physical differences? A Hotcam doesn't have the auto decomp on it, so one may drop in if the journals are the same. I can't believe that someone doesnt have a dual carb and single carb head and/or valve that they can measure.

They are swappable but it's too complicated to explain in short. I've got both heads and compared them extensively. All the measurements and geometry of the bottom end is the same from day one. General rule use ALL the same rocker box/cam components and timing chain/gears and you should be OK. In other words, Hotcam, 88 or newer rocker box assy that will seal to the head properly and 88 or newer timing chain and sprockets. Lots easier than mix/match various year components that might result in an unforeseen problem down the road.

Edited May 8, 2014 by valvesrule