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Discussion Starter #1
Hello
Could someone please tell me if the head of an old '88 klr 600 can be used for a 2005 klr 650?
thanks
PS apologies if this message is in the wrong place - interweb forum beginner
 

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shacklock,

We have had this discussion before, interchanging heads between the 600 and the 650 going both ways.

Unfortunately, we've never had a complete resolution because the posters disappear before we find out if it worked. I think we do know that one guy salvaged a 650 head onto a 600, so the head bolt pattern should not be an issue. It should bolt up.

The common concern when talking about putting a 600 head on a 650 is the height between the bottom of the head (top of the cylinder) and the center-line of the cam bores and the squish volume of the head. The bore and stroke of the 600 was smaller and shorter, if memory serves.

If the dimension from the bottom of the head to the center-line of the cam bore to the bottom of the head is the same or within a couple millimeters then the cam timing is not a great concern. If it is off quite a bit then the cam timing culd be affected, but may be able to be accommodated well enough. If the height is shorter, there might be an issue with the valves hitting the piston.

The KLR600 piston was a pop-up design here in the States from '84 to '86, and we didn't see them after that. The 650 piston is, of course, a flat-top. What they did with the 600 in overseas markets (you're in SA, right?) is an unknown to me. With the pop-up piston the question becomes "What is the combustion chamber volume in the 600 head?". If it has a volume greater than the 650, which is about 65cc, then the compression ratio, when you put the 600 head on the 650, would drop.

That's all a very long-winded way of saying "I don't know". I will qualify my comments by saying that I've never worked ont eh a 600 top end.

Were I in your position I'd loosely assemble the 600 head to the 650 and see what the cam timing looked like, then turn it through to see if there is any interference. I'd do a visual comparison of the combustion chambers and see if there was anything really different, perhaps cc'ing the head to get an idea of the head volume. If it works, hey, it works!

Please tell us more about your situation and keep us in the loop. We'd love to know the answer! Especially, what went wrong with your 650 head? There is a shop here in the States that has good succes with line-boring the cam journals and installing babbit bearings to repair galled cam journals. It can be done.

Tom
 

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Discussion Starter #3
Thank you for the prompt reply and assistance Tom - I shall surely let you know if I go this route as I have a project 2005 KLR that I am working on with the usual head seize. I am trying to locate a reasonably priced head or alternatively cam shafts and caps for the bike as new parts here in SA hurt financially. Even the aftermarket here is very thinly traded and owned by specialists.

I am a farmer and also an absolute beginner at bike mechanics so I am trying to be as cheap as possible, hence the question around KLR600 to KLR650 head swop - the reason is the KLR600 are really old and engine head can be obtained for a more reasonable sum than the highly prized 650 head. The down side is that there are very limited KLR600's available so patience is key.

Should I go down this road I shall definitely keep you appraised on the engineering logistics and there success or otherwise....

Cheers for now
Richard Shacklock
 

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Sorry Tom
I forgot to give a few details of the fault on my bike - Oil starvation seize with the result that head has had a few chunks taken out and the exhaust cam is "graunched" beyond repair according to the engineers. Also the kickstart decompression lobe on the end of the cam has been broken off. The previous owner rode the bike with very low oil and worked it quite hard and it went bang. Previous owner did the initial strip down and the camshaft caps and the exhaust cam are pieces/unsalvageable respectively. Valves, springs, guides and shims lost. The engineering shop has said they could rebuild the head with new cams and caps and the usual sundries valves, springs shims etc

I like the sound of your engineering shop that has a line boring solution and it sounds like something I heard about. Appparently an old Honda XL500 (pre 1990's) that came out with a white metal bearing that would give up - they would then line bore and fit a bearing which is apparently something that the Yamaha XT500 had? (This is just my information from listening to some conversations so don't quote me)

Oh well at the very least I am learning stacks about bike parts and engineering and I am a complete greenhorn!

Cheers for now
Richard
 

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I am trying to locate a reasonably priced head or alternatively cam shafts and caps for the bike as new parts here in SA hurt financially.
Forget about the cam caps, shacklock! Like the camshaft journals, the cam caps are UNIQUE. No replacements apply.

Sad, but . . . true!
 

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Richard,

Heads used to be reasonably priced and fairly available. That was before the '08 and '09 Gen 2 bikes started to burn oil badly. Owners didn't keep an eye on the oil level and ran them dry. Fried heads became a rampant problem and the price of a head went up accordingly.

The situation has caused a sad end to many an older KLR; we're happy that at least one shop has seen fit to take the effort to work out a fix.

These are pictures of the work that Engine Dynamics of Petaluma, CA USA does. Picture credit to Tristan Savatier. Perhaps you could show these to your local engineering shop and see if they can do this sort of repair on your head. This has turned into a bit of a cottage industry for ED, with them receiving damaged heads from far and wide as their reputation for this repair expands.





If you right click on them and choose "Open image in a new tab" they will come up in the new tab at original size so that greater detail can be seen.

If you have pictures that you would like to post send me a Private Message and I'll return with my e-mail address. I'll be happy to post any pictures you have until you reach the 15 posts needed. Alternatively you can go to the 'Please put your test posts here" thread and put up some nonsense posts to get to the 15. It's a pain but it keeps spammers in check.

Tom
 
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