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-   -   Xl600lm monster (http://www.horizonsunlimited.com/hubb/honda-tech/xl600lm-monster-8748)

Stuart Jenkins 1 Aug 2004 22:41

Xl600lm monster
Why is it that fettling with bikes usually opens up a large can of worms?

I decided to replace my cam chain, tensioner, and guides as it was getting a bit noisy. So setting aside a few days to get on with it i got out the spanners.

Everything went fine, engine out of frame on work bench, rocker cover off, i started to undo the cylinder head bolts and noticed one very under torqued compared to the others!Sure enough when it came out i noticed that tell tale sign of aluminium in the bolt thread arrgh!!!

Resolved to the fact that it was going to have to be fixed, i unbolted the barrel. Inspecting the bore and piston, i could see it was time for a rebore. time for horror number two...

On measuring the bore and piston i noticed it wasn't anwhere near the 100mm for the Xl but nearer 97.8 of the XR600.

So now i realise that the previous owner has replace the standard XL barrel, piston, and head (cam-shaft is XR spec to)with that from a XR! Not only that but when i cleaned the piston i noticed it stamped with 1.00mm! so it has already been rebored a couple of times!

...So my question after al this ramble is...

is the barrel at it's rebore limit (it has a steel liner not coated ali)?
Or should i get it re-sleeved back to original XR spec?

Is there a good and trusted company in or around London to get this done (or in the UK)?

Are there problems waiting to happen with any of the other components because of this XL/XR mix?


Stuart (off the road)

frnas 3 Aug 2004 16:10

Dont worry, the xlm actually has a bore of 97.0 mm, but i am not surre of how big overbore you can have on these bikes. Stripping the treads on these bikes is rather common.


Stuart Jenkins 3 Aug 2004 23:24


Thanks for your reply

I've only just found this out! both the Clymer and Haynes manuals said that the 87 XL model where 100mmx74mm,bore and stroke, i suppose it just shows that you can't beleive everything you read!!!

I found out that the bore and stroke is actually 97mmx80mm (same as the XR) on the German site: www.xl600.de

Apparently Wiseco do a 100mm piston which is 3mm over-size! I have spoken to an engineer and says it is alright to go this large.

...But know i've found out that the con-rod needs replacing as well!!! what a money pit this bike is becoming!



Bossit 4 Aug 2004 12:22

Hi Stuart,

I've been riding an XL600LM overland to S-E-Asia,still gotta continue to Oz.It's an '86 engine which i rebuilded as well.Didn't have any problems with the piston or big things like you mention.But had problems with alu treads coming out on 3 out of the 4 bolts of the cilinder.Putted helicoils and that did the job.No prob's now even after 45.000 k's.
I was just wondering.Wouldn't it be a cheaper solution an less pain in the ass if you buy another engine.If you look around,i can't imagine there so expensive.I bought my whloe bike for a 1000 Euro.And even later another one in better condition for my girlfriend(which she sold again) for 1250Euro.
Maybe i'm wrong but just thought abou tit as another option.
Hope everything works out well.

P.S.:I think that german website is reliable,so why don't you ask the people there?

frnas 4 Aug 2004 15:14

I do not think there is an manual out for your model PD04,XL600LM , at least clymer is refering to the PD03, XL600R. The conrod is an pressfit solution whit the crank, so the only solution is to buy an new, that is horrible expensive. I know it is possible to buy an new NX650 engine, maybee there is posible to buy an XLM as well? I do not think crank shaft problem is comon on these RFVC engines, so an used bike/engine can be a solution. But as you have experienced, buying used is a lottery.

god luck

[This message has been edited by frnas (edited 04 August 2004).]

Bossit 4 Aug 2004 17:41


I've got a copy of a workshop manuel.But can't help you on it right now as I'm in Thailand and I'll be home for a few weeks somewhere end of august beginning of september.If you still want it then,you can let me know.I 'll need to scan everything then.
Anyway,like I said before,a used engine could be a solution as frnas says as well.

Good luck!

Stuart Jenkins 5 Aug 2004 17:27

Thanks for the replies.

I did think about a second hand engine, but the breakers i contacted had already taken parts off (for other braken XL's!), and you never know what your getting with second hand. I could end up in the same position i'm in now.

The engineer who is doing my rebore, also does crank-shaft rebuilds. Wiseco do a 3mm over-bore piston at 100mmm bore (629cc), and conrods as well.

I've worked out that it will cost a bit over a second hand engine, but i'll be getting a like new engine out of it, and i will at least know the engines mechanical history.

Thanks again


P.s Bossit is the manual for the PD04 model? As i have the Haynes and Clymer, but they only cover the PD03.

Bossit 5 Aug 2004 19:09

Hey Stuart,

Seems that it's all gonna work out fine.Good to hear that!Yes the manual I'm talking about covers the PD04.If you give me your mail adress I'll drop you a line when I'm home and see or i can manage to scan and sent it,if you're interested.

Keep in touch,

Stuart Jenkins 7 Aug 2004 00:21


Thanks for the offer of the catalogue,
My e-mail is

iamstuartjenkins at hotmail dot com (delete the spaces ;o))

Happy riding


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