XR600 engine differences

[Boyracer]

Does anyone know what the differences were between the 600RF engines and later models at all please?

[ghostdancing]

all XR600 are 591cc 97X80 bore\stroke; early model 85 - 87 is twin carb equipped, 88 - 00 are single carb.

design of the heads are different between these 2 versions: the later (single carb) has automatic (centrifugal) decompression system (it's mounted on the camshaft right side), so camshaft are different (non interchangeable); the camchain and its wheels are narrower in the single carb motor (to have room for the decompression device).

except the heads, the motors are identical, except for the covers: magnesium (super lite and brittle) for the early 2 carb motors, solid , heavier alloy for the single carb motors (anyway they are interchangeable)

note that the XL600R motor (83 - 87, twincarb) are very similar, but they are 100X75; many parts are interchangeable with the XR motors; actually the XL600R it's a larger bore XR500 (83 - 84) motor

all these motors are bulletproof, if you care to provide them frequent oil changes: only the stator failure (they become fried often) can stop them

[Tony.Brown]

88-90 were chrome bore weren't they?

[TT5 Matt]

yeah 1st 2 or 3 single carb models were chrome bore after that they went back to the steel reboreable liners.all in all they wern't a bad motor and  responded to all the usual 4t mods and had a lot stronger gearbox then tt600's.I'd buy 1 again but wouldn't touch a tt600 with a 10 foot barge pole!

[80-85 husky]

when did they fix the gearbox?? wasn't 4th a bit of a drama for uprated engines??

[Mick D]

Great machines,,,lots of torque,,,super durable especially if you consider the massive milage some of them have done before they end up as disrespected bush hacks.

Parts a plenty,,,new and used.

Some great insight given here too,,,,thanks fellas 

[Mick D]

yeah 1st 2 or 3 single carb models were chrome bore after that they went back to the steel reboreable liners.all in all they wern't a bad motor and  responded to all the usual 4t mods and had a lot stronger gearbox then tt600's.I'd buy 1 again but wouldn't touch a tt600 with a 10 foot barge pole!

Fully in agreeance there Matt,,,,and I reckon their 5 speed big bore two bangers are weak in the box too,,,
Mine fell of the stand whilst not running,,,landed on the gear lever and bent a shift fork,,,,
I have had some good Yammies but those two were not two of them.

[Boyracer]

I had a TT600 that developed a false neutral between 4th and 5th, besides that I was happy with it

[crossedup2]

I think the last two years also a chrome bore (1998 to2000) also.

My first XR600 a 88 model had 60+K on it when I sold it. Had 20K when I bought it. Only thing I did on it was cam chain ( one at 20K and one at 40k) in the 4 years I owned.

My current one, 95 Ballard 630 model has only done 30K. I won't sell it because I know that with a service, I could put the big tank on it head off anywhere for 4 weeks. The only real problem I have ever had with either 600 is that I don't get enough time on the bike.

There was no real troubles with gearboxes in the 600's but the early XR400 had gearbox problems.

The XR600 is like an old axe, keep the thing sharp and you can do anything with!

Peter B

[Mick D]

[Hoony]

what do you guys think of the water cooled XR650 ?
i rode one of these many years ago at a Honda ride day at Barrabool MX track and was very impressed.

[James Lee]

My XR600 developed a skip in 2nd, on inspection the dogs on 2nd and the 5th gear dog slots worn out but I think it was all because of a bent shift fork.
Apparently some of the translap or 650 gears interchange and changes the ratios.
Mine has a 100mm JE piston and a big pipe and was very happy with it apart from the gear failure.
there is a detent roller available that makes them shift better.

[80-85 husky]

rocket rod has had one for years (650) and loves it. it got pinched a year or so ago and he was devastated then the pos that knicked it did a big mono in front of the cops...got his bike back minimal damage