Alrighty then! I tightened the chain yesterday but it's obvious the chain and sprockets (13/45) are past their best and need changing as it's stretched all the way now. I've decided to go with an x-ring chain and 13/42 to make it more road friendly.

JT x-ring chain ordered - Check
Steel JT sprockets ordered - Check

Now I've had a look at the chain slider and although I could get away with not changing it it would benefit from a new one due to the deep grooves worked in it from the existing chain. I noticed Leisure Trail charge £51.75 for their standard chain slider!! Is there an alternative as that seems exorbitant by any standards. I tried looking on eBay with no joy. I suppose the CR250 chain sliders are a different sizing?

The second thing is giving consideration to the rear lower chain guide . Am I right in thinking I just need to change the plastic/rubber part of that? Leisure Trail offer that for £13.28 so that's okay. Is it worth replacing and how do i tell if I don't really need to change it?

The third thing is chain rollers. My MK2 does not appear to have any chain rollers... is this correct or am I missing something!? The only thing remotely like one is a piece of plastic around the gear selector, but that's definitely not a chain roller. The reason I'm asking is because Leisure Trail offer a chain roller for £7.95... but I can't see where i would fit it...

Love the bike BTW. Followed the starting procedure in the FAQ and it starts 2nd or 3rd kick from cold now, really chuffed!

TBOK, the only one that fits will be the CRM one, but I stand to be corrected.
The chain guide at the rear will need a visual inspection, if your down to the sleeves the holding bolts pass through, change it.
There should be chain roller below the swinging arm, this helps keep the chain running true, and takes the whip out of the chain, on the CRM it's about 25/30 mm dia.with a bearing inside to aid spinning.
I run 14/45 gearing, which for me and my riding works, but at the expense of acceleration, though fuel economy is improved.
Mike

Thanks Mike. If you had to buy a chain slider, would your only option be via Leisure Trail or does anywhere else sell them?

I will go out and have another look in a minute and see if I can see the chain roller.

Just inspected the rear chain guard rubber block. While it's probably not fully worn, I'm going treat the bike and buy a fresh one.

I see the chain roller now! An online search seems to indicate that 32mm chain rollers will fit the vast majority of dirt bikes. Would that work?

Does anyone know for the chain slider if part number: 52170-KAE-020 will work?

Part Numbers:

52417-KAE-770 is the correct part number for the swingarm slider (nothing else fits correctly)
52147-MN1-670 is for the lower rubber block
52175-KCN-000 is the roller

I know they will fit.

Thank you!

helisupp wrote: 52417-KAE-770 is the correct part number for the swingarm slider

Do you mean 52170-KAE-770?

770 is the AR slider which is slightly different from the others I believe. Not sure if LT have these anymore. They will fit other CRMs.

All CRMs have Mk specific numbers if the parts are 'version specific'. 000 is Mk1/870 is Mk2/740 is Mk3/770 is AR. The parts maybe completely interchangeable and may in fact be no different but that's Mr Honda for you............. There are also version numbers so 741 would be the second version of that part made for a Mk3. So we are up to 773 for AR ECUs... but that's another story............

The chain roller is on the main frame under the back of the engine.

Yep... confused now. I've found a site that sells 52170-KAE-770 but don't want to buy it in case it doesn't fit my Mk2.

I think I've no choice but to order the chain slider and roller from LT and see what turns up. I did however find a UFO lower guide rubber block for £9.99 delivered though so that's something.

I'll update the thread when I've got the bits from LT. It might have proper part numbers on the slider packet to confirm for other people.

Thank you guys for all the info though - learning more all the time.

Ooops wrong number.

Attached page from parts manual, part number is the one you stated.

I figured out the chain roller too. 52175-KCN-000 fits the CRM250, XR400, CRF150 and CRF230. Once I knew that, looking at aftermarkets for those more common Honda models I was able establish any 32mm chain roller will fit the CRM250.