Another box of bits....

[caravanmonster]

Hello all. I've been tasked with yet another one of my mates ebay specials and am hoping for some guidance. It's a mk2.2. The chassis is thankfully about ok, but the engine came in pieces. It looks like it had been swimming (cases full of grit), then the main seals gave way and the piston did something catastrophic (without doing much damage to anything else) judging by the reeds which were coated in gearbox oil and shrapnel.

I've cleaned everything and removed the main bearings (for peace of mind more than anything) and the balance shaft needle roller. Gearbox bearings seem fine.

Today's questions are:

1. Which piston kit to buy ? Pattern or oem ?

2. Am I looking for anything specific with regard to the balancer shaft ? There seems to be some reference on the web to it being noisy due to infrequent oil changes, but is this a symptom of worn bearings, or the shaft itself, or something else ? Having only worked on competition engines before, I'm not really familiar with balancer shafts, so any advice is appreciated.

3. Is it worth going to the local bearing supplier for bearings and seals, or will they all be weird honda sizes that will cost the same from David Silver ?

4. Do I chance it with this intake manifold ? There's a little damage which I might get away with, but it doesn't feel brittle or prone to crack at all (sorry, don't seem to be able to post images on this forum)

[url=http://www.flickr.com/photos/61798297@N05/8261941362/][img]http://farm9.staticflickr.com/8361/8261 ... 20d3_c.jpg[/img][/url]

Thanks in advance for any help. Shall I do a picture step by step as it goes back together (maybe not worthwhile as there is already a site with a 2.2 rebuild on it) ?

[caravanmonster]

edit: Ignore Q1 - it's covered in FAQ, my mistake

[knackeredMk1]

1 & 2 you can find answers in the Honda CRM250 FAQs section.

3 Many bearings are cheaper from stockists but some are Honda specific.

4 OK if you can get the uncut area to seal.

As you like but there is a site specifically for a Mk2 engine rebuild though as you say.

[caravanmonster]

[quote="caravanmonster"]edit: Ignore Q1 - it's covered in FAQ, my mistake [/quote]

doh ! Q2 as well, sorry

[jompy]

Why not do a step by step thread on the rebuild ? i'd follow it

[Mudfacetony]

1 & 2 you can find answers in the Honda CRM250 FAQs section.

3 Many bearings are cheaper from stockists but some are Honda specific.

4 OK if you can get the uncut area to seal.

As you like but there is a site specifically for a Mk2 engine rebuild though as you say.

Re No3, I have recently bought bearings, seals and bushes for the swing arm / linkage. Seals are cheaper from a bearings supplier, bearing where common ae cheaper and for the bushes and the Hond specific bearings, Leisure Trail are marginally cheaper than David Silver Spares

[caravanmonster]

Getting there. Was pleasantly surprised how at how many of the engine bearings and seals were available from the local bearing shop. Only little end brg, balancer shaft needle roller and drive side main seal had to come from honda.

Could anyone point me to a timing the balancer shaft 'how to' ? I'm sure I was reading one the other day, but can't find it now. Can't see any timing marks or suchlike. Apologies in advance if I have missed the blindingly obvious again

[knackeredMk1]

Align marks as per -

[caravanmonster]

Thanks Mk1, much appreciated. It's obvious when you know what you're looking for !

Another question: any chance the flywheel is the the kokusan 2k3 (used in the majority of current european enduro bikes)? It looks very similar. The reason I ask is that it would appear that someone has taken a hammer to the centre of the CRM flywheel and distorted the threads to the extent that it is not possible to use a flywheel puller, so it cannot be installed because it would be near on impossible to remove again.

I'll pull the flywheel off my gas gas and see if they are one and the same. Any thoughts from the CRM collective ?

[knackeredMk1]

I have spare Mk1, 2 and 3 flywheels they are all different.

[fallenmikethebike]

Thanks Mk1, much appreciated. It's obvious when you know what you're looking for !

Another question: any chance the flywheel is the the kokusan 2k3 (used in the majority of current european enduro bikes)? It looks very similar. The reason I ask is that it would appear that someone has taken a hammer to the centre of the CRM flywheel and distorted the threads to the extent that it is not possible to use a flywheel puller, so it cannot be installed because it would be near on impossible to remove again.

I'll pull the flywheel off my gas gas and see if they are one and the same. Any thoughts from the CRM collective ?

The timing will be different in all likelihood.
Mike

[caravanmonster]

[quote="fallenmikethebike"]The timing will be different in all likelihood.
Mike[/quote]

That was my guess too. Non issue now, thanks to Mk1, so onward with the build and finding out what else is missing or broken !

[caravanmonster]

After a load of work getting the tape off the loom and inspecting for breaks and cracks, there's no spark and it looks like the ignition part of the PGM has failed. I spoke to Leisure Trail and they offered the same diagnosis. The mounts on the PGM were both broken off, so I guess there's every chance something has broken with all the bouncing off the seat base and airbox. I've emailed 2TRacelabs to see if he's still doing repairs...

I couldn't fathom what the engine had died of - the previous owner had split it, but there were no tell tale signs of mechanical failiure. The mains were ok, the barrel perfect, the crank cases didn't have any serious marks or cracks and the crank is straight. Although the bent flywheel is still a mystery

I've returned the CRM to it's owner until a solution to the PGM can be found. Anyone got any ideas

[knackeredMk1]

Have you checked the main coil for continuity/resistance and any power when kicked over

Another potential area for no spark is a faulty run switch on the bars, but there could be so many things wrong when inheriting a 'box of bits'.