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Sherco 250 Main Bearing Replacement

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Hi there, I've recently bought a 2000 250 knowing it needed the mains changed. Having ordered and recieved all the parts need to replace the bearings(from splatshop(great service)). I've stripped the motor to the point of replacing the bearings. whilst cleaning the old gasket off I spotted a piece of sprung metal lying under the gear selector drum. Managed to get it out but on inspection I can't for the life of me work out where its from. All of the springs that I can see on the parts manual are all present and appear to be complete, also the piece does not seem to match any of them in shape. I'm gonna try and attached a couple of photo's of the metal and where I found it in the hope one of you more experienced will be able to help me outpost-18134-0-44334800-1363394372_thumb.jpgpost-18134-0-34252600-1363394669_thumb.jpg. I'm sorry if the pics are too big or don't show up .

Looks like a leg off the gearchange return spring possibly, part number RB/M110

Looks like a leg off the gearchange return spring possibly, part number RB/M110

Yes, and may have gotton cought up in the primarys at some point!, Inspect for damaged cogs in the crank gear and clutch basket.

Have you ever heard it run? Does it make a knocking noise? Thus so.

Edited by copemech

  • Author

Thanks for the replys guys,the metal piece is definatly of the same gauge as the return spring , just suprised it could of been bent into the shape it is now(being sprung steel). Gears all look good so hopefully no no more damage has been done. Haven't heard it running but was told it had an engine rumble. Anyways it has been fun stripping it down and getting to know the bike and also giving me a good chance to check it over. As I can't see any broken springs I'm going to continue with the rebuild and get it back together today hopefully.post-18134-0-31572900-1363433553_thumb.jpg

  • Author

Hi all, well I did find a bit of damage to one of the teeth on the primary drive gear. Will have to look into getting a replacement but thought as I could replace that with the engine still in the frame I rebuilt it to ensure she would run and that all the bits were there(bought as a non runner). Eventually got her running and there seems to be a fair bit of piston slap I think. Not sure what to do at the moment as dont want to invest too much in it if its going to be a money pit. Would I be better off just putting up with noise as its a bike for me to learn on and then buy a newer bike in the future or is a 13 year old bike worth spending another few hundred pounds on.

There is another spring in there number M117 index spring It appears to sit under the selector drum in the photo It may be the kick start spring broken and when replaced the broken parts not fully removed

  • Author

Hi mate, yeah found that one all ok. Think your right about a previous owner leaving a bit behind. the main oilway runs at the bottom of the casing and exits under the selector drum. It could even be after they realised the spring had gone they drained the oil from the box and the draining oil pulled the spring piece through the oilway and under the selector drum.

Obviously a bit hard to decypher over the tinternet, yet I suppose a bit of piston rattle would not be unexpected on a bike that age. Once again not to be confused with the damaged primary gear.

I would suppose nothing there preventing riding the thing, and other stuff to be done later.

Prolly still as good old bike as most. Tart it up as you can, as I figure you got it cheap anyway, and if one is lucky he may take a bit worn cylinder, hone it a bit and just slip in a "B or C" piston to tone things down, as compared to a replate.

  • 4 weeks later...
  • Author

Sorry its taken so long to get back to this topic. Yeah got it cheap (I think £300) Ive put a video on youtube so you can have a listen if you fancy

hopefully this link will work as its the first time i've tried linking to a video.

Edited by lamby

My impression and my "christ-all" ball say the top end is a bit rattly, yet you still have an underlying knock sound coming from the primary gearset which was damaged by the offending piece you found. Both gears will likely require replacement. Might as well figure a new style clutch basket assy and the crank gear. This will be an upgrade to the dampened basket so good.

As far as it "working" for now, it will run, just sounds like a box-o -rocks!

Bike looks tidy enough otherwise, so a good project, and a lot less than a new bike if tou put 1K in it!

Edited by copemech

I also wonder if the kickstart is partially engaging going on the video.

The later clutch is certainly better until the rubbers shrink/get hard & then it gets noisier, with what you said that you paid for your bike it may be a bit more than you want to spend.

How bad was the damage to the gears, I've seen the high spots o f where a ball bearing got into the primary drive gears stoned off as short term fix & it worked well, could be worth trying

Looking at the front end of your bike someone has fitted later forks which have no adjustment but are better forks with the mudguard mounts part of the main casting rather than seperate

Hi Just listenend to your video, I ve always thought shercos were noisy, but that is loud!!!

You did say in your earlier post that you enjoyed stripping the engine apart.

think you need to have another go,

TLTEL

I also wonder if the kickstart is partially engaging going on the video.

The 2000 2.9 I used to own had that problem. There is a small replaceable metal piece that separates the kickstart gears when not in use. this piece wore too thin and did not separate the gears completely. Piece 5.15. it can be accessed by taking clutch cover off............too bad coolent will need to be emptied to do it.

3045.jpg?1358377294

  • Author

Thanks for the replys guys, have just placed another order with splatshop, getting a new primary gear(think the clutch basket gear will be ok),also the ratchet that Zippy mentioned and some other bits and bobs. Will let you know if these improve the situation.

Over the 7 or 8 years I owned that Sherco 2.9 I got REAL familiar with the insides of the motor.........................................Sometimes it was something I did that caused me to need to split the cases and fix it :wall: other times was just normal wear and tear.

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