Small end bearing replacement on GP100

[Milo]

My uncle tells me that the small knocking sound is the small end bearing that need replacement...problem is I'm not sure where to find 'em and where's a good place to buy them from.
I've got a Haynes manual I've had a flick through so it all seems simple enough. Plus one of the reasons I got this bike was as a project so I could learn more about the inner workings of engines, so this'll be a good oppertunity for me to learn.

Right, so where's good to get 'em from? I don't really want to pay delivery on what I assume to be a cheap part, though I'll be needing a new gasket at the same time according to Haynes.

Something else I've been thinking of - while I've got it apart would it be a good idea to get a Dremmel in there to polish the cylinder up a bit? Apparently the bike will do 80 easily but it'll currently only do 60 on the flat.

Any info much appreciated!

Adam
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[mr jamez]

Small end bearing will be on the end of the conrod, where the piston attaches to it, gudgeon pin goes through the middle of the bearing which in turn is attached to the piston. The bearing for my NSR was about £6 I think, genuine honda part so they are not expensive.

[Kickstart]

Hi

As above, but you will need a top end gasket set.

The GP100 will not do 80. 60 is probably a bit down on what it should do, but 70 is about the limit. Polishing the ports will give you next to nothing.

All the best

Keith
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[Robby]

Doing a little end for fun? I would call you silly, but I just did a head gasket on a straight 6 for fun.
And I fucked up, so I'm going to do it again.

Well yes you'll need a head and a base gasket, and if it was me I'd fit a new set of piston rings while you're at it.

If the heads a bit coked up I'd rub it off with a scotchbrite pad or similar, and remember, scrape off ALL traces of the old gasket with a gasket scraper. That was my expensive mistake.

[stinkwheel]

Don't forget the new gudgeon pin circlips!

They cost 50p each and if one fails because you reused it, your whole engine is toast.

That is the small wire clip, one each end of the piston that stops the gudgeon pin from slipping out.
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[Guest]

What everybody else said

You'll need ............

Head gasket
Base gasket
Exhaust gasket
2 off piston circlips
Little end bearing.

As said, it won't hurt to change the rings while it's apart, but you'll need to know whether it's standard bore or not.

Parts should be off the shelf at ......

Crooks Suzuki
36-44 Crellin Street,
Barrow-in-Furness,
Cumbria,
LA14 1DY
Telephone (01229) 822342/822120
Fax 01229 870051
https://www.crooks-suzuki.com/


or .........

Robinsons
Broadoak Road,
Canterbury,
Kent
CT2 7QG
Telephone (01227) 454366
Fax (01227) 454726
https://www.robinsonsfoundry.co.uk/

*Patronising mode on*

Stuff a rag in the crancase mouth as you lift the barrel to stop anything dropping in - same when you take the piston circlips out and replace them.

Put the gudgeon pin in the freezer the night before you re-build it, and leave the piston on a radiator for half an hour - the cooling and expansion makes pushing the pin in so much easier. Dribble a bit of two-stroke oil in the little end bearing when you fit it.

Don't forget to put the base gasket on first. Line the piston ring ends up with the locating pegs and be careful as you slide the barrel back on - don't snap the rings.

Tighten the head bolts down evenly and do them 'crossways' a bit at a time.

Run it in for about 100 miles, re-check the head nuts and then use it as normal.

*Patronising mode off*

[Milo]

Nice one - cheers for the very useful info!

Adam
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Shaft drives rule.

[Robby]

If you order off robinson's, mention the VX800 list/owners club to get 10 or 15% off.

[sickpup]

And what did everyone forget?



















New Gudgeon pin

[gsxrboy]

I doubt very much the Gudgeon pin would be worn or damaged, it is a very strong component.
Check it with a micrometer and roll it on a surface table if you have access to one.
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