Scorpa sy crank rebuild help!

[Rob1985]

I’m planning on giving my scorpa sy a full engine rebuild for a project over winter, I have the crank out and planning on sending it away to get rebuilt but the only part I’m struggling to find is the crank pin that sits inside the big end bearing that’s pressed in, would anyone know of any alternatives from other bikes? Or anywhere that might still have any? 

[mcman56]

That should come with the rod kit.

[Rob1985]

I can’t find an oem or aftermarket Conrod kit, ive sourced all the parts individually except for the crank pin

[Tr1AL]

1 hour ago, Rob1985 said:

I can’t find an oem or aftermarket Conrod kit, ive sourced all the parts individually except for the crank pin

YAMAHA or SHERCO motor , if its a SHERCO then Splat Shop have 24X58 for £25. If it is a TYZ motor did you call the UK SCORPA importer Birkett Motosport.

[Rob1985]

Yamaha sy 250, I haven’t tried birketts yet  I’ll give them a ring on Monday see what they say, apparently Yamaha stopped making them so it’ll be old stock if I’m lucky enough to find one, or if anyone has had any luck with a suitable alternative 

[feetupfun]

5 hours ago, Rob1985 said:

Yamaha sy 250, I haven’t tried birketts yet  I’ll give them a ring on Monday see what they say, apparently Yamaha stopped making them so it’ll be old stock if I’m lucky enough to find one, or if anyone has had any luck with a suitable alternative 

There will probably be an aftermarket rod kit available because the TY250Z motor is based on the YZ250 motor of the same era (ie probably the same conrod)

[Rob1985]

I’d be suprised if there wasn’t something available as an aftermarket kit, a few people have mentioned about the yz 250 being a possible match but just need this to be confirmed, ive emailed a few trials bike dealers and need to ring a few on Monday, if I find out I’ll post back here for anyone in the same position. 

[mcman56]

Attached is a scan from an old Hotrods catalog.  It shows all rod/ pin dimensions for a number of YZ250 engines.  I would be curious to hear if one matches your engine.  The catalog also shows pins available by size but it is from 2007. 

I see that Hotrods is now part of the Allballs group and still sells individual pins.

https://www.allballsracinggroup.com/p126-crank-pin

Scanned Document.pdf

[faussy]

Id ask your engine builder to check the new pin is tight when refitting it. They were known to be on the loose side compared to the euro makes when they came new. Was it hard to press out? If birkett doesnt have any in stock he will definitely to be able to tell you whats compatible, some would say scorpa copied his bike 🤣

Edited December 3, 2023 by faussy

[Rob1985]

I contacted birkett motorsport, nigel and his wife were extremely helpful, all parts I need in stock and an alternative crank pin on the shelf as Yamaha did stop making them. It’s good to know spares for the sy are still readily available. 

[Tr1AL]

13 hours ago, Rob1985 said:

I contacted birkett motorsport, nigel and his wife were extremely helpful, all parts I need in stock and an alternative crank pin on the shelf as Yamaha did stop making them. It’s good to know spares for the sy are still readily available. 

@Rob1985 Yes  Nigel Birkett is a mechanic/engineer and worked for a few Trials bike manufacturers during his earlier career to develop their products including the later TY bikes like the mono,  if he cannot sort you with bits for a Yamaha Trials bike then its unlikely any one else would know any better  than him . He is your first port of call for your bike and its motor when you need parts/help.

[Tr1AL]

@Rob1985  Your Scorpa SY is a rip off of a Bike that Birkett designed and built himself using the TYZ motor he used to make them to order before Scorpa made the SY you can see the obvious similarities https://www.trialscentral.com/forums/uploads/post-12-1077274121.jpg