Sleeving down 2-strokes?

[Mrs Busa Pete]

Im interested in sleaving down an aprillia rs 125 for buckets how do you find out how far to go to make it a 100cc let alone what piston to fit in it .After watching the rg150 sleaved to 100 im keen to explore this option any help on this apreciated .
Where to get it sleaved.
Where to size new piston.
that sort of thing

[Kickaha]

Working on the RS125 having a 54.5 mm stroke you'll need a 48mm piston to give you 99cc, a 49mm piston will give you 103cc which still fits within the rules

http://www.johnmaherracing.co.uk/enginecalc.htm

[Mrs Busa Pete]

Working on the RS125 having a 54.5 mm stroke you'll need a 48mm piston to give you 99cc, a 49mm piston will give you 103cc which still fits within the rules

http://www.johnmaherracing.co.uk/enginecalc.htm

so on that note a kx 100 being 48.5mm would do the job then

[Kickaha]

so on that note a kx 100 being 48.5mm would do the job then

It would give you 101cc, there's other things to look at like gudgeon pin size, deck height as well

[TZ350]

ESE works engine tuner on the buckets forum has pics and links to a Japanese site that used an alloy sleeve.

http://www.kiwibiker.co.nz/forums/sh...=86554&page=39

.

[F5 Dave]

That RG is a 150 with a 125 top end via RGV250. But same sort of deal.

Many things to watch out for, but a sleeving specialist like Boss eng or Collier would do it ok. Expect to pay 600 notes + a piston. Then you have to be careful to remachine the head to suit. One then needs to consider the porting & the effect it will have moving the transfers etc backward in the bore & also if the new piston will cover the exhaust port when at Top dead centre & peg will run in a supported area. Then have to consider if pin right size for rod & if bearing will be restricted from moving with new piston (ie: can't move too far to one side if that area is wider in new piston). Oh yeah & deck height of piston may be different so you will need to move barrel up or down to retain same port timing & skim to get compression ration the same (or increase). Need to consider powervalves if fitted. You may find the KX ring tends to wear a steel bore pretty quickly compared to the plated bore, a Wiseco KX piston will likely handle steel bore better.

So how are you feeling so far? Still keen?

[Mrs Busa Pete]

That RG is a 150 with a 125 top end via RGV250. But same sort of deal.

Many things to watch out for, but a sleeving specialist like Boss eng or Collier would do it ok. Expect to pay 600 notes + a piston. Then you have to be careful to remachine the head to suit. One then needs to consider the porting & the effect it will have moving the transfers etc backward in the bore & also if the new piston will cover the exhaust port when at Top dead centre & peg will run in a supported area. Then have to consider if pin right size for rod & if bearing will be restricted from moving with new piston (ie: can't move too far to one side if that area is wider in new piston). Oh yeah & deck height of piston may be different so you will need to move barrel up or down to retain same port timing & skim to get compression ration the same (or increase). Need to consider powervalves if fitted. You may find the KX ring tends to wear a steel bore pretty quickly compared to the plated bore, a Wiseco KX piston will likely handle steel bore better.

So how are you feeling so far? Still keen?

Ok i used the aprillia as a reference for the tzr 125 2rm motor wih power valves of trade me that i got from duners $500 incleds loom/pipe& carb .Boss enginering are in east tamaki where are colliers .the tzr is 56.4/50.7 and wiseco list a yz 100 1976-1983 at 50/50 only thing is air cooled piston are they diferent to water cooled and then there the porting

[Mrs Busa Pete]

next step is the frame best bet is proberbly the tzr 250 as the ysr frame is to small for the motor let alone the out put of the motor and chamber

[F5 Dave]

Colliers in Levin I think, www.yellow pages.

Air-cooled & water cooled different shape, best try find watercooled piston if can,