750 Slabby motors - how far can you take them?

[Gammaboy]

So I know the easy option is slotting an 1100/1200 into them, but how far can you take a slabby 750 motor? Obviously adding in 750 short stroke barrels/pistons/head would help, but what sort of hp can be expected from a hot one?

[kokolis]

Slabby 750 engines have dif inner dimention than short stroke, them component s dont exactly work on the other.

There are kits 884 iirc or maybe you still can find rare racing parts.Racing slabby s went 130bhp

[banoffee]

@gsxr884 could be your man here.

[clivegto]

 Obviously adding in 750 short stroke barrels/pistons/head would help, but what sort of hp can be expected from a hot one?

Guden pins are difrent sizes.

[Gammaboy]

Fair enough - never really paid much attention to the little oil boilers, been playing with aircooled stuff mainly. What are the pin sizes?

[gsxr884]

JE do a 955 kit , its not so much extra HP that you get as Torque.

I have an M with an 884 kit gas flowed head  RS 36's and a full Cobra system , never been dyno'd , well not since i got it.

And an RK with an 884 kit gas flowed head FCR39s and a full Yoshi system ,, made 125 rwhp last time on the dyno but there is more to come , the afr meter wasn't working so we couldn't get a reading , I am sure it is running rich and that the Yoshi is holding it back, I need to get a tapered header and link pipe system made for it and I reckon it will be over 135 then .

Slightly different is the 750 watercooled slingy, I have a JE 907 kit and TMR 40s to put together , that should be in the region of 135-140 if I can get an exhaust that will let it breathe. 

Too many projects and not enough time

[gsxr884]

the short stroke pistons don't fit the long stroke rods without reaming the little end by 1 mm and I wouldn't trust the rod then.

The rods don't swap over either , the heads don't swap across barrels , mating face is a different shape.

B12 liners could be fitted into 750 block as a cheap liner option , I must try this out, I have spare barrels to play with  .

I have thought about getting stepped or sleeved gudgeon(wrist)pins made to allow use of B12 or 1100 pistons or its get JE to do custom ones.

Piston kits are about £350 to £400 , new aftermarket liners are about £75 each plus the gaskets its cheaper to chuck a B12 motor in but I like the craziness of the 6 speed box as the ratios are closer together

[Gammaboy]

So long stroke is an 18mm pin and short stroke is a 19mm pin?

[gsxr884]

correct 

 

[Fula28]

You could if it was a track bike and had roller starter! Just flow the stock head big valves and get comp ratio upto 15:1 - 19:1 buy taking 0.010" 0.015" off head + with race fuel .easy be over 130bhp .

Its been done before !!!