More power; 125cc twin or single?

[CGK1]

Thinking of upgrading my CG, but i want to keep it a honda engine, and 125cc. The standard engine is pushrod, and a would like so an ohc engine.

So, do i go for a CB125 single or twin? Either way, the engine will be tuned ie. higher compression ratio, MAYBE bored up slightly.


Cheers

[ben1]

they do a chineese engine in a 250 (bigger head etc) they can come pretty cheap and more responsive than 125.

I have no idea which of the 125s are quicker but i do know a CG would sound awsome with twin exhaust pipes!

[TerraRoot]

try searching up bucket racers from NZ, although the regs allow them to have 150cc four strokes they are pretty much the only people in the world who competively tune/race tiny 125's

millions of pounds and an army of techs with computers at f1 level can net 300bhp pre litre from a four stroke.
most production 125cc two strokes make that as standard. Fit a softy tuned two stroke more power more reliably definitely cheaper.

[CGK1]

Problem is, fitting a 2 stroke will look like a right bodge in my CG, but the other engine will fit right in :/

I was thinking about just working on the current engine, cbx550+2 piston for about 137 cc, and skim the barrel for 10:1 compression or even 10.5:1.

I think the bottom end should take this as it's a japanese built engine and not a later brazillian one, but i dont know if theres any point doing this to a pushrod engine really, if their naturally less powerful and rev happy than the ohc CB engines :/

Oh, one last thing, on ebay i found a head for a cg copy with twin exhaust ports, dunno about the performance gains, but it would look pretty cool

[lewisweaver]

You could try shoe-horning a cb125t engine into it?

[CGK1]

Thought id bring the thread back, im still having ideas. The cb125t is the engine i want in it, but i dont know if it will fit :L those engines have about 16hp standard, and im guessing they could be taken to about 19 or even 20 hp. That would be perfect, but i dont wanna make any huge changes to my frame....

[davytelford]

heres an idea i had thinking of this all night

cardboard template find the dimensions on the net or buy a scrap engine but im sure that it'll fit

[CGK1]

Thats a brilliant idea, im gonna give it a go