Scooterotica

I have a rebuilt GP175 engine sitting in the shed waiting to go in my scooter.
It runs a 30mm Dellorto and a Franspeed JL3 pipe and put out just over 14 bhp on JBs Dyno.

It's ok but I was wondering what tuning options there are for a cast iron barrel these days.

Open to looking at anything really.... Suggestions please.

No options? Lol

dopeshots wrote:No options? Lol

Don't let Eden here you say that.

Sounds fine as it is but most options are open to you, it just depends what you want the motor to do and how much you want to spend. If it currently returns 14bhp and is reliable (?), what more do you want from a spare smallblock engine?

If you are simply after performance return then you might want to look at kits or moving to a 200 casing and see what options that opens up. Otherwise, it sounds like a half decent spare motor in its current form.

Adam

Thanks Adam. I was thinking more along the lines of a Suzuki piston conversion and getting the barrel ported but don't know what is still done these days if anything?

dopeshots wrote:Thanks Adam. I was thinking more along the lines of a Suzuki piston conversion and getting the barrel ported but don't know what is still done these days if anything?

I think that would depend on what's already been done to it, the ports must have been re-worked a fair bit to get it up to 14 bhp. Any idea what the current port timings are?

Hi Coaster I'm sorry I have no idea. It was a std AF175kit then JB matched the inlet and set everything else up. No work was done to the ports by JB that I am aware of.....

Best thing to do then is take top end off, and post some pics of cylinder and piston up here.....along with some measurements of port widths, and height of port (from top of cylinder to top of port) and we can help make some suggestions if you then either wanna try some 'home brew' tuning, or send it off to be ported etc ;0)

Ok, I'll do that.. Cheers Russ

If you're localish to JB then I'd be tempted to take it along to them or at least give them a call to see if they have any record of the work they did. You would then hopefully have any idea of what options you have.
No reason why you can't still have an old school Suzuki 190 conversion with a shortened barrel if the ports work OK, or you may be better off with a longer con rod (TV or RD400) in your crank and avoid the barrel machining. I'm sure most of the tuners will be able to help you with this work.

Another option would be to see if Corrado still has a 64mm Deanspeed Piston for sale which could be the simplest conversion, a Mugello piston might be worth considering too - or a forged Race-Tour one from MB.