Hi Blueberry,

I'd not say extensively modified, I only did the ports and squish to a mild tune, I've never even touched the bottom end. There is plenty left in it yet. Its just I did all the calcs first and set off with a goal in mind rather than just hacking a bit of here and there and hoping it worked.

The prop I'm using a German "Super 16x8" but I've ordered a 16x8 APC today so that will provide a very relaible benchmark for everyone.

Exhuast, have a look on RCMF and you'll see the guts of the exhuast. I found it was good on the one shown in the pic above bit it certainly needs the baffle in to provide back pressure otherwise the low speed pickup when you bang the throttle flat out is terrible. Full open pipes just knacker the bottom end performance. With my 2 exits if I block either one takes 400rpm off though!

Gain just from the exhuast, difficult to say as I said, it all works together but my new exhaust would probably make very little difference to a std engine, maybe even make it worse, same with the carb. I always get asked "what if I just did this, or just did that" well the answer is usually either stick with what you've got, or do the lot, but don't mess about doing a half of the job. If you are not sure about the calcs to get the port angles and areas, just get on amazon, buy a book and get reading. If you can do simple maths you can do the port calcs, and if you can use MS Excel it just about does it for you.

With you americans having a supply for these engines at $25 each go for it! I wish I could get them at any money, I've been searching for 2 weeks now and cannot get another at any money and the ebay seller won;t even reply to my mails.



Cheers,
Rich