Scooterotica

I'm liking the attention to detail and the fact that you are doing so much of this yourself

Nice!

Adam

coaster wrote:

soullad wrote:Col, just a thought, and in no way a criticism, if you look at that last pic do you think the fat ring of the Avanti head will act as a barrier to the forced air of the flywheel. If you dremelled that ring between the fins on this side, would you not increase both the surface area of the head and increase air flow through the fins to the rest of the head? On an Avanti barrel this probably wouldn't be called for, but on this?
Also does the exhaust port region suffer from any reduced cooling effect or does the bigger head simply act as a sink, drawing heat away?

I can see your logic Mike but I'm assured by the fact that AF are supplying these for use on the RB250 so I don't anticipate any problems for my lowly TS1. There have been other big heads used on Lambrettas (MB did one) which did away with the cowling alltogether. Either way I'll be using a CHT

what sort/brand is your cht?

joespeed wrote:

coaster wrote:what sort/brand is your cht?

I'm using a very basic one from Skydrive on my Avanti but I picked up a digital one from China recently and intend to use it on the TS1 coupled to a Skydrive probe.

Trannies seem a bit tall for that exhaust port: As Mr. Taylor suggests a bit more exhaust lead would be beneficial. But given the pipe and requirements not crucial by any means. imho.

Avanti head looks good: optimise volume (check cr) and adjust the squish profile.

The head will get a blast of cool air right on the squish/seal line: no bad thing imho. Though it will be a bit unevenly cooled as a result, the sheer mass of the head should cope easily.

Lookin good imho!

Any head gasket in use ?

love the suggestion about drimmeling out the fins on the near side as it can only help matters cooling wise and air flow around the head overall .

Darrell Taylor wrote:Any head gasket in use ?

No gasket needed as I adjusted the squish at the base. If I don't like the way it rides I can always swap to using a thickish head gasket.

Re the dremelling between the fins, it would be easier to get them milled out, but as I said, AF are fitting them to thier RB25's and one presumes they are an improvement over the 'standard type heads. The head does have to get up to a suitable operating temp to promote efficient combustion, it is possible to have too much cooling...or so I've read somewhere.

Good point about the CR Yanker, I will check it although I'm pretty certain that the chamber volume is relatively large. I've just realised that I didn't measure the distance to the top of the exhaust port for the corrected CR

Adam_Winstone wrote:I'm liking the attention to detail and the fact that you are doing so much of this yourself

Nice!

Adam

Doing it myself (wherever possible) is usually my preferred route, partly out of being tight but also the occational pleasure of getting it right. Being a 'glass half full' kind of guy helps as if I reflected on my record of failures or what COULD go wrong I would propbably buy a Honda

sean brady scooters wrote:love the suggestion about drimmeling out the fins on the near side as it can only help matters cooling wise and air flow around the head overall .

it works very well

Darrell Taylor wrote:

sean brady scooters wrote:love the suggestion about drimmeling out the fins on the near side as it can only help matters cooling wise and air flow around the head overall .

it works very well

Don't suppose you've any before and after dynos to show what difference this makes have you Darrell?