Scooterotica

Time for a new kit, running with a 60mm crank with 1 mm base gasket, I have an old avanti head so thinking of fitting this with a ts1 but have been told I need to lower the compression of the head. What does this entail? Cheers

Should've been clearer, 60 x 107 crank, can get current iron barrel rebored & new piston & use but thinking of TS1, just wanted to know what needs to be done to make it work with this crank? All advice welcome.

well it depends what your after, 60mm and a 1mm base packer is gonna make peaky timings

have a go with this

http://lambretta-images.com/archive/por ... gJ9rc7-tFU

ts1 has standard timings of around 190 exhaust 130 transfers so put that into the calculator above and start playing around,

depending on what kind of ride your after your after you will be adjusting the height of the barrel to suit

it seems to me the question is a little confused.
I believe from your first post you are asking if you can run an avanti head with a ts1? it would depend on a few things, the chamber volume of the head, the profile of the piston used and its relationship to the head, and final compression ratio corrected or uncorrected once youve built the top end. I dont believe this to be a simple yes or no answer, you either choose to do it properly and work out the values to avoid getting stung later on or you don't, but if youre concerned about the chamber volume of an avanti head i would argue that its a relatively new head design and therefore compression is within a safe zone for current fuels. as for the squish profile working with whatever piston you decide to use, no idea.
however, if your simply asking how to build a top end with a 60mm crank, well it raises your piston by 1mm at tdc. you could therefore fit and forget with a 1mm packer but as we all know that isnt the correct method. (also bare in mind you may need to make casing alterations for the big end to clear and you may also experience the piston bottoming out as its also 1mm further down and bdc, but this probably wont be the case.)
work out where your piston sits at tdc in relation to top of barrel. use port time calculator and a port map to work out what timings that gives you. report back or do some reading, but think about what exhaust you are using and what you want to achieve.
you can then manipulate the timings with base gaskets / packers and then set up the squish properly.

I hope thats clear and doesnt state the obvious, i found it difficult to gauge what you were asking though.
best of luck

Thanks it was a bit muddled but that helps. Food for thought