Tune Specs

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scooble
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Tune Specs

Post by scooble »

Apart from the Port Map on MJ's Team Sparrow site, does anyone else have any other tried and tested KR1S port maps and or tunning specs which they would like to share?
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Post by TwoStroke Institute »

What are you trying to achieve?
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Post by scooble »

TwoStroke Institute wrote:What are you trying to achieve?
more speed maybe, as I heard a rumour it might help :-k
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Post by TwoStroke Institute »

More top speed ? Lower lap times? Both??
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Post by scooble »

a bit of top speed never hurt anyone, neither did lower lap tmes.

The cyclinders I have at the moment are not really a matched pair, one has some slight porting, the other hasn't, althought I did have both barrells skimmed to bring them down to the same height, also re-cut the squish to give me 0.8mm clearance, other than that its standard.
I have a spare set of KR1 case that I plan on flowing in the usual places, a set of PWK35 carbs (not used yet) and currently using Nikon expansion chambers.

I've ridden peaky bikes in the past and just never really got on with them, despite some of them having respectable peak power. I raced a Bob Farnham KR1S as well as a Stan Stephens TZR250, both of which had massive stomp out of corners which translated into very resepectable top speed (131.5 for the TZR).

So, I am looking for a tuning spec that will give me good midrange, and although I know MJ has posted his spec on Team Sparrow, I wondered if anyone else had anything more to add
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Post by TwoStroke Institute »

OK.
A bolt on part would be an ignition and a quickshifter. The quickshift will drop 0.1-15sec off each up shift. Ignition benefits are well known.

Engine
Depending on the fuel run 13.5+ compression probably more if you keeps revs down to 10,500 peak.
Ports
Extend the aux exhaust port window to around near the end of the main transfer.
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Post by mgtkr1 »

widening the ports is a good route to more gas flow without messing with port timings bu as ou know, be carefull what pistons you run. the std pistons are the limiting factor here. ex port 27mm from top is a well known mod irc. case mods, lowering the ex aux ports also helps with midrange aswell as widening. im unsure of exact specs but the cases/filler along with matching evrerything so it blends/no sharp edges or steps should give a grunty motor. the boost port at the back also has a horrid step, i remove this. i also leave a nice finish using the stone and wd40 on all the surfaces. the ex port gets polisished to help prevent carbon buildup. ill try dig out some better info for you scoob. also f3 kips helps account for discrepencies in the linkages.
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