> Thomas Peffer Wrote:
> So I have stripped the bolt threads that go on the cylinder intake on my
> 70cc DMP piston port kit for my e50 Maxi. I ordered a new polini reed
> kit from doscycles and an 88 jet for my 15mm Bing and MLM Cali pipe that
> I'm running. I have ditched the old boss pipe that I had on it before.
> What differences can I expect from the polini and new setup overall
> versus the DMP?
You could expect a kit and crank/engine seize with that pipe and kit if your running stock ignition and stock unported bottom end which I believe you said you were prior.
A polini kit is a whole new ballgame they’re not as hearty or forgiving as a dmp or Kstar (tho the old 2006 era polini kits were heartier and more forgiving then ones made today)
It’s hard to keep a polini cool with a lower rpm cooler running pipe like estroil, circuit types as it is with stock ignition even at a perfect 14° btdc with no points/timing mark bounce and only going 8,500-9,000 rpm
Any more rpm that the timing needs to go lower then 14° and it can’t with static set/points timing that’s why electronics ignition with a curve is needed,
At 8,500 rpm you’re just getting into the thick of the power on that Cali pipe, your stock crank/bottom end and stock ignition are at the limit of cool/reliable running, (maybe just retap/fix the hardier dmp kit and run a estroil/circuit type pipe)
A rebuilt bottom end with a needle crank and a hpi/retarding ignition type ignition is needed for any kind of reliability with a polini kit and Hi powered pipe like Cali
(For on a 2 stroke engine the pipe is the supercharger so the more boost the more the timing/tuning/compression needs adjusted/lowered for no boom)
Polini kits need cleanup/chamfer the ports, gap ring smooth/prep intake for no air leaks (because you can’t tighten it really tight or the piston will bind) as well as a good case match so all the ports (especially boost ports) get gas mix to the piston (for no hot spots) and perfect jetting/tuning (though close ya can’t just guess 88 jet).
If you just slap it on like the dmp kit was you’ll have to baby it even more than you did with dmp set up if it don’t fail the moment you get out of the driveway.