I finally coughed for a new Malossi 172 kit for my T5 and installed it this week. It is just as noisy at idle as one i bought second hand a few months ago so seeing as this one is brand spanking new, i’ve just consoled myself that these kits are just a bit rattle-ey!
The question concerns the jetting.
I setup the piston and barrel, changed timing to about 13.5 deg before TDC and installed the main jet that comes with the kit (122).
After running in for a few hours i started to open her up and the motor stated missing pretty badly and basically wouldn’t rev up to 5000 rpm smoothly under load. It would stutter and then finally find it’s feet at the higher revs.
I swapped the main to a 118 that i had in my kit and it seems a lot better … pretty much spot on. The plug looks much healthier too (it was pretty black with the 122.
So… why would my motor not run with the recommended jet for the kit? Does that mean there is something wrong with my carb? Should i be concerned?
Thanks a bunch.
Standard Del’orto 24/24g
120 air, 50/100 slow running, 60 cold start, Be4 mixer.