Derbi kit on a hobbit - runs but not well.

Emil Kniemel /
This single post is part of a larger thread. Start from the top or view this post in context.

I probably bit off more than I can chew but here it goes. Decided to install my previously used 50cc gila derbi kit onto my basket pa50ii hobbit (the bearings were originally busted and it had a pa50i cylinder on it-- so i figured it was the best time to experiment). here are the specs:

-original hobbit case bored out to accept derbi kit, 12mm crank installed

-6mm studs (using original stud holes on cylinder and head)

-moby av7 intake with a 15mm SHA clone (runtong) - 68 jet

-derbi pp head (no decomp channel) sanded down for < 2mm squish, decomp is not hooked up

-one-way bearing

-derbi 6-roller + treats rumpus plate @ 16 grams

-new treatland replica belt

-hack weld pipe

it runs and idles (rather well) but is very slow. its also jetted super low (currently at 68) compared to what i think it should be (maybe more like 80) but will 4-stroke and foul a plug if i go up any higher.

it only hits about 32 mph but SHOULD be going over 40 pretty easily i think maybe closer to 50.

any ideas? now that i've typed it all out i think i should tune my variator more precisely and maybe throw a temp gauge on it. (edited)

This single post is part of a larger thread. Start from the top or view this post in context.

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account