View Single Post
Old 01-04-2010, 11:33 PM
mountain80 mountain80 is offline
Motorized Bicycle Elite Member
Join Date: Aug 2008
Location: Red Deer, Alberta
Posts: 247
Default Re: New Carb. Dellorto Style or "Performance" carb?

To answer you're questions: NO the phbg series is not a simple bolt on, I machined a nylon bushing in order to adapt it. The id of the carb where it sits was 26 mm and my stock ht manifold OD measured around 0.744'' but I measured everything out with mics and such. By the time I got the carb we were into winter and have not run it BUT their is a rule of thumb that says for every 1 mm increase in carb bore size you must increase jet size 10%. My ported and polished taper bored stock carb ht motor runs a 0.66 mm jet and i am at 4400 feet elev but i also am running 160 psi compression so it uses less fuel.
I am starting with what i hope is overly rich 0.79 mm jet and will lean down from there. Also fwiw the pilot jet from factory are generally acknowleged to be hugely rich, mine came with a 50 pj and i have ordered several al the way down to 35. The engine is a generic ''80"" off ebay which has been completely gutted, rebuilt with new bearings fasteners and a trued crankshaft. Also if you are going to go with the dellorto google the tuning manual it can be downloaded for free somewhere and will be highly useful. Also check out the pics elswhere in the high performance area under first pics with the new dellorto to see how it went together

Reply With Quote