22 September, 2015
ARTICLE BY DAVE WHEELER ABOUT KMT JETS
Jetting your scooter is probably the hardest job to do on a lambretta,especially up here where dyno facilities are so distant, even if you believe they work.
Those that can set up a carburettor seem to think its easy, to those that don`t understand the process its a baffling and potentially disastrous for your motor
The easiest method is to set your bike up very rich so it runs really badly and gradually reduce the jet size until the engine runs well.
It should be an easy task but the trouble is many shops sell jets as genuine Dellorto but are actually pattern unstamped jets and of an unknown accuracy of drilling.
Dellorto jets are stamped with a number than refers to the size of the hole, so a 100 jet is 1mm in diameter, a 115 is 1.15mm, a tiny amount larger but one will let
your engine run fine and the other will blow it up.
So how accurate are they drilled, no-one knows! Even worse even genuine dellorto jets are not above suspicion, this makes trying to jet up motor a lottery,
no winners just losers!
Kmt products are a uk firm who have spotted this problem and have done something about it. Very accurate drilling leads to accurate and predictable fuelling and
makes the whole process much easier to undertake
I bought a set for my series 1 and the jetting progression was consistent with the changes i made and the results i expected to see, they will sell you individual jets or
packs so you can find the perfect setting, in 5mm jets for original lambretta carbs or 6mm for phbh/l dellorto carburettors.
So all in all an excellent product, that could save you a fortune in expensive engine repairs, you would expect such a carefully manufactured, UK made product
to cost a lot more than the pattern or even genuine Dellorto jets, they are in fact half the price!
Whats not to like!