VHSH Carb, want a bit of knowledge
Posted: Tue Nov 07, 2017 1:56 pmI’m OK with the PHBH carb in knowing atomisers, needles, rich to weak and the best combinations. However, I also have a VHSH carb, that was dynod and jetted for my by a cart man. This was after I did the mods, such as drill out the half-moon to the inlet and put a 3.5 float valve in. However, the atomiser is a DQ264 and the needle is a K98, MJ 155 and 60 pilot and 60 choke in a TS1. Now looking at the forums, I never see a K98 needle. So, can anyone explain what are the best needle/atomisers to run in this carb from weak to rich needle.
Why I say all this is that the dyno had the initial clip position was 1.5 from the top. This was OK up to 5000rpm, then my CHT shot up to 650 centigrade and as it approached that dizzy figure, I blipped the throttle and rammed the thumb choke on. Eventually repeated this and did a plug chop which did show that it was lean. I’m now on clip 4, but the bottom end is rich and I’m still hitting 650 centigrade at 6000rpm.
I will take it back to the dyno chap, but the more knowledge I have, the better.
Also, what’s the difference between the A, B and H versions of this carb.
Why I say all this is that the dyno had the initial clip position was 1.5 from the top. This was OK up to 5000rpm, then my CHT shot up to 650 centigrade and as it approached that dizzy figure, I blipped the throttle and rammed the thumb choke on. Eventually repeated this and did a plug chop which did show that it was lean. I’m now on clip 4, but the bottom end is rich and I’m still hitting 650 centigrade at 6000rpm.
I will take it back to the dyno chap, but the more knowledge I have, the better.
Also, what’s the difference between the A, B and H versions of this carb.