Bonneville America Forums Forums Technical Forums Performance Mods Carb drilling?????

OK, question for you. I had found a site ( dont remember where now ) where someone had opened up the vacuum ports in their carbs for a faster throttle response of their slides. basically it described how to use a drill to do this, anyone else done this????
mark

I did it. I saw it on Triumphants site.
I'd made a slight difference. I hear its a better mod on older bikes...mine is an 07 and was 2.7mm already. The mod being drilling to 3mm I believe.

the site

Look at page 4 and 11 of this link. Actually the whole article is excellent.
http://www.triumph-bonneville.com/images/Carb%20Jetting%20Info%202007.pdf
I just drilled my slides on my 790 and noticed an improvement in throttle response. Not tremendous but every little bit helps.

The newer slides already have the larger openings drilling should make little or no difference. What is being done is drilling the earlier slide openings to the size of the later models like the 07 should already be. Allowing vacuum to build faster above the diaphram to lift the slide faster when the throttle is opened fast.