PFM Float Height Adjustment

TassieDevil · Post by **TassieDevil** » Wed Aug 17, 2011 4:28 am

Hi All,
I have my carbies apart and am checking the floats for the correct adjustment. Have found the info on how to measure the heigths and mine are at about 22mm instead of 18mm.

My question is which bit of the float arm do I actually bend to bring the height back to 18mm? The Dellorto tuning manual says to bend the float arms - but these are fairly solid and would take a bit of bending and does not sound right.

rwhc80 · Post by **rwhc80** » Fri Aug 19, 2011 6:27 pm

Gordon,

It's the little centre tang that depresses the needle jet that is bent. not the float arms as you mentioned.

Cheers
Rick

machten · Post by **machten** » Sat Aug 20, 2011 4:17 am

It's the little centre tang that depresses the needle jet that is bent. not the float arms as you mentioned.

I'd disagree with this because that assumes the two floats will sit in the fuel at the same level. This is rarely the case in my experience. I always bend the the float arms on both sides to acheive the right level consistent across both floats.

Kev

Post by **BevHevSteve** » Sat Aug 20, 2011 8:02 am

I concur with Kev - in fact I'll also ad that you run a huge risk of causing a sticking float needle if you mess around with the tab that holds it as suggested. Ive rebuilt a lot of Dellorto carbs and can't tell you how many I have seen with needles hanging up on the tab because people bent that tab trying to adjust the float height and squished or said better, limited the clearance on that thing. So unless the floats are way off just bend each arm so each float is at the proper height.

TassieDevil · Post by **TassieDevil** » Wed Aug 24, 2011 4:03 am

Thanks guys. I will have a look at bending the float arms. They don't have to move much - about 4mm.

I wonder if that is enough to worry about?

machten · Post by **machten** » Wed Aug 24, 2011 4:27 am

I've never found PHF and PHM carbs to be particularly sensitive to float level, but 4mm is over 20% out of spec from memory. (at least for PHF's).

Because of the angle of carbs on some bikes, I always pay close attention to getting them right (both carbs on darmahs and 750GT's, front carbs on Sports, G/F's and I think other SS's (having a seniors moment!)). Make sure you bend them up near the pivot point on the flats of the arms. I use long nose pliers to do it. It can take a few goes to get it, but it isn't difficult to acheive.

Kev