How much do I raise these jet needles...

[hikermikem]

I'm getting ready to re-assemble the carbs from an '81 750L (16V).

Stock exhaust, with a K&N drop in air filter in the stock airbox.

I've gone up one main jet size, (112.5 to 115) because I needed to replace a broken one and I had the 115's laying around.

I want to raise the jet needles a bit as well & was wondering by how much to start? The plastic spacer measures .099". Each one of my Radio-Shack washers measures .023".

If I use 3 washers I raise the needles .030". If I use 2 washers I raise them .053".

Where should I start?? Looking for opinions...

TIA,

Mike

[paco13]

If all is stock except for the filter, and you are using the air-box lid, you probably won't have to move the needle. The bigger main should do it.
On my '81 750 with 4-1 pipe and Uni high flow foam filter in stock box, with lid on. I didn't move the needle. I went 2 up on the Main and 1 up on the Pilot jet. Runs great.

[Steve]

Personally, I would use three washers and leave the pilot jet alone. Might turn the mixture screw out to about three turns, though.

.

[hikermikem]

Personally, I would use three washers and leave the pilot jet alone. Might turn the mixture screw out to about three turns, though. .

Thanks Steve,

Actually, I had already re-assembled the jet needle/slide assy & used three washers, then I got 2nd thoughts... apparently we think alike (is that good?)

Thanks for the 3-turn recomendation on the mix screws - I wasn't sure where to start those at. Didn't plan on touching the pilots.

I have quite a bit of work left to do, with very little free time to devote to this project, before I'm ready to start this puppy...

However, I'll post some pics when she's ready for her closeup.

Mike

[Road_Clam]

I'm getting ready to re-assemble the carbs from an '81 750L (16V).

Stock exhaust, with a K&N drop in air filter in the stock airbox.

I've gone up one main jet size, (112.5 to 115) because I needed to replace a broken one and I had the 115's laying around.

I want to raise the jet needles a bit as well & was wondering by how much to start? The plastic spacer measures .099". Each one of my Radio-Shack washers measures .023".

If I use 3 washers I raise the needles .030". If I use 2 washers I raise them .053".

Where should I start?? Looking for opinions...

TIA,

Mike

When you buy a "needle shim kit" the washers are about .020" thick. This is about equal to raising or lowering one needle clip position on carbs that have standard adjustable needles.

[progas]

Actually, .020" is a half- a- clip adjustment, .040" is a full clip adjutment.

[Road_Clam]

Actually, .020" is a half- a- clip adjustment, .040" is a full clip adjutment.

Yea, actually you are correct, I have exactly just that a "1/2" shim kit, I got my facts backwards. I bought the kit many years ago. Sorry for bad info..

[hikermikem]

Thanks for the respones guys - I did know .040" was the clip distance between each "notch" on needles that can be adjusted... thanks for verifying.

I will start with .030" (3/4 notch) and go from there - just looking to improve the mid-range response.

Happy bikin'

mike