Forum

[windmill john]

I’m upping my main jet. Don’t worry about other settings, it’s just the main jet I’m upping; needle already moved.
Bogs if you twist. No, I don’t normally ride at half to full throttle, normally 1/8th to 1/4.

I think the carb is a 376, bike is Bullet 350, 2002/3

Jet fitted is 200. Now without anyone to ask, I’d just step up one to 210.
I don’t know what standard was and it has a foam filter on carb.

Just wondered if anyone thought 2 steps was too much, I.e, 220.

I know they’re only £3, so could buy both; I’m trying to save money!

Just opinions thanks.

John

[windmill john]

Actually, thinking about it, it’s a silly question. Sensible would be making one step at a time, 210.
I just thought maybe monoblocs might want more of a step.

Ignore me, I’m waffling, I’ll just order a 210.

[Wheaters]

Are you sure it's actually too weak? A 200 sounds quite large.

My 350 uses a 26mm Concentric with a mere 160 main jet.

[Daiwiskers]

Hi John
Do you have a choke fitted if so mark twistgrip 1/4 1/2 3/4 then try applying a slight bit of choke to see if it makes things better or worse if better full throttle then go up on main jet if worse go down one then try without choke see how it runs if worse go back up to where you started
Then go through all the other settings changing all other jets and don't forget the slide
Pain in the backside what Paul (bullet whisperer) and I did was if it pinked under heavy load, up the main and try again after many miles and many months I an running
35 pilot
107 needle jet
Number 3 slide
And a 260 main
But these settings are for a 389 on a engine that's in a high state of tune
We started with
25 pilot
106 needle jet
3.5 slide
210 main
If I remember correctly a stock 350 with a 376 monobloc would have had
20 pilot
106 needle jet
3.5 slide
190 main
If all that has been changed on your bike is the air filter and exhaust you're not far off
I think the timing on a stock ish bike is 6 mm btdc fully advanced this may be your problem
A old boy told me many years ago that 9 out of 10 carburetor problems are electrical !
Food for thought Dai

[Daiwiskers]

Sorry don't know how to edit
Have a look on YouTube Paul Henshaw performance classics you will see some of the build on my engine and others
Most of the set up problems with mine (asbo 30) were down to a advance retard unit that was breaking up letting the timing move all over the place (I had 4advance retard units at home and 3of them were loose) the one in there now is the one that we welded up
Yes the devcon bodge ( my idea not Paul's) is still holding up well
Cheers Dai

[vince]

Hi, Wheaters, concentric carb have smaller jets for the equivalent bore size monobloc.Vince

[windmill john]

Thanks all for the input.

PO had fitted electronic ignition. Whilst it could be out.....

Okay, I did a plug chop at full throttle and it was on the lean side a tad.
Did the same at half throttle and again, lean.

I moved the needle up one notch and then had to play with mixture screw. Definitely better up to mid throttle. I’m not saying acceleration, well maybe a tad, but not bogging.

If I crank on the throttle, then bike bogs.

My view is a main jet change is cheaper than a slide change and quicker than a timing change. I think for £3 it’s worth a test.

Oh, it has the small baffle in the silencer too.

You can almost see my cone filter here:

http://jalbum.net/en/browse/user/album/1945137

[Wheaters]

Vince,
Yes, obviously so.

However, my old highly tuned BSA 272 had a Monobloc carb and it still only only ran a 150 or 160 main jet.
It had grass track "methanol" cams, works bottom end and a 12:1 piston from a Triumph Trident. It was built by Roy Pidcock, who was the E. Midlands grass track champion at the time and it was a lot quicker than my 350 Bullet.

[Wheaters]

Windmill John, have you checked the float chamber fuel level? It can make a noticeable difference to overall mixture strength.

[Daiwiskers]

If you want more top end retarding the inlet cam one tooth will help,, you will lose a bit at the bottom end but not as much as you gain at the top
Worth trying it costs nothing well OK it may cost a timing cover gasket if yours tears removing the cover
All explained on Paul's YouTube channel
They don't call him the bullet whisperer for nothing
Cheers Dai