Hitchcocks Forum

Hi all, I'm a newbie Bullet owner- so please be gentle with me..
I've a 2002 350 Standard with Boyer, and a recently added Host 'less restrictive' pipe- rejetted 100m / 27.5p

May well be unrelated, but since fitting I've picked up a full throttle (only) misfire. Backing off just a touch makes it disappear completely, and the bike otherwise pulls well.
With a couple of priming swings, the bike always starts firsrt kick. Plug looks ok- maybe even a little sooty- and other than a little burble there's no overrun backfire so the jetting must be close.

The on / off nature is making me think OE air filter restricting flow or electrical. The plug lead is stiff, so I'll be replacing that along with the plug & cap ASAP. Coincidentally, the handlebar kill s/w is disconnected / faulty.

I'm an engineer, so I will be working through the basics but just wondered if anyone has had a similar experience?

All the best, Duncan

It may be you need to go a little larger with the main jet, maybe 105.

Closing the throttle back to cure does sound like classic weak symptoms..

You could try removing the air filter, (test only) just to see if it gets horribly worse but don't ride to far or fast if it does, don't wish to hole the piston...

Other thing to check is the fuel filter and tap, make sure delivery to carb is adequate. May be running dry at full chat..

I have had problems in the past with blocked air vent holes in the fuel tank filler cap causing an airlock, might be worth checking yours. A.

WOT misfire = main jet no less than 2 sizes too small.

It does seem a classic case of main jet too small but with a standard air filter 100 main jet should be OK.
Worth trying a 105 though but that's as big as an unturned 350 should need. .

Thanks for the replies, guys

I've ordered 102.5, 105, 107.5 and 110 so I'll have a little play when they arrive (along with new plug, cap, HT lead) and see how that goes.