For those who are interested.........
I phoned the Australian distributor in Melbourne, who wanted me to contact Dynojet UK? So I did....
I sent the following to "Dynojet UK Technical Support" <technical@dynojet.co.uk>
To whom it may concern
I have an '03 790cc Triumph Bonneville America.
I wanted to get a few extra horses out of the engine (before playing with the gearing)
I removed all 3 snorkles from the airbox.
I cut a neat round 65 to 70mm hole through the barrier inside the air box (between the two holes where the carburettor intake snorkles were.)
I installed a lightly oiled foam Unifilter element.
I have Triumph Off Road Short pipes on the bike.
After months of tuning I have settled for 45 pilot, 145 main, Triumph Thunderbird Sport needles, with one small shim under each.
The bike runs rich - black plugs (not wet) and black sooty residue in the pipes after a long run.
It took forever to get rid of the lean spot at approx 1/4 throttle - highway speed in top gear.
Changing the standard 42 pilot to the 45 cured all lean spot problems, but now it runs too rich at idle. It will rev high then sink low etc, and on the right day I can smell it is running rich.
The Triumph Thunderbird Sport needles were put in as a hopeful cure to the lean spot. I could tune out the lean spot with 5 small shims under the original needles. But eventually went back to the TBS needles.
Air / fuel mixture screw has varied in adjustment from 4 1/5 turns to 3 during all these attempts. Presently at 3 3/4.
My problem would seem to be midrange. Just can't get a needle with the right profile. Some friends have suggested the Triumph Thruxton needles. They are physically shorter (sit between standard and TBS) but I really feel the profile will be similar (as it was designed for a standard bike designed to meet todays emission and noise control limits - just like the Triumph Bonneville America!)
How can you help me?
This was the response Hello,
Unfortunately we don't list any off-the-shelf parts for the Bonneville America. My recommendation would be think about getting some dyno time at one of our approved tuning centres, these guys will be able to perform several types of diagnostic runs and tell you exactly what needs to be changed and where, they could even undertake the work for you.
Please visit
http://www.dynojet.co.uk/tuningcentres.php?type=1 for a list of approved tuning centres.
Sorry I can't be more help, Martin.
Martin Winstanley
Dynojet UK
01995 600500
martin@dynojet.co.ukwww.dynojet.co.uk
