U.k. Bonneville

Tom,
sadly the table seems to specifically deal with usa and canada rather than uk bikes and according to it J is Hinkley, T is Thailand which didn't match my bike as I don't have a letter as the 11th digit, though the H might be the power output 85ps as mine as G which stands for the same thing

 

Lurking under the tank sticking out of the loom on the spine you will find an apparently redundant T socket for just such a purpose.

 

LH yellow arrow!

 

Something is not right........

You should (on std gearing) be getting nearly 50mpg (Imperial gallons!) even if you are ragging it and nearer 54mpg if you are not.

Binding brakes? Blocked air filter? I wonder if the previous owner has gone a bit too big on jets having fitted TORs. Do you know what they are?

 

That model bike and colour was on the cusp of the 790 to 865 transition. Different jets and needles.....
Now, the TORs were supplied with 115 (vice standard 110) for the 790 but the 865 has the tapered Thruxton needle and, with no other mods, should supposedly not need re-jetting.
So, which motor and what mods?

 

It is easy to be daunted but in truth the whole shebang is not that complicated if you can wield a screwdriver and read a manual and take a few digital photos. Like Hansel and Gretel you can then find your way back......
If your mpg is poor you are losing performance as well as money.....even if it is just clutch slip. Accessing the carb float bowls is a fiddle freeing them from the air box and rotating them to access the screws. However, if you assign a weekend and remove the rank you can clean and lubricate the linkages and cables and clean the carbs themselves. The jets are threaded brass inserts with small numbers indicating their size. You standard pilot jets are size 40 and provide most of the fuel from off idle to 3000 rpm where the mains take over. The size of main is as much a function of your airbox set up as exhaust. Equally an over oiled K&N can mess up that calculation too.
What are you up for in terms of rolling up your sleeves? Can your budget stretch to £25?

 

If the screws on your carbs have not already been replaced with allen bolts, then you might want to consider getting these: https://www.squaredeals-ltd.co.uk/b...burettor-stainless-steel-screw-kit-3973-p.asp makes life easier in the future.

 

As you already have TORs fitted I would open up the airbox by removing the rubber snorkel and internal baffle

Instructions: https://www.triumphtwinpower.com/triumph-twin-easy-airbox-baffle-removal.php

Leave the filter and contoured bellmouth for now. Strip down the carbs and find out what is in there. TTP can supply the right jets for your 2-1 exhaust set up combined with your airbox mods. If you feel flush then fit a Breathe too. The paper OEM filter is fine unprotected unless you intend to ride in the rain. It will survive the odd shower!

 

Just spotted this thread - so a bit late to the conversation. The spare socket under the tank (at least on my 2012 SE) is not switched with the ignition, it is permanently live. I wired a USB socket to it and then changed my mind because of this and connected the USB socket via a "piggy back" connector to the horn.