Triumph Thunderbird Sport Tuning Tips
Here are some Triumph Thunderbird Sport tuning tips from “J.B.”:
I live in England and have a ’99 T’Bird Sport.
Couple of hints for you, just reading the excellent article on valve clearance adjustment, which I had a go at myself not so long ago. Couple of things I found out about this engine:
I really do understand the frustration with the lack of clearance under the frame tube, so I found that it is really much easier to remove the coolant junction pipe that is bolted to the left hand side of the cylinder head, it takes two minutes, and whilst still attached to the hose, it will fold neatly out of the way to allow you to work. Once removed, dry thoroughly around the mating area and when bone dry cover the hole with gaffer tape, err, believe me stuff can fall in there!
The engine goes “quiet” when the valve tappet clearances are too tight! Honest, so be very suspicious of an overly quiet engine – the healthy rustle is what you want to hear.
The engine power is largely restricted by the awful exhaust system (especially the downpipes/header pipes), and of course the standard airbox.
- Exhaust – I had a set of custom stainless downpipes made that run into a large (but handsome) 3 into 1 large collector, to allow expansion, these were then mated to the custom silencers (mufflers), made for me by OS Stainless, Hixon, Staffordshire, England. The difference that this mod alone makes is very noticeable. (See the wBW Motorcycle Exhaust Systems page)
- Airbox – if you look at the airbox, you will see that the engine is trying to breathe through something like a 1.25 dia pipe. Not enough volume perhaps? That’s what I thought anyway. K&N make an air filter kit for the bike, they just fit individually to each carb. They are pucker filters so damage to the engine bore/pistons and rings etc from particulate matter should not occur if fitted properly. Then all I would suggest is checking the mixture to make sure you are not running lean. No one at Triumph or Wilcox will confirm this (to busy trying to sell you cams and engine work………………), but I believe that doing these two mods will give you in the region of 80BHP at the back wheel, maybe a bit more or less. I’ll let you know when I’ve done a dyno run.
Best Regards, J.B.
Thanks J.B. for sending these tips!