Triumphrat

spiki-spikester · 07-01-2007

Can anyone offer any help please ? I'm brewing up for another round of mods and am looking to get more power.

In particular, I'm after more acceleration (and a bit smoother if possible) from (1) a standing start and (2) roll on in 2nd gear throughout the 20 - 50 mph range. Power thrugh the rest of the range would be good too, but the immediate focus is the low / mid range power. Top end doesn't bother me that much, although I'd be happy enough if it improved as a side effect of other improvements.

The current power set up is:
AI removal, standard 790 carbs, Thrux needles (no shim), 120 / 40 jets, mototwin pipes (similar to Epco's ?), 18T front sprocket, Unifilter, no snorkel.

I have decided against airbox removal as the weather over here means too much water and mess gets thrown around, but I am considering things such as different carbs, porting the heads, removing the airbox restrictor plate, changing jets, adding shims, etc.

Having considered switching back to a 17T sprocket, I'm going to stick with the 18T as I like the power delivery at 4,000 / 5,000 rpm and it suits the speeds I want to go ...

Words of wisdom anyone ? Some plain old common sense would help me too :-D

Thanks all

ivar · 07-02-2007

You might want to check out Jenks' airbox removal kit, it is supposedly designed with th Blighty's weather in mind.

SCCTrim · 07-02-2007

Even with no airbox at all you shouldnt have to be concerned about rain. I have a elim kit on my bike and have rode several hours in the rain with no problems.

Ditch the airbox, put on the 17 tooth sprocket..( this will gain you 6% torque that you lost when you installed the 18 tooth )...and look into aftermarket carbs...or a big bore kit.

Either carbs or bb will make your bike feel like a totally different machine.

sweatmachine · 07-02-2007

what trim said.

robnobrakes · 07-02-2007

Quote:

On 2007-07-01 02:36, spiki-spikester wrote:

I have decided against airbox removal as the weather over here means too much water and mess gets thrown around,

Thanks all

I have been running my Thruxton with open velocity stacks. The last 3 rides have been in pouring rain. Needless to say, I have had no problems with rain ingress. I previously had K&N pod filters fitted, again with no water ingress problems. Airbox removal is too good to miss out on. Do it :-D
K&N's

Open stacks

Mecchanica · 07-02-2007

My Thrux has the stock 18T gbx sprocket and 43T rear wheel sprocket.
I got very good low to midrange boost with the stock carbs and mufflers by installing the Dynojet kit, including opening up the vacuum port in the slides, and drilling six 3/8" holes in the end of each muffler, down through the inner baffle plate. The end of the muffler looks like a gatling gun. Mellow tone, lower than if you baffelectomized the mufflers and quieter, to boot.
Total cost is about 85 bucks and takes about an hour to do. I didn't remove the carbs, just popped the tops off, and didn't need to change any jets, yet. That comes next week. I like to work incrementally, to minimize variables at each step. First, I will remove the snorkel and then see where that takes me.

[ This message was edited by: Mecchanica on 2007-07-02 13:36 ]

spiki-spikester · 07-02-2007

Thanks for the advice guys :chug:

The Jenks prototype looks very interesting & more suitable for me than the Mototwin one. Jenks says his Thrux gave nearly 70 bhp at the wheel (140 jets). I was thinking of a velocity stack, bigger jets & drilling the slide - coincidentally this was similar to the comparison Jenks used:

"The same bike, fitted with a Unifilter, Power Velocity Stack and 125 main jets the same bike gave 62 bhp at the rear wheel and stock it was about 57 More importantly, torque is more than 50 ft/lbs from 3000 rpm to 6500 rpm, peaking at 53 ft lbs - more a torque platform than a curve. Compared with the stock bike the torque stays over 50 ft lbs for longer. This smooth torque delivery means great acceleration in all gears. It also "makes" the bike, in this riders view!"

If I go this route, a couple of questions:
1. does it get a lot noisier ? I want to have some consideration for my neighbours !
2. would there still be any point in drilling the slide or removing the restrictor plate ?

Thanks again :upthumb: