Triumphrat

Regiz · 04-06-2007

After years of fun My T309 has gone (a rod badly disconnected from engineshaft)

I bought a TBS engine with his carbs and putted on my Adventurer.

Sprint Cams I had on prev engine were traslated to new by my mechanics.
It was necessary to reverse rearset leverage to get 1st down.
I arranged some rubbers (fork types) to keep the same airbox (it was drilled when I putted on cams, Mikunis had 110 MJ) and I rejetted little less richer (STOCK 98 MJ)obtaining a good erogation.

When on the road I feel the gears keeping very very long. Anyway the bike comes without problems to 170 KMH, (about 100 MPH) at 7500-8000 RPM in 4th speed, (with two left to put in) then stalls...

I was wondering about putting on a 48 teeth rear sprocket to shorten gears run. Is there so much final diameters difference between 17"x60mm TBS and 16"x80mm ADV wheels to justify that gear gap or I lost some power?

What is the best I can do next to solve my doubts? (es. dynoruns, sprocket swapping, TBS airbox...)

denny · 04-07-2007

the only difference in the air box is the mounting lugs for the TBS style air box covers. Any new air box you buy from Triumph will have those lugs on it.

Sorry i can't help with your other questions.

Not sure I understand all your question either.

Did you keep the stock Adventurer rear wheel?
Do you have the mikiunis or kehins on the bike?

Are you using stock jetting now?

Regiz · 04-10-2007

Thanks to your reply, good to know there's no difference in the Airbox...

I have TBS Kehins, that have different intake edge from Mikuni(so I made hoses) and I'm using stock T-Bird MJ.

I got the stock 16" ADV rear wheel.

ACT.SIT.: bike stalls in 4th speed at about 100 MPH

The only thing I want to know is if to you it seems a lost in power or it's simply a misgearing due to the difference in the weel (sprockets are same).

TNKX, BYE.

sweatmachine · 04-10-2007

maybe go down a few teeth on the front sprocket?

Regiz · 04-11-2007

Yes, it could be easier than changing rear one (nearly same chain lenght), but 17 teeth (stock) is the lesser I've found for my bike.

If I will find it, could 15 front (from 17) be compared to 48 rear (from 43)? Is there a simple Math ratio for sizing transmission?

TNKX

04-11-2007

16/45 would give you a 2.81 ratio; very close to the 2.82 you would get from 17/48. I got the gear ratios from this site.

I think I read that it can be dangerous to use smaller front sprockets with the T3 motors due to tight clearances, but I can't remember details. I see that JT Sprockets doesn't make anything smaller than 17.

Maybe I'm missing something, but I don't understand why your bike is stalling or how changing sprockets will prevent it from doing so.

Just for reference, my Trident has the 97 HP 6-speed engine, 9700 RPM redline, 18" rear wheel, & stock 17/46 gearing. 7500 RPM in 4th is about 80MPH for me. (I think; I'll update next time I have a chance to verify.)

HTH,
-Kit

Regiz · 04-12-2007

Many thanks to have confirmed my suspects about front sprocket.

If there is no difference from TBS'ratios it means that bike got not enough power (for ex due to carbs inlet or bad carbs conditions) to raise up and to manage the two gears left. Before doing any mod I will do a dyno-run.

R.

[ This message was edited by: Regiz on 2007-04-12 10:05 ]