Triumphrat

dunringil · 04-22-2004, 04:48 PM

I have a 96 adventurer with mikuni's, my mixture screws are 3 turns out. Can I go any further without re-jetting?

Will it richen any more by going 4 turns out?

I have a k&n jet kit installed already.

tbsrider2000 · 04-22-2004, 06:16 PM

If you could adjust the idle mixture with the bike running, you would notice your idle speed increase as you turn the mixture screw out. To a point.. This can be done on some bikes, not ours though of course..

After about 3 turns out, maybe even a bit before, you would notice your idle speed dropping again because the idle mixture would be too rich..

The ideal spot being just before the idle mixture starts to drop again.. I would believe going much beyond three turns would start getting a bit rich..

jimmyj900 · 04-23-2004, 12:26 AM

>>I have a 96 adventurer with mikuni's, my mixture screws are 3 turns out. Can I go any further without re-jetting? Will it richen any more by going 4 turns out? I have a k&n jet kit installed already.<<

What's the problem and/or what are you trying to accomplish?

Jim

Slinky · 04-23-2004, 04:02 AM

There comes a point where turning out the mixture screws ceases to have any effect. The restriction is all gone by 3 to 3.5 turns out.

If you are still running lean at this stage, you need to go up one size on the pilot jets, and (probably) screw the mixture screws back in to find the optimum setting

The stock pilots are #38, next size up is #40

dunringil · 04-23-2004, 11:42 AM

My bike had the restrictive carb rubbers, I just replaced them with the non restrictive type. It already has a jet kit installed, using the larger jet from the kit. I have off road pipes.

Before replacing the carb rubbers I had drilled 3 holes in each side of my airbox. The bike ran good with 4 holes uncovered. When I Installed the carb rubbers, I backed out my mixture screws from 2.23 to 3 full turns. But it was still way too lean, So I covered up all the holes in the airbox.

I was wondering if I had any more room to richen the mixture, so that I could open up the airbox again.

By the way, I'm very pleased so far with my mods, the bike has a lot more low end torque.

Slinky · 04-23-2004, 04:16 PM

With the mixture screws you are really only affecting the mixture at idle. At low throttle openings the height & profile of the needles come into play. At very low throttle openings the mixture screw setting has some effect, but it is minimal.

FWIW I fitted the unrestricted rubbers to my bike and I was never entirely happy with the way it ran at low throttle openings, despite fitting later Keihin carbs and shimming up the needles.

I have now gone back to the restricted rubbers, with smaller mains in the Keihins, and I swear it runs better. Of course, impressions are just subjective without dyno testing.

jimmyj900 · 04-25-2004, 04:38 PM

>>I was wondering if I had any more room to richen the mixture, so that I could open up the airbox again.<<

More room to richen the mixture depends on how much you want to open the filter box.

I'm currently running my 2K Adventurer with a modified Trophy filter box, K&N filter, #150 main jets, #42 pilots and Factory Pro needles and 1 turn on the mixture screws. I'm going down to #40 pilots since it's a bit rich on the bottom end. I don't have any fuel consumption figures as yet.

A friend in Texas has a similar setup with a modified Classics filter box, K&N filter, #145 mains, #40 pilots, and FP needles. He's currently reporting 81 peak rear wheel hp on the dyno and about 40 mpg with the 5-speed transmission.

Take a look at the "Classic Triumph Tuning" file in the downloads area for the info on filter box mods. I don't have specific info for the Mikuni carbs, but the setup should be close to the Keihins.

Jim