Triumphrat

jimmyj900 · 07-01-2008

Quote:

Originally Posted by Mag00

BTW, what is the correct routing for the fuel hose from the petcock to the carbs? My Adventurer has just the single fuel line hooking up between carbs 2 and 3.

That's correct.

Reading over the posts so far, it's time to go back to the beginning.

The first issue was the carbs being way out of balance with a really high vacuum on #3 (the right one) followed by a rough idle that won't smooth out now that they're balanced.

Is that correct so far?

The second issue is weak operation over about 4K or so.

When the bike is running weak, do you get any misfiring? Does the sound of the exhaust get sharper or duller?

How many miles are on the bike?

Jim

Mag00 · 07-01-2008

Quote:

Originally Posted by jimmyj900

That's correct.

Reading over the posts so far, it's time to go back to the beginning.

The first issue was the carbs being way out of balance with a really high vacuum on #3 (the right one) followed by a rough idle that won't smooth out now that they're balanced.

Is that correct so far?

The second issue is weak operation over about 4K or so.

When the bike is running weak, do you get any misfiring? Does the sound of the exhaust get sharper or duller?

How many miles are on the bike?

Jim

Answers to questions:

1. Yes.

2. Yes.

3. No. No Misfiring. Sound of the exhaust gets duller.

4. Approx. 1850 miles on the bike.

Mag00 · 07-02-2008

Ok. I may have made a mistake. Not sure. Where are the pilot screws located on the Mikuni carbs and how are they adjusted once the carbs are installed?

jimmyj900 · 07-03-2008

Interesting...

The exhaust note going duller indicates that the fuel mixture is going rich. That's a symptom of needle jet wear but you don't have enough miles on the bike for that to be the problem.

You've also renewed the filter box and checked that the intake circuit is clear, so rich running isn't an intake issue.

Also, the altitude where you live is around 600 feet so that's not a big issue.

That leads me to suspect that either the needles are set wrong or someone has put in bigger main jets, so you're going to have to check that. (Sorry)

The stock Mikunis should have #90 main jets, #40 pilot jets and a needle stamped 5E1, set at the 3rd slot from the top.

I haven't messed with a Mikuni BS in a few years, but the structure is very similar to the Keihin carbs and the mixture screws are located at the bottom rear of the carbs toward the engine. There's a cutaway drawing of a CV-type carb in my photo album, so take a look there and see if it makes sense.

Keep us posted!

Jim