Did you fiddle with the Pilots at all?

 

No, pilots are stock.

Here's the generic break down on jetting:

From idle to 1/4 throttle; adjust the pilot jet

From 1/4 throttle to 3/4 throttle; adjust the needle.

From 3/4 throttle to full throttle; adjust the main jet.

Air screws are fine tuners.(start out in the stock position, make other adjustments, then adjust air screw.)

Because air filters, exhaust systems and altitude vary, your jetting and adjustments may vary.

 

sounds like a good tuning guide. I haven't done anything with the carbs yet. I imagine you have to take the carbs out and open them up to do these adjustments, except maybe the air screw adjustment and the needles. I'm going to be diggin in because mine just started sputtering, backfiring, knocking, and stalling, all since i pulled the airbox off to find a couple screws I dropped.

thanks for posting this guide,

nathan

Because air filters, exhaust systems and altitude vary, your jetting and adjustments may vary.

 

#48 pilots will help with decel popping. They fatten it up on closed throttle decel.

They also fatten up the low-speed, from idle and midrange, as the needles open up. It's not really a 0-1/4 throttle thing. These circuits act in parallel. But the pilots have a diminishing effect as the slides pull the needles up.

If you are not experiencing a stumble at part throttle, ~3k, I would change the pilots only, then see where you are.

Not arguing. It's all good advice here. Just a slightly different perspective.

 

i'm on the stock pilot jet bandwagon ( just like greg states ). i went up to 48 and ended up closing the a/f screws. the next carb pull i dropped back down to the 45's 2.5 turns out. ( a couple hundred feet above sea level ).

i went up because i overlook a very slight vacuum leak, self created


tim

 

I'm down with that.
I was pointed in that direction for decel popping (PAIR was blocked off).
A shim under the needle should fatten it up a bit at closed throttle, as well.
Incremental changes are good.

 

off idle lean is an odd thing because there are a few directions to go... increase pilot jet, shim the needle or decrease the slide spring tension.

which solution is best ? who's to say, each probably has it's +/-'s

tim

 

So.. Do I try shimming it? Or do I just live with it? Or do I Jet it?

Any recommendations?

Thanks![/QUOTE]

here's my 2 cents. I took mine apart yesterday because I dropped a couple screws(front right airbox lid) and when I put it back, it was doing the VTR boogie(sputtering, backfiring, stalling, pulling choke out to get it to run smooth--on road,it ran good).

What I found, not the screws-where can't I get these?
seemed like the gasket on front carb may have been sucking air or leaking something based on how it compared with the rear carb(dry). I coated with K&N air filter grease lightly since I didn't have new rubber gaskets.

I wasn't putting it back together without doing the deal, so:
TPS out of spec so far I had to turn it 1/4" past mounting holes to get to 500 ohm. Drilled new hole in mount plate and wire tied the other mount.
took air mixture screw out of bottom of carbs with a modified tweezers and slotted with dremmel for screwdriver adjustment-set at 2 1/4 turns out.
removed needles and removed washer under needle and replaced with .40 washer. Started it up and now it's doing the "good vtr boogie"-cold start up good, no sputtering, backfiring, stalling. On the road, strong all the way through the rpm range. yeehah!

thanks, nathan