Jets and tranny

[OneHand]

Hi

Will a larger main jet affect the idling/low rpm circuit? (79F - capped pilot)
Currently running std jets (137.5 and 42.5) with a 4 in 1 and aftermarket filter and drilled airbox. I assume that it's running lean because of that, but dont have a colortune to check.

Vader still has a slight hesitation under 3K, and feels like starving when I close the throttle, coast a while and open to accellerate again at low revs ( under 3K). Should I try air pilot screw out by 1/2 a turn or so? (currently 1&1/4)

Also, 3rd to 4th shift (and back) is (sometimes only) much chunkier that the rest. If I go a bit harder, say more than 6 or 7k rpm, I sometimes hit a false neutral. Question : Can I break something (appart from my neck!)if I ride it with the chunky shift, or will the tranny have to come appart sometime?

Rgds
1H

[skids]

In older model carbs, yes, larger mains can affect low and middle range richness.

[mro]

Above 3k engine pulling good?

Before changing to larger mains would adjust pilot. The 1 1/4 out is a good starting place.

Then recheck float height. Early carbs can be set just below 27mm and still be in spec as per Yamaha manual.

If set at 25mm would try 26, then up to 27mm.

"Higher" setting will enrichen it some.

reading spark plugs
http://www.xs11.com/tips/maintenance/maint21.shtml


mro

[DiverRay]

The third to fourth shift is a known problem with the bike. Just be sure the shifter has returned to a neutral position, and shift firmly up and down. You are moving two shift forks on that shift, so it is a little slower.

[Pat Kelly]

I thought this thread was reviving Joe Namath wearing pantyhose......

[TopCatGr58]

Hey One Hand,

The Pilot jet is a fuel jet, not an air jet, and turning it out allows more fuel to flow thru the circuit, just didn't want you to get confused with what you're doing when you turn it.

Secondly, clarification on what MRO said, if it's running lean, then you would want to set the floats LOWER when they are upside down, less than the stock 25mm height. MRO said to set the floats higher, but he means when right side up, and he's talking about the position of the floats, not about the float height being set higher, going from 25mm to 27mm will be setting it leaner.
T.C.

[OneHand]

The full story...

IIRC, floats were set at +-28mm when upside down as 25mm did not work at that time - had a bad pickup and rotor. Havnt changed it since. Was also bench synced as close as I could.

I dont have access to a vacuum sync or colortune, so have to go by ear. Idles fine right down to 900rpm when hot, but is currently set at about 1200rpm, as it keeps dying when cold.

It pulls fine after 3k, with it really coming on steam after 4.5k.
Havn't checked the plugs since the pick-up fix, as I've only done about 300km (I know..Its a shame!) since X-mas. Think I'll play with the mixture screws a bit before taking the carbs off again. I want to put the 140's in, because IIRC it had better pull in the mid range when those were in.

Then... got only 160km (100mi) from full tank till having to go on reserve. I can hear a lot of gas sloshing around, but it feels like its starving... Bad petcock maybe? I can't believe that the consumption can be that BAD!!! Can't find any traces of gas leaking any more, but it has been standing about a month with that gas, only commuting one or twice a week. (Bad weather)Any ideas?

[skids]

Re: The full story...

Once, I pulled the petcocks off of the tank and they were full of gas! They were not leaking through the screens. They looked clean. I shot them with carb cleaned (with fear that it would eat the plastic) and it solved the problem. Another problem might be the vacuum hose and/or that portion of the petcock. Unhook the gas line and rout it to a container. Suck on the vacuum hose to open fuel flow and see if fuel flows (Oh I just know there will be some wise cracks here!).

Originally posted by OneHand

Then... got only 160km (100mi) from full tank till having to go on reserve. I can hear a lot of gas sloshing around, but it feels like its starving... Bad petcock maybe? I can't believe that the consumption can be that BAD!!! Can't find any traces of gas leaking any more, but it has been standing about a month with that gas, only commuting one or twice a week. (Bad weather)Any ideas?