Idle Hangs on My Sprint Exec... Any Thoughts?

[roadweazel]

Cable freeplay is good, chokes are closing all the way. No obvious loose clamps or anything. I'm gonna get some carb cleaner and spray around looking for air leaks later tonight but I thought I'd ask if y'all have heard of any common causes for this issue on the T3s.
Thanx.
Weazel

[sailfish]

On my thumper that would indicate a lean condition so I think that you're on the right track. I doubt much can go wrong in this area but check the function of the idle knob and cable relative to the carburetor linkage, maybe something is amiss there.

[MotT3]

It's always been either the throttle cable or the grip sticking (to the bar or bar end weight ) with me...doesn't take much to keep the revs up !

[roadweazel]

I'll check these and let you guys know the results.
Thanx.
Weazel

[faffi]

In my experience, there are several things that can cause revs to hang up:

Lean mixture - either from missing/wrong air filter, clogged jets, low fuel level in the floats or false air.

Hanging up - butterflies, cables, anything that should move and doesn't properly.

Idle speed - if it's set too high, especially together with a little lean mixture (not falsely lean, but borderline as carbs are often set up for emissions).

Synchronation - carbs out of synch tend to leave the revs hanging until they suddently drop, often enough for the engine to die.

[roadweazel]

I tore into it last night.
No air leaks.
Cable is not hanging up.
Synch is good.
I'm actually starting to think that it too rich. I rejetted and removed the snorkles, already have the pipes and K&N filter installed. I drilled the pilot jets to a 42ish size and I think they're probably closer to a 44 or so. My 'Hanging' is only when warmed up, which works together with my theory.
I'll order some 40s and 42s, install them and see how that goes.
Thanx again.
Colin

[KitNYC]

Put the snorkels back on too. The airbox design is a real pig to deal with in the shop, but it works very well as-is on the road and making any kind of change to its setup is likely to cause you problems. Feel free to make changes, especially if you're starting from one of the setups documented here, but be aware that the airbox is highly tuned and messing with it usually decreases performance.

I don't like K&N's because of their filtering abilities, but that's more of a long-term issue and it shouldn't be affecting you here. The snorkels are part of the tuned system, and putting them back on will likely help.

You should have Keihin carbs on an Exec; it's much easier to move to pods with those than it is with the Mikunis, and it's probably what I would do with a Keihin T3. If you stick with the airbox, though, stick with the whole airbox.

Cheers, HTH,
-Kit

[roadweazel]

The bike runs better without the snorkles, and installing them last night did nothing. The snorks help between 2-3000 RPM but they're costing me 5+ HP and 5+ pounds of torque at 5200 RPM. The blue line is my bike with snorks installed, the red line is with them removed. My bike's actually much happier without them.

I'll get the jets ordered and try a set of 40 pilot jets first. I really feel it's too rich on the bottom.
Thanx again for all of the input.
Weazel

[KitNYC]

Well hell, what are you askin' us for if you got a dyno?!?!

Seriously, apologies if I sounded like I was telling you what to do; that's not what I meant. I meant to tell you what works for most people. And yeah, that hole at 2-3k is exactly what the snorkels fix. A lot of us are willing to give up the 5 horses up top to fill in the off-idle hole, but if you want to go for max power, by all means go for max power!

Cheers,
-Kit

[faffi]

Originally Posted by roadweazel

I'm actually starting to think that it too rich.

Although it defies logic, my revs also hung up when it was running badly rich (overflowing carbs, not enough air for the jets) like it was lean Typically, you'd expect revs to drop rapidly to below idle and then climb back up when it's rich, but for whatever reason my triple didn't. I'd forgotten about it because it's so atypical.