Cold #3 exhaust pipe...

[hikermikem]

I've noticed the #3 exhaust pipe on my "81 (16V) 750L stays stone cold for a little while at start up. Haven't noticed a missing cylinder while riding really, but still, why so cold?? It eventually gets hot, but the color of the pipe isn't the nice golden hue as the other three, so I guess it never gets up to the same temp as the others. No complaints about the running of the engine however.

Clean carbs, recent valve adjustment, no air leaks, there's spark to the plug & the plug has good color...

Only thing I can think of is, the bike had sat for quite a while before I got her and maybe the valves have seated at bit more no that she's being run. I'm planning on checking them all again to verify (gotta love them 16V engines for that) but was wondering if you guys had any words of wisdom??

Thanks,

Mike

[Steve]

Are you using the 'choke' while you notice that #3 is not getting warm?

Could be that the pick-up tube in the float bowl is clogged, not allowing that carb to richen up like the others.

When the engine is warm it's not needed, so operation would be smooth.

.

[hikermikem]

Are you using the 'choke' while you notice that #3 is not getting warm?

Could be that the pick-up tube in the float bowl is clogged, not allowing that carb to richen up like the others.

When the engine is warm it's not needed, so operation would be smooth.

.

Yes, choke on... clogged tube, that's a good guess (you're talking about that little brass one that sticks out from the carb body into the float bowl, right?)

Hopefully I can remove the float bowl & get at that tube with a small pc of wire without removing the carbs. What a giant PITA to remove those off this bike...

Tomorrow I'll have a go at it...

thanks

[Nessism]

Are you using the 'choke' while you notice that #3 is not getting warm?

Could be that the pick-up tube in the float bowl is clogged, not allowing that carb to richen up like the others.

When the engine is warm it's not needed, so operation would be smooth.

.

Pretty good guess here I think. Those choke feed tubes are pretty small. Hope this pans out for you Mike.

[hikermikem]

Pretty good guess here I think. Those choke feed tubes are pretty small. Hope this pans out for you Mike.

I agree, makes sense considering the bike runs fine after warming up...

Pretty smart guy that Steve

[Steve]

Yes, choke on... clogged tube, that's a good guess (you're talking about that little brass one that sticks out from the carb body into the float bowl, right?)

Yep, that's the one.

After poking with a wire, activate the 'choke', use the little nozzle, spray some carb cleaner through the tube. Activating the 'choke' will move the plunger and give that spray somewhere to go, maybe flushing the crud out in the process. Once the crud is out of the little tube, it should continue through the carb into the cylinder with no further obstruction.

.

[tkent02]

Also make sure the passage in the bowl itself is clear, the one that supplies fuel to this brass choke tube, it commonly gums up on bikes that have sat.

[Steve]

Also make sure the passage in the bowl itself is clear, the one that supplies fuel to this brass choke tube, it commonly gums up on bikes that have sat.

Yeah, and when you spray into it, be sure to be wearing your safety glasses.

Carb spray in the eyes HURTS.

.

[tkent02]

Yeah, and when you spray into it, be sure to be wearing your safety glasses.

Carb spray in the eyes HURTS.

.

Not as bad as brake fluid, and nowhere near as bad as battery acid.

[TheCafeKid]

my first GS carb cleaning experience included carb spray in the eye. For a second I thought to myself "Yikes that sucks." Then it went on to include my thought that my eyeball was actually MELTING out of my head. Its exquisitely painfull. Fortunately, ive never yet had brake fluid or battery acid in the eye thus far, lets hope it never happens. I know i SHOULD wear saftey glasses, but sometimes....well im just gonna do this real quick, and the glasses are WAYYYYYYYYYYY over there....heh..

[chef1366]

Did you sync the carbs?

[hikermikem]

Also make sure the passage in the bowl itself is clear, the one that supplies fuel to this brass choke tube, it commonly gums up on bikes that have sat.

yeah, I've cleaned a few sets of these CV carbs now & I make it a point to be certain both that tube & mating bowl passage are free & clear afterwards. However, maybe a really stubborn spec-o-crud got lodged there after my best efforts...

I'll mess with it today & see if I can affect any change without removing the carbs from the bike.

[hikermikem]

Yeah, and when you spray into it, be sure to be wearing your safety glasses.

Carb spray in the eyes HURTS.

.

Yup, had the "pleasure" of that experience a few times over the years, and you're right, that bowl passage somehow ALWAYS shoots right back at your head.

(I usually remember that immediately after spraying the first one )

[hikermikem]

Did you sync the carbs?

Yup, sync'ed them at 4K and that made a marked improvement in vibration at highway speeds, as compared to sync'ing at idle...

[steve murdoch]

Not as bad as brake fluid, and nowhere near as bad as battery acid.

...or suicide chicken wing sauce...i had to sit at the bar with a shot glass full of water held against my eye just to finish the wings and beer. Not a proud moment.