1986 Sportster Carb What is this?

[IronMick]

I have a 1986 XL Harley Keihin type carb that i bought on eBay. Going to use it on my 1980. It has the VOES port that i want, and a better fast idle linkage which i also want.

See the attached pic. What is this extra port? The carb arrived with this plugged; i removed the plug for the pic.

This is a slightly updated version of the original Keihin carb that is on my 1980. It arrived with a 155 main and a 52 slow which presumably was correct for a 1986 Evo.

Any ideas about starting jetting for this carb on a 1980? The jetting on the original carb was 160/68 which i changed to 165/68. I have a feeling this carb may need the smaller slow as it has a more sophisticated circuit; but i do not know; so i am thinking of starting with 165/52.

[thefrenchowl]

Hi Mick,

Dunno, could be extra venting to air cleaner or other version of vaccum switch...

Anyway, in my opinion, the Keihin only falls into 2 categories: the pre-1979 which are designed and OK for iron heads, the post-1980 which only deserve to be kept for parts like floats, gaskets etc...the rest, bodies, jets etc can be put without hesitation in the garbage can as they were designed with EPA regs in mind, not performance, hence they have wrong venturis and don't flow half as well as the earlier types...

I speak from experience, probably have 20 of the buggers on my shelves, the only decent ones are easy to identify: all pre-79 are single cable operation AND adjustable iddle mixture screws, not hidden ones under blanks...

I usually run my earlier ones with 75 to 100 iddle jet, 160 to 175 main jets.

All the best from Patrick

[jamman]

Vacumm for the petcock

[ironhead red]

I agree, the pre-1979 Keihin's are a good, reliable, easy to tune carb, for daily riding, & I talked on this in another thread, you can get some performance out of them.

Red

[83XLX]

I answered this question on the "other" thread, so here's a repeat:

The circled port is where the VOES hose on an '83 connects. The '84 and later butterfly carbs added another port at the intake manifold connection flange. They capped the original one, and attached the VOES hose to the new port. I suspect that the capped port was for the California models evap cannister hose.
On a stock motor with stock air cleaner and pipes/mufflers, a 160/52 was standard on the last ironheads. Starting out with a 165/52 is probably fine, too.

I'll add that I don't think it's for a vacuum petcock, as these came along much later. Also, there's nothing wrong with the later Kehin butterfly carbs. A few simple mods and the EPA crap is history.

[ted]

Have the same carb on wife's early 87. That tube has a rubber cover on it. Very easy carb to tune. Works very good on wife's bike.
Ted

[OutlawTexan67]

I dont really know either Mick but I am going to swap my keihin with the S&S Super B and get rid of the Jap crap.

[83XLX]

Originally Posted by OutlawTexan67

I dont really know either Mick but I am going to swap my keihin with the S&S Super B and get rid of the Jap crap.

Better throw your front forks and rear shocks in the trash, too, if you still have the originals. Made in Japan.

[OutlawTexan67]

Originally Posted by 83XLX

Better throw your front forks and rear shocks in the trash, too, if you still have the originals. Made in Japan.

Already done about 3 months ago

[thefrenchowl]

ted

A few simple mods and the EPA crap is history

Not so easy in my view, what do you do then with the awful cast in post 79 venturi that's absolutly useless for high revs/engine response?

It's "built in" untunability...

Patrick