Boorrrringggg Build/Rebuild/Refres&restore

[TopCatGr58]

The last 3 photos in that tech tip show both the brass tube you were referring to, along with the recess/tunnel and the START JET that is pressed into the float bowl(non-removable), the bottom GREEN arrow in the last photo. That brass tube sucks the fuel from the float bowl via/thru the START jet when you pull the enrichener plunger out...it's a direct source for fuel into the carb bypassing the main/pilot jets and their circuits....the START jet dumps fuel directly into the throat of the carb via that LARGE opening in the carb throat that goes up to the plunger and down to that brass tube! It's when that START jet is clogged that prevents folks from easy CHOKE/Enrichener starting when they activate/pull the choke lever!

T.C.

[DiverRay]

Try reading the first part of this. The pics and arrows show the jets and how to find them.http://www.xs11.com/forum/showthread.php?t=36017
Let me know if you need any other pics!

[puskrat]

Time for newb confessions

Appears I'm due to admit I dont' know what I'm doing. To most of you, this is no surprise. Some may be too charitable to say it, but others of you simply HAVE to be saying "seriously?" a lot when I post.

I've bookmarked several pages on the site. I return often to the jets chart, http://www.xs11.com/forum/showthread.php?t=73

We already know I was unable to find the jets I need to order as I made progress through my teardown, and had to be bailed out on that one. But there's more:

I've been assuming 'start jet' is the same thing as 'starter jet'. Google keeps asking me if that's what I mean, so it seems confused as well. My general inexperience is probably why I am unsure about some terminology. I've removed the air jets (8 oclock position), This is the pilot air jet, right? Where is the main air jet? Also, the "Throttle valve" listed in the chart: are there alternative sizes? Is this the butterfly? Ive read several references to throttle seals, but I'm guessing I am kind of caught in a trap of not knowing what I don't know. I took those seals to be located where the throttle shaft goes through the bodies. Oh yeah, and back to the starter jet....IS it the start jet? and where is it? I've used 101 and tech tips to accomplish what I have, but I dont think I've come across a start jet or anything removable on the throttles. I have pilot jets, the 8:00 jets, main jets and emulsion tubes/needle jets out, working on float needles and seats. How did I miss this 'start jet'? One last question that may cause me to slap my forehead.....What is that brass tube sticking out of the carb body in the bottom right corner of the carb body (in the upside down position)?

[puskrat]

update...emulsion tubes (needle jets) extracting. Interestingly, the slides that gave me trouble were in the very same carbs as the emulsion tubes which are resisting. Of course, as expected, these are the carbs fed by the failed petcock. Yay Ethanol. (did I mention Ethanol is theft?) God bless America.

[DiverRay]

No, the early carbs are easier to tune, and will work well on the bike. Just make SURE you have ONLY Mikuni parts in the carbs!

[puskrat]

Yeah, I have 79 carbs. Guess I missed the clip vs. screws difference on the old carbz. thanks again peoples.

i have oodles of carburetion in my parts pile. would it be worth it to scare up some late carbs out of the inventory?

[motoman]

Thanks Phil. Which immediately brings me to my next question. The Tech Tips chart shows main jet size is 137.5. When ordering I find only whole numbered jets, no fractional sizes. should I get a 136 and drill it out? If so, is there a thread where I can get familiar with the practice before I start destroying things? Am I doing this all wrong, and should I wait until I have everything out to try to understand jet selection?

Every 2.5 numbers equals one step, and is the way ALL Mikuni main jets are numbered.
Also, use Genuine Mikuni ONLY!........no aftermarket junk(K&L, RD, etc.).

[3Phase]

At least you're not still bored, are you?

.

[puskrat]

Someone put the early 1978/'79 style carburetors on your 1980 bike. Don't mess up the clip position on the jet needle.

Do your carburetors have the idle mixture screw like I showed in the picture instead of recessed in the tower like the ones in 'Kat's picture?

It may not matter because you can easily change them but do your carbs have brass floats or plastic floats?

.

Yeah, I have 79 carbs. Guess I missed the clip vs. screws difference on the old carbz. thanks again peoples.

[puskrat]

ah, so the question is what are those slides you have. They have a snap ring holding in a plastic retainer for the slide needle.



anyone familiar with these?

that reads like a lob. No, more like tee ball

[3Phase]

so its okay there are no screws there? should i be celebrating? cause i sorta am

Someone put the early 1978/'79 style carburetors on your 1980 bike. Don't mess up the clip position on the jet needle.

Do your carburetors have the idle mixture screw like I showed in the picture instead of recessed in the tower like the ones in 'Kat's picture?

It may not matter because you can easily change them but do your carbs have brass floats or plastic floats?

.

[bikerphil]

The 78-79 carbs don't use screws like the 80-81 type pictured in Wildkat's thread.

[puskrat]

so its okay there are no screws there? should i be celebrating? cause i sorta am

[3Phase]

Ah, so the question is what are those slides you have. They have a snap ring holding in a plastic retainer for the slide needle.



Anyone familiar with these?

Yep, they're for the '78/'79 carburetors:

1978/'79 Mikuni BS-34II carburetor slide and diaphragm. The jet needle retainer clip and idle mixture screw are circled in Green.


.

[Prothec]

Ah, so the question is what are those slides you have. They have a snap ring holding in a plastic retainer for the slide needle.



Anyone familiar with these?