Boorrrringggg Build/Rebuild/Refres&restore

[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?

[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]

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.

[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)?

[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!

[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.

[puskrat]

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!

thanks ray. thats the thread/tip I refer to as 101. Tis how I found the main, pilot, pilot air and needle jets, and also the whole disassembly procedure. irreplacably valuable.

on to topcat's post: after I figure that out I'll try to apply it, but I think two answers are: 1. the brass tube is not the start jet,and 2: i dont need to order/replace start jets.

[puskrat]

"reloading" for carbs?

Final disassembly: Just pulled the last of the floats/pins/needles. (Yes, I went out of order, but I had a reason) You, faithful reader, will remember my left petcock was leaking when I disconnected it from the fuel line, that that same valve was largely disintegrated when i disassembled it, that my right side bowls bowls were tough to pull off, slides three and four were bound up, and that i had gasoil way back at my first oil change last summer. No surprise that number four float needle had to be pried out with a needle nosed plier. it seems to be cleaning up okay so far, but I'll be replacing it. IF I can find a part number. So far I've tried three sources: jetsrus, mikes, and partsreloaded. No one shows a seat speced for a BS34, but jets has a pretty detailed chart of options....perhaps a matching part. Anyone have a link?

As for three more bowl needles/seats: i want to get everything sparkly clean. These are tiny parts with teensy bits. I can soak things in carb bowls, scrub them with teethbrushes, rinse them in more carb cleaner, etc. I am not confident visual inspection will find all the crud. I don't have a sonic cleaner, and i don't want to heat any solvents. has anyone tried tumbling undelicate things like float needles and main jets in corn cob? I've a loaded a rotary tumbler up for polishing brass cartridge cases, and have been mulling over it's applicability for this carb work during the whole process. I see limitations as to WHAT could be polished this way, but no reason thus far not to try it for the smallest, sturdiest items. Thoughts?

and another ask.....does the gineuine Mikuni only rule applicable to float needle assemblies also? Anyone used mikesxs's replacements?

[DiverRay]

Order 4 of these:
http://www.jetsrus.com/individual_parts/KL_18_4652.html
Don't bother trying to clean the old needles!
These are for the '78-79 carbs.
Here is the page I got the numbers from:
http://www.jetsrus.com/needle_valve_...aha_street.htm
pick year from here:
http://www.jetsrus.com/a_jet_kit_str...ion.htm#yamaha
Carb jets from here. Remember, ONLY genuine Mikuni!!!
http://www.jetsrus.com/a_jet_kit_str...S1100_1978.htm
These are for the '78, '79 will be almost the same.

[puskrat]

yes sir
yes sir
and yes sir.

Let's put this mess to bed.

[puskrat]

one more yes sir. left it off

[CaptonZap]

My advice on the corn cob media is do not do it.
If your eyesight is bad enough that you can't see into the little holes as is, then you will miss the little pieces o cob that will get into the little holes. And once they get wedged in, they are a booger to get out.
Get a magnifying glass and a strong light bouncing off a white surface, (piece o paper), and you should be able to see light through all the holes, except the ones in the bowls and the air jet. Compressed air through the passages will tell you that they are clean. I squirt some solvent into the passage, then apply air, and when the mist comes out the other end of the passage like a spray gun, I figure it is clear.
One of the beauties of these bikes is that most faults are revealed by a GOOD visual inspection.

CZ

[motoman]

Final disassembly: Just pulled the last of the floats/pins/needles. (Yes, I went out of order, but I had a reason) You, faithful reader, will remember my left petcock was leaking when I disconnected it from the fuel line, that that same valve was largely disintegrated when i disassembled it, that my right side bowls bowls were tough to pull off, slides three and four were bound up, and that i had gasoil way back at my first oil change last summer. No surprise that number four float needle had to be pried out with a needle nosed plier. it seems to be cleaning up okay so far, but I'll be replacing it. IF I can find a part number. So far I've tried three sources: jetsrus, mikes, and partsreloaded. No one shows a seat speced for a BS34, but jets has a pretty detailed chart of options....perhaps a matching part. Anyone have a link?

As for three more bowl needles/seats: i want to get everything sparkly clean. These are tiny parts with teensy bits. I can soak things in carb bowls, scrub them with teethbrushes, rinse them in more carb cleaner, etc. I am not confident visual inspection will find all the crud. I don't have a sonic cleaner, and i don't want to heat any solvents. has anyone tried tumbling undelicate things like float needles and main jets in corn cob? I've a loaded a rotary tumbler up for polishing brass cartridge cases, and have been mulling over it's applicability for this carb work during the whole process. I see limitations as to WHAT could be polished this way, but no reason thus far not to try it for the smallest, sturdiest items. Thoughts?

and another ask.....does the gineuine Mikuni only rule applicable to float needle assemblies also? Anyone used mikesxs's replacements?

Shell case tumbler highly NOT recommended.........that comes from an avid reloader.........and carb rebuilder.

[puskrat]

Shell case tumbler highly NOT recommended.........that comes from an avid reloader.........and carb rebuilder.

Glad to know
thanks so much

[puskrat]

My advice on the corn cob media is do not do it.
If your eyesight is bad enough that you can't see into the little holes as is, then you will miss the little pieces o cob that will get into the little holes. And once they get wedged in, they are a booger to get out.
Get a magnifying glass and a strong light bouncing off a white surface, (piece o paper), and you should be able to see light through all the holes, except the ones in the bowls and the air jet. Compressed air through the passages will tell you that they are clean. I squirt some solvent into the passage, then apply air, and when the mist comes out the other end of the passage like a spray gun, I figure it is clear.
One of the beauties of these bikes is that most faults are revealed by a GOOD visual inspection.

CZ

Thanks Cap