Main Jets

[RKevin]

New member here. I just bought a 100% stock 1980 XS11 with 5900 miles, after clean up it's beautiful! I started it with seller and we put it on my trailer, I brought it home and tore it down. I've gone through the carbs and ready to put the bowls back on. The service manual and info here says the main jets should be #110 for carbs 1 and 4; #120 for carbs 2 and 3. It came with #110 in all 4. The exhaust pipes are pale straw or pale gold color at the first bend. I don't plan to ride it hard, I'm 64 and haven't ridin in 42 years. #120's came in carb kits, so I can install. What would you guys do?......leave all 4 at #110 or put #120 in 2 & 3? Thanks

[cajun31]

New member here. I just bought a 100% stock 1980 XS11 with 5900 miles, after clean up it's beautiful! I started it with seller and we put it on my trailer, I brought it home and tore it down. I've gone through the carbs and ready to put the bowls back on. The service manual and info here says the main jets should be #110 for carbs 1 and 4; #120 for carbs 2 and 3. It came with #110 in all 4. The exhaust pipes are pale straw or pale gold color at the first bend. I don't plan to ride it hard, I'm 64 and haven't ridin in 42 years. #120's came in carb kits, so I can install. What would you guys do?......leave all 4 at #110 or put #120 in 2 & 3? Thanks

From the factory they came with the 120s in 2 and 3 to make those run cooler then the outer two. It was a good idea but the temp difference does not prove the theory. You will be fine with 110s across the board. I run all of mine that way. I own three midnight specials. The big thing concerning the carbs is to make sure they are tuned in properly and synched. As for aftermarket kits you don't want to use the jets from those because they are generally not made by mikuni. Only use mikuni jets ... period. You will have far less problems getting the carbs tuned. Not saying it can't be done it is just far easier with original mikuni jets. What kind of exhaust are you running. The reason I ask is because it sounds like aftermarket because the originals that came on these bikes were double walled on the headers and you rarely saw pipe discoloration unless the bike was running way hot. Gold is not too bad. When you see them dark blue you are running way too hot. Good luck on the bike and if you need more help just ask. There are many members on here that are more then willing to help with any problem you might face.

I just wanted to add one more point. Be sure to read the tech tips on cleaning the carbs. It may have already been done by the previous owner but is something I always do anyway. If you do clean them be sure to measure the pilot jet screws before removing them. What I mean by that is you will want to turn them to the right and count and record how many turns you go before they each lightly seat. You can then put them back there when you reinstall them. You will notice in your carb kits, that is if you bought complete carb kits, some new pilot jet screws with the small springs, washers, and small rubber o rings. On the older carbs if they have never been rebuilt those o rings will be hard and brittle. The tech tip goes through all of that and is a good read regardless. You will learn a lot by reading through it.

[LAB3]

I'll agree with sticking to genuine Mikuni parts, use the gaskets and orings out of your rebuild kit and toss the rest of what came with it.

[cajun31]

Carb Cleaning 101 - XS11.club Forums

[RKevin]

Thanks Much "cajun31" and "LAB3", 110"s it is! Bike has stock exhaust system. All 4 pilot jet screws were at 2.5 + - .1 turns and put them right back. I'm making the carb sync set-up from this site. Just got my 4-way valve, already have a good vac gauge, looking for a piece of 4" PVC now.

[motoman]

RKevin, the Special and Standard used dfferent metering rods as in taper and overall length(marked with letter/numbering at top on the side of each metering rod), which also required the use of different main jetting for the Standard and Special. This being done at the factory is what made the Special a bit quicker response and was called the "bar hopper" as opposed to the Standards less abrupt response which made it a bit smoother accelerating when riding long distances

[Radioguylogs]

My 1980 XS1100SG (Special) came with #110 mains on all four cylinders.

[motoman]

My 1980 XS1100SG (Special) came with #110 mains on all four cylinders.

.........as did ALL the 1980 Specials from the factory.

[jetmechmarty]

I have a Jardine 4 into 1 exhaust on mine with a K&N filter in the airbox. It runs happily on stock jetting. It has over 100,000 miles and it starts and runs like a new bike.

[cajun31]

.........as did ALL the 1980 Specials from the factory.

Brant ... I beg to differ. My 1980 new to me LG came with 120's in 2 and 3 and 110s in 1 and 4. I have run across many special carbs stock with the same configuration. Carburetor Facts - Models and Jetting - XS11.club Forums

[motoman]

Brant ... I beg to differ. My 1980 new to me LG came with 120's in 2 and 3 and 110s in 1 and 4. I have run across many special carbs stock with the same configuration. Carburetor Facts - Models and Jetting - XS11.club Forums

Interesting cajun31, thanks for added info.

[RKevin]

Update: I didn't change any of the jets, 110's went back in. Floats with new Needle & Seats set at .900". Engine idles perfect....sooo smooth at 1000 rpm. 42 years of not riding, then taking it out for the 1st cruise.........what a Rush!!!! .........Oh the acceleration!!!!!!

Thanks Everyone.......Kevin

[DiverRay]

You want a rush, put the bike in 5th gear at about 30MPH, and then just twist the throttle! You will then know what the bike is known for.

[RKevin]

Since we're talking carbs.....I can't believe all 4 carburetors breath through this tiny air snorkel tube that runs under the seat. It's cross section appears to be the size/area of just one carb! I see several mods that eliminate the stock air box and then add individual filters to each carb. I have not found any performance comments after this modification is completed. Can anyone comment on the stock vs individual air filter mod? Seems like it would be Huge, after re-jetted properly.

[DiverRay]

Most don't need to go up more than one size for the pod filters. What I did was drill three 1" holes in the CENTER of the lower cover. The dirty side of the air cleaner is the inside, so drill as you need it. And yes, not much of a gain, but you hear the intake a little more....