New member NEED CARB HELP!

[metricbiker]

Hello all! Glad to be a part of this site and back on an XS. I owned one in the past and gave it to my brother and he loves it. I just bought another XS this week and need help.

I just bought an 81 XS1100H. I verified the frame and engine number with resources on this site. It is the touring model but does not have the fairing boxes and sissy bar. It does have the oil cooler which is awesome for the Arizona desert and a beefy suspension which will handle all of my travel needs.

So for the problem......

Between 4k and 5k rpms in every gear the bike acts like its hit a rev limiter. Also when the throttle is past half it does the same. Starts and idles great right at 1100 rpms, revs fine in neutral. In fact ive never seen an XS idle so well. So basically when its time for the main jets to kick in the bike loses all power and just stutters like crazy. I have no other choice but to drive it right now and babby it to 4k rpms max in every gear.

The PO took out the air box and added pods. K&N pods and I know they arent blocking any of the carb ports. Also the mufflers were cut off and welded on straight pipes and yes they are baffled so I have back pressure. It seems the octopus is gone as well, fuel lines stright to carbs.

So i went to my mechanics house today (he has a full bike shop in his garage and is a great mechanic though hes not an XS expert he has the know i need combined with this site) we pulled the carbs and everything is as clean as a whistle. No gunk dirt clogs gumming or anything. I mean someone did a great job on these.

The problem we found is the main jets are WAY too big! Its has 132.5 main jets all the way across and the stock sizes are 115 for the outers and 120 for the inners. Also there are no plugs on the pilot jets. Are these 100 percent necessary? Im confused as to whether or not the pilot plugs are rubber or metal or does either work? without the plugs right now it starts and idles fine. pilot jet is 45 instead of 42.5 stock. that shouldnt be a big deal. my inner jets are 12.5 bigger and the outers are 17.5 bigger, what a joke. The jets say " A D" whatever that is and they need to go!

I am putting the stock airbox back in. Pods are way more hassle than they will ever be worth. I wish the exhaust was stock but its what i have to deal with for now. I hate when PO's get dumb ideas and ruin a perfectly good thing.

the igniter box and coils are fine. brand new plugs and battery and the plug boots are clean and i snipped some wire for good contact. Fresh 91 gas with a little sea foam. the bike is super clean.

This is my only vehicle and i desperately need the right main jets and maybe the washers just in case. I also need some pilot jet plugs just in case. I would rather have what i need/dont need than not. i wanna pull the carbs apart as little as possible and start with this blatent problem before going anywhere else.

If someone has these that would be amazing! I will pay and pay for priority 2 day or overnight shipping. Or knowing where i can get these asap !

Thanks,

Tim

[metricbiker]

also the intake boots are brand new.

[fredintoon]

Hi Tim and welcome,
the giant main jets are for the '79 & earlier carbs because those carbs also fed the pilot jets through the main jets.
The '80 carbs feed both jets through the bowl so use wall to wall 115s and DON'T plug the pilots.
Your bike is a Standard and the dreaded octopus was only on the Specials.
Stock Standard gas taps are vacuum operated and don't use a central vacuum cut-off.
You can hacksaw off the straights and use any kinda slip-on you can find at a swapmeet.
Perhaps your PO was driven by necessity when the stock mufflers rusted out?

[metricbiker]

Arizona bike. no rust. Someone had the grand idea it needed pods and exhaust. I dont mine the stright pipes at all since they are baffled. when i can i will just find a stock set.

I am putting the bike back to as stock as possible but im stuck with these pipes for now. they sound great actually. i want em a bit louder so i can just cut the baffles a bit but will keep them because i know i need the backpressure.

I just need to know where i can get these jets asap!

[jjz28]

here is http://www.motosport.com/cruiser/oem...00/CARBURETORa site that has them, I am sure there are more places too. Well it has the 120's. Out of the 115. I am pretty sure if you google them, you will find them though.

[metricbiker]

will the jets listed on mikes xs work?

[bikerphil]

will the jets listed on mikes xs work?

Yes they will, as long as they are the "large round type".

[DGXSER]

Ok, just to play devils advocate, are you certain you have the newer style carbs and no the older style? Is ther 4 holes in the inlet bells? One or two sets of Ts (lower only or upper and lower each side)?

Only ask as those to can be swapped out. As Fred indicated, if your running the newer style carbs, you do not need the plugs in the pilot jets. Well, even that can be tricky, you need to remove the emulsion tube and see if there is a crossover hole drilled between the main jet tower and the pilot jet tower. If none exist, no plugs required.

Those mains do sound huge for the newer style carbs! Go to your local Yamaha dealer or any bike shop, they can order the "large round Mikuni" jets you need for you, about $4 a piece IIRC.

[metricbiker]

ordered. got 2 x 115 and 2 x 120 to go stock. cant wait to get them and put the stock airbox in and feel it go! also got some washers just in case.

If it wasnt for all the info on this site i would have been lost. i was able to to eliminate so many factors and when i opened the carbs it was like theres the problem. AWESOME!

it amazes me how someone could open up the exhaust a bit and throw on some pods and think going up 17.5 and 12.5 in jet sizes would be necessary.

[metricbiker]

yes 4 holes, braces on each side, idle adjuster towards engine. newer carbs

[natemoen]

Should only be 3 holes in the inlet cell on the newer carbs.

Are you counting the oval shaped opening at the top? Or are there 4 smaller round openings on the sides, 2 on the right and 2 on the left.

[metricbiker]

just as in the identifier guide on the site it has 4 holes plus the oval on top, two supports railes one on each side, only the fuel tees, idle adjust towards engine.

[petejw]

just as in the identifier guide on the site it has 4 holes plus the oval on top, two supports railes one on each side, only the fuel tees, idle adjust towards engine.

yep thats the later model carbs.

[DGXSER]

Definitely later model carbs, good work. Now, do the bowl drains have a bottom bolt or a side screw? The side screws were an 81 change. The only reason I ask is there is the "bastard" 80 carbs that look just like the newer style and are identical in every way, except that they have the crossover of the older style carbs from the main to the pilot tunnels. Those need the rubber plugs installed over the pilot jets, but still get jetted the same as your planning.

My best guess is that the PO tried to run without the baffles and wound up with that big of jets before he finally realized he needed some back pressure and put the baffling in place.

[natemoen]

Don't know why I had that backwards in my head, sorry.