carb swap/ HELP!!!

[coletrain777]

Hey everybody
Well I just ordered a total rebuild kit for the carbs on my 79 XS1100. I don't know that I need the full kit as the carbs are extremely clean, but since I needed to replace the needle and seat I figured why not treat the old girl right. So today while preparing the carbs for the new kit I decided to remove the pilot jets. This had never been done as the brass caps were still over them. So I took out my drill and drilled away. The first three came out extremely easy but the fourth was another matter. The bottom line is that I believe I ruined the carb trying to get it out (threads for the pilot screw are all gone). So my question is
1. does anyone have a carb body that they could let go of? This is the #1 carb (the one farthest to the left when looking at the back of the bank of carbs).

2. I have read the posts about using the GSXR carbs and I like what I read. Has anyone here done this swap (or any other for that matter) and if so what are the benefits/downfalls. I don't mind doing a fair amount of engineering and spending some cash on the old girl if the swap will be worthwhile. It sure would be nice to have that a carbs that parts are a little cheaper for, and is made from more modern engineering. Not to say that the 1100 carbs are nice, it just seem like they require more maintenance than more modern carbs.
Sorry for the long post but I really appreciate all of the knowledge on this forum.
Cole

[buffalo]

Should be the same as my 78E.. send me your addy and I will dig one out of my parts box and send it to you

[Geezer]

Most likely the drip bit caught the screw and screwed it in so tight that it couldn't be removed.

For future reference put a peice of steel or copper tube over the drill bit so only about 1/8" of the bit protrudes. Then drill out the plugs. This will keep the bit safely away from the mixture screw.

Geezer

[coletrain777]

Thanks for the replies everyone. I just went to the Yamaha parts info site and according to the serial numbers on my carbs it looks like I have carbs from a 1981 XS1100LH. The funny thing is that they still have the older style float bowls on them without the outlet to attach the line to to measure fuel level in the bowl. If you guys have any more info or thoughts about fixing the carbs or about any carbs swaps please let me know. Thanks again

[rover]

Hey, Coletrain, are you sure about your carbs being from an 81 LH? Thos carbs only have one set of tee's, and they are for the fuel inlet. The older carbs have another pair of tee's for venting the float bowls. I have 2 79's, and both have the vent tee's, and the 81's that I have do not. All of them have the drain plug in the bottom of the float chambers. All the 79's have the same floats, that can be measured, and my 81LH has a different type of float. I am not sure, but I think the floats are interchangeable.
I read the thread on setting the newer floats with a clear hose to get the level, but I don't know how high the fuel should be. I would rather use the newer carbs, but I can't seem to get the levels right. I had them 1/2 inch from the top of the bowls, and it ran rich, and leaked when on the side stand. Then I set 1 inch from the top, and could not get a decent idle. If someone reads this, please tell me what the proper height of the fuel in the bowls should be, then I can set other things to get the idle back

[chevy45412001]

carb swap

I've been toying with the idea of installing fj1200 carbs on my xj.Two small differences i came across were.1 the fuel inlet on the fj carbs is monsterous and they work off the push,pull throttle cable set up.The reason to switch for me is they are 36mm openings instead of my 34mm and they are smoth bore flat slides. Little better throttle response and more air and fuel more power. I guess? I did have them on and running but the idle was way to high. But i did not even try messing with them riding season was on.

[Geezer]

Re: carb swap

Originally posted by chevy45412001
I've been toying with the idea of installing fj1200 carbs on my xj.Two small differences i came across were.1 the fuel inlet on the fj carbs is monsterous and they work off the push,pull throttle cable set up.The reason to switch for me is they are 36mm openings instead of my 34mm and they are smoth bore flat slides. Little better throttle response and more air and fuel more power. I guess? I did have them on and running but the idle was way to high. But i did not even try messing with them riding season was on.

I have a set of KZ1000 carbs I'd like to try but the spacing is wrong. These are 34mm round slide Mikunis and would flow more than the CV carbs the XS11 came with stock.

Geezer

[coletrain777]

hey guys
Thanks for all of the help so far (great ideas). Rover, I believe that my carbs are from a 81 LH (the only reason I say this is becuse the casting number on the carb is 4H3-00. When I checkedc the Yamaha site it said that these carbs were off of a 81. The casting number for the other years was different. That doesn't mean the Yamaha is right, but they probably are. I appreciate all the feedback and lets keep the carb swap discussion going. I love the idea of having alternate part sources out there (especially when they are newer and cheaper than the stock replacements). Keep it coming everyone.Rover

[rover]

The casting number you stated IS from an 81 LH, but the insides that you described are from the older style carbs. I am having probs with my carbs, and I would really like to switch to a one or two carb set-up. The four carb set-up is way too complicated. I would rather go through the hassle of making new manifolds than to continue with these carbs. I have two good running 79's and one beat up 81 LH, and so far ALL my probs are with the carbs. I got lucky and got four new old stock diaphragms for the 79 carbs for $16.00 each. But that is the least of my troubles. I am a good mechanic, but I just can not get the carbs to stay working. I can get them to work for a while, then they f@#& up again. I have put new kits in ALL of them, cleaned several times, adjusted and got them working, but only for a few weeks. There has to be a better system. My XS650 carbs work fine, but these 1100 carbs just will not cooperate.

[chevy45412001]

carbs

I have got to be the luckiest xj owner alive. I got my bike 6years ago.it was sitting for two years when i bought it.Put gas in the tank started it up and away i went.I've had the carbs off many times sprayed them with carb cleaner and rejetted thats it.(knock on wood) but not because of problems just me looking for that little extra.Now fuel tank thats another story

[coletrain777]

Yeah, I know how ya feel with all of the carb problems. I can't believe the amount of trouble that can be had with these carbs. Most of the time it is do to leaking needle and seat (or the infamous triple clean). I deal with a lot of other bikes and xs people are the only group that even think about cleaning a carb 3 times. There has to be a better alternative. I would think that any carbs from a large displacement inline four could be made to work as long as carb throat was the same size (34mm?). I want to make it a mission to come with another alternative to these carbs, even though they are great when they work (kinda slow throttle response). Well lets keep going on this and hopefully one of us will get it figured out. Keep the ideas and responses coming guys.

[chevy45412001]

oops

No ivnener 3x cleand anything never replased diafram, man i mean nothing. This bike has run great for the six years i've had it.Carb wise that is.first time i took them off there was 1 inch of rust in all the bowls ,I just sprayed carb cleaner in them put them back on and went riding.This bike is the bomb.pull wheelies race at the drags,take me to work,Take me and the lil women out,This bike does not quit! gotta love it.

[nashville_bill]

Fuel Filters!

I installed fuel filters on my '81 about a year ago and haven't had any carb problems since. If you haven't put the filters in, try them. You might just get rid of your carb problems.

[coletrain777]

I think that you guys are having better luck with your carbs than a lot of other guys. My carbs are spotless, I have always run inline filters, the floats are set to manual specs and they still won't stay in tune. Now this isn't the worst problem as I love tinkering, but the real reason I started this thread is to hopefully get some ideas going about carb swaps. We talk about big bore kits and cams and most other performance issues but it doesn't seem like anybody ever tries to find a carb upgrade. I searched for any info about this and I did find some threads about GSXR carbs, but it doesn't seem like anyone ever completed the work to let us know if they are a worthwhile swap. So what about GSXR carbs, or flatslides, smoothbores, etc? I just like to know what options are out there. You guys are awesome thanks for all the replies, and I would like to keep this an ongoing thread in an effort to help everyone gain as much info as possible about performance and the machines we love.

[chevy45412001]

cab swap

Back to the carb thingy, The fj carbs have the same spacing as our xs-xj's. I dont really want to switch to a push -pull throttle cable setup. Can i run them with my stock cable? Anyone?Tia.