Need to rant about carbs

[ruffrider]

I thought I almost had it dialed in and probably should of left well enough alone. I'm losing track of how many times I've had carbs off. Must be at least 5 times. Set plastic MikesXS floats to 23mm above gasket (in place) surface. Still ran lean, which leads me to believe that you should measure without gasket which is about 1mm difference. OK, so then I thought gee whiz I'll set slide needles one notch lower than middle (to raise needle). Did that with carbs still on bike. What fun! It actually helped some but still ran lean. Next, hank carbs off once again and set floats 22mm above gasket. Reinstall...much better but still lean at WOT. Now at least the bike would rev up past 6k and get close to redline. So, briliant me thinks to raise slide needle up one more notch, ( did this with carbs on bike.. way more fun), and now it runs like crap! Should've left it alone and been satisfied cuz it was rideable. But oh no, its got to be perfect. Probably need to set floats at 21mm. Has any one gone this high? Upside down low?!? I'm not only ranting I think the gas fumes are getting to my brain. Now I'm thinking I should set slide needles back to normal middle notch also. Any advice is appreciated. Also, thanks to Prom for the great compression check tips. All cylinders read good 140 psi+. These carbs are really fussy and driving me mad. Well at least I'm on strike and have the time now to mess with it. Hopefully, the next time will be the charm. I'm not only ranting I think the gas fumes are getting to my brain

[trbig]

You are correct. Float heights set with gasket off.

Quit sniffing the gas fumes so much or you'll end up like our poor Promiscuous.. err.. I mean Prometheus.


Tod

[Jeremy_Sells]

Describe the condition that you are having that makes you think it is running lean. With only 10.5K miles, have you changed/modded anything else on this bike besides the carb settings?

[trbig]

Better yet...

Go out and buy some good beer, and some good meat. Bologna/ hot dogs doesn't count. Most guys are carnivors. Offer it up to whoever could come help oversee this and maybe give some pointers. Might learn something AND find a riding buddy. It looks like you are in an area for some XSellent riding.


Tod

[ross]

been 2 carb h*ll and back...

hey there ruffrider....i feel for ya brother......been there done that.....and will probably do it again to make her run right....thats the problem, it's like a sickness with no cure, but to get the d*mn things to run right.....below i'm linking the posting i had doing mine....it also shows how i checked the fuel level in the bowls before you put them back on the bike...(saves needless teardowns, swear words, lost hair, and lastly, time!).....i know it's crude, but what the f*ck, it seemed 2 work for me....if ya need more info about it, feel free get ahold of me....hopefully i can help online, because you DEFINITELY do not have enough beer, steak, or strippers (well, maybe strippers) to get me to ride over to help ya fix it....good luck and may the force be with you....may your gas tank always be full and your petcocks turned "on"...talk 2 ya later...ross

http://www.xs11.com/forum/showthread...threadid=17116

[tarzan]

Hey ruffrider,
Welcome to the club.I've had mine off at least 4 times myself.
You do have to make sure all passages and everything inside is clean and clear.Check your floats to see if they are cocked to one side,they have to be stright so both side measure the same.I didnt read if you put kits in your carbs but I know good needles are important also.Just take your time and be thorough and you have it running right with perserverence.Good luck.

[TADracer]

Ruffrider, I know you will not want to hear this because it means pulling your carbs off again but.......sometimes it is best to just start from scratch since changing over changes can make you lose track of where you actually are. I was in your situation several years ago and here is what I did.

First, make sure you have the correct spark plugs in. NGK BP-6ES or equal since heat range can affect the read of the plugs. A hotter plug will may give a lean read on the plug when you are not actually lean.

79SF float height should be 25.7 from the gasket surface (no gasket) for the stock brass floats. I am not sure what impact the plastic floats have but a MM or two should not affect you that much. I run mine at 27MM which puts the fuel level a bit lower than stock with great results (my carbs never leak). Measure both sides of the float from the gasket surface with, and this is important, the float resting on the spring in the needle valve. Do not push the float down and measure because that will make your fuel level really low in the bowl.

Set your needles back to the center notch, make sure you have stock jets in both main and pilot locations, gently seat and then open your idle mixture screws 1 1/4 turns out and then start tuning your carbs with these settings.

I have tuned from the top down. I know it is a PIA because you may have to remove the carb rack a few times but, you can actually hit it right for all RPM speeds. Then, write all your settings down for future reference because as long as you do not make any changes to your bike, such as air filters, exhaust, cam timing, etc. you will not need to vary from the tuneup.

Here is the web address for how to tune from top down. http://www.factorypro.com/tech_tunin...m_engines.html

Worked for me. Have fun.

[psycoreefer]

Your just getting started....

only had the carbs off 5 or 6 times? I've had mine off at least 2 dozen times and I've had the bike for less then a year. Its not really that big a deal to pull them off, I mean really its like 7 screws and a few wing nuts. I can have mine off in like 5 or 10 minutes, apart and adjusted in another 10 and back on the bike in about the same time it took to take them off. All and all its about a 30 min job to make an adjustment. Then after a short ride if it seems like there was an improvement I'll spend the extra 30 mins or so to adjust the idle mixture and balance the carbs.

Keep at it a few more times and you'll have your technique down. Then it will get faster and faster. The pay off is when you finally get it running just right, that feels good knowing you did it all yourself.

I'll also second what was said by TADracer - It might be time to start over from stock. You shouldn't need the needles raised that far or the float hight so high unless you've done some major changes to the intake/engine/exhaust.
I went through all this with mine and now I've got +1 size main jets and floats at 24.5mm, but I've still got a little stumble just off idle so I'm not finished. Its just that you get to a point were everything is so far off that your chasing your own tail trying to get it right.

[ruffrider]

Thanks one and all

I'm ready to tackle the rascal one more time. Hey Tadracer, I do have the correct plugs as you describe. My big misstep me thinks is when I raised the needles to high. All jets are stock and air box is stock. No mods except muffs are not stock. 4 into 2 stock headers tho. I'm going back out to the garage now to make adjustments. Needles back to middle and tweak the floats some more. The reason I know its still lean is the plugs were bone white when I started with plastic MikesXS floats at 23mm above in place gasket surface. Big improvement came at 22mm with plugs showing slight tanning and bike would rev past 6k but still hungry for more gas. Tally ho here I go!

[ClarkGriswald]

I agree, go back to stock as much as possible. Even a stock air filter and tape off any extra air holes. Stock is always the best reference point and certianly the most reliable/stable state if all is working right.

Im not sure what all this triple clean stuff is about. If its not perfect like a new carb then its not clean. It pays to be anal about that stuff, I dont think just carb cleaner and air is enough. I used mothers polish on pipe cleaners to go as far into any port/channel as I possibly could, not trying to polish it like a mirror but remove the chalky corrosion that you know is in there at some level. Thats all it takes to provide a little resistance to flow even if its not decreasing the inside diameter. Granted you better be able to blast out the polish residue that may get even deeper in (the bends and points where ports/channels meet and the blind plugs). Detergent degreaser like purple or the green stuff, will break down polish and wash it away pretty well so I shoot that in there and blast it with air back and forth.. I finally end up with my carbs in the kitchen sink soakin in hot dish water. (after soakin in gunk tank, then all that crazy tiny scrubbing and reamin holes). You have to figure that in all the lower portions of these "hidden" areas there is deposits of whatever. Those are the bottlenecks that could drive anyone crazy tryin to troubleshoot.

Brass thats been cleaned off with carb cleaner isnt clean enough as far as im concerned. It should be polished like a mirror. A Q-tip and some metal polish will get in both sides of a jet (or emulsion tube) and not usually make it thru the actual orifice (polishing the backside and front but not sizing the hole)..

Its too bad that mobile home/rv cleaner is so agressive (etching) or that would be a fast way to clean all that. I would be afraid to do that.

Have you had the banks apart so far to check your throttle shaft seals?? Your gonna be fighting a lean condition forever if they are dried out and leaking air.. they are 2.55 $ a piece on bikebandit. The screws in the butterflies are staked so you have to file the ends first before removing them and loctite em back in or replace with new screws (still loctite or restake). (stainless 3mm)

I imagine that air could also sneak past the tops of the slide rubbers where they set in that groove under the covers if they were bad or a scratch or something, I wonder if there shouldnt be a little oil in that groove like an o ring would have. Would have the same effect as leaking throttle seals.

Just a few rambling ideas. hope it sparks somethin

[psycoreefer]

If you're all stock you shouldn't need to re-jet. Maybe +1 on the mains if increasing the float height doesn't color up your plugs. If it pulls hard to red line I might just leave it a bit lean up there. Be honest how much time to you spend WOT above 6k rpms anyways? If its not much and you've got stock jets I wouldn't worry about it being a little lean.

I've got the mikes plastic floats in my 79 and it seems they like to be set a bit higher then the brass floats. Mine ran well with the brass floats at 26ish but didn't like the plastic floats at that height. I went all the way to 24mm and that was to much, backed off to 24.5 and that seems about right, at least for me. Of course your numbers will be different cuz your measuring off the top of the gasket and I removed mine.

[ruffrider]

hey ClarkGriswald, psycoreefer

I replaced butterfy shaft seals after soaking carb bodies in cleaner. Oops! It actually didn't eat them up but I replaced anyway. Wow, you are pretty anal about cleaning. Mine should be clean cuz I soaked each carb for 1 week each in cleaner and blew em out real good and have gave them the once over each time I have em off. I just got the bleeders and other stuff to do the clear tube fuel level test before I change float height. Send good vibes. Thanks, Ruffrider

[ClarkGriswald]

Good vibes transmitting.. Wish I could do the tube thing, my #1 carb has been molested by some monster.. (or some horrible accident most likely) and doesnt have a drain fitting on the bottom anymore (or a bottom, its jbweld).

[ruffrider]

Hallelujah! Finally got it right. Carb update

Yes,Yes,Yes.... by George I think I've got it!
Well fellow XSives all the good advice on this forum has finally paid off. I did the old tubular in the clear float level check and ended up at 21mm or 27/32nd's above gasket. The level ended up right about washer level of float bowl screws. Instead of gas I used water cuz its less stinky and my addled brain needed a break. A silly millimeter really makes a differrence. Remember Virginia Slims? After blowing out carbs and a mysterious missing float seat needle in #3 ( I must of blown the thing out with air... didn't think that was possible) & recheck float height one more time it was time to reinstall. Now I'm not quite as fast as Psycoreefer, but I'm getting better. Fired right up and sputtered a bit from left over H20 we went for a jaunt. After a bit of coaxing she started to run decent and then good.

[TADracer]

Glad to hear it! Persistance pays off every time.