1980 xs11 special dies with throttle

[skids]

I wonder if you are running at idle primarily with the pilot screws. You crack open the throttle and you are using the mains. I think roll-on throttle depends more on a good pilot jet and circuit.

If you goose it and you get good ignition past that trouble zone of rpms, and you have good ignition at idle, I have a hard time believing that the HT coils/plugs/wires are an issue.

You said you pulled the vacuum advance hose and it seemed to run better. Did you plug off the entrance to the carb? If not, you allowed air in the mix and leaned carb No. 2. You were having issues with overly rich mixtures. When hot, the engine will run richer. Allowing air with the hose unplugged and with it running slightly better might indicate that it is rich when hooked back up.

Make double sure you have the correct pilot jets, even if they are mikunis.

Make sure that the gaskets (if you replaced them) have the holes punched where needed.

Make sure that the "choke" mechanism is working for all 4 carbs.

Are the tabs on the floats at nearly 90 degrees to the valve needles? Aftermarket needles may be the wrong length, causing excessive bending of the tabs for float height adjustment. This can cause inconsistent fuel levels or binding.

When you cleaned the carbs, did you spray into the pilot jet tunnels, ensuring it flows out of the three pin-holes in the top of the carbs?

Are the Main jet needles stock or do you have aftermarket needles? The needles have not been shimmed upwards have they?

I figure that you have already considered all of these things, but these are things that come to mind.

One last thing. I would get the engine warm, and throw in some plugs to check color. Slowly throttle up to where it is having some issues but still runs. Hold it there for 5 minutes or so and kill it. Examine the plugs.

[darylcaribou69]

I'll have to reclean the carbs again. I've boiled them in lemon juice. What is a good soak? Where I can leave them in for a few days and not worry about the metal getting etched or eaten?

[motoman]

daryl, with more input from ya', and I haven't bothered looking at video, those sync screws are WAY outa' wack. Way outa' wack meaning the throttle plates are to far open pulling fuel from main circuit.....not good. Sounds like you've messed with the carb sync screws enough you've gotten things way outa' wack. Re-sync the four carbs just get things close again, THEN re-set idle mixtures. After which, go back and re-sync those carbs. Then again, reset idle mixtures, after which, go back and re-sync carbs again. May sound like a lotta' repetition, but you've gotten mixture settings and sync so outa' wack your totally gonna have to start over with setting idle mixtures then re-sync carbs.

[skids]

I'll have to reclean the carbs again. I've boiled them in lemon juice. What is a good soak? Where I can leave them in for a few days and not worry about the metal getting etched or eaten?

I recommend that you do not soak them. The reason is that it will corrode the throttle shaft seals and any other rubber not removed. The throttle shaft seals removal are a PITA and you risk stripping the tiny screws. I heard that Yamaha has a solution that is kinder to rubber, but then again you have to separate the carbs from the bank...

You can leave the carbs on the bank and you can use carb cleaner spray effectively, but I recommend that you remove the diaphragms as they are delicate and don't spray the throttle shaft seals.

[TopCatGr58]

Hey Again,

Okay, you've already been under the timing cover fixing the PU Coil wires. Sorry it wasn't suggested to take apart the mechanical timing parts ie. centrifugal advance and clean/lube before reassembling. One way you can check Before tearing into it is to put a timing light, disconnect/plug the vac. adv. again, and run engine, and then rev and see if the timing changes/advances. If it doesn't, then that will indicate that the cent. adv. parts aren't moving freely and need cleaning/lubing. It should indicate ~35 degrees adv. at ~5k rpm.

As for soaking the carbs, folks have used regular Pine-Sol in ultrasonic cleaners. Just be sure to get the regular Pine Sol which has a relative neutral PH 6-8, other types are much more Alkaline/Base and that eats aluminum.

T.C.

[darylcaribou69]

Hey all,

I have decided to sell the bike.

Not really but sometimes I would like to. Hooked up the timing light. I get 35* at 5k rpm. So the ignition system seems to be working properly. I'm going to get the carbs torn apart again and cleaned. I bought a cheapo ultrasonic cleaner from Harbor Faithful. It got decent reviews, hopefully it does the trick. If that doesn't help I'm going to assume the pilot jets are wrong. I'm not sure what else it could be. It stumbles through that range. Someone mentioned that maybe the slides aren't lifting with the lower rpm just at wide open. Maybe they're binding somewhere in the carb. I didn't think they were, but I'm no mechanic. I'm going to look again for pinholes in the diaphragms as well. It's cold so I don't really want to mess with it too much at a time. Thank you all for your input.

Daryl

[DiverRay]

Use a mixture of distilled water and PineSol for the cleaning solution. NOT generic, but the real PineSol! Works great, cleans very well and easy to rinse with hot water. And I like my HF cleaner.

[dansmith65]

Not sure if this helps, but it reminded me of your issue. Mostly because someone mentioned diaphragms might not be moving freely.

here's an excerpt that summarises what the post is about:

When you get done CLEANING a set of carbs; you need to do "CLEAN-TUNING" too. You do this by conducting a "CLUNK TEST©."
With the top off ... spring out ... and diaphragm un-seated to its locating channel -- LIFT the brass piston to the top of its travel and let it drop. It needs to FALL!
It absolutely MUST drop ... from being raised-up and let-go ... like a safe out a second-story window! If it chatters down, hesitates, acts like it being hydraulically controlled, is slow, stops and goes ... or, does anything, other than drop ... like a wet bag of cement ... you got a performance problem.

- RickCoMatic

https://www.facebook.com/groups/3826...6078257409604/

[darylcaribou69]

http://www.xs11.com/forum/showthread.php?t=32854&page=3

Good little read.

Going to look harder into ignition and electrics system for now going to take apart and clean the advance mechanism. What precautions need to be taken when doing this? Is it a simple unplug and play? Or is it a process that, as the repair manual says, "should be left to the dealer?" Left to the dealer who won't touch it because it's too old.

After the ignition system is rehabilitated. The carbs will be re super cleaned in the new ultrasonic.

Chasing this issue isn't fun so a more structured approach will keep me sane and find the issue. Eliminating one system at a time.

Thank you for your input.

[darylcaribou69]

How pronounced is a choke needle seal supposed to be? Was just watching a video on YouTube out of boredom and that guy mentioned it. Just realized that mine are quite hard and look worn, im not aure how theyre supposed to be though. If these seals leak it'll give me too much fuel and cause it to stall.

[darylcaribou69]

http://www.xs11.com/forum/showthread...t=Needle+valve

Found this thread on this site. It says that the k&l float needles need a different float height. When the PO got the carbs rebuilt they used these aftermarket needles and seats. This could be causing my issue. My question is, which direction does the float need to be adjusted. Down (closer to the gasket when upside down) or up? I don't have the original parts so I have no reference point. Any advice is appreciated. Thank you.

[skids]

http://www.xs11.com/forum/showthread...t=Needle+valve

Found this thread on this site. It says that the k&l float needles need a different float height. When the PO got the carbs rebuilt they used these aftermarket needles and seats. This could be causing my issue. My question is, which direction does the float need to be adjusted. Down (closer to the gasket when upside down) or up? I don't have the original parts so I have no reference point. Any advice is appreciated. Thank you.

If in doubt of the affects of the plunger pin spring effect, I have heard that some xser's rotate the carb bank when taking measurements to take the weight off of the pins (barely). I have tried the method and IMO it is hard enough to take measurements with the carb body surface horizontal! Did you try and color plugs as I previously suggested?

[darylcaribou69]

The plugs get black after a few minute s of running. I didn't get a chance to clean some plugs up and run them in the trouble range yet. Going to clean things up this weekend. The throat of the carbs also get wet when running.

[jetmechmarty]

If you measure the fuel level, instead of float height, the question will be answered. Somewhere in this forum is info on exactly where the proper fuel level is.

[motoman]

If you measure the fuel level, instead of float height, the question will be answered. Somewhere in this forum is info on exactly where the proper fuel level is.

3mm DOWN from where bowl and carb body meet. This IS the factory suggested method for 81-XJ models.These models have nipple on bottom of bowl to slip a fuel hose over and hold up beside carb bowl for fuel level check with bike idleing, as specified in shop manual. Drain seal screw is on side of fuel bowl.