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[aquamantx]

Hello all, Starting a project on a 81 midnight. Think it will take a bit. Will try to get her back as close to new as possible. Current decision is to rering or hope for the best. Stone cold it is #1 65 psi #2 70 psi #3 30 psi and #4 at 65 psi. Adding oil into 3 pushed it to 65. Bike has clocked 65000 miles.

[DiverRay]

How long has the engine sat? IF it's been over 1 year, you probably do NOT need to take it apart! These engines will go for about 150K miles, and if it sites, bad compression is usually buildup behind the rings and on the valves. Pour a 50/50 mix of ATF(automatic trans fluid) and Acetone into the spark plug holes and let it set for two days. Then turn it over with plugs out to expel the mixture and try again. Most of us find it takes about 500 miles of riding to get everything back to normal.
Welcome to the wealth of motorcycle knowledge.

[TopCatGr58]

Hey Aquamantx,

Also, no aspersions on your knowledge, but when you did the Comp test, were the carbs still on...and did you OPEN the throttle to Wide Open?? IF you didn't, then that contributed to your low comp values.

Like Ray said, soak in ATF and Acetone,....or Marvel Mystery Oil....can help UNSTICK stuck rings. Then retry comp test with OPEN throttle. Stock new should be ~140 psi...but 90 or above will work and after putting several hundred miles, retest, and you'll probably find it higher. Just take a look at the Ugly Duckling thread....he experienced the same thing at first.

T.C.

[Bonz]

I second what DiverRay said, soak the rings for a few days via the spark plug hole. I have used Marvel Mystery oil poured straight in the plug holes. Be liberal wth it, a couple of tablespoons per cylinder as it will only go down into the crankcase to mix with the oil. By using Marvel oil, you can then ride the bike with it in the crankcase to further help remove deposits, not so much with acetone and ATF. Marvel oil has been mixed with oil literally for a century in crankcases and will not be an issue when used for this intended purpose in this quantity.

Put the bike on the center stand so the engine is as "flat" as possible to get an even soak. Worked very well on a neglected 80G to free up sticky oil control rings.

[aquamantx]

Bike went down with bad cabs in 07. Been in my shed the rest of the time. Was tested with carbs off. Experience is medium at best. Redid a couple of yamaha 650s but no carb work or rings. Have pulled heads and done a couple of clutches on 76 wings. Had an old xlch so basic bolt stuff back on after bolts vibrated out. Will try to clean rings as suggested. How bad are the cv carbs to rebuild?

[DiverRay]

fairly easy if you've done carbs before. Big thing is CLEAN the carbs. I use an ultrasonic cleaner with Pinesol/water mix, as it will not eat the rubber seals in the carbs, but will get them clean. DO NOT put the carb BODIES into a dunk carb cleaner. You WILL be taking them ALL the way apart to replace the throttle shaft seals, and that IS a pain. do not spend any money on a kit, as all you really need will be new needle and seats, and that is maybe. This should help: http://www.xs11.com/forum/showthread.php?t=39

[aquamantx]

Well have never really worked on them but you must learn new things. Have the carb bank out but they are bad enough that the slides are stuck. Probably a little wd 40 might loosen them. Worried about damaging the diaphragms.
Thanks for the good suggestion on the method of cleaning. I was concerned about killing the old seals with a strong chemical. Where did you pick up the sonic cleaner?

[TopCatGr58]

Hey again,

Aside from the tip Ray provided, IF you're a bit more visual, here's another how to tip a bit newer and it has PICTURES!

http://www.xs11.com/forum/showthread.php?t=36017

For the vac slides, take the TOP caps off, then you can pull up the rubber diaphragms away from the carb bodies....then you can squirt CARB CLEANER downward below the diaphragms onto the slides and the carb slide bores to help break down the gum/varnish to get them loose. Once the top caps are off, you can then apply gentle pressure from the carb throat to push upwards on the bottom of the slides as you spritz them with carb cleaner.

If you want to spend the $, you can get an ultrasonic cleaner from Harbor Freight...I think folks have gotten the smaller one, but they took their carb rack apart to be able to clean one at a time in the smaller sonic cleaner. I think I remember others just using a large rectangular pot/bin and actually boiled them in the pinesol solution since they didn't have an actual ultrasonic cleaner. Hopefully some others will chime in about how they used the Pinesol, I'll do a search and see what I can find. I haven't used it, just carb cleaner SPRAY and a dunking tank for just the loose parts.

T.C.

[aquamantx]

Thanks T.C.
With enough time and money we can accomplish anything.

[BA80]

I've got a set that the slides are so stuck that just as an experiment I tried a 60,000lb press to break them loose............the carb broke.

It's one of my visual aids now.

[aquamantx]

Well i hope they are not that stuck. Amazing what ethenol does to old bikes,

[DiverRay]

I used my 50/50 mix of ATF and acetone on a set that would NOT move. I squirted a little around the slides and left the carbs upside down overnight, and they all came loose with no problems.

[aquamantx]

Well I have started with the carbs. I have a couple of issues to confront. First to break apart the bank for cleaning. Second is the butterfly is stuck on carb 3. Interestingly the fluid (no longer can call it gas ) coming out of the carbs is a nice jade green color. Cylinder 3 is the one that had the low compression reading. plug from that cylinder look ok.

[BA80]

Not really necessary to break them apart. These are on my bike right now and I just replaced the pilots and mains (not necessary but I was changing sizes) and cleaned all the passages and orifices with spray carb cleaner and air.

[aquamantx]

Thanks,
Ill give it a shot.