Rebuilding Petcocks & Carbs

[LoHo]

The scary part for me is the old oil and dust burning off the surface of the engine and exhaust that hasn't been hot in over a decade, especially if one had a gas overflow from the vents as the newly rebuilt carbs find their way in sealing. I keep waiting for a flash, and yes, I clean up the overflow fuel before starting, but the prospect of finally getting her going after so long is hard to resist. After a quick ride, it has all burned off and it's good to go.

[sail4free]

Make sure there is no spark around acetone. DAHIK

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Some things more flammable than others? We don't use acetone much at work but we do use lacquer thinner quite a bit. If the lid is left off, the whole container will evaporate in short order. I suspect acetone does as well?
JIM P.
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[sail4free]

Burning Off Old Oil & Dust

The scary part for me is the old oil and dust burning off the surface of the engine and exhaust that hasn't been hot in over a decade, especially if one had a gas overflow from the vents as the newly rebuilt carbs find their way in sealing. I keep waiting for a flash, and yes, I clean up the overflow fuel before starting, but the prospect of finally getting her going after so long is hard to resist. After a quick ride, it has all burned off and it's good to go.

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Yeah -- I really wish I had stopped at the car wash enroute to Tyler's shop, but I'll be picking her up soon and the car wash is nearly across the street. Maybe I'll stop there on the way home and blast off some of that 12 years worth of crime and corruption. Yet another good reason to run a fan while running in place, eh? (Keep those vapors dissipated.) Keep a fire extinguisher at the ready?
JIM P.
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[sail4free]

MMO or ATF/Acetone Blend?

The ATF mixture is for an engine that has not turned for a while. I remove the plugs and put about 3 ounces in each hole. Let it set for 24 hours, and then slowly turn the engine by hand. Sometimes you need to go back and forth a few times to get it to turn easily. Once it has started, and run for a bit. I shut it down, pull plugs and put about 2 ounces of SeaFoam into each plug hole. Let that set for about 1/2 to one hour, crank engine over a few times, and then re-install the plugs and start it up.
The ATF mix takes care of any light rust, and allows the rings to move a bit. The SeaFoam takes care of any varnish still behind or around the rings so they work almost like new.

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As my bike has been run (after a 12 year sleep) -- at least long enough to sync the carbs . . . and I'll be riding it (gently) home a few blocks before I do anything more, is the ATF/Acetone blend still recommended or should I just do the MMO treatment that Top Cat recommends? Do you start it with that ATF/Acetone in the cylinders(!)? I know some guys are running the SeaFoam with *every* tank 24/7 . . . how much goes in each tankful? (Assuming the exact ratio isn't too critical.) I'm surprised about the caution of not putting ANY load on the engine with MMO in the engine oil -- some guys swear by that stuff too but I'm thinking *any* solvent-based whatever will NOT provide proper lubrication under load.
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Back in the day, we sold some Justice Brother's 'miracle in a can' for quieting noisy lifters. It worked! That stuff sold itself. Not sure what it did *or* how long I would leave it in the engine oil but it was amazing to pour it in with the engine running and hear those lifters quiet right down.
JIM P.
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[DiverRay]

ATF/Acetone is just to free up the engine BEFORE the first start. You do not need to do that on your engine.
You can run SeaFoam OR MMO, your choice. The idea is to get something in the engine that will clean things out. I would think about putting a pint in the oil and running it on the center stand for about 10 minutes or so, with the fan on it. then the oil change, then refill with GOOD oil and a new filter.
If you put SeaFoam in the gas, just about two ounces per tank, about every third or fourth tank is more than plenty. I usually put it in the tank just before parking for a while in place of Sta-Bil, and that is about the only time I use it.

[sail4free]

You can run SeaFoam OR MMO, your choice. The idea is to get something in the engine that will clean things out. I would think about putting a pint in the oil and running it on the center stand for about 10 minutes or so, with the fan on it. then the oil change, then refill with GOOD oil and a new filter.
If you put SeaFoam in the gas, just about two ounces per tank, about every third or fourth tank is more than plenty. I usually put it in the tank just before parking for a while in place of Sta-Bil, and that is about the only time I use it.

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I'm bringing the ol' girl home this evening. Tyler ran her around the block a few times -- says she still isn't running quite right -- "nothing *I* can't handle," he says It's sounding like that initial run with the fan is just to knock the worst of it loose . . . hoping the rest will clean up in the first few hundred miles or so -- after refilling with good oil and a new filter. I'll be surprised if he got the carbs cleaned right the first go 'round, but at least she's running -- and that's enough to keep me inspired to do the rest.
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Before I blame the carbs for everything, I want to check all my grounds and knowing what I know about the pickup (?coil?), I'll be *very* surprised if there isn't some issue there. Can we replace these with a pre-wired unit? New or are we still using old stock?
JIM P.
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[IanDMacDonald]

I'm so confused. What exactly was Tyler tasked with?

[sail4free]

I'm so confused. What exactly was Tyler tasked with?

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Basically just to get her running -- after sitting for 12 years -- which he has done. So, all the usual, new battery & plugs, clean & line the tank, rebuild the carbs & petcocks, change all fluids & filter. He did a running sync of the carbs with his mercury gauges *and* loaned 'em to me for a re-sync once I get the rings cleaned up.
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I think the next step will be DiverRay's recommend of idling for about 5 minutes with a full can of SeaFoam in the crankcase (with the fan on), (maybe running it lightly -- at idle -- through the gears on the centerstand as well?), letting it cool for 15 and then changing the filter and the oil. I think I'll run the recommended percentage of MMO for the first several hundred miles as well. How often should we normally change the oil/filter in these machines? For now, she runs (which is very encouraging) but the warmed-up idle is high and plenty of smoke -- I just need to get the rings cleaned up enough to rack up some lower-speed miles so I can re-sync the carbs before I have to give that great tool back and go from there.
JIM P.
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[DiverRay]

How often should we normally change the oil/filter in these machines?

By the book, 2,500 miles. That assumes good oil and a filter every time. I would do the first one after the clean at 1,000miles, as things will be getting into the oil. Biggest problem with going too long between changes is the oil breaks down due to shear. This is the transmission gears ripping and squeezing the oil. A poor oil breaks down from this faster than a good oil. I will NOT go into what to use, cause we do NOT need another oil thread. I use Castrol 20-50 in my machines that can't handle the friction modifiers, but you make your own choice.

[Jeffintampa]

Please lol

Hey Jim,

Not sure what you mean by funky O-ring under the Jet thing phrase???

The pilot jet SCREW on the top front of the carb body inside the recessed tube has an O-ring as well as a washer on the end along with the spring for the later carbs...80-81's. The 78-79's had the pilot screw EXTERNALLY mounted on the top front of the carb body.

The Float valve needle seat also uses an O-ring to seal the PRESS IN Seat that is secured with a U clamp and screw on the latter carbs. The early carbs use a fiber washer under the SCREW IN valve seat assembly.

HTH.
T.C.

Please come to florida and rebuild my carbs lol

[IanDMacDonald]

There are great threads here pertaining to rebuilding the Mikuni carbs. If you are versed in other bikes, many other bikes used Mikuni carbs similar to our's. MKII's and BS-34's are similar. If our forum's write-up's frazzle you, try the Triple's forum, or the GS Resources forum.

[jetmechmarty]

Maybe this will help.

http://youtu.be/95nlrP-yn2I

[Jeffintampa]

Thank Jet

Maybe this will help.

http://youtu.be/95nlrP-yn2I

Well I watched it and think I am going to give it a try. I think I have one of the float pins gets stuck sometimes. I am kind of scared and think I should order some parts a head of time. I will have to probably do at least 2-3 float pin cleanings

what would you start this project with as in supplies. I do not have much money to put in this, so minimums please.

Thanks

[DiverRay]

I would do the 4 "O" rings on the seat/needle, and just clean everything else. You really don't need much for the carbs, other than the needle now and then. The '80 up carbs had viton tipped needles, and they seem to go for quite a while.
mikesxs may have the o-rings, if not, try georgefix on ebay.

[Jeffintampa]

Thanks driver

4 "O" rings on the seat/needle is this them?

http://www.ebay.com/itm/1978-83-yama...3a9b82&vxp=mtr