Bike finally running and on the road!

[TopCatGr58]

I wanted to clarify that when I tried to downshift I didn't even feel it trying to click into place, the shifter was just bottoming out with out grabbing anything.

Yep, that's the worn return spring symptom! To get it to downshift without breaking the shift lever is really easy! Just use the side of your foot to gently lift up on the shift lever just far enough to allow the shift pawl to grab the next dowel on the shift drum, just not far enough to upshift to the next gear, then you'll be able to downshift 1 gear, then repeat above again to allow it to grab the next dowel before attempting to downshift. Hammering the shifter with your foot just puts undue stress on the shifter/forks. Some people get lucky and it bounces back up enough to reset the ratchet action so they keep banging it! Just a gentle lift with the side of your foot on the lever is all that is needed....until you replace the spring of course!
T.C.

BTW, if you used a proper hardening paint you shouldn't have paint drip stains on the tank....I think you repainted the tank didn't you?? If not, then not sure what to suggest, cause don't want to use something that WILL remove the paint!

[manshack_one]

I didn't have the tank repainted, just sanded and sprayed the emblems. The drip marks are from gas running down the side of the tank I'm sure. I guess right now though all my time and money needs to go into getting it fixed and running rather than looking pretty.


I'll find some time to look at that spring and see what I can do. Bike runs great otherwise until I get it past that 5K rpm mark.

[BrianB]

Sorry to hear about the incident.

I got gas on my tank when I first got it home. I was adding fuel to the tank from my 2 gallon container and it leaked. My paint is factory and not dull at all but the gas getting on it left a real dull stained look.

I used rubbing compound and gave it a real good going over. Then I buffed it with Mequires clear coat. When that was done I applied another application. Really brought out the shine. I am thinking the tank had probably not been waxed and the paint had no protection on it and was dry.

Last time I was at the gas station I accidently got a couple drops on it and with a cloth in hand, just in case, whiped it quickly and the gas did not do any damage this time.

[manshack_one]

I have some of that compound stuff but don't have the Meguires so I may pick some up.

Right now I have more pressing issues. I pulled the carbs to see about leaning out the needles by moving the circlip up a notch. All went frustratingly fine getting the carbs out. They even went fine getting the slides out. They even went swimmingly when I grinded down an old pair of needle-nose pliers to make circlip removers. Where things went wrong is when I popped the small circlip off of the needle itself and it shot off to some dark corner of my garage never to be seen again. So now I have a nice clean set of carbs with one slide missing because of a tiny little circlip that has dissapeared. Maybe in the sunlight it will reappear today when I'm home for lunch.

[manshack_one]

And I was thinking of something that bugs me. I think I was having two separate problems last sunday. 1 being the stuck rpms at 5K. The other being the return spring. With the clutch pulled in it should have idled back down regardless of being able to downshift. So I have to figure out why it would stick at 5K rpms. I know all the suggestions about air leaks but could someone explain to me how a small vaccuum leak would have the pressure to keep those butterflies open when the spring on throttle is so tight? Seems like there has to be a ton of pressure sucking through there to keep those butterflies open. Then I also need to look at that spring.

Also I noticed that my bench sync may have done nothing as all the butterflies appeared to be completely closed when it was back on the bench. What kind of lube should you use for those springs that control opening the butterflies and throttle? I guess I idled down that knob too far and closed them back up? If I get it running before this weekend I'd really like to drive it to someone for a good sync. Anyone available Sunday? I can comfortably make about a 1 hr trip one way so that puts bryan, college station, jacksonville, tyler and huntsville in the radius. Please let me know if anyone has the sync tool and could help a fellow out.

[AlanB]

Hi Manshak,

Vac leak does not do anything to the butterflies. The engine does not mind where it draws air from; it will pull it in from wherever it can. Any leak on the engine side of the butterflies will provide a source of air which BYPASSES the butterflies!

However, other things CAN open the butterflies against the spring; favourite is the cable itself; be sure that there is free-play in it.

carb clamps and fuel lines can also get in the way of the linkage and prevent the linkage (ANY part of the linkage!) from shutting down. It is easy to see what is going on when the tank is lifted, much harder with it in place..........

AlanB

[manshack_one]

Ok. I was thinking the vacuum leak was somehow keeping the butterflies open but the linkage just seemed to stiff for that to happen. So the leak would have to be on the boot then right? Isn't that about the only thing on the engine side of the carb before it hits the sparkplugs? So the vacuum leak would mean the bike is sucking too much air which in turn draws more gas in and revs it up. I get the concept but now I have to fix the whole needle problem that cropped up last night before I can put the bike back together.

In the case of the carb boots: Someone had posted once about some plastic spray that basically would create a gasket. Could that stuff be used to recover the boots? I think it was called Plasti-something.?

[81xsproject]

don't forget about the vacuum plugs on the boots. If the caps are cracked, you can leak there, too. I threaded mine and use small screws and fuel line sealing tape to plug them instead of the rubber caps.

[TopCatGr58]

Vacuum leaks SUCK!

Hey Manshack,

MikesXS has what you need!

Slide Needle Clip
Carb Slide Needle Clip (pk./2) - Fits: Slide Needles on 1974-84 650's
with stock Mikuni BS34/38 CV Carbs.

OEM Ref.# 256-14919-00


Part #48-0668 $1.00 USD /Pk/2

Okay, Plastidip is what you were referring to, and it's been recommended for sealing the cracks on carb boots, but it's usually more of a cosmetic thing, they are double walled/lined, and rarely leak in the middle! IT's usually where they attach to the engine, as well as the synch port and it's cap that can leak!

Have you taken a BIC barbeque lighter, squeezed it so that it's releasing gas but not far enough to actuate the spark, and waved it around the carbs and boots while running to listen for a change in idle speed which would help you find where it's leaking?? Don't forget to test the butterfly shaft seals!

You've got the carbs off, but you didn't say whether you tested your cable for smooth operation, no binding, and even lubricated it?? Hang in there, you're going to get it!
T.C.

[manshack_one]

Topcat,

I saw those clips this morning but couldn't stand paying 7 bucks to ship a 1 dollar part so I went back to the shop that had the bike originally and got a clip from them. The guy was actually happy to hear it was running. He even told me to bring it in and get it synced up when I put it back together. He's got a new fancy digital carb sync tool. Anyway, put the carbs back together and was cleaning up a little more while doing so. I wanted to check something so I blew air into the gas tubes going into the carbs. What's weird is 1&2 were no problem at all to blow air through but 3&4 were difficult. It blows back fine through the air tubes on both sets. I may have to pull them apart a little more to find out what's blocking the air. Where does the gas go into the carbs at first when it's filling the bowls?

[AlanB]

Hi Manshack,

From the hose, the fuel enters a rubber-coated "tee" piece which puts it into the two carb bodies.

From there, into the float valves, and down into the bowls.

The brass seat for the float valve has a fine brass screen on top. I would be pulling those and checking the screens........

AlanB

[manshack_one]

That's what I was thinking but couldn't be sure. I'll pull those floats off at lunch maybe and check them. No time later tonight because of trick-or-treating and I stayed up till 1 AM last night fiddling with stuff so I'm pretty tired today.

[manshack_one]

Well, that hour went quick! Lunch oughta be at least 2 hrs when you work for the state.

Anyway, the screens were fine. I think what was happening is that the little tang underneath the float valve was pushed up and partially closing it. Either way they both blow fine now. So, what was left to do but try it out right? Carbs sure go back on easier than they come off. Left the tank on backwards and kicked them over to prime (since I dont' have an octopus). I gave it about 30 sec or so before trying to turn it over and while I was waiting gas started pouring out the airbox again. I think this goes back to another thread where I think Topcat mentioned that when the bowls are completely dry that sometimes the valve needle will slip a little too far out and you have to tap the bowls to get it to float again. It leaked pretty good but why let a puddle of flammable substance like gas keep you from starting up your air cooled bike right over it? After getting it to crank up and run I still notice some extremely rich exhaust (I think it was black smoke?) whenever I would rev it up. I probably need to go for a ride and see how it feels after a few miles on the road rather than gunning it in my driveway. Oh, and a carb sync wouldn't hurt either. Now that it's driveable I may schedule some time to get it synced at a local shop here. The mechanic was really happy about some new digital mercury sticks he had just bought for the shop so I offered my ride as a test vehicle. You know, for testing purposes.....

More later.....

[skids]

Did you bend the tang out of the way? Is it the one that you bend to adjust the float level? Did the oring stay in the groove when you pushed the fuel valve into place or did it perhaps split?

[TopCatGr58]

Hey Skids,

That was my question also, was busy writing my reply to the Ignition Module thread.

Yes, Manshack, if that "TANG" was the same one you bent/adjusted to set the float height, then you have just messed up your float height adjustment, and would allow the floats to rise much farther before shutting off the fuel....IF it can rise enough to shut off the fuel=leaking out the intake!?

The float valves may have just been slightly stuck into the seats, which cause the restriction of air flow into the carbs, but as long as air was flowing into them, then fuel would also have been able to flow into them! You may have fixed a non problem, and thereby created a real problem? Sorry, but you'll probably need to take them off to recheck and possibly reset the float levels!

Saw you post about an exhaust leak! You'll want to get that fixed BEFORE you bother with vacuum synching, or it's be off after you fix the leak!
T.C.