After 28 Years It Started! - Now What?

[rickt]

Just a short history. The '78 GS750C was given to me by the husband of a co-worker. The bike was parked in 1981 with 2098 miles. Gas tank removed and carbs drained (partially). I started the restoration in 2007 and finally reached the point of trying to start it today. I should say that everything (and I mean everything) has been replaced with new OEM or cleaned and polished to be as new. The carbs were a problem as residue from the evaporated gas froze serveral needles in the bores. The tips broke off when I tried to remove them and I ended up sending the carbs to a restoration shop in the South were the tips were align drilled out. Carbs were rebuild with new needles, o-rings, etc. and set to original specs. So much for the history.

I put a small amount of fuel in the tank and to my amazement it fired up the minute I pushed the start button. I was able to ride it around the neighborhood and put on a couple of miles. Seems to idle reasonably well. Now to my list of problems in order of importance.

1) gas leaks from the float bowl vent hoses of a couple of carbs. This is not just a drip here and there. Gas shoots out of the hose when the bike is just sitting. Does not appear to leak when the bike is running. Is this a sticking float needle problem? Removed the float bowl of #1 but didn't see anything strange.

2) A little flat off idle, but seems to come on fairly strong with more throttle. Probably carb adjustment - where to start?

3) weak backfire through exhaust when coming off the throttle. Another carb adjustment?

4) Both tach and speedo appear to be moving in slow motion. I'm certain that they are reading way low. The tach takes a few seconds to come to zero after the engine is off. Both cables are new. Could this be a cable lubrication problem or ?

I'm all ears for suggestions on how to manage my list of problems. Obviously, I'm most concerned about the gas leaks. I don't want to park it in my garage and I really don't look forward to pulling the carbs and airbox.

Thanks
rickt

 

[Nessism]

You have at least one stuck float/needle. If the carbs were rebuilt properly, it may just be a matter of rapping on the floatbowl with a screwdriver handle to get the float to drop down. Until you fix this problem you can not judge carb tuning.

 

[Big T]

You have at least one stuck float/needle. If the carbs were rebuilt properly, it may just be a matter of rapping on the floatbowl with a screwdriver handle to get the float to drop down. Until you fix this problem you can not judge carb tuning.

Exactly - I'd complain to the builder if tapping the bowl doesn't solve the problem

2. Carbs need to be synced and adjusted - altho they will do that when not fully warmed up
3. Ditto - a bit lean

 

[rickt]

Sticky Instruments

Sticky Instruments

Anyone have any thoughts on the "slow motion" tach and speedo?

Since both seem to work I assume the cables are ok?

Could 28 years of non-use gummed up the instruments? Is there some way to lubricate or free them up?

rickt

BTW, I can't be too hard on the person who rebuilt the carbs since that person was me!

 

[Stefnwolf]

Clocks in slow mothin

Clocks in slow mothin

I'd guess the clocks might be gummed up from 28 years of non use.
Don't know how the Zook ones are built but on other 1970s clocks I've had apart the cable spins a magnetised disk, and the needle is moved by a corresponding magnetised disk, against a spring. There is a small air gap between the disks. Drag on the needle disk means more force is needed to move it, hence the 'slow motion'.
I'd take them apart and spray the works with WD40 if it was mine.

 

[Big T]

BTW, I can't be too hard on the person who rebuilt the carbs since that person was me!

Well, just blame it on beer, then!

As for your guages, they are probably gummed up.

I'd use Electrical Parts cleaner, followed by spray Seafoam. The EPC will completely strip off any gunk and the Seafoam will protect and lubricate.