fuel leak out of R cyl

[aslsmm]

so i have been bashing my head against this bike ever since i got it. at first it wasnt sparking on cyl R so i replaced the points with BB electronic ignition. after wrestling with that system for a day i finally got it installed and was getting tons of spark on all coils.

I have yet to get this on the road. i was installing the new water pump gear today and i got everything put back together and now only the middle cyl will fire. the L cyl wont fire and the R cyl is leaking what looks like fuel out of the exhaust. could it just be flooded and thats why fuel is leaking from the exhaust cyl? its leaking from the front of the bike not the back end of the exhaust.

as far as the timing is concerned i have slowly rotated the ignition plate 360 degrees while turning it over and i can only get the middle cyl to consistently fire. the other two cyls wont fire at all even though they are getting spark. any help would be grand. i really want to get to riding and out af my garage. thanx.

[pearljam724]

Concerning the fuel leak. You most likely have rust in your fuel tank. Particles have most likely trickled down to your needle valve seat causing the needle valve to be partially open or not closing properly. You need to clean and seal the tank from rust. Follow that by removing the carbs and PROPERLY cleaning them. Taking the carbs apart and visually inspecting the bowls for debris is simply not enough. You must disassemble all parts, clean by wire and soak for considerable amounts of time. Also add an inline fuel filter to prevent this issue. Even when tanks of this age seem to be fairly clean, there is enough rust particles to become a problem. The valves being stuck open is causing the carbs and motor to be flooded with gasoline because the fuel is not being shut off by the floats and needle valve. When you remove the carbs also check to see if the valve springs return like they should. The needles can be worn at the tips, the springs can also be worn or jammed. Causing hard starts and flooding of gas into the motor, exhaust, air box, etc. Being it's leaking at the right cylinder exhaust. That cylinder is most likely the needle valve causing the problem. Also remove and clean your fuel petcock filter screen. It's screwed onto the bottom. They clog quickly, even on a moderately clean tank.

[aslsmm]

thank you., i ordered a carb rebuild kit and im just waiting on it arrival. i am cleaning the carbs now.

[Coyote]

If you have rust in your gas tank, you will be cleaning your carbs every week. Been there - Done that.

[oldjapanesebikes]

An in-line filter might help ?

[pearljam724]

If you have rust in your gas tank, you will be cleaning your carbs every week. Been there - Done that.

Yep, you would be wasting your time. If you don't take the time and money to seal the tank properly. Cleaning it without sealing will not remedy the issue. Rust will reappear in a matter of days. I suppose if the tank has some specks here and there, you could clean it and get by with a filter alone. Without sealing it. But, that's a very short remedy and surely problems will reoccur soon enough. I can't imagine very many of these tanks have no rust, that have never been sealed. My 550 has very little, but has never been sealed. Therefore, I have had to change the inline filter and clean the petcock screen a few times over a year. It's due for a carb clean I imagine.

[aslsmm]

how do i seal the tank? a link explaining it will be great. also the center carb was shattered in the bowl so i am thinking that it was causing the other two carbs too flood. will a 74+ carb set work on a 73? thanks.

[pearljam724]

Do you mean the bowl was cracked ? To seal. You can do one of two things. Buy a motorcycle tank sealer kit on line. Read those directions very carefully to the manufacturers exact instructions. It's very easy to do, but you must follow the exact instructions. Or you can pay a radiator shop to seal it for you. A reasonable price would be between $50-$100. Not sure about the 74 and 73 550 carbs. But, I pretty sure they are different. If you have a cracked bowl. They pop up on Ebay all of the time. Ranging between 15 and 25 bucks.

[aslsmm]

no its a 750. and the bowl is fine. the stem that the float connects too is broken. so the body of the carb is junk. the 74+ carbs are different then the 73 thats why i was wondering if they will work on it. there is a set f 73 carbs on ebay but the 74 are considerable cheaper and i accidentally ordered a 74 rebuild kit. lol. so if i can just go with 74+ i will. thanx for the help guys. i will get a tank sealing kit asap. and an inline filter.

its good to have friends in the field. makes fixing this bike alot funner.

[aslsmm]

one thing that just occurred to me is that these carbs are running pods. i googled "74 carbs on 73 gt750" and it sent me here to a thread that talked about pods messing up the cv carbs. having said all this, i do love the look of the pods and am not doing a restoration. Im doing a street fighter. so who do you guys recommend for after market carbs that work with pods? i dont mind spending money but i dont want to drop to much on it. thanks. im headed back to google.

ps: most of the questions i ask are after i searched. i trust a few of you guys on here way more than what just happens to pop up on the interweb. reason being, oldjapanesbikes has his own web page with extream detail on his restorations. so finding him on here is nice cause information can cme straight from him instead of whoserbob who is just guessing what he would do.

[pearljam724]

What you are referring to being cracked is the carb body, not a bowl. Yes, if you cracked a stem that holds the float pin. That body is pretty much worthless. A lot guys like pods. But, I am not one of them for a few reasons. Which I don't care to start a meaningless debate. There are no aftermarket carbs that I am aware of. The carbs on the 73 and 74 750 are very different. So is the porting on those 2 motors. I imagine it could work. But, You would definitely need to play with the jetting if it does. If you're patient enough, I imagine you can easily find one body on Ebay. They pop up quite often also. For reasonable prices.

[aslsmm]

i think i found my answer

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also i didnt crack the stem, it was broke when i opened it. im going to bed. ill post up eventually with a running bike.

[aslsmm]

Great news!! its firing on L cyl now.

Bad news. thats the only cyl. lol. i havnt had time to tinker with it but im pretty sure its got some kind of issue with settings. the bars will jst dump out gas when im starting it. so i will be ordering the RIGHT carb repair kits now.

any one want a new unopend carb repair kit for 74-77 gt750? or trade for 73 kit? i know there is a value difference so even if you want to trade for 1 that way i just need 2 more that would be cool. thanks.

[tz375]

Did you end up replacing the carb or carb body on the one with a broken post?