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 Post subject: Re: carburetor
PostPosted: Sun Jan 28, 2018 7:39 pm 
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On the street
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Joined: Thu Dec 28, 2017 9:22 am
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Country: United States
Bikes owned: 1970 Suzuki T350
Well i got the fuel tank installed and when the gas is turned on it leaks out of the bottom of my left carburetor? :roll: I am not sure what is causing it. I can get it to start but all it will do is rev up really high and then cut off?


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 Post subject: Re: no spark 1970 T350
PostPosted: Mon Jan 29, 2018 5:16 am 
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Location: southwestern Pennsylvania
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Bikes owned: 69 T350 thru 75 GT750
The float bowl is vented to the atmosphere. This creates the pressure drop that causes fuel to flow up into the carb jets.
The fuel level is so high that fuel is pouring out that vent.

By turned on, do you mean the stock petcock in the on position or a manual aftermarket petcock in the on position?
The stock petcock has 3 positions: on, reserve & prime. On & reserve are vacuum operated — fuel should only flow when the motor is spinning & generating a vacuum. Fuel always flows in the prime position.

The high fuel level in the left carb can be caused by a sunken or dented float, dirty or badly worn needle valve, or badly adjusted float.
A sunken float leaks gas into it and sinks rather that cut off the fuel flow as it should.
A dented float doesn’t displace the correct amount of fuel so it sits lower in the gas & causes the fuel level to be too high. A repaired float can do the same.

You likely have a number of problems. It may be cutting off because the motor is flooded. Another issue is causing it to rev too high. Be prepared because once you have the flooding fixed, the motor might want to over rev dangerously high. (These motors don’t have any inherent rev limiter.)

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BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 project & 75
GT380 72
T500 73 project
T350 69, 71 & 72 project
T250 72
Honda 85 CB650SC & 86 CB700SC
Yamaha 75 XS650
09 Triumph Bonneville SE


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 Post subject: Re: no spark 1970 T350
PostPosted: Mon Jan 29, 2018 6:45 am 
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Joined: Fri Aug 11, 2017 7:09 am
Posts: 170
Country: england
Bikes owned: several gt250 ramairs
good advice from jab :)
when you take your carbs off, have a look at the 2 insulators and their gaskets [as well as the carb 'o' rings].
the insulators can crack across the bolt holes and these are dead easy to miss, but will give you an air leak, which can also cause high revs. when you pull the carbs off, have a look at the gasket faces and if these are wet it's a sure sign they aren't sealing properly. fit new gaskets [or make your own] DON'T USE VESRAH GASKETS, as they are made of some cousin to blotting paper and they are useless. give them a very light smear of grease before fitting and they should be ok. also check the carb flanges to make sure they are perfectly flat. some people tend to tighten the carb nuts up as tight as they can and this can warp the flanges - again causing air leaks. hope that helps some? :D
cheers, dd.

_________________
RGT250LC road registered. RG250 gamma engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.


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 Post subject: Re: Very high idle rev.
PostPosted: Fri Feb 02, 2018 6:31 pm 
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Joined: Thu Dec 28, 2017 9:22 am
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Country: United States
Bikes owned: 1970 Suzuki T350
Thanks for the advice!
I took carbs off and did a quick clean.. they were both very dirty and clogged. I put them back on just to see what would happen. It will crank on one kick and stay on but it revs up to 4-5rpm :shock: so i have to kill it with the ignition every time. Float on the right carb. is sunken in on the sides, left float looks okay. I felt the engine and it seems that only the right exhaust pipe is getting hot?
What to do? :)


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 Post subject: Re: no spark 1970 T350
PostPosted: Fri Feb 02, 2018 7:06 pm 
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Posts: 3124
Location: southwestern Pennsylvania
Country: USA
Bikes owned: 69 T350 thru 75 GT750
The dented float has to be replaced. Its causing the right carb to get way too much gas.
Fixing this will give you a starting point for identifying other issues.

It could easily be unnecessary, but some forum members would replace both floats just to be sure.

_________________
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 project & 75
GT380 72
T500 73 project
T350 69, 71 & 72 project
T250 72
Honda 85 CB650SC & 86 CB700SC
Yamaha 75 XS650
09 Triumph Bonneville SE


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 Post subject: Re: no spark 1970 T350
PostPosted: Tue Feb 13, 2018 8:38 pm 
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Joined: Thu Dec 28, 2017 9:22 am
Posts: 15
Country: United States
Bikes owned: 1970 Suzuki T350
I have Mikuni carburetors and think they are the original ones. I have not replaced any parts. I tried taking the sunken float off but the corrosion on the float pin is causing it not to come out. Do you have any suggestions as to what I should replace to get the high idle rev(5-6k rpm) down to normal rpm? It cranks very easy but it goes straight to 5-6 rpm and would probably go higher if i let it. I would like to get parts and only have to uninstall and reinstall the carbs minimal times. :mrgreen:

Everything seems to be working its just the high idle that I need to get fixed. Thanks!


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 Post subject: Re: no spark 1970 T350
PostPosted: Wed Feb 14, 2018 3:30 am 
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Joined: Mon Dec 13, 2010 4:32 pm
Posts: 3124
Location: southwestern Pennsylvania
Country: USA
Bikes owned: 69 T350 thru 75 GT750
If its not dented too badly, you still might be able to get good fuel levels.
You adjust fuel levels by holding the carbs level & using a fuel level gauge.
Image

You should find some posts about it if you search for “fuel level”.
I got a fuel level gauge from Z1enterprises but they are currently out of stock.
https://www.z1enterprises.com/fuel-level-gauge-tool-kawasaki-suzuki.html

The carb slide might not be closing completely. Use a mirror to check to see if both sides are at the same level when the throttle is closed.

_________________
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 project & 75
GT380 72
T500 73 project
T350 69, 71 & 72 project
T250 72
Honda 85 CB650SC & 86 CB700SC
Yamaha 75 XS650
09 Triumph Bonneville SE


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 Post subject: Re: no spark 1970 T350
PostPosted: Wed Feb 14, 2018 5:25 pm 
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Yeah Man, the Interstate

Joined: Wed Jul 10, 2013 12:04 pm
Posts: 657
Country: England, UK
Bikes owned: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S
russt wrote:
I tried taking the sunken float off but the corrosion on the float pin is causing it not to come out. Do you have any suggestions as to what I should replace to get the high idle rev(5-6k rpm) down to normal rpm? It cranks very easy but it goes straight to 5-6 rpm and would probably go higher if i let it. I would like to get parts and only have to uninstall and reinstall the carbs minimal times. :mrgreen:

Everything seems to be working its just the high idle that I need to get fixed. Thanks!

Corroded float pin? try tapping it the other way. Many float pins will only be extracted one way.
Now the main problem of high revving is not likely to be from incorrect float level. It is more likely to be from throttle slide not closing fully or from an inlet leak.
Check your throttle cables are not too tight and that your slides are correctly installed and seating fully.
Check that you don't have any inlet leaks. Check for cracks in any rubber inlet stubs, if cracked, replace them. Check they are seated correctly and fully. When rubber gets old, it gets hard and sometimes fails to seat fully. Try using some blue Hylomar to seal them with or replace with new ones if in doubt.
The next thing to check would be possible crankcase or base gasket leaks.

Ultimately there is only one reason your engine can rev too high; too much air! You just need to find out where it is coming from and plug the leak.


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 Post subject: Re: no spark 1970 T350
PostPosted: Wed Feb 14, 2018 6:28 pm 
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Joined: Mon Dec 13, 2010 4:32 pm
Posts: 3124
Location: southwestern Pennsylvania
Country: USA
Bikes owned: 69 T350 thru 75 GT750
That reminds me…
Make sure the slide moves freely over the entire travel before installing the carbs. The carbs can warp over time to the point this is a problem. Let us know if this is a problem.

If you overtighten the carb flange mounts it can distort the slides and prevent them from moving freely. So check to make sure this didn’t happen.

Before I knew about this issue, I installed the carbs & overtightened the nuts. Then installed the slide which did not close completely. Then I loosened the nuts to remove the carb, and the slide quickly snapped closed. Lesson learned.

_________________
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 project & 75
GT380 72
T500 73 project
T350 69, 71 & 72 project
T250 72
Honda 85 CB650SC & 86 CB700SC
Yamaha 75 XS650
09 Triumph Bonneville SE


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 Post subject: Re: no spark 1970 T350
PostPosted: Fri Feb 16, 2018 5:27 pm 
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Joined: Tue May 18, 2010 5:38 pm
Posts: 1385
Location: New Hampshire
Country: USA
Bikes owned: Suz, Yam, Honda, Kaw.
jabcb wrote:
Before I knew about this issue, I installed the carbs & overtightened the nuts


+1. Just tighten them easy overtime they will reshape and you can tighten a little more and eventually to spec. But if have fresh lock washer tighten just enough to flatten it out. The other issue is the Idle adjusting rod, If that is bent or has kinks the slide will bind on this and stick too. It is very common it is bent as people try to reinstall with carbs on bike. These are still available from Suz. I suppose if it bent like a 16 penny nail can attempt to straighten with hammer... but small short kinks will cause it to bind. use new

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 Post subject: Re: no spark 1970 T350
PostPosted: Wed Mar 14, 2018 8:34 pm 
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Joined: Thu Dec 28, 2017 9:22 am
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Bikes owned: 1970 Suzuki T350
I am still trying to figure out the very high idle. I can take the air box off and control the air flow to the carbs with a piece of cardboard and it will idle up and down with me moving the cardboard near and away from the carb intakes. I am not sure what else to do for correcting the air flow?I do not see any oil leaks around the engine.

Thanks for the post :D


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 Post subject: Re: no spark 1970 T350
PostPosted: Thu Mar 15, 2018 1:23 pm 
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Yeah Man, the Interstate

Joined: Wed Jul 10, 2013 12:04 pm
Posts: 657
Country: England, UK
Bikes owned: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S
The leak you most likely have is not an oil leak, but an air leak. It is most likely sucking unregulated air into the engine, causing it to rev too high. I assume you have tried adjusting the pilot screw. If carb adjustments do not fix the problem. then I suggest you get a can of easy-start and spray it all around the inlet rubbers, cylinder base gaskets and head gaskets while the engine is running. If the engine note changes (up or down) when you spray, then you have a leak there. Just don't spray into airbox side of the carbs, as that will give you a false positive.


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 Post subject: Re: no spark 1970 T350
PostPosted: Sat Mar 24, 2018 5:04 pm 
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Joined: Wed Mar 31, 2010 6:13 pm
Posts: 36
Not to hijack this thread, but I have a 1969 T125 Stinger with no spark. I noticed in this thread that it seems that the bike will not start without a battery? I thought my bike was a mag style that does not need a battery to produce spark. Am I wrong? I am just trying to get the engine running and have rebuilt the carbs and have all new cables. Most of the wiring is unplugged and I hoped to plug in just enough wiring to get it to run to see the condition of the engine before a complete teardown.

Rob


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 Post subject: Re: no spark 1970 T350
PostPosted: Sun Mar 25, 2018 12:32 pm 
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On the main road

Joined: Fri Aug 11, 2017 7:09 am
Posts: 170
Country: england
Bikes owned: several gt250 ramairs
on my engine [ts250] dependent on how it's wired, the ignition switch circuit [including the battery for the lights etc] contains half of the kill switch circuit. namely, if the ignition switch is off, then the black/yellow kill switch wire is earthed. hence no spark :D
cheers, dd.

_________________
RGT250LC road registered. RG250 gamma engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.


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 Post subject: Re: no spark 1970 T350
PostPosted: Sat Apr 07, 2018 1:59 pm 
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Joined: Thu Dec 28, 2017 9:22 am
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Country: United States
Bikes owned: 1970 Suzuki T350
Does an air filter matter to the amount of air that it sucks? I pulled the old one off and noticed that it is starting to rot. I also completed all the suggestions and nothing seems to be working. I rode the bike with the high idle and it seems to ride okay. I just cant let it idle.
Thanks for any other suggestions!


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