All the necessities none of the amenities.

[Noidea]

im back with same ol bike sort of diffeeent problem. I got new dealer floats they’re in tip top shape. Set to the correct spec the carbs are all blown out for the 15+ time. I also replaced the coils with new ones cause old ones went bad. I have spark on both sides air and fuel or so I think I do my compression is 150 on both sides yet my left cylinder stays cold. I’ve swapped the coils, plugs, and plug leads to each side and no dice. It idles great with the right side cylinder. But nothing on the left. I also ran it and lifted the diaphragm to see if I get any pop but nothing. Next step I’m gonna spray some carb cleaner in left carb when running see if get something. I don’t think it’s igntion considering there’s spark on both sides and when I swap the leads and coils that left cylinder is still firing. Any help be appreciated.

 

[Superjet]

Just recently my bike after I removed the tank and drained the line started with the left cylinder only working. Tried a few more times and still the same. I put the bike on a bike stand, tapped the float bowl then tried again and both cylinders fired. Easy! Sometimes things are simple to fix I have learned. Lol

 

[Noidea]

That doesn’t do anything. I had a float problem prior but all the floats are good now. When I spray carb cleaner into the cylinder it fires up which leads me to beleive the carb isn’t letting gas through not sure why my float level is 25.5 perhaps I’ll raise it another mm see what that does I checked the float assembly it was fine. The spring moved as it was supposed to.

 

[5twins]

Sounds like your pilot jet or pilot circuit is plugged on that left carb.

 

[Noidea]

Theyre all clear I just re cleaned them thinking the same thing and no dice I also lifted the floats just to 26mm and nothing

 

[5twins]

Since you're measuring the floats with the carbs upside down, a larger number or measurement results in the float sitting lower and a lower fuel level in the bowl when you turn the carbs back right side up. If you want more fuel in the bowls, set the floats to 23 or 24.

You say the jet is clean but did you try blowing cleaner (or just something mild like WD40) through the passageway the jet feeds? There are 4 tiny holes in the main bore around the butterfly plate that the cleaner should come out of.

 

[Paul Sutton]

I get caught on that float thing every time. Somehow it seems logical at first glimpse that a higher float level means a higher fuel level. I will make that mistake again before I die.

 

[nj1639]

On re-awakening my '77 this year, I was having similar issues in my left carb. Plugged pilot circuit in the carb bowl.

 

[Noidea]

Yea it’s pretty confusing with the float height but my right side is set to 26 it fires fine. Lowered the left side to 24 and still nada. It’s the strangest thing and it’s right there. Feel like there’s something I’m missing can’t put my finger on it .

 

[Noidea]

And yes to 5twins trust me the holes in the carb are all clear. I’ve blown compressed air and carb cleaner through the holes every time I take the carbs out just cause paranoid about it

 

[5twins]

Well, it might be a sync thing then. If the carbs are out of sync, one side could be effectively shut off at idle.

 

[fredintoon]

And yes to 5twins trust me the holes in the carb are all clear. I’ve blown compressed air and carb cleaner through the holes every time I take the carbs out just cause paranoid about it

Hi Noidea,
blowing stuff through the jets may not fully clean them.
Poking 'em through with a length of appropriate diameter wire works better.

 

[weekendrider]

But if you look through them and see a well defined circle of sky does it really matter how it was cleaned?

 

[Noidea]

My carbs are clean trust me. Also my carbs I’m pretty sure don’t need to be synced I have bs38 on a 73tx650 they’re sort of independent they each have their own throttle cable and idle adjustment etc. The spark on both sides isn’t a strong blue it’s more like a sharp orange would this perhaps have something to do with it although the right one still fires regardless?

 

[nj1639]

Swap the carb bowls and see if the problem goes to the right side.......or swap carbs since they're independent.

 

[weekendrider]

You will still need to sync those carbs.

 

[Noidea]

How would I sync them l? I do a bench sync just by opening the throttle plate at the equal amount and turning the idle screw out the same side there’s no vaccum barb on my manifold to use a carb sync tool. I could probably swAp them. They have a crossover tube for air and fuel I’ll just use a long fuel line to connect them both since theyll be opposite sides. Swapping bowls sounds like a good idea. So is it safe to say my problem is carb related?

 

[nj1639]

If you swap bowls or the whole carbs and the problem moves to the other side then, yeah (probably), carb related. You swapped the plug wires with no change. Same thing here in principle. Process of elimination with the only cost being your time.

 

[Noidea]

Will do I’ll try it out tommorow and update you guys thanks!!

 

[Noidea]

Yea I tried it out yestarday and nothing can’t really swap the carbs they’re link with the crossover tube that doesn’t concern me but than the throttle cables get caught under. I swapped bowls nothing. It runs great on left cylinder I even removed the left plug while running to see if there’s spark and there is. I’m gonna check valve timing on left make sure it’s correct. As well as my intake manifold see if there’s blockage which is highly unlikely but worth. A shot besides that I’m all out of what else I should be checking. :///