I know, another "not starting" thread..

[boostfreak]

Hey guys, this is my first post. I've read dozens of threads on this, but I really am stumped on this one.

I'm from Manitoba, up here in Canada eh.

I bought this great '82 HS this winter. Price and mileage were so good, I didn't care if it ran or not. Only 19,000 kms.

Once I got it home and tried to start it, it would only run on one cylinder, the left one. When given enough throttle, the right side would wake up and start firing. So with that I assumed the idle circuit in the right carburetor must be dead/clogged.

I pulled the carbs, boiled them, cleaned them 150%, new intake boots, new slide diaphragms, new orings everywhere, new float needles and seats. Even new top and bowl bolts. Set the (plastic) float height at 22mm, idle screws are 2.5 turns out. I sprayed the idle passages thoroughly, and watched the spray come out the 3 little bore holes. My diaphragms hold perfect vacuum.

Put them back on the bike, and now nothing. I have spark on both sides (though the left seems a little weaker), and it will run for a few seconds if I shoot carb spray into the cylinders, so the carbs are not providing the fuel on their own. On full choke I have nothing happening. The small passage in the bowls is also clear, I checked twice. The carbs have fuel, and the petcock is in the prime position.

My next step is to rig up one of those clear plastic tubes and see just how much fuel is in those bowls. I only confirmed the presence of fuel by opening the drains.

My coils ohm out at 2.4/2.5 ohms as well.

Any help would be appreciated.

 

[danisawesome]

I'm thinking your float height may be off? On my 82 HS I have it set at I think 26 or 27mm (measured without the gasket in place) and it works great. Granted, I have brass floats, so I'm not sure if that changes what the height should be. Where did you get that number if you don't mind me asking?

 

[boostfreak]

It does make a difference. I found that number from reading a lot of threads on here and googling a lot, haha. I've seen your build, looks amazing.

I also ohm'd the secondary side of my coils, they were around 300k ohms. Either I wasn't measuring properly or yikes, I need new coils. But how would I get a spark with that much resistance?

Stumped.

This is the third time I've had the carbs off, and I hear that is the magic number for getting the bike actually running

 

[danisawesome]

Thanks man! I'm a moto-noob still, but I'm trying!

That's really weird, but I would assume if you have spark and it runs if you spray carb fluid into it that it may be starved for gas? Did you do a rough set of the idle adjustment screw and the sync screw? I know when we were trying to get a buddy of mine's 360 to run we had the idle screw way off so it wouldn't start. Did you measure the float heights before your re-set them?

 

[boostfreak]

I bench synced them, yes. I adjusted the idle to just cover that small hole in the bore with the throttle plates, I remember reading that somewhere, maybe it is wrong.

The float heights were around 18mm when I started.

I'm also assuming the carbs are not flowing fuel on their own, and I cant figure out why. They were "rebuilt" by a previous owner and spraybombed black. I took all the paint off during the cleaning process too. The jets are also all the proper OEM size.

 

[danisawesome]

I think your next step (checking fuel level in bowls) is a good one then. Have you checked to see if your plugs are fouled or wet? Those are cheap and easy and can clear up tons of problems even if you don't think they're the culprit.

 

[boostfreak]

Yeah changed out the plugs with new ones. No change.

 

[Liamthedevastator]

Damn, I was going to say change the plugs

I had misfiring cylinders on my gixxer that new plugs fixed so as they say, "i'm a believer".

good luck with the carb work!

 

[boostfreak]

Well, I ordered some new coils off Ebay. Going to check the fuel level with clear tube once I figure out how to make one that fits in the drain without leaking. How do you guys do it?

Also going to blow out the carb circuits again. Who knows, maybe something got lodged in there.

 

[boostfreak]

Figured it out.

Blew out my choke circuits again. Rigged up a clear tube, my float levels are perfect.

Interestingly enough, the float bowls wouldn't fill with fuel the first time around until I cracked the drain open a touch. I guess they airlocked themselves or something silly.

She still runs on one cylinder at idle, just like before. It has to be the bad ignition coils. Once you give it some rpm and increase the system voltage it clears up and purrs.

I'll update when those arrive and I have a chance to install them.

 

[danisawesome]

Weird, never heard of that, but definitely making a note of it. Curious to see if the coils do the trick!

 

[boostfreak]

Well, threw some other used coils on and now I've got two cylinders running great. Still has some small issues like not coming down from revs, some popping while idling, and a high idle with the choke on. I know these carbs are clean (I think, lol), but I do have a small exhaust leak so I'm going to rectify that first.

From dead cold it starts in one kick, so I am happy about that, finally.

 

[boostfreak]

Richened up the pilot screws a tad and synced the carbs. Bike runs like new now! Very happy with it. No issues and lots of power through the whole RPM range. Just in time for riding season.

My "exhaust leak" turned out to be the factory moisture drain holes