so close to running, need advice

[chuck c]

This bike has been sitting for 3 years. I've had it going a few times and it seems the left side is not firing or firing only sometimes. It barely gets warm when the right side is too hot to touch. The exhaust on the left puffs a bit of smoke and smells like it has a lot of unburned gas. I removed the intake tubes right after a try and there's some visible liquid gas around the valves. The good news is it looks like the carbs work.

I confirmed there is spark with a timing light. The plugs are only days old. So why isn't the left side firing?

PS I'm pretty sure the wires are on right. They were marked 2 and 4. how can I check to be sure they are?

 

[backyardtrouble]

Even though you have spark, that could be a coil issue - weak spark, spark plug wire issue, spark plug resistors in the caps, bad spark plug caps, valves not set right, and also check your pulse generator wire plugs - they may need to be cleaned. the timing belt could have jumped a notch...so several things i would check for a piece of mind. And i have had new plugs that did not work like they were suppose to. You could be sucking to much air on that side, intake tubes - o ring on the bottom not sealing correctly, or the clamps not tight enough. Maybe To much gas from the carbs...i'm running out of ideas now... :headscratch:

 

[slabghost]

might be a rats nest in the left muffler.

 

[chuck c]

I'd think even with a weak spark it would still fire but I'll check it out. The possibility of a jumped tooth is one I never thought of. That would mess up both cylinders on one side. I wish there was a way to check without removing the radiator and covers, but new belts were on the list anyway.

Too much gas is possible. They might be gunked up from sitting. and dumping fuel.

 

[backyardtrouble]

The float bowls in the carbs could be set wrong too...i know you did not want to hear any of that, but check your sync on all four carbs ( fire it up..let it warm up a little) and check them...having to run it a high rpm to get it cleared up sounds a little out of sync to me on the carbs.

 

[joedrum]

hmmmm sheesh ... if this is project bike id check the belts for timing just to make sure thats right and go from there ... its useally a mix of carb and ignition issues

 

[SteveA-wing]

What he said, also if you haven't done it yet, go ahead and spring for some new plugs. The side that is running hot is indicative of a mixture running way lean. Sounds like you could still have some clogged ports in the carbs causing the lean burn issue.

 

[chuck c]

SteveA-wing » Sun Apr 20, 2014 9:34 pm[/url]":33w63lix]
What he said, also if you haven't done it yet, go ahead and spring for some new plugs. The side that is running hot is indicative of a mixture running way lean. Sounds like you could still have some clogged ports in the carbs causing the lean burn issue.

The right side isn't running abnormally hot, the left side is abnormally cool. After 30 sec. or so of running the right pipes are too hot to touch and the left are just nicely warm. I'm sure the problem is on the left.

 

[chuck c]

According to the PO he noticed something wrong when he parked it but never investigated. The first thing I'm going to check is the timing. I have no interest in dealing with the carbs, I plan to go straight for a single setup. It's just not worth spending the time and money on them.

 

[dan filipi]

First thing I'd do is check the compression.
Valves out of adjustment can cause low compression.

 

[joedrum]

i agree ... its money much better spent for sure ... once you get doen to checking timing ..the valves and compression testing are right there too like dan says

 

[Steve83]

It's possible, but unlikely, that the left plug wires are reversed. They would have to also be reversed at the coils for the numbers on the wires to be wrong at the plugs. One coil fires the front cylinders together, the other fires the rears - a good ol' wasted spark system.

More than likely, you have a carb issue, if you're seeing liguid gas in the intake port. Also, as Slabghost said, check for a plugged left muffler.

If you haven't replaced the timing belts, and you think the left side has jumped a tooth, don't run it until you check them. If it jumped one, it could easily jump more, and that would be catastrophic!

 

[Joep]

Amusing the valves is as easy as it gets in troubleshooting.. remove 2 caps and valve covers.. got to timing marks and adjust the appropriate valves.. rotate engine by hand wrench and adjust remaining valves.. button system up and move from there.. you can just loosen the radiator.. remove the bolts.. and using the bolts holes.. support the traitor out ofc the way.. careful with hoses.. you only need clearance to be able to see the belts and timing marks ... then rotate the motor by hand and check the timing marks... tension of the belts and condition.... then go from there

 

[chuck c]

dan filipi » Sun Apr 20, 2014 9:48 pm[/url]":135yxuxm]
First thing I'd do is check the compression.
Valves out of adjustment can cause low compression.

Good idea, I can do that without tearing it apart. Now if only I had a compression tester..... Some auto parts stores lend them. If I'm going to work on old bikes I need to have one anyway.

 

[chuck c]

Compression check results: 1-175, 2-165, 3-175, 4-160. Those numbers make me happy. Engine is nice and tight. I'm back to the carbs not carborating. It's a darned shame only half the engine works, two more working carbs and I could ride this beast! I ordered new radiator hoses today and will get timing belts soon. Anything rubber that I take off is being replaced.

 

[slabghost]

Is the left exhaust clear? On my 80 I tried seafoam for a month but it only ran on all 4 temporarily. Once I pulled the jets they didn't look real bad but I cleaned them and put them back. It ran fine. I forced drywall screws in the jets and levered them out with diagonal cutting pliers.

 

[chuck c]

Exhaust seems to be clear, there's exhaust coming out of it. It could still be restricted. I'll check it next.