Need your help to get my chopper running right again.

Yamaha_chop

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Hey guys, hoping to get an answer here before the weekend so I can ride again. I got my chopper done and ready in time for the ride last weekend- not without my share of troubles though.
I'll post pictures of the first ride in awhile, but first, here's the backstory. Tried to get the bike running last thursday, was having problems even then. Bike did not want to fire on the left cylinder. Swapped the coil no change, pulled carbs completely apart and cleaned all passageways and blew them out with compressed air, no change. Then I swapped condensers, vroom, fired right up and ran great, Ok cool found it right? Sat. morning comes and I try to fire it up, bam same problem running crappy on left cylinder, mess around with it for awhile, change the ground wire on the condenser to the head, and vroom fires up great. Bike runs fantastic all day, do a few rides.
Sun. I go out to the bike, and it's doing it again! but a little different this time. It'll have trouble running at idle on both cylinders, but once under load the left cylinder kicked in just fine and it rode great. I went to lunch with it, and when I got back I looked it over and the only thing I could find is the crankcase breather tube cap had come off. I have the one with two outlets, so I just capped one off and have a hose running off of the other one. I put a new cap on the one side and it ran perfect again? Craziness i know I can't explain that one at all.
So now it's Sunday afternoon and the bike is running good. I decide to ride with my bro-in-law to a town about 20miles away. Things are going good bike is running perfectly when about 2 miles from our destination the bike backfires and starting running on one cylinder and popping like crazy out the exhaust. Also, my Bro-in-law tells me that just after the backfire the lights all went out.
I get my Dad to load the bike in the back of my truck to take home and look at later. Sure enough all my lights are blown. Guess i used too large of a fuse :( Anyway, the battery is toast, completely dry. I figure OK new battery, check to see if the voltage is too high and I should be good. I get a new battery and now it's running only on the right side again. Left side will kick in very occasionally, usually just an intermittent backfire every now and then. HOWEVER, now as never before, if I put the choke on, the left cylinder fires right up and the bike revs clean.
It would seem to me that maybe the pilot jet is somehow plugged again or something? I dropped the bowl earlier and everything looked really clean, but tomorrow I'm going to pull the carbs back off and disassemble them again. :(
I'm kind of frustrated at this point, I really just want to ride this thing, but it seems like I'm having problem after problem.

Pertinent points:
Timing is dead on
Points, coils, condensers are all good.
It definitely seems to be a fuel issue at this point.
BS38 carbs
I believe factory jetting can check tomorrow for sure, but it always ran great before
diaphrams are ok
straight through exhaust
Pod filters

Any questions you have or info you need to know hopefully I'll be able to answer. I'm writing this really late at night so I'm probably forgetting some important point, but anyway....

Thanks for any and all help
Sky
 
check plugs and wires.....I have gotten brand new bad ones.....

check for intake leaks......

When is the last time you sync'd the carbs?

Are the filters snug and in the right spot?

Check your fuel lines for pinholes and make sure they are securely on....I am not familiar with the XS setup exactly.......I don't have one yet......so I don't know how the fuel flows from tank to carbs but make sure it is all clear and in good shape and secure.....

I'll come up with more....And I am sure more experienced and knowledgeable members will be along.....

Don't get too frustrated......take a break and have a beer or something......motorcycles.....at least the older ones......are fairly simple machines....

Start easy and cheap and go from there.....

And take some solace.....I have 4 downdraft carbs to keep right:thumbsup:
 
I sense that your knowledge of carbs is a little weak. Try to find someone in your area that can be with you when you take the carbs apart again.

Does the fuel tank have rust in it? If it does, then you can clean the carbs repeatily and the rust/debris will still come back and cause problems. Start with a rust free tank and use inline fuel filters.

High voltage blowing fuses..................you will need to repair this, you can't just keep buying new batteries. Either the regulator is defective or it has lost the sensing connection. If the voltage sensing connection or the black ground wire connection is lost, then the regulator calls for full voltage output from the alternator. Output can go up to 17 or 18 volts ....................very hard on batteries and bulbs, as you have seen.

If you are using original stock type ignition coils.........................they give a very weak spark.................replace with a new dual output coil.
 
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I am with RG on this. With straight pipes and pod filters you should not be running stock jets. You probably need to go a couple sizes bigger.
What do your spark plugs look like?
 
More ideas: plug cables, swap them see if the problem moves with them. Check your petcocks. They have an internal screen that can clog. I assume you have good gas, preferably alcohol-free. Does removing the air filters help (replace)? No kink in your left fuel line? Look under tank and make sure no wiring is grounding out (like a plug cable, for instance). Run the bike in the dark and see if you detect arcing (like, you guessed it, a plug wire). Are you sure the plugs are good?

Have you tried cussing it yet? That's usually the first thing I do.
 
Have you tried cussing it yet? That's usually the first thing I do.

Took care of that one :laugh:

Took the left side carb apart and checked everything over. Sure enough, there was a tiny piece of rubber or something wedged in my pilot jet. Everything else looked clean, but I flushed it all with carb cleaner and blew out the passageways anyway. Put it back together and it runs like a champ. :thumbsup:

However, as to the other half of my problem, it's definitely overcharging. It's giving me about 15v at idle and about 17-18v when revved up. I'm using the regulator and radio shack made rectifier talked about over at the garage.

I was going to run to NAPA tomorrow and pick up another regulator if they've got one and see if that takes care of the problem.

Thanks for the replies
Sky

(Edit: ) Just wanted to add that I checked the ground and power feed coming to the regulator and they are both good. I'm not entirely positive about the green sensor wire. It looks fine but I'll have to remove it from the + brush to check continuity.
 
The green wire isn't the voltage senser wire, The brown wire too the regulator is.
The brushes got battery power on the brown wire. Through the rotor, out on the green wire. The green wire goes to the regulator where the regulator grounds the green to control the current in the rotor.
The brown wire to the regulator is senseing wire. This is how the regulator knows when to turn the current in the rotor on and off.
If your green wire is shorting to ground it will make the alternator run at full output. This is one of the tests in Curly's guide to check for alternator output.
You need full battery voltage on the brown wire at both the regulator and at the brush.
I would check this out before swapping the regulator.
 
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