Please HELP me! I need to ride.

[remainincognito]

I've read numerous posts and different forums but the info seems per each persons bike so:


I've been working on a chopper project and I'm having problems. I running a 2 into 1 intake with a mikuni 38 carb with a 190 main and 25 pilot, it has a pamco ignition, a brand new battery. It will start pretty easily but after It warms up it idles high and dies. It will also pop or backfire when I give it gas. More info:battery reads 12.5-12.7 with the bike off but with key on and headlight it drops to 12.1 and when I gas it does not go up like it's not charging. It has a brand new green monster coil that I bought cause I thought the other was bad. Any help would be greatly appreciated as I WANT TO RIDE.

Anybody near Rochester,NY that could give me a hand?

 

[TeeCat]

Here is my setup for my Mikuni 36:

- Wiseguy Customs 2-into-1 chrome ceramic-coated intake manifold (cafe/tracker configuration)
- air screw currently @1 turn out
- main air correction jet in intake bell: removed
- pilot jet: 25
- main jet: 200
- 159-P8 needle jet/6F9 needle (clip in middle slot)

What intake are you running? You sound lean (off-idle).

Also, you should be seeing about 13.5 to 14.5V at 3,000 rpm.

 

[fancyketchup]

Charging issue is definitely a big one. Bike wont run correctly or at all without voltage to the coil.

 

[remainincognito]

TC....I have the same setup at you with the exception of my 190 main and will pick up a 200 today.

Guess I'll try looking at the coil again.

 

[TeeCat]

Well, your carb does have a touch bigger barrel, which may make some diff. But that off-idle stumbling does make me think lean (since the circuits do cross over), and/or coil/weak battery.

Keep us posted!

TC

 

[remainincognito]

Brand new coil and battery. Bike starts easily but revs high with choke off and cannot get it down.

 

[TeeCat]

Right, but the voltage you reported seems low at 3,000 rpm, so you can't be sure you're charging.

Bike starts easily but revs high with choke off and cannot get it down.

I wonder if your advance weights are hanging at full or partial advance? Mine was doing that til I replaced the springs and eventually the ATU to rule out worn parts. Pop your right cam cover off and block the weights closed (in toward the rod) with a little piece of cardboard so they can't open. Don't ride the bike like that... just give it some throttle and see if the bike returns to idle. If it does, you may have a mechanical advance vice a carb problem. Can't hurt to rule that out before going at the carb.

TC

 

[Classic]

What year is your bs38?

If it's 78-79 I'd recommend 142.5 main, 30 pilot, and needle on #4.

And make sure your float height is set right.

 

[TeeCat]

Oh, is it a BS or a VM? I had it in my head that it's a VM.

 

[remainincognito]

It's a vm. How do I check the charging system? That is my achilles heal. Don't know electrical at all..I had someone do the pamco and wiring.

 

[Classic]

There's a guide to testing the alternator under Tech at the top of the forum. Pretty much grab your smallest feeler gauge and hold it close to the alternator cover. Turn the key on and the feeler should slap the housing. That is a sign of a good magnet. To test the rotor with a dmm connect the two leads to each place that the brushes touch. Should read 5.4 if i recall correctly. A new alternator can be had from custom rewind for about 165 shipped with your core.

 

[remainincognito]

I'm really an idiot when it comes to electrical. Even when reading the techs I still not quite sure where to touch the red and where to touch the black to test my alt/stator and coil and do I have the key on or off? Anybody want to give a charging test for dummies/retards?