Too Rich?

[Lucien Harpress]

(Yeah, THAT'S a problem I'd like to have....)

Anyhoo, my bike's been having a bit of an issue lately, and I just want to be sure I'm "fixing" it correctly.

My motorcycle starts up fine, idles fine (after it warms up), and runs fine most of the time. However, sometimes when I ease up the throttle a bit, the engine "misses"; it sort of bogs down, doesn't run as smooth, and I can give it a whole fistful of throttle and it won't do nothing except make a lot of noise.

I can usually "fix" it by either shifting gears, or letting the motor drop down to near-idle RPMs. This is usually accompanied by a nice loud "pop" from the exhaust. Then it's fine again.

In addition, whenever I decelerate it pops like crazy out the exhausts. I'm I correct in assuming that the mixture I'm running is too rich? I adjusted the carbs lean and it seemed to fix the problem a bit. Maybe I didn't go far enough?

----

(Maybe) similar question. Today was the first time riding my motorcycle in the rain, and suffice to say it didn't like it in the least. Sputtered like crazy all the way home (sorta like the problems I'm describing above). Would this be more of an electrical issue, you think? It's not a big deal, as I don't plan on riding in the rain that much, but still something to think about.

Thanks in advance!

[natemoen]

With the rain issue Start the bike up and let it warm up turn all the lights off and when your in the dark start spraying water on the bike (no need to drench it) See if you start seeing sparks jumping from the plug wires. Its a common problem especially if you have the original coils/wires.

What are your floats set at?

[cywelchjr]

Popping on decel is usually a sign of being too lean. However, it can also be a sign of an exhaust leak at the head. That said, what do your plugs look like? The plug color will tell you what their seeing on average, and if they are not pretty much the same, you may need to do a series of plug chops to find out whats happening at different throttle settings.

[WMarshy]

What are your plugs telling you? I would start by pulling them, that will tell you the most. Sounds to me like it could be too lean (pop in decell). How does it act if you pull out the enricher one click when its acting bad? If it perks back up and straightens out then that will confirm your running lean. Good suggestion about checking the plug wires too.

[Lucien Harpress]

Well, took a look at 3 of the 4 plugs. Two looked fine, while the last was quite lean. Couple turns of the mixture screws, and hopefully everything's alright.

Why didn't I check the fourth, you ask? Well, somehow, the %@&# thing got stuck in the engine block! I don't know if I crossed the threads last time I put it in, but now the plug will only back out a turn or two before it jams up. I put quite a bit of force into it too (probably more than I should've...), and it isn't going anywhere.

Guess that one will stay a mystery...

[natemoen]

Guess that one will stay a mystery...

For Now! (Insert evil laugh)

[Lucien Harpress]

I'm just counting the days until the little ^&%$%er decides to quit on me and I HAVE to get it out..... followed closely by re-tapping the engine block....

[cywelchjr]

Well, took a look at 3 of the 4 plugs. Two looked fine, while the last was quite lean. Couple turns of the mixture screws, and hopefully everything's alright.

Why didn't I check the fourth, you ask? Well, somehow, the %@&# thing got stuck in the engine block! I don't know if I crossed the threads last time I put it in, but now the plug will only back out a turn or two before it jams up. I put quite a bit of force into it too (probably more than I should've...), and it isn't going anywhere.

Guess that one will stay a mystery...

Thats the reason I always turn them in by hand all the way till the gasket touches. No chance of a crossthread that way. Of course all bets are off when you put PO's into the picture.

[planedick]

similiar

My neighbor has a Yamaha Virago 250 and right after he got it his brother got him some supposedly "hot" plugs and decided to install 'em himself. Put it in the socket on the ratchet and proceeded to wrench it in, crosstreaded of course and kept going even though it was extremely hard going. He came to me later and wanted to know if I could help..... Took me two days to get it out and rethread the head.

[skids]

Steel threads of the plug and aluminum head can cause "fusing". I had to rethread a head once because of this. Lesson: always use never-sieze compound on spark plug threads.

[TopCatGr58]

Hey Lucien,

Can't recall...have you done the pickup coil wires fix??? Sounds suspiciously like that....at cruising speed/low throttle, vacuum increases and timing advance increases...timing plate spins/turns farther, and PU coil wires get stretched...if broken internally can cause loss of signal=miss, until you either let the rpm back down, or grab a bunch of throttle which lowers vacuum letting the timing plate rotate back pushing the PU coil wires back together, and then you get signal again....runs!

T.C.

[cywelchjr]

Hey Lucien,

Can't recall...have you done the pickup coil wires fix??? Sounds suspiciously like that....at cruising speed/low throttle, vacuum increases and timing advance increases...timing plate spins/turns farther, and PU coil wires get stretched...if broken internally can cause loss of signal=miss, until you either let the rpm back down, or grab a bunch of throttle which lowers vacuum letting the timing plate rotate back pushing the PU coil wires back together, and then you get signal again....runs!

T.C.

I have a question (not trying to hyjack the thread btw), looking at how the centrifugal advance works, it appears to work like every other one I have worked with, in that it's the spinning parts on the shaft that move as the weights move out, which doesn't move the wires at all. The only thing that I can see that moves the timing plate is the vacuum advance. Only moving the timing place (that which the pickups are mounted to) flexes the wires from what I can determine, yet everybody says (and experience may show this as well but I don't know if this is true) that 81's have less trouble with the pickup coil wires. Other than maybe better quality wires in the 81's I can't see any mechanical reason for this. I'm open to correction, but I can't see on either of my engines (both 80's) where anything but the vacuum advance causes any flexing of the wires (well, or wind of you ride it with the cover off).