bad flat spot - poor idle

[racetrips]

Just got an 80 g model and am having progressivlely worse drivability problems with it. Problems are:

Poor torque below 3k, hard to ride in town. Needs some definite rpms to pull away from stop. Generally not happy below 3k.

Poor idle. Idles rough and problem is sporadic. After good run down freeway idle will slowly fall from about 1300 to 950 or so. Gets rougher as it drops and frequently dies. Often dies if throttle is just cracked off idle - revved a little more it's fine.

Almost as vexing is an intermittant 'sticking problem'. If driven at steady very light throttle anywhere below 3000rpm something hangs and the motor goes flat. Won't rev or make power. Only way to clear it is to pull clutch, let rpm drop below 2k, rev it briskly to clean it out and re-engage clutch. While sporadic, it's very frequent. Has done it a few times even at the 4000rpm or so on the freeway and occasionally at downshift.

It's also getting increasingly hard to start, with odor of fuel. It's quite cold blooded and has to be run a good 3-5 miles before it'll idle without some choke.

I've taken the carbs off and cleaned them by blowing cleaner and compressed air throughout, but didn't take the diaphrams off for fear of tearing them. Found 1 float/needle that when upside down, did not hold float at same height as other three and didn't have any spring to it. The cleaning mad absolutely no difference at all, if fact it's getting worse in the week since.

I got a replacement needle for $8 but not the needle and seat as it was $45. Am going to replace the apparently bad needle but would really appreciate any suggestions of what else to be sure to check while it's apart.

Thanks for your time in reading this and any help. I wouldn't have bought the bike except I found this terrific site.

Robert

[mitch]

carbs need to be cleaned

You need to take the tops off and remove the tubes all the jets need to come out and be cleaned ! Then they need to be at least bench scynked, Did you check your oil to make sure no gas was in it ? Did you check your coil pick up wires ? If not all this info is in the Maitenance and repair sections , check it out read,read,read,. All of the above are quite simple, you already cleaned about half your carbs. When its running spray some wd40 around the front of your carbs to see if you have any leaks on your intake, if you do it will reve up a little when you find it . Good Luck HTH......................MITCH

[TopCatGr58]

Hey there Racetrips,

What Mitch has said pretty much covers it!! The tech tips are quite good with many of the common maladies that afflict these wonderful machines. And even though it sounds like it's carb related, due to the flexing of the wires in the pickup coils assembly, and the vacuum advance pulling and rotating it, you can get these same stalling, loss of power symptoms due to the pickup coils not transmitting the signals to the TCI(Black Box) consistently.

While you are in your carbs, note the size of the main/pilot jets, and you need to pull the idle pilot circuit screws out(they are on top front edge where they attach to the intakes; along with the pilot jets....on bottom next to main jets and soak them in cleaner and ensure the little ports are all clean, along with then spraying cleaner thru the holes the jets came out of to ensure the idle circuit paths are clear!

The rubber diaphragms have a little alignment tag that you can gently get ahold of to pull them loose from the carb body, that way once you remove the main jets, you can then remove the center emulsion tube by pushing it up thru the body, and soak and clean it as well!! Read the tech tips and have fun.

PS, if you would update your profile to include your general location, like city/state you might find others in your vicinity willing to drop by to lend some assistance!?

[Ken Talbot]

it also sounds like you may have problems with broken pick-up coil wires. This will leave you running on two cylinders until the break comes together, then all four start banging and it feels okay. There is a tech tip that covers how to diagnose and fix this problem too.

[Renegade]

I had a similar problem with mine when I first got it. After several tries at cleaning the carbs (soaking overnight, pressurised air, etc) with no positive results, I found a shop that used an ultrasonic cleaner for carb cleaning. Two days and $150 later, it ran like a new bike.

See if any shops in your area have an ultrasonic cleaner, it makes all the difference in the world if you have carburetor problems.

[Hawkins]

could also be a sticky bearing in the vacuum advance assembly - binds when it gets hot. had it happen to me.

[TopCatGr58]

Fixed, was pickup wires!

Racetrips PM'd me and said it was his pickup coil wires, even though they had been repaired before, broke again, got it fixed, and it's running like a new machine again.
T.C.