Wont run.

[xoomer]

first off, I think my carbs are done, and I just need new ones.   

However If I pull the carbs, close the butterflys and set everything to bone stock (two and a half turns)  I will get it to start sometimes, and when it does I get popping from the exhaust, and out a couple of carbs.  and on top of that I have to fight it to come up off of Idle. (to rev the motor.)

I'm kind of a newb to motorcycles, I've worked on a few thumpers before but I just don't get this thing.  Any help or ideas would be appreciated.

I also have A/M pod Filters and a Sh*tcan  Muffler on this bike so this is not helping. 

[FJmonkey]

Some history will help us help you... Some carb issues are not tough to solve... What can you fill in? How long was it sitting?

[Pat Conlon]

Have you sync'ed the carbs?

[craigo]

If money is no object, send them to Randy @ RMP. He will set you up with an as new set ready to install. If money is, check out the files section. Andy posted some excellent tutorials on carbs there.

CraigO

[xoomer]

I really don't know much about the bike, I've tried rebuilding the carbs, (I've rebuilt weber carbs many times)  and I just can't dial it in.  When I bought it, it was running.  Unfortunatly I didn't look at the tank and everything got clogged up.   I've pulled it apart with the files available and put it back together.   but I still cant get it to run.

[moonrunnah]

I will get it to start sometimes, and when it does I get popping from the exhaust, and out a couple of carbs.  and on top of that I have to fight it to come up off of Idle. (to rev the motor.)
. 

explain popping out of the carbs because that sounds like an old four wheeler i had and i bent the intake valves it cause a popping or explosions out of the carb (littleraly had flames popping out of the carb)

[yamaha fj rider]

If this has not run for awhile could be blocked pilot circuits. With junk in thank even just cleaned carbs can be blocked. Clean the fuel tank then carbs and flush lines, fresh gas, probably fix the problem. Hope this helps.

Kurt   

[SlowOldGuy]

"Popping" in the exhaust and "spitting" back through the carbs (NOT backfiring!) is typically a clogged idle jet/circuit.

This should also be the reason you can't get it up off of idle speed.  The carbs also need to be synced, like Pat said.

DavidR.

[pdxfj]

Go to your local Harbor Freight and grab their big ultra sonic cleaner.  See if you can find someone who sells Amway and get some of their LOC.

Fill the ultrasonic cleaner with water and LOC.  Run the heating cycle until it's really hot.  Heating water on the stove can quicken up this process.  Don't bring it to boiling.

Disassemble one carb at a time.  Remove everything.  Put the carb, jets, emulsion tube and float bowl in the UC cleaner and run a cleaning cycle.  Flip the carb over and and run another cycle.

Rinse carb off in hot water and repeat the process on the other carbs.  If you feel the carbs need more cleaning, just run more cycles. Be sure to keep the heater on so the water says really hot.

Be sure to change the solution after each carb.  I've done this on several sets of motorcycle carbs, clutch and brake masters and it really works well.  Everything comes out looking new.

[ribbert]

Just to make sure the basics are covered, is the choke connected and working? 
What you describe is not unlike trying to start a cold motor with no choke.
Noel

[xoomer]

Its really weird, as sometimes it will start just fine and idle up with no popping and will rev just fine.  then other times it basicly sticks its middle finger at me and wont start.  I'm really thinking I need to buy the new carbs from RPM but, I havn't had the bike running long enough to know how good the motor is.  (unless someone knows where I can find a motor.)

[craigo]

Run a compression test. Easy to do and the part is cheap (relatively) Just take the plugs out and screw the end of the tester into each hole. Crank the motor and write down the number. Should be in the 140's across the board. I could be mistaken on that number and I'm sure someone more in the know will chime in.

CraigO

[ribbert]

Run a compression test. Easy to do and the part is cheap (relatively) Just take the plugs out and screw the end of the tester into each hole. Crank the motor and write down the number. Should be in the 140's across the board. I could be mistaken on that number and I'm sure someone more in the know will chime in.

CraigO

.....and the motor should be at operating temp with the throttle held wide open while cranking.

[andyb]

If you're an admitted novice to working on bikes, why do you diagnose the carbs as "done"?  Takes a healthy wallet to support that quality of troubleshooting.


What do the plugs say?
What does a compression check show?
Is there a common thread with weather conditions in which it runs well?
How old is the gasoline?
How much history of the bike do you have?
Why do you set the mixture screws at stock when there are modifications?

It's just an engine.  Fuel, spark, air.

[markmartin]

Have you sync'ed the carbs?

Or even bench sync'd it after the rebuild?

xoomer, stick with it.  From what I've seen on this forum, it's pretty hard to actually kill one of these bikes. It sounds like your willing to dive in and do things.  Good.  Answer the questions that are asked of you when you are seeking help.  There are folks on this forum that can and will walk you through every nut, bolt and bit on your bike until you get it running.  

Think about how good it's going to feel to get that baby running again.

Mark