81 Yamaha maxim (Not GS) no start!

[feelergaugephil]

I know, it's not a GS, but I figured I would ask you guys.......
1981 Yamaha Maxim 550 (or if your in UK, XJ550)
It got dropped off at my house to be fixed, Non runner.
4600 original miles, and original, a superclean under the dust!
So, I charged the battery up and put some fresh fuel in it and it cranked right up!!
I let in run for 20 mins with a rev now and again (fan placed in front of engine to keep it cooler)
So, now for a test drive on this classic bike!
I backed it out the shed (still running) once backed up, I sat on it, revved it again, back to idle, put it in gear and it instantly cut off!!!!
I tried the starter but it spun but no start!!

Figuring that it's been in a shed for 25 years!!!!!!!! the carbs were stopped up!
I stripped down the carbs and the float bowls were the worst I have seen in years, it looked like old jello!!!
Once fully stripped, I cleaned out the jets and all passage ways with compressor,now, its all clean, put back together again....
Cleaned out the tank, and even the fuel petcock filter was clean....

Put carbs back on, SAME THING! spin no start!!!!
So I whipped out the ORIGINAL champion spark plugs and they spark on spin!
So, I get some easy start and spray some in the air box, still Spin no start!!! WTF!

(Oh, the side stand switch was fully OUT before anyone thinks its that)

So, I have spark, and I know I'm getting fuel!
The vacuum hose is working correctly, it does pump fuel when spun over.
Anyone have any ideas?
Could it be the original spark plugs gave out? I could understand one or two! but not all 4!
Like I said, they do spark,,,,,
Please help! I'm actually thinking of buying this bike if the guy doesnt want it!
Phil.

 

[Steve]

I see where you "stripped down the carbs", but I did not see where you DIPPED them.

The problems we have with our GSs are not exclusive. Dirty carbs are still dirty carbs, you have to clean all the passages inside the carb body that you can't see, hence "the dip".


Concerning the cut-out when you put it in gear: temporarily connect a test light to the power side of the coil. Does that also cut out when you put it in gear? If so, you need to find out why. The side stand switch is one possibility, even though you say it's fully out, but there may be more than one set of contacts. In fact, the contacts inside the switch might be stuck together. Use a meter or a test light to verify.

.

 

[feelergaugephil]

Thanks. Will try that then.

 

[baz666]

You can also try xjbikes.com
Great site similar to this one, but for Yam XJ machines.

 

[feelergaugephil]

You can also try xjbikes.com
Great site similar to this one, but for Yam XJ machines.

We have simular minds!!!! I just joined!!!!!!!!