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Guys,
Thanks for helpful advice on my other thread regarding fitting XJR carbs on my XS. I never really got started going down that lane after realizing that the XJR carbs I got were designed for a very different angle of alignment than the original carbs.
New carbs or not, my bike suffers from very bad performance. I've nailed it down to the carbs, but despite ultra sound cleaning and about five disassemble/assemble runs, there's no improvement. I surrendered and called the local Yamaha shop. They were very hesitant to bring it in ("it's more than 25 years old, it's not engineering any more, more like witch doctoring, expect it to be expensive"). So last Saturday, after mourning the Swedish soccer team's lousy game against Trinidad&Tobago in the World Championship, I decided to give it a final try.
Symptoms: bike ran fine for one ride after my last working on it, then during second ride suffered from one cylinder dropping out. All plugs carboned, 1st plug carboned and wet. Very weak performance, difficult to rev it, far too weak to ride it. Didn't think carb problems could affect all four cylinders, suspected ignition instead. Checked ignition, timing advancer, ballast resistor, the lot. When I turned the petcocks to prime, gas came gushing out one of the vent hoses from cyl 1&2 - aha! While dismantling the carbs, I noted a puddle of gas at the bottom of the air filter box. Suspected that carb 1 needle valve wouldn't close, but it did. It wasn't until I dropped the floats into a can of kerosene that I realized that one part of it had a leak, since it sank. Found the leak after wiping the float and looking for where it got wet again - it's damn hard to see such a leak. I got a picture, the actual leak doesn't show (it's under the holder arm) but I circled a similar corrosion spot:
http://web.telia.com/~u01801126/Pics/XS1100/Float2m.jpg
Soldered the leak, assembled everything - and the bike runs like a charm!!! On all cylinders!!!
I have learned a lot from reading hundreds of posts from all the helpful people on this forum, and I post this as a reminder to myself and others of what I myself learned this weekend. I recon it's evident to most clever people, and that it ought to be mentioned in some of the zillion posts which I overlooked, but anyway, here it is:
A float problem, leading to a flooding carb, will make all cylinders run too rich when the flooding gas reaches the air filter box
Now I'm so much happier. Even made me forget the soccer game.
Thanks for helpful advice on my other thread regarding fitting XJR carbs on my XS. I never really got started going down that lane after realizing that the XJR carbs I got were designed for a very different angle of alignment than the original carbs.
New carbs or not, my bike suffers from very bad performance. I've nailed it down to the carbs, but despite ultra sound cleaning and about five disassemble/assemble runs, there's no improvement. I surrendered and called the local Yamaha shop. They were very hesitant to bring it in ("it's more than 25 years old, it's not engineering any more, more like witch doctoring, expect it to be expensive"). So last Saturday, after mourning the Swedish soccer team's lousy game against Trinidad&Tobago in the World Championship, I decided to give it a final try.
Symptoms: bike ran fine for one ride after my last working on it, then during second ride suffered from one cylinder dropping out. All plugs carboned, 1st plug carboned and wet. Very weak performance, difficult to rev it, far too weak to ride it. Didn't think carb problems could affect all four cylinders, suspected ignition instead. Checked ignition, timing advancer, ballast resistor, the lot. When I turned the petcocks to prime, gas came gushing out one of the vent hoses from cyl 1&2 - aha! While dismantling the carbs, I noted a puddle of gas at the bottom of the air filter box. Suspected that carb 1 needle valve wouldn't close, but it did. It wasn't until I dropped the floats into a can of kerosene that I realized that one part of it had a leak, since it sank. Found the leak after wiping the float and looking for where it got wet again - it's damn hard to see such a leak. I got a picture, the actual leak doesn't show (it's under the holder arm) but I circled a similar corrosion spot:
http://web.telia.com/~u01801126/Pics/XS1100/Float2m.jpg
Soldered the leak, assembled everything - and the bike runs like a charm!!! On all cylinders!!!
I have learned a lot from reading hundreds of posts from all the helpful people on this forum, and I post this as a reminder to myself and others of what I myself learned this weekend. I recon it's evident to most clever people, and that it ought to be mentioned in some of the zillion posts which I overlooked, but anyway, here it is:
A float problem, leading to a flooding carb, will make all cylinders run too rich when the flooding gas reaches the air filter box
Now I'm so much happier. Even made me forget the soccer game.
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