fred calvert
XS650 Member
red hot pipes why
Red hot pipes,Reply; It's a 1975 xs650, I got it 3 weeks ago. no wiring on it everything in boxes, what I bought was a roller. When I got it home I wanted to see if I could start it up and work from there. I ran the necessary wiring, checked valve setting, cleaned the carbs, cleaned points and set cam chain tention, sprayed some starting fluid in it and hit the button. It started and I kept it running with the choke, it got to the a point to were I could rev it up,Thats when I noticed the left pipe look very hot, I had to look real close see a red glow on the left pipe but it was there the right side wasn't to bad but still hot. It did blow a lot of black soot out the 2 into 1 pipe. I checked the plugs and they were dry. Anyway I pulled the carbs back off and re-cleaned them. I was thinking maybe adjust needle valve from 3rd slot to 4th slot. If that don't work I'm lost. Thanks for the help. Fred CalvertWhat have you checked, done so far?
+1 on lean. Rich is cool running. (unless you have a catalytic converter, they don't like that). Maybe a vacuum leak. Are you running it with the air filter/s on?its got compression or it wouldnt be running, your not to concerned with how much it has at this point, some motors have more than others due to use and age and condition, but it runs so get passed the compression part, start looking at fuel and air mixture. You need to look at the plugs, they will tell you lean or rich conditions. I would bet money on them looking white-ish or the left being whiter than the other side. The carb could need cleaning on the left, it could be an air leak (vacuum) on the rubber intake that holds the carb or the mating surface to the head, if the carb is clean and its sucking in air, it would lean the mixture and still run.
me personally, I would check plugs.
Excess fuel will not make them run red unless the motor is built to make wicked compression and power and then you know its gonna do that on an extended run up. If we are talking a stock motor, and we are, then a red pipe means LEAN, not enough fuel. You can richen these motors up so much that it will wash the cylinders down and never make enough power to run the pipes red. Run it lean for a second and see what the pipes do.