Motorcycle Repair: xl175 slows down


Question
QUESTION: my xl starts and revs up fine,goes through first and second gear then starts slowing down choking it kills it.

ANSWER: Dave, any number of things can be happening with your XL175....
First check the compression to see if it is around 160-180 psi.
Adjust the valves to .002" on the intake valve and .003" on the exhaust valve (at T mark on the flywheel alignment with both valves closed).

Make sure the whole fuel system is clean ....  gas cap vent hole, petcock internal passages and screen, fuel line, carburetor float bowl, float valve with float level set at 22.5mm.

Gap points to .016" at the widest gap during rotation, then set the backing plate so the points just OPEN at the F mark indicator on the flywheel index marks.

Make sure your drive chain is not over-tightened and there is plenty of clean fresh oil in the crankcases.

Spark plug gap is about .025" Put in a new one if the old plug is oil/fuel fouled.

Check spark plug cap for 5K ohm resistance.

The standard main jet is #110, but if you change the air filter or exhaust system, you may need to jet it up one step.

Bill Silver

---------- FOLLOW-UP ----------

QUESTION: I've done everything but the jet change I noticed something you might have some experence with. My xl gets up to about 35 mph then the ground speed drops but the RPMs stay up, weird.

Answer
Dave, the clutch is slipping....

Either go over the adjustment procedure to ensure that you have some freeplay at the clutch lever or you will have to pull the clutch cover and replace worn/damaged clutch plates and/or clutch springs.

Bill Silver