[GSjimmy]

still trying to get the XR92 started. Verified the timing (3rd time), cam is down, O is at 12 o'clock, bolts on the gear level, set to the "T" mark. When kicked over I have great spark. But only get an occasional pop. I verified that I am at TDC at the "t" mark.

Carb is from a 2003 XR100, all stock and freshly cleaned. Everything is in good shape.

Bike ran fine as an 80cc, overbored and installed a CB400f piston (200 thousands over). Nothing else besides the carb is different. This is driving me nuts.

BTW fuel and plug are both fresh.

 

[mrrcx]

Comp ratio change much? Proper plug heat range? Proper octane? Forget the woodruff key in the crank? All wires connected and grounded properly?

 

[kenglaze10]

valves adjusted properly?

 

[GSjimmy]

valves are adjusted correctly. compression is good plug is a NGK ch7hsa.

 

[kenglaze10]

Did you try starter fluid. . If it fires with that then its your carb. Just trying to narrow it down for you

 

[GSjimmy]

Did you try starter fluid. . If it fires with that then its your carb. Just trying to narrow it down for you

Yep, still nothing. Going to check my timing against a different flywheel ('79 XR80, known bad). It could have a different set of marks in relation to the keyway. The "doner engine" is a 1984 XR80R, rechecked the serial number.

 

[ajcmbrown]

Do you have the old carb just to test it?

 

[ajcmbrown]

One other way to test the timing/flywheel is to attach a timing light to the bike and the pos and neg leads to any battery, take the plug out, mark the timing mark on the flywheel with some correction fluid and have someone kick it over and see where the timing mark when it flashes in relation to the notch on the crankcase. If the flywheel has the incorrect marks, it could be anywhere.