78 LF issues

[JDXspec]

This could be under racing since it is a cc but a LF too. Anyway I have a 78 340 LF that runs cold on the Mag side. the PTO side will read 200 degrees on the exh pipe and mag will only read about 100 degrees. carbs are clean, it has new seals on the crankshaft, excellent spark with a good stator installed last spring, 140 psi in both sides. it will start right up, idle ok and drive ok. but not with alot of power. Any ideas? I'm thinking maybe a flooding carb? Thanks

[lwb140]

i had this with a 78 liquifire that had been sitting for EVER not exactly sure what fixed it but i had the carbs apart several times had crap in pilots every time i took them apart but i think the needle and seat deal was a big part of it i swappped carbs left to right and the problem moved with the carbs wade

[harleysportster]

This could be under racing since it is a cc but a LF too. Anyway I have a 78 340 LF that runs cold on the Mag side. the PTO side will read 200 degrees on the exh pipe and mag will only read about 100 degrees. carbs are clean, it has new seals on the crankshaft, excellent spark with a good stator installed last spring, 140 psi in both sides. it will start right up, idle ok and drive ok. but not with alot of power. Any ideas? I'm thinking maybe a flooding carb? Thanks

Dustin,
Since you mentioned low exhaust temp and lack of power, I would lean towards lose of spark on that side. It could be firing on both at idle but as it revs up, one side couls be dropping out.

[JDXspec]

I don't think its spark related, as it seems the mag cyl never does consistantly fire. I had my tester on that side while idling it and it was bright blue, consistant,and even occassionaly going from the clip on the tester to the base if the plug, (thats 1 1/2" ) i will swap carbs to see what happens, If I still have decent snow.

[JDXspec]

Well good news I got it running pretty good. Bad news I really don't know what I did.I swapped carbs and fired it up and it ran well. Both cyls were pretty even temp wise. ButI did hear a cyl miss a few time at idle. So a coil or cdi box could be at fault yet. But that can wait till it fails more consistantly. I think it needs some clutching work now. the engine seems to work hard. if it gets more rpms its fine but it pulls down in more powdery snow. like it shifts too fast. I tightened the secondary and that didn't help much so i think primary springs or weights may be in order. Progress!