Got my LC out of hibernation last week. Cleaned the carbs, fresh fuel. Cleaned up the plugs and all was fine.
Started it today and it was only running on the left cylinder. Gave it a rev and it spat out some oil from the right and then ran ok for a bit. As it warmed up though the revs started rising to c5k and wouldn't drop.
Any ideas? I didn't strip the carbs, just blew them through with carb cleaner and air.
Post by shaunthe2nd on Apr 22, 2020 16:31:28 GMT 1
Sounds like an air leak. Check firstly the carb link pipe is snug fit and not hardened or slipped off. Then check the rubbers on cylinder and airbox side of both carbs for cracks or hardening etc. Replace if necessary. Also check that carb slides not sticking as old fuel can go quite gooey. If so, carbs off and ultrasonically clean.
RD 350 LC - 1982 - bounty like my bike in the 80's, finally got an original UK one. 31K/Aprilia RS hybrid - ex Yogi and Muttsnuts bike - my first hybrid Triumph Street Triple R (sorry!) ...and a box of bits I hope to be able to turn into a 1983 31K
How did you clean the spark plugs? I used to leave mine in all season (in recent years) and then just replace them. Sometimes 'cleaned' spark plugs don't work too well.
Back in the day I tried running my 350lc on Champion N3G plugs. It ran fine for about 1000 miles then started behaving as if the carb slides were sticking partially open, (most odd). I swapped back to standard NGK plugs and the problem disappeared instantly and never returned. What I'm saying is the plugs can sometimes cause crazy symptoms that you wouldn't normally associate with.
check that your throttle cables are fully seated in the cable junction box, if they aren't fully seated one of your slides could be open and will cause it not to start cleanly and then rev over once warmed up
If I remember correctly I used to have to change the plugs somewhere between 1000 and 2000 miles on the LC I had from new in 1983, never looked much wrong with them and cleaning didn`t help , used to use Shell 2T oil I think.
It would gradually start running rougher until I fed it another set.