Running in and broke down!

fump · Post by **fump** » Fri Jan 20, 2012 8:04 am

The 18S is back on the road, sort of.......Completed the fitting of new Piston and rings today all assembled and tested at home. Also had a valve lapping done by engineer. All appeared well so took her for a ride and all was well until 7 miles when there was a strange noise from the front part of the engine and it stopped. I declutched and pulled over thinking the engine has siezed but no, it would turn over okay and had good compression but would not fire. The engine appeared a normal temperature no smoke or oil leaks either. After about 30 minutes it started again and I was able to get home with no trouble at all.
But I could not restart it 5 minutes after arriving home.
I would appreciate some informed opinion on what may have caused the engine stop. I did not exceed 40 MPH at any stage and was mostly at 30 MPH.......

GOLDSTAR · Post by **GOLDSTAR** » Fri Jan 20, 2012 8:49 am

what sort of ignition do you have, is there a spark, has the timing slipped?kind regards

itma · Post by **itma** » Fri Jan 20, 2012 9:46 am

sounds ot me as if eitehr he piston nipped up or a valve stuck
your running in technique is out of date, the engine need to work, but not labour.

I won't ask what oil.

fump · Post by **fump** » Fri Jan 20, 2012 10:01 am

Thanks for your inputs. I was not able to check spark at the roadside as had left my plug spanner at home !! Though I did have 2 fresh plugs !

I have been wondering about the exhaust valve. At the start of the ride there was no compression until I worked the valve lifter, then it was fine. So maybe the exhaust valve it sticking sometimes. If so...what should I do about it? Leave it to work itself in?

itma · Post by **itma** » Fri Jan 20, 2012 12:42 pm

see posts passism re redex, ethenol fuel and sticky valves

bigwol · Post by **bigwol** » Fri Jan 20, 2012 2:26 pm

Is the oil feed to the exhaust guide clear/adjusted correctly

fump · Post by **fump** » Fri Jan 20, 2012 9:19 pm

Interesting.........thank you .........well the oil is a good quality motor cycle mineral oil 10W/40. I also use Valvemaster lead substitute additive with 91 Octane fuel. The comment about the oil feed could be a good place to start. perhaps I will make an adjustment there, but I need to read the manual first.
But how does the poor hot starting tie in with a valve problem, if the compression is okay?

itma · Post by **itma** » Fri Jan 20, 2012 9:33 pm

10W/40.?
down under in your kind of heat I wouldnt even start the bike up on that.

Redex is different to lead replacement in that its a lubricant,; No Redex, ? a spoonful of 2 stroke oil per gallon will do fine.

To me you have all the syptoms of a nipped piston; if it were mine I would lift the barrel to check.
you cannot adjust the feed to the exhaust guide only the inlet, which is about 1/8th turn open max.

fump · Post by **fump** » Fri Jan 20, 2012 9:37 pm

Lift the barrel ARRGH...............Edited by - fump on 20 Jan 2012 9:38:13 PM

itma · Post by **itma** » Fri Jan 20, 2012 10:02 pm

double check everything else first of course
esp for sticky valves.
A stuck valve can cause a pushrod to bend or jump off the bottom tappet