Forum

[Howzie]

Hello one & all,
Having a spot of bother with the exhaust tappet on my 59 250cc clipper, no matter how many times I adjust it, it still end up with no gap after a run, inlet stay fine at 4 thou, but not the bloody exhaust, when I last adjusted it to 6 thou I also give the adjusting nut a pop with the old centre punch. thinking of trying some lock tight an ideas please.
Cheers.

[Presto]

Loss of adjustment on the exhaust pushrod after the bike has been ridden is often the result of a burnt exhaust valve.

[Mark M]

Sometimes the threads become worn and simply won't lock together, try replacing the adjuster. If you were getting a gap appearing from a burnt valve you'd have other performance problems as well!
REgards, Mark

[Gwilly]

Valve seat regression mayhap? That might burn the valve a touch as well..

[Howzie]

Hello Again,
I had the bike out for a run a few of days ago, roughly 50 miles and it went really well, wasn't till I was about 10 miles or so from home when it went a bit flat and I lost the tick over so had to keep the revs up when stopping etc, just managed to make home. Checked the tappets next day and that's when I found no gap on the exhaust.
Cheers.

[Alan R]

Sounds like valve seat recession to me...........If the gap has closed but the adjuster remains at the same setting then your valve stem is moving towards the rocker..........Can you obtain a spare head ??? ---- this will keep you on the road whilst you investigate this problem further..........

[Presto]

Those symptoms - slight loss of power, loss of tickover, no tappet adjustment - are all signs of early stage exhaust valve burning. It's a bit of a pain, but I'll stay with my first suggestion! REgards - as they say!

[Alan R]

Sorry, but I just can't resist this opportunity to say }---- Hey, PRESTO ( Alright, alright----I apologise !!LoL..)...... I think the general agreement here is that our friend HOWZIE will need to remove the head in any event..............Personally I hope it's the burnt valve as it'll be a whole lot cheaper to repair, BUT....................... ???

[Howzie]

Hello all, Thanks for your reply's brilliant as usual, changed the tappet adjuster on the exhaust valve, see how that goes, in not off with the head.
Cheers Howzie.