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inlet valves stuck open

Posted: Mon Jul 15, 2013 11:58 am
Author: stevez1
Hi,
I am having trouble with my Z1B.
The liner in my fuel tank which had been in there since Adam was a lad, had started to break down. I removed the old liner and put in a new one. I also ultrasonically cleaned the carbs and fuel tap and everything seemed to be fine.....
However, the inlet valves now stay open and the engine won't run. It has been suggested that the old liner was to blame - some of which may have got into the engine! Has anyone else experienced this?
Anyway it has got to be a head off job and I only hope the valves aren't bent and the pistons damaged.

Posted: Mon Jul 15, 2013 2:39 pm
Author: PAULJAC47
Seems unusual! how are you checking that all 4 valves are staying fully open?

Posted: Mon Jul 15, 2013 2:49 pm
Author: hillbilly
I had this once,it was cam buckets sticking.

Posted: Mon Jul 15, 2013 4:57 pm
Author: sid123
most likely cause is new liner is being dissolved by the petrol - and being sprayed onto valve stems - remove carbs and look into inlet to see if coating of like a resin on valve stems - this will confirm if this is the case

I had this once when a can that had contained laquer was used to store petrol

p.s it also gets up back of stem seals if run for too long and damages them




Sid

Posted: Tue Jul 16, 2013 8:19 am
Author: stevez1
Thanks for the replies, There was no compression when turning the engine over, so took out a plug and had a look - then another etc. The tank with new liner had only been fitted and 1/4 filled with petrol for a few minutes after being left to cure for about 3 weeks.
Will be taking the carbs off and the head if necessary to have a closer look shortly unless anyone can advise an easier way......
Not looking forward to removing another liner!!!!!
Thanks again
steve

Re: inlet valves stuck open

Posted: Tue Jul 16, 2013 10:48 am
Author: snotie1965
stevez1 wrote:Hi,
I am having trouble with my Z1B.
The liner in my fuel tank which had been in there since Adam was a lad, had started to break down. I removed the old liner and put in a new one. I also ultrasonically cleaned the carbs and fuel tap and everything seemed to be fine.....
However, the inlet valves now stay open and the engine won't run. It has been suggested that the old liner was to blame - some of which may have got into the engine! Has anyone else experienced this?
Anyway it has got to be a head off job and I only hope the valves aren't bent and the pistons damaged.

What do you mean "liner" is it a treatment solution ?

Posted: Tue Jul 16, 2013 2:47 pm
Author: Pigford
I can't see how the tank liner can get thru' the carbs (jets) & coat/stick the valves :|

Posted: Tue Jul 16, 2013 5:41 pm
Author: ZedHead
Pigford wrote:I can't see how the tank liner can get thru' the carbs (jets) & coat/stick the valves :|


Me neither, I thought these liners are resin based and non soluble in petrol.

Posted: Tue Jul 16, 2013 9:03 pm
Author: ADRIAN H
ZedHead wrote:
Pigford wrote:I can't see how the tank liner can get thru' the carbs (jets) & coat/stick the valves :|


Me neither, I thought these liners are resin based and non soluble in petrol.


Unfortunately some are not Ethanol resistant.

Posted: Thu Jul 18, 2013 9:22 am
Author: stevez1
Carbs are now off and seem ok. I did ponder how the dissolved liner could get through the carbs but can't see what else would make the valves stick!

Posted: Thu Jul 18, 2013 10:01 am
Author: ZedHead
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