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Side valve running hot

Posted: Mon Jul 22, 2019 9:14 am
by SteveBerry
Hello folks, new here and to ariels although not new to British bikes. My recently acquired VA SV seems to be running far to hot for comfort which I believe is a common issue. The engine is in a healthy condition and starts/idles well. I've set the timing at 5/16" but I've heard this is not enough advance. Also I've been told that fitting an A6/664 cam improves things. I've got one knocking round so will try that if this is true. It seems to be running better in esso super which is 97 grade and ethanol free. I also add valve master. Any info is very welcome. Thanks Steve

Re: Side valve running hot

Posted: Mon Jul 22, 2019 9:28 am
by Dave.Barkshire
My old 51 VB used to run very hot and it seems to be normal for them. The down pipe would sometimes glow orange which was obvious during a dark night after a long run but this was usually after the valves were burnt out which happened at least once. With new valves the compression was restored and presumably the running temperature lowered.

I rode to to work every day and would ride flat out most of the time but it always started first kick and always ran. It would eat a spark plug every now and then but it was very reliable and had the best front brake of any drum brake I've every encountered (sometime must have been wrong with it). I did use the advance/retard a lot and it was almost interchangable with the throttle which is not the best way to ride but I was a teenager and enjoyed playing with it.

If your timing is too retarded then they will run very hot. If you can stand on the kickstart without it going down easily then your valves are probably ok, if it goes down too easily then you might have burnt valves.

Re: Side valve running hot

Posted: Mon Jul 22, 2019 9:37 am
by SteveBerry
Thanks Dave, the compression feels good but maybe not good enough so that might be worth thinking about as it's a bit asthmatic going up hills and starting off.

Re: Side valve running hot

Posted: Mon Jul 22, 2019 11:21 am
by john.whiting
Upping the compression ratio will cool the exhaust quite noticably,and increase the performance..........if you want a hot motor ,get a pocket valve Harley......the heat from the rear cylinder exhaust port will blister your leg....