Pushrod Length for model 20 / g9

joolz · Post by **joolz** » Fri Sep 10, 2004 2:30 pm

Hiya

The pushrods on my basket case model 20 (500 twin) are wrong (too long - the head won't go on!). Can anyone tell me what length they should be?

I understand there are three different pushrod lengths fitted to the twins -
i) 500 & 600cc are the same
ii) 650cc 1959
iii) 650cc 1960 on

Many Thanks

Joolz

Biscuit · Post by **Biscuit** » Fri Sep 10, 2004 5:59 pm

I'm sure your not trying to put the heads on with a cam on full or partial lift, so it seems to indicate new rods. The Club spares scheme has them as well as Andrews Engineering. There is also a difference in the centre to centre distance on the cam followers, after '53 (reading from the spares book) the length was increased. If short followers are fitted to later engines, the push rods rub on the tunnel near the cylinder base.

speedhog · Post by **speedhog** » Tue Sep 14, 2004 11:10 am

Hi Joolz,
the length of G9 pushrod is 81/16 ins
i broke one in my 1951 G9 and replaced it with one from a 1953 model same length
hope this helps you
regards Bill

joolz · Post by **joolz** » Tue Sep 14, 2004 2:42 pm

Brilliant, - thanks to both of you.

You see, there were two basket cases from the same garage, a 500 and a 650. I've got the 500, and my mate's got the 650.

It seems the 650 has a modified 500 crankcase, and a variety of pushrod lengths were found, with various degrees of rubbing on the pushrod tunnels! So although both bikes are post '53 the info about the cam followers is useful too.

No we know what the standard setup should be, we can hopefully work out what goes where!

Cheers

Joolz