AJS & Matchless Owners Club

The Typhoon, as many know, is a G80CS 500cc bored to 88mm for 1959 & 89 for later years. The stroke is increased as well to give 588 or 598cc. The special pistons are similar but have higher location of the pin to use the same connecting rod. The pistons are relieved around the top edge to fit into the G80CS heads so with the same combustion chamber the CR is increased, 8.7 tp 9.2 for the 1960-up.

Bill Basset, North American Section member has had these later ones made up by a high quality maker in the past & told me he would have more made to order. The maker is a specialist in modern racing pistons & the same as makes them for PMLI to use in the 500cc late CS. I have been running one in my G80CS & they are superior to the original & weigh about the same, actually, slightly lighter so need no material removed nor rebalancing of the crankshaft. With a properly tuned machine & the standard CR, using 91 octane, (R+R/2), it starts first kick, runs very well & there are no noises from piston or combustion irregularities.

These pistons must be made in batches of four but the two parties will accept orders of one each & resell the excess. Anyone interested can PM me for more details.

Cheers, Don.

So are the barrels the same as the 500 but with a thinner liner?

Same liner bored thinner but plenty of metal left. I think AMC liners are rough on the outside & cast in. Cheers, Don.

Don, did you get anywhere with the piston? would be interested in a price and time scale.
For referance i am in the finishing stage's of completing a batch of 96mm stroke flywheels which accept the stock axles and bigend as per factory spec.
thanks.
james

Hello, James & all Typhoon lovers. The contact is: Bill Basset, jagwillei@bassetsjaguar@neccoxmail.com.

Copies of emails: Don,
I had pistons made by Arias for the later Typhoon and sold the extras on ebay for my cost. I had planned on doing them again as needed for some of the club members. My pistons had the same dimensions and shape as the original one with the exception of the rist pin. It was .875 instead of .874. It worked out well because the bush could be honed to the larger size without having to replace it. I think I sold them for $156.00 apiece, I had also done ovesize od valve guides with a smaller id. Bill



On Mon, May 9, 2011 at 7:35 PM, Don Madden wrote:


Hi, Bill. While researching getting some Typhoon pistons made I was told you had obtained some from Arias Piston. I am running an Arias piston provided by PML in my newly restored G80CS engine. Is it true that you bought a batch of four & sold the unneeded ones on ebay? If so, which engine were they for, 1959 or 1960-62? Does the crown shape match the original, important for efficieny? What was the cost of the pistons, I am aware that a minimum of four must be ordered.

I hope you don't mind answering the questions. Myself & others are in need of Typhoon pistons but they are thin on the ground. Cheers, Don.

That's All, Folks. Cheers, Don.

The factory issued a Typhoon Model (600cc) Technical Data, that was printed by a C Baldwin Ltd, Tunbridge Wells. Nest to this at the botton of the page is a number 156/60. It is only a small or A5 size sheet of paper, but now i suppose very rare. It came in the back of of a green coloured Supplementary Instruction Book for Competition Models, for the 350 and 500 scrambler and trials models. I have had this and two others of these small booklet since 1969. I thought it may be of interest to Typhoon owners who may not know of its exsistence.

I would like to have a copy, & can print from an email attachent. I do have the thin competition supplement manual & the standard owners manual, all original with my 1956 G3LCS. Cheers, Don.

I shall have to get a photo copy of it and post it to you, as i do not have a copier to send it via an email.

Thanks, Don.

Don you had better send me your address, so that i can send it to you, as and when i can get it photo copied. I thought that you would have had such an item. I also have the factory build book for the 7R, G50 and the G50CS, from 1958 through to 1962. Now that makes very interesting reading.