O/T Definately not your usual what bike engine question

[Mark (smokey mow)]

As a few of you know I now have a 1966 Johnny Walker Racing JW4 single seater in my car collection for a bit of a restoration.

Various incarnations of the JW4 was built between 1965 and 1969.  The early mk1 cars supplied from the factory were fitted with the 250cc Villiers Starmaker Engine, the Mk2 with a 650cc BSA A65 engines, Mk3 with Saab engines and Mk4's were designed for the IMP engine.  My car is a Mk2.

The Formula 4 regulations at the time stipulated that the retail price of a running engine should not exceed £150, this was intended to keep the cost down for competitors and any possibility of engine tuning to gain an unfair advantage. As such cars were often sold without engines to allow owners to choose their own.  Several different bike engines were fitted which typically included BSA, Norton, Triumph, JAP and Ducatti.

As my car currently has no engine, The question is what to go for myself?

The criteria is....

Built before 1969

650cc or under

Air cooled

Ideally a unit twin

While I'd quite fancy a british engine, they are generally underpowered compared to some of the Japanese offerings from the same era in standard tune so my current thinking is the Yamaha XS650, but has anyone any other suggestions?

For those that can't offer any help but are reading this and wondering what Formula4 or the JW4 was then have a watch of this period film

http://bps.britishpathe.com/hls-vod/flash/00000000/00004000/00004168.mp4.m3u8

And before anyone asks, yes I do have a better roll bar

[XTR2Turbo]

Personally I would lean towards authenticity rather than power.

 

So one of the classic British engines

[XTR2Turbo]

Mark I seem to have a problem with your link -  it is trying to open as mp3 file

[Norman Verona]

Agree with XTR2.

 

I'd go for the 650cc BSA A65.

[Mark (smokey mow)]

Mark I seem to have a problem with your link -  it is trying to open as mp3 file

It opens ok for me but try this

http://www.britishpathe.com/video/formula-four-racing-cars/query/Formula+four+racing+cars

[XTR2Turbo]

that's better ..

[davidgh]

Mark

 

Wiki indicates that the XS650 engine of the time was 654cc! Are you a cad or a bounder, Sir? 

 

I don't think you've given us the information we need, though. Do you want to have the car admired? Or, do you want to win competitive stuff?

 

I think a little reflection on that question will give you a clue as to what you best do.

[Nick Algar - Competition Secretary]

I had a BSA 650 in a Norton frame back (NORBSA) then and it was a cracking engine, OK no supposed to be the Yamaha power, but still very good low down grunt and go.

[Mark (smokey mow)]

Mark

 

Wiki indicates that the XS650 engine of the time was 654cc! Are you a cad or a bounder, Sir? 

 

I don't think you've given us the information we need, though. Do you want to have the car admired? Or, do you want to win competitive stuff?

 

I think a little reflection on that question will give you a clue as to what you best do.

Thanks David, and well spotted thats 4 too many cc's

It's a car to show rather than go, if I wanted to win races then I'd fit a modern engine and there are at least a couple that now wear Jedi bodywork. I'm in the rather fortunate position that I have all the original bodywork so the intention is to restore completely within period using only parts that were available during it's period of manufacture.

[davidgh]

Thanks David, and well spotted thats 4 too many cc's

It's a car to show rather than go, if I wanted to win races then I'd fit a modern engine and there are at least a couple that now wear Jedi bodywork. I'm in the rather fortunate position that I have all the original bodywork so the intention is to restore completely within period using only parts that were available during it's period of manufacture.

British twin of the period then, Mark 

[Terry Everall]

I used to ride a 500cc triumph T100 and that would beat all the 650cc engines around at the time including Norton Dominator

[Mark (smokey mow)]

I used to ride a 500cc triumph T100 and that would beat all the 650cc engines around at the time including Norton Dominator

Thanks Terry, the triumph engine has been done in the 650cc variety (I assume the T110?) so that's a possible option

http://i457.photobucket.com/albums/qq299/mark_wendon/JW4/650.jpg

The 500cc would be an interesting choice as it also opens up a few options thrn for sprinting it with the 500owners association.

[Graham0127]

Mark.......Listen to Terry.....you won`t do better than a T100 engine.I have a mate with a Vincent engined Mk2,beautiful but cost a fortune.

T100...compact ,really good looking and lighter.My Triton (T100) was awesome.Think I`ve still got some spares somwhere.

[Mooch]

Mark,

 

I've just e-mailed my mate who is your equivalent in gurudom for all things pre 1970 and british twin motorcycle based.  I shall pass on his reply when I get it.  

[Mark (smokey mow)]

Mark,

 

I've just e-mailed my mate who is your equivalent in gurudom for all things pre 1970 and british twin motorcycle based.  I shall pass on his reply when I get it.  

Excellent, thanks Mike