jps mockup bikes

[Wayne]

Hi allI have always wonderd did the 2 mock up jps race bikes on the john player merchandice stand get broken up, sold or made in to running bikes, as far as i know the bikes had no internals.

[graham]

Hi Wayne,Do you mean this one:http://www.grahamwilshaw.co.uk/displayi ... 4&pos=4and..... this one:http://www.grahamwilshaw.co.uk/displayi ... um=4&pos=5 If so, I can fill in the details. Graham.

[johnbirchjar]

Looking at Grahams pics: of the Arbus rotary made me think of a chat I was having at the Beezumph a couple of years back with a guy that raced the only (he said)rotary comb:lot.(bike & chair)also claimed to have the engine from said Arbus bike,so I assume that Nortons?(was it a Norton factory bike?)had more than one engine,('course they did,silly old fool!)probably four or five,(I'ts me age guv,)J.B.

[Wayne]

Hi GrahamThe year i saw them would be 1990-1 on he jps stand, am i correct in that one of the bikes picture runs a standard commando engine if i heard the rider corect, and dose this is explaine why, its one of the old jps mockups.regards wayneps have you got any six speed gerboxes in, i am still looking

[johnbirchjar]

Hi Wayne,I too am looking for a six speed box,I have heard of a possible source of three companies that will make you one,(at a price)the guy that races the rotary comb;lot told me that the company that made the special "box" for his comb; and specialised in "one off's" and was based in Peterbro',their is another company in Kent(I found that one on the web)and the company that made the G/box's for the racing rotaries,in Stafford? (if they are still trading)unless of course Graham has one or two lying around,regards,J.B.

[johnbirchjar]

I have remembered reading in an old copy of M.C.N.(which I kept)about this guy that was re-building a special,and had a new G/box built from scratch,he suplied (Honda)circlips spacers and countershaft,all the new gears were machined from scratch,cost?£750quid!!(2008 prices) the company?Nova Racing Transmisions,Peterbro'(01733 210082) I realy must give them a call and will report back,regards,J.B.

[johnbirchjar]

Hi guys,reporting back,just got off the phone after a very interesting chat with the boss of New R acing Trans:he said that he is working with the new Norton people on a new G/box for a rotary? and went at great lengths to explain why a six speed box would be of no advantage re:top speed or ecconomy(something about the "direct drive from engine to box"?and no,one cannot fit an "overdrive" a la cars & commercial vehicles)he then went on to tell me that the company in Kent already manufactured six speed boxes for our F1&FISports (he did'nt know the asking price,hazarded a guess at a couple of grand+)he then went on to say that Harlies fitted a box withan "overdrive" on their V Max and that may be worth a look,but we are now talking serious dosh,and not realy worth the trouble/money, so it looks like I will have to stick with what Norton fitted,(I fitted an 18tooth sprocket on the G/box some years back in an attemp to improve ecconomy,made no noticable difference,)sorry if I woffled on,regards,J.B.

[gripper]

Sounds to me like the man talking about Harley gearboxes is waffling. I presume he meant "V Rod" as the V Max is a Yamaha. Unless you fit a higher ratio top gear (or final drive ratio) and have the power to drive it, there is little to be achieved by changing the gearbox internals. With the torque spread of the rotary engine, five gears is more than enough. The six speed boxes fitted to modern bikes are to deal with their (relatively) narrow power band. A good example of this would have been the racing 50cc bikes from the late sixties with anything up to sixteen gears. The gearbox fitted to IP2/Classic/Commander is Triumph box from the early Trident (T150) and I believe it was designed by Quaife. That bike was putting out about 60 bhp. The changes made to use it for the rotary are to take the input from one side and cross the bike to the other side for the output. The poor quality and finish of the gears supplied to Norton is why these gearboxes wear so badly. The technique of only going down one gear to negotiate roundabouts etc and then pulling away in fourth, lacks any mechanical sympathy. (It also over oils the engine) Better to work the gearbox like a conventional bike. The ratios on the bikes mentioned above, seem well spaced to me. I believe that is not the case with the F1. It would have to be pretty bad for me to justify the outlay for a new six speed cluster.

[Wayne]

second hand fz750 6 speed £150 to 200ow01 race box in versions a,b,c or d £800 to 1000 newas far as i know any of the above will workit may even be possible to fit an r1 gearbox over to graham and richard on this one

[johnbirchjar]

The "woffle" is my mistake, the g/box man did say "V Rod" and I was looking for six speeds hoping that number six would be an "overdrive" for more ecconomy,no other reason,but not possible.In answer to Wayne's choice of box's,am I right in thinking that only the FI&FISport can fit theese,because they run backwards? or am I getting confused with the race bikes?.On an entirely different tack,an article in M.C.N. a couple of weeks back caught my eye,(and rattled my cage)one of their "experts" was casting aspersions on our beloved rotories!!so I need to get my facts right before I "put pen to paper"(1)most prolific years of manufacture?'80s?(2)Reliability, mollied engine,80,000 miles?.(3)ecconomy,(my Classic averages about 45mpg)Commanders, F1&Sports?.(4)"Low on Torque"? I do'nt think so!!,( can anyone quote figures to me with comparisons?)thanks in advance,J.B.

[johnbirchjar]

OOPS!! of course I ment the ENGINES run backwards(I realy am getting worse!!)J.B.