74 Space Frame JPN Replica ( Pile of Tubes)

4 years in the making my dream project finally took to the track last June, small niggling teething problems spoilt a few meetings in the summer and ended up with 2 blown head gaskets , a seizure , a broken gearbox ,fuel starvation and a set of Mk2 carbs that refused to be set up. when we finally got it running something like , I fell off it trying to hard in the wet! Still 2014 season is calling and with new carbs and a 6 speed gearbox I'm hoping for better things .

The bike is as " Home Made " as It can be , and as close as the original as I could make it ,mainly by studying photographs .

The first outing was a bit worrying, as this was my teach yourself bronze welding project, and the words of my pal suggesting that the frame would return to a " Pile of Tubes " the first time i applied the front brake. That name has now stuck and forever the bike is to be referred to as "the pile of tubes".

Originally a Peter Williams replica and knowing of Peters dislike of this bike I think now I'll say its a Dave Croxford Replica!
For personal reasons my Bike does not advertise a cigarette company ( nobody seems to notice) although I accept that no tobacco money , no JPN team.

When I started this project JPNs seemed to be the forgotten bike of the seventies , Rob North 3's being the replica of choice, but lately space frames & JPN' monocoques seem to be coming out of the woodwork. So I thought is was time to go public with mine .

If anyones thinking of building one , I am willing to answer any questions or offer advice , would i build another , maybe not theres an awful lot of tubes and brazing to do .

Welcome to the forum (Mike, I assume?).

Beautiful work and very interesting to say the least. I wish you well in your endeavors on track and in the shop.

Please keep us apprised of your activities, by all means.

Definitely a labor of love. I'm certainly impressed. Could we see more pictures? Did you replicate the factory primary drive or go with a more modern belt drive?

Ken

lcrken said:

Definitely a labor of love. I'm certainly impressed. Could we see more pictures? Did you replicate the factory primary drive or go with a more modern belt drive?

Ken

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Thanks for that Ken, After a lot of deliberation ( and the state of my Bank balance ) I opted for a Belt drive and a modified MK3 chaincase which looks not to dissimilar. Since then Basil Knight ( ex JPN Team) provided me with a drawing ,but the complexity especially with the longer mainshaft for the dry clutch would have proved to be extremely expensive . To convince myself i reckoned that if Belts were available then they would have used them too. However since Peter Williams is now producing replicas the parts may be available . Maybe Next Year. Once I have mastered posting photographs , I have some of the build if your interested.

Mike

Thanks, Mike.

By all means post more build pictures. I'm not the only one here who would be interested in them.

My friend, Mick O'field, who worked at Norton back in the day, and also raced Nortons, told me that the race shop had tried a belt drive, but decided against it after too many failures. The modern HTD style belts are much superior to what was available then, and I suspect they would have happily used them if they had been available.

Ken

See you soon Mike. defo at "three corner" Darley, and the very best for 2014!

Moto55UK said:

4 years in the making my dream project finally took to the track last June, small niggling teething problems spoilt a few meetings in the summer and ended up with 2 blown head gaskets , a seizure , a broken gearbox ,fuel starvation and a set of Mk2 carbs that refused to be set up. when we finally got it running something like , I fell off it trying to hard in the wet! Still 2014 season is calling and with new carbs and a 6 speed gearbox I'm hoping for better things .

The bike is as " Home Made " as It can be , and as close as the original as I could make it ,mainly by studying photographs .

The first outing was a bit worrying, as this was my teach yourself bronze welding project, and the words of my pal suggesting that the frame would return to a " Pile of Tubes " the first time i applied the front brake. That name has now stuck and forever the bike is to be referred to as "the pile of tubes".

Originally a Peter Williams replica and knowing of Peters dislike of this bike I think now I'll say its a Dave Croxford Replica!
For personal reasons my Bike does not advertise a cigarette company ( nobody seems to notice) although I accept that no tobacco money , no JPN team.

When I started this project JPNs seemed to be the forgotten bike of the seventies , Rob North 3's being the replica of choice, but lately space frames & JPN' monocoques seem to be coming out of the woodwork. So I thought is was time to go public with mine .

If anyones thinking of building one , I am willing to answer any questions or offer advice , would i build another , maybe not theres an awful lot of tubes and brazing to do .

Click to expand...

Super moto, congratulations for your work, good luck on the track!!!!!!!!

lcrken said:

Thanks, Mike.

By all means post more build pictures. I'm not the only one here who would be interested in them.

My friend, Mick O'field, who worked at Norton back in the day, and also raced Nortons, told me that the race shop had tried a belt drive, but decided against it after too many failures. The modern HTD style belts are much superior to what was available then, and I suspect they would have happily used them if they had been available.

Ken

Click to expand...

Ken is your friend Mick Ofield the Mick Ofield I knew back in the seventies , originally from Wolverhamton and raced at Darley Moor on a 750 Norton fitted in a BSA Bandit frame , I seem to remember he emigrated to the U.S. if they are one and the same then what a spooky small world !
If it is ask him if he can remember a start line incident involving the two of us, Mick was on the row in front of me , dead engine start, the flag drops, we push off , Mick jumps on side saddle & so do I , Micks back wheel locks he loses his balance and falls right on top of me, lots of noise and smoke as all the other bikes roar away leaving Mick and me and our bikes in a heap, I'm underneath with my bike on top of me, Mick tangled up with My Bike (which is running ) and his Bike on the top, Eventually the marshals extract Mick and his Bike and give him a push to send him on his way leaving me on my own to scramble out from under my bike ,pick it up and set off in pursuit.

I might not be able to remember what I did this morning but memories like that will always be clear,

After all of that , I hope its the same guy, either way with hindsight it was a funny moment.

A superb achievement Mike. Although the monocoque is a fabulous piece of kit, the space frame will always my favourite. A couple of questions....is it as cramped as it looks and did you make the yokes, sliders & wheels?
Martyn.

Man oh man Moto55UK if not for bad luck events might not have any luck out there. That one piece top on the pile of tubes is arrgressive looking combo.

Looks marvellous.
BTW, is it my imagination, but does your frame have an extra tube where the JPS version does not ?
I always thought that that JPS version was missing something....

Do you have any problems with eligibility to race, being a replica ?

Matchless said:

A superb achievement Mike. Although the monocoque is a fabulous piece of kit, the space frame will always my favourite. A couple of questions....is it as cramped as it looks and did you make the yokes, sliders & wheels?
Martyn.

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yes it is cramped , not so when riding it, but especially when wheeling it about,the bars have to be quite short so as not to foul the fairing . your arms fit into the bar shrouds , it crashes quite well as there's not much sticking out and the fairing acts as a big crash bung!

The yokes are AJS stormer ( as JPN) wheels are Peter Williams ( Tony Foale ) not exact but pretty close and the sliders are mine , Copied off photos. I drew them up, made the patterns , had them cast and then machined . The guy who was to machine them was to busy so he put me onto a guy who would be able to do them. I gave him my drawing and the blank castings , he looked at them and said " not bad but we did that different " Turns out I'd just given my efforts over to the guy who designed /drew them up in the first place , Basil Knight The JPN draughtsmen! Basil then produced a drawing of the originals!

My forks are based on the standard commando fork but 2inches shorter,hence I was able to fit the lansdowne conversion kit
thanks to John Bould. Now theres a guy who provides a service , I rang him on Monday he suggested the way to go was for him to make aspecial pair 2inches shorter than standard, I placed my order, wednesday evening he brought them round to my house and helped me fit them. Half hour to fit them 2 hours talking shit , fantastic.

Rohan said:

Looks marvellous.
BTW, is it my imagination, but does your frame have an extra tube where the JPS version does not ?
I always thought that that JPS version was missing something....

Do you have any problems with eligibility to race, being a replica ?

Click to expand...

Well done you spotted the deliberate mistake , that is if your talking about the front engine Mounts, when I set out the frame I'd only seen photographs and most of those had a fairing fitted so I made a lot of guesses, 3 years later when I fitted the front mounting oil tank and the forks and wheel I realised that there wasnt enough room between the tyre and the oil tank so instead of scrapping it and starting again I performed an engineering workaround to move the front isolastic back a bit !

Not had any questions about eligibility so far , my local club arent to fussy or anal , its about bikes on grids!

Excellent work Mike and +1 for more pics!

Moto55UK said:

Not had any questions about eligibility so far , my local club arent to fussy or anal , its about bikes on grids!

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That's the right sort of attitude - top marks to them.

Well done ! There must be a market for that frame if you can make production easier. Have you got drawings and specs for all the tubes ? Once you have the jig, you are in business. Have you got a supplier for the tank/seat ? I've looked at the original space frame many times and thought about it. It would be really lovely to own one. There is a lot of potential in what you have created.

Moto55UK said:

Ken is your friend Mick Ofield the Mick Ofield I knew back in the seventies , originally from Wolverhamton and raced at Darley Moor on a 750 Norton fitted in a BSA Bandit frame , I seem to remember he emigrated to the U.S. if they are one and the same then what a spooky small world !
If it is ask him if he can remember a start line incident involving the two of us, Mick was on the row in front of me , dead engine start, the flag drops, we push off , Mick jumps on side saddle & so do I , Micks back wheel locks he loses his balance and falls right on top of me, lots of noise and smoke as all the other bikes roar away leaving Mick and me and our bikes in a heap, I'm underneath with my bike on top of me, Mick tangled up with My Bike (which is running ) and his Bike on the top, Eventually the marshals extract Mick and his Bike and give him a push to send him on his way leaving me on my own to scramble out from under my bike ,pick it up and set off in pursuit.

I might not be able to remember what I did this morning but memories like that will always be clear,

After all of that , I hope its the same guy, either way with hindsight it was a funny moment.

Click to expand...

I think that is probably the same Mick Ofield I know. He worked for Norton back in the '70s, and raced a Norton at the same time. I believe he was responsible for the graphic design of the JPN Replica Commando before he emigrated. I don't know what sort of bike he raced back in the UK, but he mentioned some experience on a featherbed/commando racer. He emigrated to the US, living in Long Beach, California, and worked for Bates Leathers for several years. He and I were both racing Nortons here in the '80s and early '90s, and became good friends. I don't recall exactly when he came to the US, but it had to be somewhere in the late '70s. He eventually started his own graphics art business, which he finally sold a few years ago and retired to rural Tennessee. He's now doing drawings of classic race bikes, and writing for Roadracing World. When I first met him, he was racing a Vendetta (Seeley replica) with a Commando 750 engine. After a number of years and many frame repairs, he ordered a new Rickman frame and raced that for several more years. I'll send him an email and ask if he recalls the incident. If you'd like to contact him, his email is ofieldTN@blomand.net.

Ken

Mike,

I just got a reply from Mick. He is the same Mick Ofield you remember, and he remembers you and the incident. He'd be happy to hear from you.

Ken

the Six million Dollar QUESTION , how does it RIDE ? .

The National Motorcycle museum must know something of the Chaincases , youd think - due to haveing to have replicated them :? .
Or was it Norman White & someone had some spares ? .

good Effort .
will this chap do replicers of the Works Forks to order .

Cool!

Doug MacRae said:

Cool!

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+1 , Outstanding build Moto55UK , thanks for posting :^)