Slimline Norvin twin ?

D

Devin

Joined
Nov 29, 2024
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Hey,
Question: anyone here know something about fitting a Vincent-HRD twin engine (complete, not chopped) in a slimline frame?
Slimline yes, there was once a article in Classic Bike Guide from june 1993 about a twin engine in a slimline, but I have not found that yet.
Pictures, descriptions, engine plate drawings, anything is welcome !
Thanks!
 
Devin said:
Hey,
Question: anyone here know something about fitting a Vincent-HRD twin engine (complete, not chopped) in a slimline frame?
Slimline yes, there was once a article in Classic Bike Guide from june 1993 about a twin engine in a slimline, but I have not found that yet.
Pictures, descriptions, engine plate drawings, anything is welcome !
Thanks!
Click to expand...
What difference would there be in the engine cradle from wide line too slimline?
Does the rear head not clear?
 
It has been done before but I dont have the details hence my question !
Obviously it clears but I like a flying start if I know up front what to look out for.
More questions was not what I was hoping for ;)
So... is there a difference (or not) between the engine plates for wide or slim.
If not, all the better.
Someone here have drawings or templates or info where I can get those ?
Thanks
 
No need for templates when building a Featherbed special.
I designed a kind of square tubed cradle (about three inches longer each side than the frame width) that goes on the top tubes.
Hanging from this cradle are threaded rods long enough to reach special plates on top of each head. Two rods front, two rods rear.
Now you can move your hanging engine (easier if it's empty) up and down and left or right.
Once the optimum position to clear front exhaust pipe, front carb, bottom and rear of primary case, gearbox and rear wheel sprockets in line, lock the threaded rods with nuts and the cradle with mole grips or similar.
Now you can easily draw the required plates, first from cardboard then from your chosen material.
Easier to do than describe.
I've built two Tritons and a Norvin twin using this method.
 
ericg said:
No need for templates when building a Featherbed special.
I designed a kind of square tubed cradle (about three inches longer each side than the frame width) that goes on the top tubes.
Hanging from this cradle are threaded rods long enough to reach special plates on top of each head. Two rods front, two rods rear.
Now you can move your hanging engine (easier if it's empty) up and down and left or right.
Once the optimum position to clear front exhaust pipe, front carb, bottom and rear of primary case, gearbox and rear wheel sprockets in line, lock the threaded rods with nuts and the cradle with mole grips or similar.
Now you can easily draw the required plates, first from cardboard then from your chosen material.
Easier to do than describe.
I've built two Tritons and a Norvin twin using this method.
Click to expand...
Yep I use the same method CAD (cardboard aided design) it works perfectly
 
even better is to modify the bottom tubes of frame to get engine lower for better handling. Has been done with a German wideline that Stile Italiano re-did with swoopy bodywork.
 
The really best thing to do would be to sell the slimline and contact Russ at Dresda.

They’ve made Norvin frames before and they widen the bottom rails so the engine sits lower and use a different bend at the bottom of the down tubes coz the standard bend leaves something of a dead space there twixt frame and crank cases.
 
Thanks for all the advise !
But, there is always a But.....
Selling the frame,:eek: having owned the Norton from 1982 that would be selling a family member, Hmmmm, not a good idea.
Next, my engine has a Grosset, so I think -not looked at yet- that I will need to relocate the bottom cross member tube.
While at it I suppose I can widen it also...
I have seen the Norton 'framed' bikes from JMR with a electric boot where half of the frame is gone, for me thats a no go, I dont like that.
Anyway, much to think about before I put the hacksaw in the frame !
Thanks !
 
Devin said:
Thanks for all the advise !
But, there is always a But.....
Selling the frame,:eek: having owned the Norton from 1982 that would be selling a family member, Hmmmm, not a good idea.
Next, my engine has a Grosset, so I think -not looked at yet- that I will need to relocate the bottom cross member tube.
While at it I suppose I can widen it also...
I have seen the Norton 'framed' bikes from JMR with a electric boot where half of the frame is gone, for me thats a no go, I dont like that.
Anyway, much to think about before I put the hacksaw in the frame !
Thanks !
Click to expand...
I think those JMR Norvins are horrid looking things personally !

Might still be worth talking to Russ... Dresda do a mod where they hack off the subframe of slimline frames and braze on a Manx style subframe that tapers in with the slimline main frame. It makes for a great looking frame.
 
Netherlands.
I had a look at the JMR website and there is a model with the full loop Norton type frame.
Maybe it's my PC but it looks like the frame is heigher ?
Anyway, I can see a Grosset starter (or something very similar) fitted, so it should be doable.
 
Devin said:
Netherlands.
I had a look at the JMR website and there is a model with the full loop Norton type frame.
Maybe it's my PC but it looks like the frame is heigher ?
Anyway, I can see a Grosset starter (or something very similar) fitted, so it should be doable.
Click to expand...
What kinda of spec is the Motor ?

Good uns goes like ‘ell !

Slimline Norvin twin ?
 
Devin said:
I think thats a Egli, but nevermind, very nice picture!
spec is mostly standard with 8:1 and MkII cams.
Click to expand...
It is… but we were discussing the motors !

Please do become a VIP so you can post pictures and keep us updated with your build progress…
 
I would never build a Norvin, an Egli is a much better way to go. In Victoria, Ken Lucas has a Norvin - he puts an A-grade rider on it, and it does OK. I would not like to ride it. one of my friends has worked on it. He told me the weight is evenly distributed between the front and the back -as though that is good. If you want to ride a featherbed bike fast - the weight needs to be well forward. If it feels light in the front when you accelerate in a corner, you will always back-off.
A lot of kids blame themselves when they are slow. The rider adapts to the motorcycle.
The first time you ride any motorcycle - get it mid-corner while on a lean and accelerate. If it feels great, you are on a winner. As you accelerate, it should not run wide. Forget all the bullshit about horsepower, you need to be able to use the power you have, to better effect. A low powered bike which handles is always better than a high-powered bike which does not handle, and making a high-powered bike handle, is not easy.
 
Last edited:
Understood.
I am not going racing, just a good road bike fit for highway use .
Reg. a Egli, With the Dutch RDW (Rijks Dienst Wegverkeer)- it is virtually impossible to get a road permit/licence on a custom build frame that has not been officially imported and licenced here.
If you want to live with a bit more danger then use a licence from another bike, Ha!
But when you end up having or making a accident and the numbers get cross checked you are liable for e-v-e-r-y thing.
If you want a custom made frame like a new Egli you need to get your bike tested as if it was a new product as factorys do, only for those with deep pockets .
Thats why I will use my Slimline, it has a period licence.
Frame number is 'guiding' over here, engine does (up to a point...) not matter.
German TUV is much strickter, changing a muffler -for instance- already makes the bike illegal.
They (Germany) also have a yearly test to see if it still comply's, something that -actually- has been arranged in EU fashion but every country is free (....) to fill in the details.
For the time being....no such thing as a TUVtest or MOT over here for motorcycles.
And if that shit does hit the fan, it will only be for the modern ones, after 1980 (or so) .
I like to keep it simple, use my Slimline.
 
Devin said:
Understood.
I am not going racing, just a good road bike fit for highway use .
Reg. a Egli, With the Dutch RDW (Rijks Dienst Wegverkeer)- it is virtually impossible to get a road permit/licence on a custom build frame that has not been officially imported and licenced here.
If you want to live with a bit more danger then use a licence from another bike, Ha!
But when you end up having or making a accident and the numbers get cross checked you are liable for e-v-e-r-y thing.
If you want a custom made frame like a new Egli you need to get your bike tested as if it was a new product as factorys do, only for those with deep pockets .
Thats why I will use my Slimline, it has a period licence.
Frame number is 'guiding' over here, engine does (up to a point...) not matter.
German TUV is much strickter, changing a muffler -for instance- already makes the bike illegal.
They (Germany) also have a yearly test to see if it still comply's, something that -actually- has been arranged in EU fashion but every country is free (....) to fill in the details.
For the time being....no such thing as a TUVtest or MOT over here for motorcycles.
And if that shit does hit the fan, it will only be for the modern ones, after 1980 (or so) .
I like to keep it simple, use my Slimline.
Click to expand...
Very sensible.

In general, just ignore Al. He hasn’t ridden on the road since 1903.

A Norvin can make an excellent road bike, no question.

Do keep us updated and post lots of pictures though, otherwise we’ll sulk and make Al post lots of comments.
 
OK that made me smile, AI with an i as in Artificial Intellingence? or just Al....
when I get to the point of having something decent to show, I'll post some piccies.
Thanks.
 

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