Featherbed: Twin vs Manx, handling, weight, etc

Fast Eddie

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I too would like to know a few things sorry if a bit OT.

1) As Thomasa asked, what are the benefits of a tilted engine in a featherbed vs straight up? (let's say 750 and 850 commando engine for discussion sake). And if I did this other than just buying a different set of plates are there any other things I have to take into consideration?

IMO there is no benefit in terms of handling that would be possible for a normal rider to detect. The main design benefits are styling. Plus packaging, ie making space for electric start components and big air boxes.

Yes there is a fair bit to do apart from engine plates: head steady, primary case mounting, exhaust pipes, intake manifolds. There may be internal oil system changes required too, but I’m not familiar enough with those engines to be sure.

Put simply, given all your other projects, and the fact that your Mercury is a running, functioning motorcycle, you’d be out of your freakin’ mind to consider this !
 
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IMO there is no benefit in terms of handling that would be possible for a normal rider to detect. The main design benefits are styling. Plus packaging, ie making space for electric start components and big air boxes.

Yes there is a fair bit to do apart from engine plates: head steady, primary case mounting, exhaust pipes, intake manifolds. There may be internal oil system changes required too, but I’m not familiar enough with those engines to be sure.

Put simply, given all your other projects, and the fact that your Mercury is a running, functioning motorcycle, you’d be out of your freakin’ mind to consider this !

So easier to just install a commando engine upright in a featherbed?
Ahh I already need to figure out a nicer looking headsteady option for one of my vehicles.

Speaking of headsteady for the commando Is the Dave Taylor headsteady from RGM good? Should I get the Norvil one? What's the recommended one?

I'll jump back on my thread if this is going to be a long discussion ahhah


Oh and I've gone way over the deep end so no point in me slowing down now. At this point I could have built a brand new Molnar Manx and a Seeley :D
 

baz

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So easier to just install a commando engine upright in a featherbed?
Ahh I already need to figure out a nicer looking headsteady option for one of my vehicles.

Speaking of headsteady for the commando Is the Dave Taylor headsteady from RGM good? Should I get the Norvil one? What's the recommended one?

I'll jump back on my thread if this is going to be a long discussion ahhah


Oh and I've gone way over the deep end so no point in me slowing down now. At this point I could have built a brand new Molnar Manx and a Seeley :D
No it's best to lean a commando engine forward in a featherbed frame ,as it would be in a commando frame
And it's best to keep an atlas engine upright because of the crank balance factor and the oil drain holes in the inner part of the timing chest
Some tanks are known to have clearance problems with the norvil type headsteady
So the Dave Taylor type is probably better
 
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Good to know!

Mercury and Commando and BSA will get my focus for a while.. Other three bike projects on hold for the summer as I'm too busy with other stuff anyway.
 

lcrken

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I too would like to know a few things sorry if a bit OT.

1) As Thomasa asked, what are the benefits of a tilted engine in a featherbed vs straight up? (let's say 750 and 850 commando engine for discussion sake). And if I did this other than just buying a different set of plates are there any other things I have to take into consideration?

2) @acotrel what bikes do you currently own? Photos? I know I won't see a drum brake on any of your bikes, but that's about all I know.
The main benefit (in my humble opinion, of course) of tilting the engine forward in the featherbed frame is getting a little more weight bias towards the front. I think it improves the feel during corner entry and makes it a little easier to turn in quickly.

And, as baz pointed out, If you're using a Commando engine, tilting it forward also keeps the crankcase oil pickup design in it's original configuration, but I don't know if that really makes any difference in its operation.

Ken
 

lcrken

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I guess I should also add the caveat that with the Commando engine fitted to my featherbed race bike in the tilted forward position, I did re-balance the crankshaft to suit.

Ken
 
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A Commando in a featherbed frame would be OK, if there was a way to put a sensible 2 into 1 exhaust under the motor. Fitting one around the front frame tubes is a major problem - unless you believe you do not need a 2 into 1 exhaust system. Then you need to learn how to stay on the bike when the motor does not have smooth power delivery. I like featherbed frames, but I used them for too long. My Mk3 Seeley frame is streets ahead in handling - safer and better. Even a Rickman frame would be better than a Featherbed for a Commando motor.
One thing which is worth doing is to go around all the old racing guys to see what they have which is not being used. A while back I saw a Rickman frame for $400. It was in a parts dealer's factory in Shepparton.
With featherbed frames - when you race, everything happens a bit more suddenly than with a Seeley. That steering head angle of the featherbed, makes things more critical. Some people weld a tube in behind the steering head and down to the cross tube, because the turn-buckle can change the trail.
The other thing is tyres - with a featherbed, you need 19 inch tyres, unless you can change the steering head angle. to 26 degrees from 24.5 .
 
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I probably should not comment on this topic. For many years I have been trying to forget what it was like racing my Triton. When I think of the crashes I had, it horrifies me. However there is no way my Seeley 850 could ever crash me - it is just not possible - even if I raced it again. But my wife does not believe that, so I probably won't. She does not know it is going together again. I will probably be able to start it again in a couple of weeks' time.
 
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I probably should not comment on this topic. For many years I have been trying to forget what it was like racing my Triton. When I think of the crashes I had, it horrifies me. However there is no way my Seeley 850 could ever crash me - it is just not possible - even if I raced it again. But my wife does not believe that, so I probably won't. She does not know it is going together again. I will probably be able to start it again in a couple of weeks' time.
I'll buy your Seeley, make your wife happy to see it gone and as a bonus get her some earrings and spend the rest of the money on whisky and cigars.
 
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I'll buy your Seeley, make your wife happy to see it gone and as a bonus get her some earrings and spend the rest of the money on whisky and cigars.
My problem is, the things which are keeping me alive are my interests. Old motorcycles have been a part of my life since I was 12 years old. When I was at high school, thec reason I did not study and become a doctor like most of my mates, was I actually had a happy childhood. At school I loved chemistry - the connection between chemistry and motorcycles is engineering. I spent most of my working life as a scientist working on developing better materials and processes. My Seeley 850 is an extension of that. While I was working, I was sometiimes able to go road-racing. When I did that, they were the best times of my life. I brought up 3 kids, two of them boys. Neither of them were ever interested in anything I ever did. None of my kids have visited me in Benalla in the last 20 years. I do not speak to my ex because the time for conversations with her has long gone.
My Seeley 850 has sat for a long time because of my grief. But the other day, I fixed the bit of the clutch which was giving me trouble. So it is all going back together again, and I am beginning to think differently. I really want to do some on-board video. The way it handles is very different to most other race bikes. I was not aware that it can do what it does, until I used it in a very silly way. With most race bikes, you cannot gas them flat out, all the way through a corner.
 
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I do not usually discuss where I used to work. It was in the Australian defence factories. I was the chemist in Government Aircraft Factories , Fishermen's Bend, and Ordnance Factory Maribyrnong and Explosives Factory Maribyrnong. It has always been about 'boys' toys'. After I retired, I worked as Technical Writer and Quality Manager for a company which made large furnaces. At one stage in my life, I was in charge of rocket motor firings and shooting artillery shells into Spencer's Gulf. - All fun stuff.
During my life, I only ever applied for jobs which I was interested in doing and I usually got them - And all of my tertiary qualifications were achieved through part-time study while I was working.
 
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My problem is, the things which are keeping me alive are my interests. Old motorcycles have been a part of my life since I was 12 years old. When I was at high school, thec reason I did not study and become a doctor like most of my mates, was I actually had a happy childhood. At school I loved chemistry - the connection between chemistry and motorcycles is engineering. I spent most of my working life as a scientist working on developing better materials and processes. My Seeley 850 is an extension of that. While I was working, I was sometiimes able to go road-racing. When I did that, they were the best times of my life. I brought up 3 kids, two of them boys. Neither of them were ever interested in anything I ever did. None of my kids have visited me in Benalla in the last 20 years. I do not speak to my ex because the time for conversations with her has long gone.
My Seeley 850 has sat for a long time because of my grief. But the other day, I fixed the bit of the clutch which was giving me trouble. So it is all going back together again, and I am beginning to think differently. I really want to do some on-board video. The way it handles is very different to most other race bikes. I was not aware that it can do what it does, until I used it in a very silly way. With most race bikes, you cannot gas them flat out, all the way through a corner.

First and foremost I’m sorry to hear that your kids have not visited with you in an inexcusable amount of time. If I were in AUS I’d come hang out and chat about bikes all the time!

Totally understand where you were coming from about needing interests to keep yourself active and your Seeley sounds epic and honestly would be wasted on me because I’m barely a rider never mind a racer. I just like cool looking bikes and those Seeley bikes look the business..
I’m glad you’re fixing up your bike, summer is upon us Oz/Kiwi folk. You wouldn’t want to miss another summer of good riding on that Seeley!!

It’s a shame all the cool looking bikes give me so much trouble I’m almost ready to just give up and buy a modern Royal Enfield Continental GT or something similar. But honestly like most of us on here I think well over 50% of the fun of owning a bike is working on said bike.. When things work out the way I envision them to work out I’m quite happing owning and working on vintage bikes… I’ve just run into a lot of hiccups due to inexperience and frankly really really bad luck. Again like you and I’m sure a lot of other people on here working on bikes is somewhat therapeutic in a way and something I hope I keep doing because the alternative is heavy drinking or etc!

As far as attaching a dash cam of sorts, very easy these days, you could use your phone but you’d have a better time with a GoPro as they have superior image stabilisers in small packages for things like motorsports. And these days it’s super easy to get the footage off the GoPro and onto Youtube. So we will all look forward to seeing your runs by mid summer! And some glamour shots of your bike when it’s back in tip top shape!
 

Fast Eddie

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My problem is, the things which are keeping me alive are my interests. Old motorcycles have been a part of my life since I was 12 years old. When I was at high school, thec reason I did not study and become a doctor like most of my mates, was I actually had a happy childhood. At school I loved chemistry - the connection between chemistry and motorcycles is engineering. I spent most of my working life as a scientist working on developing better materials and processes. My Seeley 850 is an extension of that. While I was working, I was sometiimes able to go road-racing. When I did that, they were the best times of my life. I brought up 3 kids, two of them boys. Neither of them were ever interested in anything I ever did. None of my kids have visited me in Benalla in the last 20 years. I do not speak to my ex because the time for conversations with her has long gone.
My Seeley 850 has sat for a long time because of my grief. But the other day, I fixed the bit of the clutch which was giving me trouble. So it is all going back together again, and I am beginning to think differently. I really want to do some on-board video. The way it handles is very different to most other race bikes. I was not aware that it can do what it does, until I used it in a very silly way. With most race bikes, you cannot gas them flat out, all the way through a corner.
Al,
Glad to hear the bike is bringing some contentment / meaning, that’s what it’s all about.

I sincerely hope you get it out and enjoy.
 

Fast Eddie

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First and foremost I’m sorry to hear that your kids have not visited with you in an inexcusable amount of time. If I were in AUS I’d come hang out and chat about bikes all the time!

Totally understand where you were coming from about needing interests to keep yourself active and your Seeley sounds epic and honestly would be wasted on me because I’m barely a rider never mind a racer. I just like cool looking bikes and those Seeley bikes look the business..
I’m glad you’re fixing up your bike, summer is upon us Oz/Kiwi folk. You wouldn’t want to miss another summer of good riding on that Seeley!!

It’s a shame all the cool looking bikes give me so much trouble I’m almost ready to just give up and buy a modern Royal Enfield Continental GT or something similar. But honestly like most of us on here I think well over 50% of the fun of owning a bike is working on said bike.. When things work out the way I envision them to work out I’m quite happing owning and working on vintage bikes… I’ve just run into a lot of hiccups due to inexperience and frankly really really bad luck. Again like you and I’m sure a lot of other people on here working on bikes is somewhat therapeutic in a way and something I hope I keep doing because the alternative is heavy drinking or etc!

As far as attaching a dash cam of sorts, very easy these days, you could use your phone but you’d have a better time with a GoPro as they have superior image stabilisers in small packages for things like motorsports. And these days it’s super easy to get the footage off the GoPro and onto Youtube. So we will all look forward to seeing your runs by mid summer! And some glamour shots of your bike when it’s back in tip top shape!
You are being way too hard, actually impossible, on yourself.

What you have to remember is that all the old farts on this forum have been playing around with these old fart bikes for DECADES.

Most started playing with these bikes when they were simply cheap old bikes. And that was cos they had (very) little money to spend.

So old worn out old bikes, owned by guys with very little money led to a long learning curve in how to fix and botch. Guys needed the thing to take them to work in the morning come what may… and necessity is the mother of invention !

As they got older and wealthier, and the bikes became ‘classics’ the tinkering and wrenching changed in nature… a LOT.

You are brand new to this. And have jumped in completely at the deepest end imaginable. You’re trying to learn 30-40 years of accumulated experience in a year !

One modern bike in the fleet (Enfield, Triumph, Indian, Harley) would indeed not be a bad idea as it would separate your tinkering from your riding, that will take the pressure off and thus allow you to enjoy both more.

All only IMHO of course.
 
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baz

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My problem is, the things which are keeping me alive are my interests. Old motorcycles have been a part of my life since I was 12 years old. When I was at high school, thec reason I did not study and become a doctor like most of my mates, was I actually had a happy childhood. At school I loved chemistry - the connection between chemistry and motorcycles is engineering. I spent most of my working life as a scientist working on developing better materials and processes. My Seeley 850 is an extension of that. While I was working, I was sometiimes able to go road-racing. When I did that, they were the best times of my life. I brought up 3 kids, two of them boys. Neither of them were ever interested in anything I ever did. None of my kids have visited me in Benalla in the last 20 years. I do not speak to my ex because the time for conversations with her has long gone.
My Seeley 850 has sat for a long time because of my grief. But the other day, I fixed the bit of the clutch which was giving me trouble. So it is all going back together again, and I am beginning to think differently. I really want to do some on-board video. The way it handles is very different to most other race bikes. I was not aware that it can do what it does, until I used it in a very silly way. With most race bikes, you cannot gas them flat out, all the way through a corner.
Al I know I've said this before but set yourself up for some crowd funding
I'll bung in a few quid , I'm sure others would too
You could get yourself out on the track and prove some of your theories
Not about winning but just getting out there
 

ashman

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So easier to just install a commando engine upright in a featherbed?
Ahh I already need to figure out a nicer looking headsteady option for one of my vehicles.

Speaking of headsteady for the commando Is the Dave Taylor headsteady from RGM good? Should I get the Norvil one? What's the recommended one?

I'll jump back on my thread if this is going to be a long discussion ahhah


Oh and I've gone way over the deep end so no point in me slowing down now. At this point I could have built a brand new Molnar Manx and a Seeley :D
They go faster with the motor tiled ;) as for the head stay make one is the best option same as engine plates, I will remove my tank today and take a pic of my head stay, use the 2 lugs on the frame one at just under the steering head (2 bolts) and the one lug on the top cross bar (one bolt) with 5mm plate cut to fit and with a plate welded to the bottom to fit the allen head bolts to the head same as the Commando, it's very important to have a very strong head stay for the Featherbed frames.
Infact I will take pics of all my engine plates fitter to show how they fit with my motor.

Ashley
 
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They go faster with the motor tiled ;) as for the head stay make one is the best option same as engine plates, I will remove my tank today and take a pic of my head stay, use the 2 lugs on the frame one at just under the steering head (2 bolts) and the one lug on the top cross bar (one bolt) with 5mm plate cut to fit and with a plate welded to the bottom to fit the allen head bolts to the head same as the Commando, it's very important to have a very strong head stay for the Featherbed frames.
Infact I will take pics of all my engine plates fitter to show how they fit with my motor.

Ashley

Yes Ash thank you so much!!! It's always good to see what other people do, gives me ideas and makes the process of getting something made a lot easier if I'm in over my head.
 

ashman

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Yes Ash thank you so much!!! It's always good to see what other people do, gives me ideas and makes the process of getting something made a lot easier if I'm in over my head.
When I built mine back in the early 80s was the first bike I ever built and only in my early 20s, but my mate Don who got me into Norton's and Featherbed frames as the first British bike I rode was his 750 Commando/Featherbed at 17 years old, his was set up with the motor sitting straight up like the Dommie it had a lighten and polish crank and had a few problems with overheating if he rode it 2 up, he sold me the Wideline frame in 79, I learned a lot off Don and learned by his mistakes, I built mine right first up, but it's very important to get the crank balanced for the Featherbed frame if you don't the Commando motor will suffer with bad vibrations, mine was balanced at 72% BF, I am running a built up 2S cam profile and have had major port work to the head as well shaved head but run stock flat top pistons (Hepilight 40th over size).
I am always willing to give advice when it comes to Commando/Featherbed set ups/builds, this is my play bike and have done many upgrades over the 40 years from building mine, it's light, it's torque, handles like it's on rails and I always ride with a big smile on my dial, I have so much fun on this bike and when up in the tight ranges it's in another world.
I am still good mate's with Don but soon after selling me the Wideline frame (he had a few) he decided to go all out Triton builds, but the funny thing he builds his own Triumph race motors with Norton one piece cranks that he makes himself as well his own over built crank case that he get made, every time he comes around he still can't believe how well and reliable my Norton has been to me, every time he races his Triton's he keep blowing them up, but he runs to high of compression on his Triumph motors but you can't tell him that as his point of view is the higher the compression the faster they go, well they go fast alright but never last long before they go bang.
I go up soon and take some pics of my set up, 80% of my Featherbed is running Commando gear except for the upgraded front brakes, JH maggie, Akront alloy wheels and round alloy oil tank and only Featherbed part is the frame and swing arm.
Featherbed: Twin vs Manx, handling, weight, etc
Featherbed: Twin vs Manx, handling, weight, etc
 

ashman

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Yes Ash thank you so much!!! It's always good to see what other people do, gives me ideas and makes the process of getting something made a lot easier if I'm in over my head.
Here is my mounts and motor set up in the Featherbed frame, bit hard to see while on the bike but here goes.
Very important to run a strong head stay and in the last pic I run a large through bolt from one side of the bottom frame engine mounts to the other with solid spacers in between the frame and engine mounts, this stiffen everything up with motor and frame, so very important to have a good balanced crank for smooth running.
I also run a 1 ltr catch bottle in between the rear engine mounts and back of the GB for my engine breather to run into instead of going back to the oil tank.
Featherbed: Twin vs Manx, handling, weight, etc
Featherbed: Twin vs Manx, handling, weight, etc
Featherbed: Twin vs Manx, handling, weight, etc
Featherbed: Twin vs Manx, handling, weight, etc
Featherbed: Twin vs Manx, handling, weight, etc
 
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