Commando motor into es2 slimline

Joined
Jun 18, 2013
Messages
26
Country flag
Good morning,
Is there any supplier of engine plates similar to Andy Molnar's kit available in the United States to put a Commando motor in a Norton single cylinder slimline frame? Just trying to save the shipping cost from the UK. Thanks...
 
I made my own engine plates not a hard job to do, set your motor up in the position and make templates out of cardboard, I made mine out of 5mm steel plate, but I had the gear to cut to the right shape but you could if you don't have the gear to cut just go to any steel fabulation shop that has a plasma cutter and they will cut them to your pattens, I had to replace one of my plates and the plasma cutter took less than 5 minutes to do.
Also make sure you make a good head stay very important with Featherbed frames.

Ashley
 
I made my own engine plates not a hard job to do, set your motor up in the position and make templates out of cardboard, I made mine out of 5mm steel plate, but I had the gear to cut to the right shape but you could if you don't have the gear to cut just go to any steel fabulation shop that has a plasma cutter and they will cut them to your pattens, I had to replace one of my plates and the plasma cutter took less than 5 minutes to do.
Also make sure you make a good head stay very important with Featherbed frames.

Ashley
I agree
It's really not hard to make engine plates
I have a plasma cutter these days but back in the day I used to chain drill them out on my pillar drill
Sure it takes forever but you can put the motor exactly where you want it
It's easy to do and gives a huge amount of satisfaction
And as Ash says make yourself a really sturdy headsteady it forms part of the structure
 
When I first started to build my hot 850 Commando/Featherbed back in 1980 I only had my own hands and limit tools, then in 82 I started work at a Tec College and had everything I need to make anything but the engine plates were all done by then, as well depends on what you do to the Commando motor make sure you get the crank balanced for the Featherbed frame, mine was balanced at 72%, I did my rebuild cheaply back in the 80s there wasn't the upgrades that are around today but the crank balance was very important for smooth running, but when I did mine everything was cheap to do.
When I first started my conversation I was in my early 20s and not working at the time so money was tight, I also only had a 125 dirt bike to get around, that was interesting taking my crank, pistons, rods etc in my back pack riding over the other side of my home city to get the crank balanced and then picking it up a week later, I also got my stock cam built up and reground to 2S specs near the same place as my crank balance, that dirt bike saved me while building getting things done to the motor, new pistons and rebore and picking up parts.
I also later down the road made alloy engine plates but after a short time went back to the 5mm steel plate, found the alloy plates weren't as smooth with vibrations, I made mine out of 6mm alloy and should have gone 8mm but the savings in weight from steel to alloy wasn't that much difference and the weight was all down low so made no difference to the handling, the 5mm steel plates are just right.
This is it after 40 years in the Featherbed and still on the road, has gone through a few upgrades over this time on the road, it's no show pony and is showing its age but that's the way I like it as it was an everyday rider up till 2013 when I brought a new Triumph, but it's still my Hot Rod Norton and still gets ridden regularly.
Mine is a 1957 Wideline Featherbed and 74 850 Commando motor and used a mix bag of Commando/Featherbed parts to build with lots of upgrades in between, most upgrade bits was added over 12 years ago when I had spare money to spend, the good thing everything built by my hands for me and always draw a crowd when parked up anywhere, it's light, handles greatttttt and with the work done to the motor it surprises a lot of modern bikes and get it up in the ranges in the tight twisties it blows a lot of bikes in my dust, it's my play bike šŸ˜‚ and fun to ride.
IMG_20210608_123208.jpg

Ashley
 
Yes. I'd probably go steel over alloy too. I cracked 6 mm alloy plates on my 500 Dommie race bike. And you have to make up longer studs and bolts if you go 8 mm.
 
  • Like
Reactions: baz
65Tiger, If the brackets on the frame are the same as the twins (anybody know?) you could look around for some Atlas or other Dommie plates. Somebody, somewhere has gone to polished alloy plates for aesthetics and not binned the original steel plates. FWIW I still have some G15/N15 steel plates I no longer need.

Ashley, I like the commando foot peg brackets! And you canted the engine forward, nice. I'm not sure how relevant this is for a featherbed discussion but my G80 has 5mm polished alloy engine plates. It's been scrambled both before and after I got it and there are no signs of cracking. Of course the torque forces are less than a Commando motor. But, I also years ago built up a G15 with alloy engine plates, 10:1 Commando head, 2S cam profile, 32mm carbs and a Commando primary. Engine was set straight up and down. I ran it hard and the guy I sold it to did also. I saw the bike parked some years later, still with alloy engine plates. I don't remember how thick.
 
I mounted my motor as close to the front as I could and tilted the motor at the same angle as it came in a Commando frame, if mounted straight up as Atlas/Dommie just don't look right and the Norton logo on the timing case just wouldn't be right, + with the motor on an angle they run faster ;) but with the engine on the angle the chain runs pretty close to the rear top engine mount cross bar so got to watch that but OK with running the stock 19 tooth front sprocket.
Another thing I did was to put spacers in between the front and top rear frame mounts so when mounting the motor when tightening the bolts that it didn't pull the mounts in as well on the bottom rail there are 2 lugs one on each side of the frame I also run a long through bolt with spacers between the frame, engine mounts it sit between the GB and motor, it just stiffens everything up.
I have a 1960 Manxman project bike (Slimline Frame), have been thinking about mounting a hot 750 Commando motor if I could get a motor cheap to build but so far the 650 Dommie motor will be used, it's an ex race bike and will be built as a cafe racer.
As for the foot peg mounts they are cut down mounts from the Commando frame, I had Dunstall rear set on it first up but I didn't like them, they wore out pretty fast and my boot toes scrapped on the road hanging into the corners, didn't like that at all, everything on my Norton that can scrape pushing it into corner has been mounted high and the exhaust system was made for the Featherbed where they are tucked in as close to the frame, so in over 40 years on the road nothing has ever scrapped and the only time the foot pegs have hit the road was when I pushed it too far and the tyres went way past their limits and gravel on the corner, didn't go to well for me, I still have a slight scare on my chin from that mistake lol.
I also run with a mod Commando Interstate seat, I have a duel seat and one with the hump which is on the bike as my Norton is only reg for solo use now, I just had to change the mounting point on the bottom of the seat base, these seats are so comfortable when doing long miles, I had a stock repo duel Featherbed seat when I first built it but just didn't like it, wasn't the most comfortable seat at all and was sold off.
Ashley
 
Last edited:
When I was 17 years old a good mate of mine Don had a hot 750 Commando motor in a Wideline Featherbed he like riding my Honda 250 trials bike so we swapped for the day and I rode his hot Norton up in the ranges, I was so stoked that 2 weeks later I bought my new 850 Commando, told no one I was buying one as all my mates were buying new Honda 4s, then in 1979 my mate Don sold me his spare Featherbed frame and in 1980 I started the conversion took me just over 2 years to build as wasn't working at the time.
A lot of my mates though I was crazy converting my near new commando to Featherbed but to me I knew which way I wanted to go, no internet in them days and I looked at all the mistakes Don did with his 750 Commando/Featherbed set up he had his motor mounted straight up like the Dommies, he also had a lighten and polish crank and had a few problems with it and I didn't like the drum brakes on it.
Don still has Featherbed frames but he went down the Triton road soon after I got my Featherbed frame off him, we are still good mates and every time he see my Norton he still can't believe how reliable and good my Norton has been in all the years I have built and owned it and it still keeps going.
I just kept telling him I did it right from day one and learned by his mistakes and found a great old English Gentleman who knew all about balance factors for what I was doing and set my crank up right for a smooth running Featherbed.

Ashley
 
Good morning,
Is there any supplier of engine plates similar to Andy Molnar's kit available in the United States to put a Commando motor in a Norton single cylinder slimline frame? Just trying to save the shipping cost from the UK. Thanks...
One risk with using the ES2 slimline as opposed to the Dommie one is the difference in the front engine mounts.
The ES2 (single) version has only one lug, part-way up the front down-tubes.
The Dommie version has extra lugs at the bend of the lower down-tubes.
The Dommie version will clearly give better load distribution - something you may wish to examine before proceeding too far with engine plates.
Cheers
Rob
 
You just make the front engine mounts to which ever front lug/lugs is on the frame.
 
You just make the front engine mounts to which ever front lug/lugs is on the frame.
Ash - the point I was making is that concentrating that load through one lug (per side) will have increased chance of failure.
I think there was a reason the twin's frame had 2 lugs.
Knowing Norton, if they could have got away with one frame type they certainly would have done that.
 
Last edited:
Rob my Wideline frame only has one lug on each side of the front frame and they came with twin cylinder motors and running a twin engine on the one lugs on the front frame hasn't had any effect in 40 years of my 850 motor mounted in the Wideline frame, they are pretty strong lugs, as well the 650 Dommie motors are a smoother running motor compared to the 750 Atlas motor and in the 60s Slimline frames there were 4 Atlas to 1 Dommie ratio in production.
As I say easy to make the steel plates to suite both for whatever motor or frame is used, in fact when I first built my Commando/Featherbed I used my Commando cradle with the back cross section cut out and added and welded the extra bits on to fit the Featherbed frame with these plates, ran it for a few years before making new rear engine plates to cut a bit of weight off them, I still have them plates as well the alloy plates hang on my shed wall.
At the time I started to build my Commando/Featherbed I used what I had, not working at the time money was tight, then getting a job at a TAFE college I had my hands on everything, tools, material, machinery and expert help when needed then doing night time courses to further my hands on with working with my hands and metal, to then working as a TA to the Maintenance Fitters.

Ashley
 
In a Featherbed frame, the engine mounting lugs are above and below the bends in the frame tubes. The engine then bridges the bend and makes the frame rigid.

Slick
 
The Wideline frames only had the lugs above the bottom bend, my 1960 Manxman Slimline frame has both above and below the bends, my Wideline is a 1957 frame, I had 2 to choose from, the one he tried to sell me had dings in the bottom rails and the one he wanted to keep was around the corner from my place at a painter mate's place, it's been sitting in an open garage for a few weeks to be painted I just walked around the corner to pick it up and carried it over my should home, it was just sitting there no one home, Don should not have told me where the good frame was as I ended up with the good one :D we are still good mates.

Ashley
 
In 1973 buddy had a spare 750 Commando Engine/Trannie/Primary and my 650SS was lagging, so the Featherbed/Commando project was born. Like others I made up cardboard engine plates, then gas-axed 1/4 steel with Oxy and a lot of hand grinding. I mounted the engine leaning forward - the only downside was it would do wheelies at the most inappropriate moments. Found an Atlas flywheel, balanced crank to around 80%. Was my daily rider for a number of years. The vibrations, even with the balanced crank would destroy the instruments, cause cracks in fenders and brackets. Upgraded to norton front disk and as the photo shows a 16" rear tire, all the rage in the late 70's in NZ. Many modifications over the years, 2 in 1, MKII amals, even a rear disk. Eventually replaced it with a shiny MK3 Elect Start 850.

Commando motor into es2 slimline
 
Good Day Guys my 1958 wideline frame has only one lug above the bend.
Regards. Geoff
Both my Widelines have only one pair of front tabs too. One of the frames has been through the ringer (raced for years), with no appearance of failure at the mounts. Not to say that two wouldn't be better, but...
 
Thanks for all of the great responses. Now I'm thinking that instead of paying for the plates premade that I might just put that $ towards a plasma cutter. Something I can use over and over verses a one time investment
 
In 1973 buddy had a spare 750 Commando Engine/Trannie/Primary and my 650SS was lagging, so the Featherbed/Commando project was born. Like others I made up cardboard engine plates, then gas-axed 1/4 steel with Oxy and a lot of hand grinding. I mounted the engine leaning forward - the only downside was it would do wheelies at the most inappropriate moments. Found an Atlas flywheel, balanced crank to around 80%. Was my daily rider for a number of years. The vibrations, even with the balanced crank would destroy the instruments, cause cracks in fenders and brackets. Upgraded to norton front disk and as the photo shows a 16" rear tire, all the rage in the late 70's in NZ. Many modifications over the years, 2 in 1, MKII amals, even a rear disk. Eventually replaced it with a shiny MK3 Elect Start 850.

Commando motor into es2 slimline
Maybe 80% BF was a bit much as my Featherbed/Commando was smooth and has never cracked anything in the 40 years it's been on the road and in all that time only lost one rear muffler mount bolt and one top GB mount nut, not bad really for a build that most kept saying things will shake off all the time without being rubber mounted like the Commando's.

Ashley
 
Back
Top