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Amateur Manx 40M preparation

25095 Views 130 Replies 9 Participants Last post by  Mike 40M
Starting a thread about my -59 Manx. Should never had bought it 3 years ago, if it had not been raced quite successfully by a friend of mine. We used to ride together on our road Nortons, he on an Atlas and I had a Dommi 99. Learnt a lot from him about race lines and how to stay alive on public roads. For some reasons, I have to get it going asap. Started collecting new bits for it a year ago. In january I started to take it apart. Also got new parts needed. As a motorcycle in pieces takes a lot of space, I started to assemble it yesterday. Frame in good shape, only minor scratches in the paint. Swingarm bushes ok, now greased. Head bearings Ok.
First thing to do was rear mudguard in bad shape., replaced with a new. I think a -59 should have alloy rear mudguard, but as I'll try to set it up as it was when my friend raced it, it got another fibreglass one. Advice and critics welcome.
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Thought it was time to put in engine and gearbox. For those of you who don't are familiar with featherbed Nortons. Front engine plates is no problem if you get some friend or relative to lift engine in place. Rear bottom bolt holding rear engine plates to engine is hidden between lower frame tubes. This means that you have to lift the engine to get that bolt in place. Same applies to bottom gearbox bolt, except that you have to lower engine plates to get the bolt in under the frame tubes. I think you have to put on right engine plate first, then gearbox and left plate last. Definitely a bit of curious engineering.
Now a problem showed it's ugly face. The TTI gearbox was a bit fatter than a normal AMC or laydown gearbox so it hit the frame. The 5-speed modified laydown gearbox from -62 will fit and I put in an ordinary AMC gearbox just to check. Have to think it over what gearbox I'll use. Maybe a Quaife?
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I'll try to take better pics in the future.
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Thank you, luck needed. Most bikes I have had turn up unsuspected problems.
A. Reason for not rebuilding original engine. Time and a strong desire to race it. A bit worried about strength of magnesium crankcase. Prefer not to kill a matching number engine. If it only should do parade laps, maybe. Don't have enough confidence in my skills. No problem with rebuilding Norton twins or goldies, but a lot of respect for the Manx engine.
Sharp eyes, no idea what the tabs are, one on each side, try to take a photo of them.
Gearbox not sorted out yet, had some other things to do.
By the way, got a stud from Andy Molnar, replacing bottom gearbox bolt. A bit heavier but a lot easier gearbox assembly.
Mystery. Why this lugs? Not checked for certain but they seems to be braced to frame.
Bicycle part Water Auto part Metal

If an angle grinder on the TTI don't work (not certain if I'm joking), then probably will use the old Arrgardh gearbox #186. By the way, it was Torsten Arrgardh, who insisted that it should have coil springs instead of hairpin springs. I stick to that.
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Original engine did some parade laps in -95. Not the faintest what oil was used then. "Spare" engine will hopefully commence run in period next month. Old engine looks good on the outside and moves freely. Only rust on bike worth mentioning is front springs and interior of clutch.Some nuts has got a brown patina. Surprisingly good bolts and nuts for a bike which has spent most of its life in a metric country. Most previous owners must have used proper tools.
Spent the afternoon replacing worn parts in front legs. Tomorrow time for finishing front fork.
Thinking of replacing handlebars and levers with modern parts. Original has obviously had some ground contact. Makes it impossible to fix barends yo them.
Seems I soon have enough original parts to build another bike.
Triple crown in place. New small issue. How much oil in fork. Talked with a Norton dommie friend from the good old days without speed limits. He had heard from a racer that a Coca-Cola bottle is right. Can anybody confirm that 192 cc is right amount?
Fork oil 20 grade. If the damper rods and damper bodies are worn you might end up using 30 grade.

Oil quantity - extend the fork fully then compress without the spring - measure the movement (x) now add 2". Fill the fork till you have an air gap of x+2 make sure the damper tubes are filled but moving the sliders up and down a few times. Don't leave less than 2" Boils law and all that.

Don't use dominator quantity as you don't have an internal spring taking up volume.

So you won't put enough in.
Just checking if I got it right,.
Using one of those modern tools for setting fork oil level.
Movement =6". Add 2" equals 8".
With fork fully compressed.
Oil level 8 inches below top of stanchion.

Found not enough 20 oil at home, have to get more.
It's normal Manx forks. Just checked level. 6.5" compressed. Seems that coke bottle idea from a famous Manx racer was a bit on the low side.
While waiting for more oil, I will do a bit of milling of the TTI-box. Alternative would be to make new engine plates with gearbox higher.
When inserting gearbox with righthand engine plate in place, it hits frame about 3/8 before it meets the engine plate.
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Gearbox will take some time. To make the workshop tidier, I will put some other things in place. Continued with forks (thanks jalsteve). For readers not familiar with fork assembly I'll show the special tools I've made. To compress fork just an ordinary luggage tie down. A rod with a long nut in one end that can be attached to the damper rod. When damper rod is up, I use a piece of metal with a milled slot. When rod is up, I slide it under the lock nut. Then it's just to replace the rod lifting tool with the fork top nut (and washer).
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To make something easy for a change turned and fitted alloy barends. Then tried out flyscreen fittings. Have to figure out best top attachment. Will probably be tyraps and a piece of rubber. Booked same racenumber as it had last time. Saves me trouble of putting on a new number. Sent result of med test to federation, paid for licence.
Then continued with slimming gearbox. After a bit of milling found that counterboring 4mm for the offending Allen screw was needed. Tried it in place once again. Close but not enough. Turned a taper on the Allen head and did a little more alloy filing. Result is .031 clearance to frame.:)
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Not much new today. Got a good idea from a guy who builds and races a homemade gasturbine landspeed bike. Use a cheesehead screw instead of the protrouding Allen screw. Only problem is that I live in a metric country where a slotted 5/16UNC x 1 is almost as rare as hens teeth. Found Gearbox could not be moved fully rear. Hit fhe nut for the adjuster stay. Some grinding fixed that. Hopefully last problem with gearbox is that upper 9/16 bolt don't fit. Seems they drilled it from both sides and not in line. Did not have right size tool, so gave it to a mechanic who will fix it early next week.
Did a simple job for a change, put on the seat.
Started with the wheels. Front no problems at all, looked fine. Rear wheel, except some cobweb, needs regreasing of the bearings.
Questions to the experts:
Rear brake, there is only one spring. Should it be two and in that case, is it a Manx specific spring?
There is no bearing seals at all in the rear wheel, is that correct?
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Hoping that jalsteve will have time to spread his wisdom on rear hub parts, I contnued with gearbox installation. Spent yesterday evening filing LH engine plate to accomodate that fat and heavy TTI-box.
Now the gearbox and LH engine plate is in place. Shortened the bottom gearbox stud 4mm, so now it's possible to take gearbox in and out without raising and/or lowering engine. Norton should have done that mod themselves. As a final touch I drilled a 2mm hole in the gearbox and a washer with a tab also drilled 2 mm. So now I can lockwire engine and gearbox drain plugs.
Only tricky part in gearbox assembly is the top rear engine bolt. To get washer and nut in place below the magneto and behind magneto chain covers is a bit problematic.
Washer was put in place with help of a small magnet. For the nut a thin plastic glove with nut inside (on left hand thumb) worked surpricingly well. Blurry on picture.
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Not surprised, some more parts needed. While waiting put on some small parts. Seat, front mudguard, handlebar grips, tacho drive cable, gearbox sprocket, rear sprocket and a sharkfin.
The torque stay in place. Front bolt replaced, some fool had used a full threaded bolt. Had to make a special nut with a spigot at rear end of it.
Been too busy with my job as eventing crosscountry course designer, preparing seven different courses with around eighty obstacles for next weekend.
Takes to much time from the Manx.
Started clutch work. Finally decided to use an ordinary Manx clutch. Got an almost new Newby clutch really cheap, but decided to use it on next winter build, a Norton caféracer.
Can't remember about lubrication of the clutch roller bearing between centre and basket. Help please.
Sad to say, have been busy with other things. Not much done to the Manx. My neighbour calls it the mailorder bike. Just because all delivery vans and lorries that come with small and big parcels.
Next week nothing will be done to it. Then I'll do the rear wheel, get primary drive in line and try to fix a leak in left fork leg.
The original (?) clutch is a mysterious thing to me.
Clutch part Gear Auto part Rotor Bicycle part

Notice the spring screws with 1/4" square holes. Basket and pressure plate lightened. No steel cage but filled with a lot of rollers. 6 Allen screws. Friction plates and centre different size of "splines" than other Nortons. Steel plates probably usual size. Sadly it had a hard life, centre much worn. Will use an Andover clutch.
Some small things done. Replaced rubber mount for float bowl and made a gear lever.
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Clutch springs round section, think original did not last for 9 years of hard racing. Friend borrowed an excavator from me, in return took new clutch parts to machine them as old one. Nice to have friends with CNC-machines, when you only have manual machines. Race scrutineers nowadays might have some opinions on some original parts, so some parts had to be made. Alloy footrests done and threaded 7/16 BSC. Since the old Arrgardh gearbox had a reverse gearlever, a temporary gearlever is made. If the bike is ever is running again, I'll decide what length it shall have and make a period looking one. The TTI-box was ordered with that in mind, so it will be the usual 1st up, the rest down as all my other English bikes have. Today made a .6mm shim under engine sprocket. Primary chain is now quite inline.
As nearest Manx I know of is some 150 miles away, there are things that I can't figure out.
What does bolt or stud holding front of chainguard look like?
Since most of the oil and breather lines was a real mess when I got the bike, advice please. That upper line to oil tank is return and lower is supply is probably right but the rest?
Have to make a tool for retainer holding rear wheel bearing. Difficult to figure out diameter for the 4 holes. Of course a hammerhappy cretin had been there.
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I hate lockwiring. Not the wiring but drilling the holes. Bolts is easy compared to nuts. Worst is nuts in oil fittings. Finally bought some tiny endmills which made it a lot easier. Starting with an endmill and then changed to a drill. Now the drill breaks when going out instead of when starting. Managed to make 5 holes whith only one broken drill. New record :)
Not much room to lockwire oil lines on a Manx. Luckily had some forceps which made it easy.
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Yes the temporary gearlever is hideous.
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Thanks, will use old chainguard with dents and welds as it is. Dents from broken chain at IOM junior TT at last lap in -63. Like to keep some parts of its history.
Old engine was rethreaded to 3/8. As you told before about chain tensioon cold vs. hot, I see the reason for the design. Easy to make it except for the knurling (lousy at making 'em).
What about rear mounting?
Very logical, no problem, easily done except that I dropped the box with assorted grommets. Took some time sorting a hundred grommets again. Some earlier owner had threaded the gusset hole to M8. Naturally it was cracked and welded and cracked again. Have worse problems than that. Oil tank leaking on at least three different places. Looking at the other 40M thread, same oil tank as mine. Guess I'll have to send a mail to Ken Macintosh. Funny thing about oil tanks, according to the previous racer, it had the oil tank in the fairing, never heard about that.
A bit of update. Inspiration lost when I found that the oil tank had to move into the original parts box. Spent some time racing a -72 Honda, had to improve my riding a bit. 4 seconds better best lap time than last year!!! Sideburns makes miracles. Plus a better fairing and some engine fixes. Also spent a lot of time on the road with a Comet.
Now a new oil tank has arrived from NZ. Looks good but some minor differences to the old one. Only experts will notice. What is the proper silver paint for a Manx? Does not worry me much because it will be built as it was raced in the sixties by a friend of mine, who said that a good paintjob didn't make it faster. Also got a proper chainguard stud from Mcintosh.
The Manx project has to wait a bit as I'm going to see the Manx GP.
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