I need Manxman info

seattle##gs

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A friend wants to build a Cafe bike using a Manxman for a base. Unknown year. The frame and engine numbers match so he would like to keep them together. He also has plenty of Atlas parts. My knowledge stops at the 1966 Atlas.
He would like to put on the 750 Atlas head and barrel on the Manxman cases....
***Are the crank journals the same so he could use better rods? Somewhere in this area Norton changed the size of the rod journals. We are considering the JS carrillos and pistons.
***Would an Atlas crank fit into the Manxman cases?
***Will the Atlas cylinders fit on the Manxman casess?
***I assume the Manxman oil pump is a three start, hopefully his Atlas motors have a six start oil pump. Any problem in this area?
 
Manxman's only came out for one year in 1960 then the following year they were 650ss, why would your friend want to put Atlas 750 head and barrels on a Manxman bottom end, to me the 650 motors run smoother than the 750 Atlas and are a better ride although they are very simlar.
I am at the moment am building a Manxman that I brought in boxes with most of the orginal parts missing as well its not the orginal motor to the frame, the motor has diffrent numbers to the frame it was used for racing and track work with history, my plan is to build it as a caferacer when finished, the motor has hi comp pistions, balanced crank, the head was missing from the bike but has twin monobloc carbs and I be using a 2S cam, has a Lucas racing maggie, alloy wheels, alloy central oil tank and a new alloy fuel tank that came with the bike, this bike has been in boxes for over 20 years now and took me 2 years to chase up a head for it.
If your mate still goes ahead with a Atlas top end and he has the 650 head and barrels I would be interested in buying them if he want to part with them.

Ashley
 
Re: I need education about NHT family

500-600-650 are small bolt pattern cases/barrel AND small bolt pattern head
read my website for head info it's been out there since august 2000.
http://atlanticgreen.com/nhth.htm

650 is one the most exotic NHT engine, specifically the raw crankcase "castings" are the same as atlas (through early commando) BUT the machined barrel bolt pattern is SMALL. 750 won't go.....750-850 are large bolt pattern barrels

650 crank cheeks are like atlas BUT the atlas style flywheel MUST have the 650 special machining or you smash your pistons. Any 1.75" NHT rods will work.

Small bolt pattern semi down draft heads 62 88SS and manxman/650SS are incredibly rare (especially in north america ) and have been going (ebay england) for over $2000

altas heads spigoted $50... 66+ no spigot $75... more if it has rockers

Ashley
where did you get your 2S/combat grind cam on a NHT twin chain 18-20-20M3 core? I got mine from Norvil.
To me a 2S is incredibly hot for a street bike and even a stock 22729 SS cam IS like a combat in these small engines.
 
thanks for the info. I know nothing about the Manxman but I have heard the motors are smoother than the Atlas...why is that? The Atlas had low compression too.
I will talk to him about the project, perhaps he would be happier with a stock Manxman motor done in Cafe trim or maybe go to an Atlas motor in his Manxman frame.
 
seattle##gs said:
A friend wants to build a Cafe bike using a Manxman for a base. Unknown year. The frame and engine numbers match so he would like to keep them together. He also has plenty of Atlas parts. My knowledge stops at the 1966 Atlas.
He would like to put on the 750 Atlas head and barrel on the Manxman cases....
***Are the crank journals the same so he could use better rods? Somewhere in this area Norton changed the size of the rod journals. We are considering the JS carrillos and pistons.
***Would an Atlas crank fit into the Manxman cases?
***Will the Atlas cylinders fit on the Manxman casess?
***I assume the Manxman oil pump is a three start, hopefully his Atlas motors have a six start oil pump. Any problem in this area?
Click to expand...

IF you Want to know about The Norton Manxman then you Need me Has its Me that has all the information on them for one the Atlas barrels will not if onto Manxman Crankcases But the Crankshafts are the Same And Early Atlas Had the 3 start oil pump and Plane big end shells YES NO OIL HOLES IN THE BIG END SHELLS AND CARRILLO RODS AND PISTONS ARE VERY GOOD BUT THERE DESIGNED FOR HIGH REVS LIKE IF YOU HAD A CAFE RACER OR WAS RACING ON A RACE TRACK If you only riding on the roads Good tested Stock parts are adequate THE NORTON PISTON FOR THE NORTON MANXMAN WERE MADE BY BHB and there stamp marked BHB on the Crown of the pistons and over sizes only go to plus 30 thou More than this you end up with cracking the barrels which now are getting very hard to find So I would stick with in ware limits and a well balanced and well put together will make a good engine
 
atlas VS 650?
"But the Crankshafts are the Same" :oops: Isn't the flywheel part of the "crankshaft" I guess not...for a x@(&%$*= moron

Obviously she has never worked on both of these engines.
ha ha I have... :mrgreen:
I now have worked on and been into every variant of NHT engine and an awful lot of NHT powered bikes...true ... not all :roll:

This is 21 of the 26 (maybe more?) that I own and use for study of NHT...
right click on pix and "view image" to see them all
I need Manxman info

front row L-R
Dynamo engines--1950 500cc model 7 engine code 12 iron head, 1953 500cc model 7 code 12 aluminum head, 1957 600cc model 99 code 14 #75050 exactly THE last engine # for 1957,
Alternator engines-1959 500cc Model 88 std engine code 122-built to 1962 88SS spec, Ron's 1961 650cc manxman code 18, 1962 650cc standard code 18

Rear row L-R
(Group of 4) 750cc code 20-atlas 1963, 1965, 1966, 1968(Dunstall)
(Group of 2) 750cc code 20M3-commando 1968-70
(single) 750cc code 20M3S 1971
(Group of 2-1/2) 750cc code 2xxxxx combat breather cases-1972 combat tune-1973 standard tune
(Group of 3) 828cc code 3xxxxx-324999? 1973 RH4 head-1974 RH4 head (920cc)-1974 RH10 head
(Group of 2)828cc code 325000+ Commando 850 MKIII-electric start
 
It is looking like the smart thing to do is to keep a stock motor.
Best place to get pistons if I need them? .030 is the highest I can go safely? And who makes .030 pistons? Odd size to find. Neither of us has any idea of what is in the motor. It is all together and looks good from the outside. If reringing is reasonable we might go that way, especially if the motor can only be bored .030. Best place for rings? I would like a 3 piece oil ring. Perhaps Total seal can make a set...anyone else?

**H ow about balancing? I had my Atlas balanced to 64% and it was an improvement. The owner will not be riding this bike hard. It will be a Sunday bike. High RPMs will not be reached for very long. Perhaps Commando rods?

If this were your motor how would you build a strong and reliable stock motor?

**How about a six start oil pump? I have two extra.
 
I'd highly urge you to pullit out and do a tear down.
LOL a local club guy bought a "rebuilt" atlas $5000

He dId not like something on it and I said bring it down and we tore it down....
all the barrel and head bolt were barely tight almost loose. the front and center head bolt...missing :shock:
Down to the crank the journal was 1.5 thou under and rough as hell and the "NEW" rod shells were really ugly after 100 miles. :oops:
Oil pump failed miserably on my test rig and it had been "refurbished" LOL a real hack job... :cry:
Nice looking cam but the "reconditioned" lifers were not done square and the wear pattern proved this out very clearly.
We will inspect further once he cleans it all up.
A quality built stock 650 SS could be a very fine motor. It's state of tune makes it as good as a atlas power wise and the lighter pistons make it's vibrations more tolerable. I have a significant professional background on vibration but I rarely go into it since most people don't have the education background level to comprehend...and I hate to type for nothing :|

pistons? RGM has std 20,40,60 over. And cylinder sleeves..... I'm gonna get some of all 500-600-650-750-828...I already have 920 :mrgreen:
I have not bought that much recently since I stocked up in the 90's and early 2000-2010 about $15K worth so can't help sourcing parts, it's not my strength.
 
also, I would like to install a belt drive primarily to stop oil leaks in the primary. There are a few available including one from Clubmans Racing which allows the use of a Commando clutch so I can soften the clutch lever pull. However, I lose the cush drive. Any experience with these belt drives? I have had a tony Heyward belt drive in my Atlas for years using a triumph clutch and an adaptor but he doesn't make the adaptor anymore.
 
seattle##gs said:
also, I would like to install a belt drive primarily to stop oil leaks in the primary. There are a few available including one from Clubmans Racing which allows the use of a Commando clutch so I can soften the clutch lever pull. However, I lose the cush drive. Any experience with these belt drives? I have had a tony Heyward belt drive in my Atlas for years using a triumph clutch and an adaptor but he doesn't make the adaptor anymore.
Click to expand...

Even fast-talking Tony might have had trouble selling Triumph clutch conversions for Nortons.
 
650 rings

1. When doing my friends 650SS/Manxman he opted for total seal rings. Back in the day (post 1992 rally) there was a east coast distribution and R&D center in Greenland NH. They had to cut his precious BhB pistons to make the compression rings fit. Well 20 + years later He gives me the project and lo and behold upon assembly it won't go together. The oil rings won't compress enough and the barrels hang up. SO I had to put them on a lathe and deepen the OIL ring groove that total seal failed to do :(

2. Several small bore nortons I have disassembled I have found the oil rings to be 1/8" instead of a somewhat less standard 6mm. Even a blind person could feel the slop. This may be a north american problem since so few people including norton parts dealers know much about nortons.
I finally sourced hasting rings for my overbore 88SS ONLY by buying individual rings by size, type and part number, rather than a set. The hastings ring tech was trying to tell me it was not possible. Competent info is hard to find. :lol:
 
Featherbed clutch/belt drive

First-to get out of the crap we will have to endure from anna, and you are not likely building a manxman, so you can drop the name to make life easy for us all.
Specifically a manxman is a forerunner of the 650SS and is basically the same, except the blue paint job, small tank, with a resultant forward moved seat, first with a 18" rear wheel, red seat. IIRC 62 manxman or 650SS still had standard 62 tin...oiltank and taillight and maybe more minor things.
63 with new tin, Home market may have gone back to 19" rear wheel. Otherwise none of this is important to your project, or me

belt drive:
1. Clubman is a prime stocking agent in the US for RGM products. They have AT10 belt drives.
2. As far as I know, Norvil does not have any full line prime stocking agent in the US. Fair Spares is maybe the closest thing. They have HTD style belt drives and offer more ratios than RGM.
3. I'd highly suggest to use a commando tranny mainshaft and commando clutch center rather than what they offer, which is a modified commando clutch center on a featherbed mainshaft.
heres why:
http://atlanticgreen.com/naclueng.htm

I have 3 of each type on the table behind me (no I'm not selling any)
The atlas/featherbed/coil spring release cam/arm is entirely adequate and fine for the diaphragm clutch. You would likely need a commando clutch rod, which is a bit longer.
If you want access to my old article on commando clutches, email me for the current link name. I renamed it due to the morons on this forum, I got tired of their crap over a 15 minute experiment.
 
dynodave said:
due to the morons on this forum, I got tired of their crap over a 15 minute experiment.
Click to expand...

Don't forget that no-one is born knowing anything of this stuff, they had to learn it someplace.
We saw your amateur 'advice' on the Model 7 Forum, obviously didn't have a clue, so you've had to learn it someplace too. Fine if you don't want to pass it on, or "waste some words", but fortunately some/many here are happy to help fellow travellers. Now, if only Anna would google to check to see if she is right / and do a bit of proofreading also.
Cheers, and Appy New Year to all !
 
OK...I will call it a 650SS. with a blue frame.
We will do very little to the motor , no Atlas top end.
Balance the crank and do what ever work it might need.
Complete valve job.
new rings or pistons depending on what we see in three weeks.
Superblends
2 new Amal concentrics
belt drive with new commando trans mainshaft
Comstock sump breather if it fits.
Sensible stuff

WHO CAN COMPLETELY OVERHAUL THE MAGNETO AND MAKE IT RELIABLE?
 
Dynodave states that one of his engines in the photograph "1953 500cc model 7 code 12 aluminum head"

It would have had an iron head of that age, fact!

Happy New Year.
 
Paul W said:
Dynodave states that one of his engines in the photograph "1953 500cc model 7 code 12 aluminum head"

It would have had an iron head of that age, fact!

Happy New Year.
Click to expand...

Sure might be If it was original/correct. Right or wrong I think it came from a bitza 88
What's your point?
It has an aluminum head on it, I have 2 more iron head's on the shelf with 10 more assorted heads. Did I claim all (or any) is exactly correct ! NO
I didn't hear you say anything about the incorrect 920 :lol:
 
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