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Amateur Manx 40M preparation

25096 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.
Bicycle fork Auto part Bicycle frame Chassis Machine
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No signs of cracks? Good that it is painted and not powder coated.
If you are not rebuilding the engine... when was the last time it ran and what kind of oil was used? Castrol R?
You will have to wait for Jalsteve to come along to enlighten you on the rear hub, I'm not familiar with that new fangled modern stuff. As for the cheese head screw, Im not sure what you would gain from that. You would need to countersink the bolt hole to recess the cheese head and you could do that with allen bolt. It looks as though there is enough meat there, but if it clears now, I would think .030 is sufficient.
McIntosh Racing sells that stud, grommet and nut for the chainguard, but there must be someone closer to you. His parts listings don't include photos, but there are some closeups of that side of the engine in his photo gallery that would give you an idea of what it looks like.
A note on Mr Yoshimura's undisputed skill. In beginning of the clip, there is indication that ends of the pipe is plugged. With the big nozzle he has on the torch, the time it takes for him to get temperature up to when it is possible to bend the tube makes me believe that it's sand filled. It is very interesting to note how he moves the torch to get the tube soft in the right parts. His combination of feel when pushing on how the tube wants to go up or down and his adjusting on where to apply heat is simply amazing. Looked at that video before my little tube adjustment. Otherwise should not have fixed it. The video is a good example of a very good craftsman doing his work with simple tools.
Yes, it would have been nice if he showed the process from the beginning. It almost looks as though he has the ends just taped off, which doesn't make sense. Here is another fellow.... it shows the tube capped and a threaded packer in one end and it also gives a better view of the torch.

Nice to see updates on the Manx btw.
Perhaps time to start brushing up on your bump starting skills? You can practice on that contraption from Stevenage in the background just in case you're a little rusty.
Congrats on the Venom. Still want one of those.... or a Thruxton. I recall watching two poor bastards at the start of the 500 production TT. Everyone else had beetled off into the distance and the only thing you could hear were these two poor guys trying to kick them into life. They were completely knackered, sweating buckets with leathers half off...... both unfortunately were DNF.
How does the Venom compare to the Comet in the acceleration department? Silly question I know, but just curious.
No idea who, but I think that is why god created roller starters and hills. I have an old rigid/girder OHC 500 Norton that has evolved over the years and I don't think my wallet or my spine would permit me to bump start it anymore. Rolled back against compression... a few good strides with a property adjusted clutch... you could time the release so your ass connected (sidesaddle) with the seat just as the piston approached TDC. It felt good when it lite up without any drama.
What plug are you running?
Don't think there is anything wrong with that reach or tip. I was wondering if someone had installed a BP10 instead of a B10. Maybe you should pick up some spark plug indexing washers and use them instead of an extra plug washer. I have no idea what the details are on that piston/combustion chamber. All of my stuff is older long stroke, so don't know if this makes sense. Maybe you can index the plug with the ground electrode in a position that gives you more clearance. Perhaps Jalsteve would know the answer to that. Or you'd have to pull the head to verify it makes a difference.If you are just wanting track time, then I would just use the indexing washer to give you some room. Keep in mind that piston will get closer over time. Might be an idea to get a gauge in there and determine exactly how much room you have. Surprised that they would let it out the door like that.
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If you purchase plugs on eBay, you need to be aware that there are knockoffs out there. I bought a bunch of NGK B6 for the road roach from EBay, but as mentioned NOS (New Old Stock) is your best bet. I found a box of NGK's made for Honda, so they came in Honda boxes that looked like they had been around for a while. It is less likely that the counterfeiters would bother with Honda or Yamaha boxes. It also seems with the new plugs it matters where they are made. Folks I know in the U.K. curse NGK and claim they easily foul in filthy old carbureted engines. There is some speculation that the ceramic used by the French factory works well in modern clean fuel injected engines, but fouls easily in richer environments. No idea if it's true, but the plugs we get on this side of the pond seem to be all made in Japan and work well.

As for the knockoffs, info can be found here PLUG STUDIO / NGK
It's older info, so the fakes may look better. I had the opportunity to inspect some knockoff oil filters and they are getting pretty good from a visual point of view, but they barf oil all over the road.
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Emptied the fuel tank. According to my calculations, she used 1.5 miles per gallon! My guess today is that the problem is something with the float chamber.
Paragraph 3 in post 81?
Test start accomplished. It'a a lovely engine (thanks Molnar), really smooth. Only air in tyres and petrol in tank (not the opposite). It's a very easy starting machine. As an old racer explained it, compression ratio should be where it gives lot of power and is easy to start. In the old days when engine was off when the flag was dropped. Seems the float bowl change worked. Now load everything in the van. Practise on track sunday
Looks very nice. It inspires me to head out to the garage and do something with the shrapnel laying under the bench.
I’m assuming there are modern bits lurking inside that mag. Wonder if they help with the starting, although nothing wrong with a old one in proper working condition (other than price). Good luck at the track. Perhaps a smidgin of R40 just to add to the religious experience.
i have never seen copper floats ,brass is what you meant i am sure,
copper is red, brass is yellow ,that is an easy way for us to distinguish the diff
re sticking viton tips this is why the japs and others have a simple dangler hook at the spring loaded stem end
it serves to mechanically pull the valve open upon a bit of float drop
the hole size in the seat has 2 distincr effects
a larger hole offers more flow at any given float drop/opening but also needs more float pressure to shut the valve

spring loaded stem tips are very desirable
Auto part Machine Tool accessory Machine tool Rotor
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yep those are all brass my color ref was regarding clean metal the brass turns brownish-red
i have in front of me now a dozen del's from early 60's on and even the remote bowl ss1 ss2 have brass floats
copper is too ,weak and would need be heavier than brass by a considerable amount to not be as fragile as a dry popcorn fart
Auto part Cylinder Gas
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