GregT

Chop strand is unpleasant to use. The bike/kart repacking mat is much nicer.

If you're still going to pack the muffler, rather than fiberglass try what I use on racebike mufflers.  Kart shops sell a muffler repack material which is a woven material in sheets about 500X500. It's quite thin so I think would fit between the perf tubes. I usually use stainless wire to hold it onto a perf core. It seems to have a long life in 4 strokes. The 2T karts saturate it in oil which is why they repack.

Have you got the cover for the cylinder head ?  That at least should be polished. It's the one thing that makes the ramair versions stand out.

Good recovery on both the problems. For some reason the X1/9's seem to have 2 or 3 jesus nuts. which if they come loose do serious damage. That shaft damage was most likely caused by the nut loosening. I found on ours the guy who fixed a rear suspension balljoint hadn't adequately tightened the nut on the end of the axle/hub carrier. Discovered it on a test drive and limped it back before anything major fell off. Wheel could go in and out 2 inches when i got back. Good design doesn't leave things up to how tight a nut is done up.

5 hours ago, igor said:

Is there any engineering benefit to the use of TTY bolts?

Not really - but the bean counters love them as you sell more parts.

1 minute ago, SOHC said:

The SC is the old 70s thing? I know where one of them is,the WR make over 60 HP

Yeah. There were only ever 2 or 3 SC's came to NZ. The guy in ChCh who owned one moved to West Australia and took his with him.

So is the WR based on the last of the air cooled YZ's ?

51 minutes ago, SOHC said:

My friend has this Yamaha WR500 for sale, I want

Is that the enduro version of the SC500 ?  The SC's make ridiculous amounts of torque - if you can master starting one.

56 minutes ago, SOHC said:

Did you ùse the gn250 rotor and attach the hub from the aermacchi?

No. unrivetted the Honda rotor hub and machined up a new hub with the right taper for the Macchi crank, The six buttonhead capscrews visible in the second pic hold the hub to the rotor.

I've used the GN ignition on several things. In the GN it triggers off a lump on the OD of the alternator rotor. I've done as in the pic several times on race motors. The alloy blade has a steel tip on it to trigger the pickup. By slotting the mounting holes it becomes adjustable. The early ignitions had a 7000rpm limiter. By reversing the 2 pickup wires you get about 15 deg of advance range - and no limiter.

Knew I had the pics somewhere. 250 Aermacchi motor with Honda alternator in place of the piss useless 6v generator.  I could also have triggered a GN250 ignition off the lump on the rotor - but left it with points as easier to repair in rural Italy.

One of my Aermacchi customers did the Moto Giro in Italy on a borrowed bike. Finished up carrying a car battery in a knapsack for 4 days. So when i built a 250 Macchi engine for him and a 250 Benelli engine for his mate so they could take their own bikes, i put Honda alternators on both. Parts as common as pigshit and about as cheap.

Can't see enough of that engine to pick what it is. If OE bits aren't available, what about a magdyno ?

I know a guy who swears by them. Brass or bronze bush would still be my favored method.

23 hours ago, sheepers said:

Today I made a shelf

I found that heavy duty moulded plastic trays - about 500X400X70 deep worked well as storage for that sort of thing. Pull them out to clean the benches as needed.

I remember going over the hill all year round on an SL350. Not a bad choice for the road over.  Never really struck any ice - but the fog was very bad at times. Funniest bit was I'd often pass Gavin Bain driving something exotic. Always passed him doing a wheelie. SL was quite good on the short straights between corners.

It's not optimum - but it does work.  The flat 6 won't have a lot of overlapping vacuum so distribution should be good enough. From experience with a 36/36 Weber on a hot 202, the volume of the main log of the manifold is fairly critical. Too small and the ends starve. Too big and response goes away.

17 minutes ago, Lord Gruntfuttock said:

I've got (counts on fingers) 5 BSAs (sort of, 3 are Dandys) and part of the attraction is that they don't make em any more. Like Datsuns.

Was excited to see they're making em again, but but disappointed in result. Hard to get right though.

A new Goldie with modern reliability would be sweet...

 

There was a British made one that lasted a month or so before the company dying. Nice frame, polished alloy tank, wire wheels - and a SR500 Yamaha motor. Don't think it ever reached production.

2 hours ago, SOHC said:

Also the reed block I will chop out the divider and make a carbon fiber single petal   

I wouldn't. One big reed has a lower natural frequency so will work slower. Carbon replacements for the OE reeds in the stock cage but with the edges of the framework radiused is a better way to go.

And 10mm lift on the exhaust.....What timing does that give you ?

It's about 50lb heavier than a real Gold Star. Makes about the same HP as a well tuned one where it should be making way more with that spec,

And yeah, Rudy's right. the visuals don't work.

Clean the seal and it's crankcase hole - and slide it back in with a smear of epoxy round the outside.

Sounds like Kev's MB100 bucket. Even after frame bracing it was directionally unstable. And it would do close to 90mph on Greymouth gearing.

Palmside in ChCh would be worth an email.

On 18/11/2023 at 16:49, JustHarry said:

 

 

Surprisingly enough Bugatti had the front end alignment pretty well sorted for the wheel/tyre combos of the time 

Ettore knew what he was doing. Even if most of his stuff is fiendishly difficult to reproduce.

The chassis forgings where tube meets rail are state of the art for the period. Welding at the time wasn't trusted - with good reason.

Looking forward to seeing the clutch parts done. The Bugatti clutch is a clever semi-centrifugal device.

Keep up the good work.

52 minutes ago, Lord Gruntfuttock said:

I tapped lots of chewed out alloy threads on the ironhead to metric coarse. 
Seemed to go ok, but it's a pin in the hole having to use metric and imperial tools... 

You can still buy imperial sized helicoils. Bit more effort but it keeps the fastener size OE.

2 hours ago, SOHC said:

1/2 UNC might bite into the alloy better?

Yes, nice and coarse.

3 hours ago, ajg193 said:

Screw cutting is a rare endeavour, but working without power feed is not fun.

Even something as simple as a DC motor with speed control will be life changing

Agree, but even if you can only get it to work in cutting direction it's a bonus.

3 hours ago, JustHarry said:

Last time we did a mag casting it got vapour blasted 

It's and engine crank case so no coating.  Just left bare mag 

 

I saw the run of JAP's for 500cc cars. Before assembly. Dark brown chromate on the crankcase satings. Wasn't told who did it.