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How wide does it need to be across the front end?  I have a GS500 swinger here that you can have for mates's rates.  I bought it for a GT750 project and ended up using a TL1000 instead.  PM me.

BTW, our local store just started selling Tim Tams (made in OZ).  If you find a good source for crumpets, I'd love to hear it.

I hate that guy.  He makes me look like a completely ham fisted gorilla. How on earth does he cut a set of crankcases with a hacksaw?  Mine walks off at different angles, and I spend months training on how to use hand tools.

He is very good and it's funny that he makes it all look so simple.  It isn't, but he makes the viewer feel that they could do that too and that's a whole other gift he shares.

First we had TEL which worked well but caused health issues.

Then I think we had MTBE which turned out to be even worse.

Alcohol is not as unhealthy for humans and the planet but it comes with some disadvantages for old designs of fuel systems.  Modern vehicles don't have much of a problem, so I don't see it changing any time soon, so our job is to work out ways to mitigate those side effects on our old scoots.

And I am sure that's where the original post came from. Looking for ways to reduce the mechanical/chemical harm to our old bikes without causing more harm to our already damaged planet.

Lots of good points being raised.  Engine Masters did an interesting series of tests that showed that as long as a motor had fuel with high enough octane to prevent detonation, more octane made absolutely no discernable difference.

Our dyno tests on small 4 stroke Honda twins showed that race fuel like say VP C12 made slightly less power than street gas in our motors. We didn't change compression to see if we could eek more power out and I suspect that the additive package might have made those small differences.

Back when we were racing RS250 Aprilias we tried different fuels and back then there were a few magazines (remember them) that tested fuels on the dyno and for sure, some chemical soup combos made more power than others.  Elf used to blend the most lethal blends of chemicals back in the days of 500GP 2 strokes and the fumes were interesting and cancer causing or so I heard. Honda techs could be seen with industrial type breathing apparatus akin to hazmat quality just to put that fuel.

But back to your main point which was that fuel without ethanol can last longer without causing deterioration of fuel system parts and that may be true but hasn't been my experience so far.  It's a worthwhile point to consider though.

When we ran a bike on methanol I had to sit down and work out the change in energy released.  Mathanol and ethanol are less energy dense than gasoline but burn at much lower stoich levels and the end result of burning over twice as much fuel with just less than half the available energy amounted to around about 17% additional power theoretically and about 10-12% increase in the real world but allowed us to run very high compression ratios and of course we had to light the fires much earlier than with gasoline.  Closer to50 degrees BTDC versus 40 or so on gas.

Yamaha changed head shapes when the FIM moved to unleaded fuel and combustion chamber shapes have continued to evolve along with multi dimensional ignition maps.

For our old bikes there are new tricks still to be learned and more power to be released.  And that's one of the aspects of playing with bikes that keeps us awake and learning. I'd like to see a test of different fuels in a motor with variable compression ratio to see the effect of raising compression with different fuels. A single cylinder motor with a range of domes (inserts) with say 3 to 5 fuels would be enough as long as the tester allowed for SG and H:C levels and energy density.  Could be fun to see the results.

I am easily confused.  The post seems to suggest that we don't need lead in fuel but that we should use it anyway.  Or did I miss thr point?

Apart from the legality, there is no need to use leaded fuels on the street.  The 89 or 91 (I don't remember which) in my RZ350 is months old and it still fires up and runs well. For sure it prefers fresh gas, but gas doesn't seem to deteriorate as fast in my bikes as others have reported, so I'm not sure what to make of that.  It is illegal for an airport to sell 100LL for use in a street vehicle and illegal to use it in one as far as I know, but that's up to the user to determine.

AvGas 100LL is slow burning and lead fouls plugs, but quality is more consistent that regular gas, but who really notices the difference in a bike IRL?

We ran 100 octane race gas in Australia in TZs and other race bikes.  We ran Methanol in our 4 strokes but that was a different story. I wouldn't run 100LL on the street because there are no real advantages.  The biggest disadvantage for most street riders is that it burns differently than unleaded and leaves a very different color on the plugs.  Leaded looks lean and plugs are gray where unleaded leaves more soot and looks rich even when it's not, so I tend to run harder (colder) plugs when running leaded gas and softer/hotter plugs with unleaded to get them to run clean.  100LL also has a different specific gravity to typical street gas IIRC so be careful with jetting.

We all have our favorite fuel and our own foibles but having tested a whole lot of drums of different race gas in a drag race GT750, I can't say that any of them were any better than street gas in terms of detonation protection or performance. Well maybe U4.4 but that doesn't seem to respond the same way in all motors.

For the street though 100LL has no use IMHO.

My preference in Sunoco race fuels is Maximal but 260 GT Plus is a good non-lead fuel and for the street, high test is adequate and stable enough to use even with high CR motors in my experience.

That's an interesting chart, but a little hard for me to read the details to work out exactly what we are looking at. 

New eyes might fix that but in the meantime are the two lines top and bottom clip positions with all other variables held constant?

And is the chart a measure of flow through the needle jet or total fuel flow into the carb or something else?

The confusion may come from some of the old advance curves on line that show 10 degrees of advance in some CDI units back in the day, but that wasn't the static timing.  That 10 degrees was initial advance over stock static timing of 19 degrees on a TZ, so the "curve" was 19 at start, rising to 29 or so at low revs and dropping back to 19 degrees by 10,000 RPM.

Not sure if that's where 10 came from, but it's easy to be confused by the info online.

What am I missing.  The rider's seat is really low and the passenger has a clear view over the rider's head.  For 1951 it at least had plunger rear suspension which was about as good as it got (generally speaking).

From what I can see it was an 11hp post war Russian oversized DKW125/Hummer/BSA Bantam based on a 30's DKW125.  That design was the spoils of war and was the basis of the Hummer and Bantam among others. 

The passenger seat was probably a valiant attempt by cash strapped Russian manufacturers to manufacture cheap transport.

Maybe that design is a case study on why we don't see a lot of Russian motorcycles in MotoGP.

On a 750.  No need to go smaller.  They are quite tame with 34s on.  My drag motor with a 750 top end is similar to an RZ motor but with a bit less mid range.  Easy to ride.

You could go bigger though.

First, Flush with wd40 and take a 3/16" drill and carefully clean to the bottom of the threads.  Then use a tap to clean the threads and after that flush the hole out with WD40 again and last but not least, lightly countersink the hole.

The reason for that is that when a bolt is tightened, it will tend to pull the threads up slightly along with the surrounding metal.  If you carefully draw file and case with a new clean fine cut file, you will see raised donuts of aluminum around most of the threaded holes.

Lol your right, my point being is the root cause of these problems can be sneaky and are a pain in the butt .i was out on a ride this summer when on of my older bikes quit running in top gear middle of the road, pulled over tried to restarting no good,,moved the kill switch a couple of times, and it started right up.

And that is why it's a good idea to spray WD40 into the switches and work them back and forth a few times before you ride or at least on a semi regular basis. My bikes don't see a lot of road time so corrosion inside switches is a high probability and easy to fix.

There are probably better solutions with special grease and so on, but I have too many bikes and never enough time, so it works for me.

If those carbs have choke (starter) jets in the float bowl, I can tell you that they don't always open up after a long hot soak in the ultrasonic cleaner.  I have had a few Mikuni carbs that had to be mechanically cleaned out with wire. 

Good idea to add that bypass hole.

What I do after I clean carb bodies is to grab a can of WD40 and blow it through one drilling and repeat on the other carb(s).  That way I can see if the same passage flows more or less the same amount on all carbs and then I move to the next drilling.  Rinse and repeat.

The starter jet is a PIA because it's pressed in and not replaceable and it sits at the bottom of a well where garbage accumulates.

As I said above, I tend to use WD40 because it's less toxic than spraying half a can of carb cleaner around the workshop.

it shouldn't matter. the slide is behind the enricher circuit which should supply plenty of vacuum to pull it up IF the slide is down far enough. Me, id drill out the starter jet a few thou and will work just fine. however, that's a neat solution.

I mean, if i can get a 350 to start on enricheners with v force reeds and 36mm carbs.... yours should work just fine.

AGree.

I kick start our drag bike which has TZ750 cylinders with Blaster reeds and 34mm carbs.  Are you 110% sure that the tiny starter jet in the float bowl is clear? They are only 0.6mm diameter and block easily. 

I would find a way to clean and mount that lamp on a small wooden stand to act as a night light at home, so your wife can remember her ancestors.

An RD is totally the wrong style bike to mount that rather nice prior period piece IMHO.

For something more period, maybe a Lucas tail lamp from a similar year might be whimsical enough and an nice reminder that Lucas was known as the prince of darkness and many people see motorcycles in general and two strokes in particular that way.

What better inheritance to leave than say a Mark Dent RG500 in say a Spondon or similar frame with say BST wheels and Ohlins suspension?  Or maybe a Suter 500 motor is a suitable chassis?