My New Bitsa - Quiz time!

markjackson

markjackson

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To get near the horsepower of one normal bike obviously needs at least two airheads, so here's my second.:D

12889603434_131f55e398.jpg


It lets me play 'project bike', 'cos the Kalahari is far too nice to butcher.

The only certainties are that the Lester? wheels will be going on ebay ASAP, wires will be be going on and the hand guard bits are fugly:barf

My plans are open at the moment; I'm not sure whether to make a 90S rep, a 100CS rep a tuned and fettled AMA rep classic racer (but probably road legal) or what, yet, but the first quiz it what actually it is?

It was listed (on e-skip) as an R90 from 1975 but the engine (Rockers/airbox/front cover/Badge) looks R100 to me and the forks and front brakes look late 70s/early 80s R100 too. So..

Any ideas Airhead experts?
 
It's an 81 to 84 r100 engine gearbox, tank, forks etc. surefoot side stand.

Good luck with getting wires on it.
 
Working on the principle the engine and frame numbers matched when bikes first came out of the factory, if you look for your engine number on this site ,it should give you the original bike your engine was fitted in.
 
Wires are easy to come by for the 80 and earlier bikes but the brembo front end needs the 2 spline hub that was fitted to the police bikes. If you fit the earlier wire front the spokes catch the calipers. It's one of these you need. They were available new but were just over £300 for just the hub.


Hub.jpg
 
Bill-H said:
Working on the principle the engine and frame numbers matched when bikes first came out of the factory, if you look for your engine number on this site ,it should give you the original bike your engine was fitted in.
Click to expand...

Thanks Bill,:beerjug:

I'll find out the engine number (can't pick it up for a few days), so will hope it's one of the less slow variants ;)
 
Rob Farmer said:
Wires are easy to come by for the 80 and earlier bikes but the brembo front end needs the 2 spline hub that was fitted to the police bikes.
Click to expand...

Ta,:thumb2

So I guess I'll have to decide on whether I'm keeping the forks (or searching for earlier ones) which will depend on my 'Big plan' before choosing a front wheel, which is a shame as I'm not in love with the Lester things.
 
markjackson said:
Thanks Bill,:beerjug:

I'll find out the engine number (can't pick it up for a few days), so will hope it's one of the less slow variants ;)
Click to expand...

They're all the same from the early 80s. Check the bevel box, it should be a 33:11. If your really lucky it will be 32:11
 
Assuming I wanted to keep the later engine and box, but make the the engine look fairly olde-skool, do the early starter motor, air box and timing covers fit on the later cases? And would R90S dellortos (or other slide carbs) be a benefit over the CV Bings?
 
Rob Farmer said:
Wires are easy to come by for the 80 and earlier bikes but the brembo front end needs the 2 spline hub that was fitted to the police bikes. If you fit the earlier wire front the spokes catch the calipers. It's one of these you need. They were available new but were just over £300 for just the hub.


Hub.jpg
Click to expand...

Very true..................unless you are prepared to do some machining...........................DAMHIK!
 
markjackson said:
Assuming I wanted to keep the later engine and box, but make the the engine look fairly olde-skool, do the early starter motor, air box and timing covers fit on the later cases? And would R90S dellortos (or other slide carbs) be a benefit over the CV Bings?
Click to expand...

the clam shell air box and starter cover fit straight on. I've just fitted a pair of dells to my bike. Not cheap and you will use more fuel.
 
It's all bullshit of course...but if it looks right

db729bada86d2cf0521fd93f87056c11_zps3eb3fb81.jpg



To be honest I'd keep it as it is and just ride it.
 
For wheel building talk to Kevin Blurton of Derby. Google him for phone number


Sent from my iPhone using Tapatalk
 
Rob , did anything ever come of your plan to use Mk 2 Amals in an Airhead ?
I am using the Amal head to carb rubber connectors, and Venhill loose cables would make that side easy, so wondered if you had made any progress on the "jetting" side of things.

I have a line in a couple of cheap Amals.

Although I see the logic in sticking with Dells---------.
 
I went for the dells instead of the amals. To be honest I wish I'd gone for amals. Both sets of floats for the dells have now sprung leaks and needed to be replaced within the first week of using them. This is a known issue that I only found out after the first one failed. No big deal I suppose but it means I need to carry a spare set. Apart from that they're a lovely carb.

I'm running the r90s jetting. Mid range and top end is superb. Feels and goes like an 1100 oil head. There's a big hole between 2 and 3k that I suspect is down to the needle. I'm on the bottom slot so cannot lift it higher. As soon as I get the time I'll take it to the dyno.
 
Bill-H said:
Working on the principle the engine and frame numbers matched when bikes first came out of the factory, if you look for your engine number on this site ,it should give you the original bike your engine was fitted in.
Click to expand...

I'm a happy fella tonight. She arrived home and While the engine number (0n bike and in logbook) match an R100rs, the frame number (on frame and logbook) have it as an R90s from November 1974 :-)

So I now need to find a proper tank and someone to spray it "ginger". :)

Although close up the blue is very 70s custom car metal flake.

12978925944_17b8570283.jpg
 
You could see if you can get it looking something like this Mark :D

r90s 1.jpg
 
Well…. My wee project starts perfectly (so far) and took me for an early saturday morning run up to Helmsley.

It rides surprisingly smoothly (at low revs) and is nice n comfy (except the height of the flip-up screen buffeting not matching my height), but it still has those fugly wheels and there is a severe carburation flaw. :moped: So I seek advice please.:)

Wheels… Given that the brakes on my '80s' front end (albeit still using cable operated under-tank MC) are truly awful, and won't look right anyway, I've decided to find and fit the proper 70s forks and ATE callipers. But I don't know what is interchangeable with others that 'look' similar. If it looks the same (from another twin disk, wire wheel 70s BMW), is it basically the same? I'll be fiddling with springs and oil anyway so not bothered about internal spec so much.

Carbs… To look and feel 'right' I fancied slide carbs, but was planning to leave this to later/when some bargains turned up, and use it on the Bings.

However, the carburation is very flawed at present. I don't want to spend dyne time to sort carbs I won't be keeping for the long-term, and the problem feels more like something is 'wrong' than just out of adjustment. Basically it works OK on small throttle settings and will pull through 'mid-throttle' awfulness in the lowest two gears to take full throttle and rev to 7k. In the higher gears it cannot pull through the mid throttle position, so is stuck at 3500rpm. The ability to take full throttle in lower gears suggests float level or blocked filters/taps is not the issue, so is there anything obvious on Bings known to cause this?
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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