Just picked me up a R100RT!

[Andy B]

So I can now claim to be the owner of a proper airhead instead of just these modern things! Picked up a 1979 R100 last week as a project bike. A bit scrappy but that was just what I was looking for. Seems to run nicely and the gearbox is sweet. Clutch bites quite quick though.

Got a bit of pinking going on - I think the carbs need some tuning, but the question is, what fuel for a 1979 bike?! It's been running on ordinary unleaded. I don't think it's had the valves upgraded so assuming it's original, what would you recommend?

 

[Kenny]

Set valve clearances as they will probably be out unless ( from Halfords ) a petrol additive has been used .

 

[Beemerboff]

Pinking will damage something if it isn't sorted quickly.

Having the timing set properly would be my priority, and by properly I mean on a dyno - every bike has different requirements and the correct figure varies from bike to bike by around 6 degrees. . But if set 2 degrees, or one tooth on the flywheel, retarded from the stock position does not fix the problem you have a fault somewhere else.
The dyno guy will probably have a fair idea where---.

Yours is probably not a bean can model , so setting it by trial and error is probably not going to be easy.

My 77/7 is still on the original valve seats, so if yours haven't gone by now they probably are not going to go - some bikes had better seats than others of the same vintage.

 

[Edward]

I use a 1979 R100RT as my everyday bike and use the higher octane fuel. This stops the tiny amount of pinking with the lower rating petrol.

 

[Deleted account 220427001]

got a picture of it !

 

[tuftywhite]

got a picture of it !

+1

 

[Andy B]

 

[Rob Farmer]

If the clutch is really sharp there's a chance the push rod may be broken. A common problem on the heavy flywheel bikes.

 

[David Nimrod]

I have a '79 RT, and I have to say, the heavy flywheel R100 is my favourite BMW engine, bar none.

The build quality is excellent, and they are genuinely good mile eaters, if you keep on top of them.!

 

[Rob Farmer]

There's some good gear on there and it's a nice colour.

Looks like Koni or ikon shocks.
Stainless exhaust system
Handle bar mounted master cylinder

There's over a grands worth in those three so somebody cared for it once.

You are running points. Have you checked the clearance and timing? That could well be the cause of the pinking. The points are in a bean can so a lot of people assume it's the later electronic ignition and don't check the timing or points gap.

 

[David Nimrod]

Handle bar mounted master cylinder

That's a big improvement for the front brakes

 

[tuftywhite]

It's got no clothes on!!!

 

[David Nimrod]

It's got no clothes on!!!

Another RT bites the dust...

 

[(RIP) Arkwright]

Another RT bites the dust...

I've told you before...........................that's how they should be......................with clip ons, rearsets hump back seat and twin LOUD exhausts!

 

[David Nimrod]

I've told you before...........................that's how they should be......................with clip ons, rearsets hump back seat and twin LOUD exhausts!

Bollix!

A heavy flywheel RT is one Airhead that's well worth preserving...

 

[tuftywhite]

It was meant to have a big heavy fairing on it, otherwise it's going to be far too fast!

 

[Andy B]

Thanks for your comments guys. I'm still formulating what to do with it and how far to go. I think it definitely needs tuning although it ticks over so sweetly - not a hint of a misfire. Just the pinking if you give it a bit of wellie.

 

[David Nimrod]

It was meant to have a big heavy fairing on it, otherwise it's going to be far too fast!

Ah, so true!