Boxerworks.com

Hi all

Greetings from London, UK.

Returning to motorbikes after a 15 year gap following arrival of children.

Picked up a 1978 R100RS which has had the fairing and bars replaced, as a sort of rolling project to bimble about on. Based on the MOT history, it has done very few miles since 2005 when it was on around 74k miles. I've a ream of receipts for various bits from 2016 when it appears to have had a going over by a previous owner - lots of fixings replaced, bits of final drive and some carb parts. The vendor put in a new battery, checked the compression and replaced the pushrod seals. Engine and frame have matching numbers.

A couple of known issues and no doubt a load of yet to be found....

Managed the trip back from NE England to London OK, brakes were not as bad as expected, runs beautifully up to around 60-70mph where there is an intermittent fuelling issue, the seat isn't quite straight (hopefully not the subframe, the bike tracks ok), Am also seeing an oil drip from the RHS carb. Its on ancient tyres so I didn't venture much beyond the indicated 70mph in a straight line..

New tyres are ordered awaiting fitting and this weekend I plan to open up the carbs as I've some replacement diaphragms, and have a look behind the front cover to see what sort of ignition system lies within..

Anyway here's a pic - its more comfortable than my R1100S was, handles like a shopping trolley if you don't set it up carefully for a turn, and needs advanced warning of a stop, but I'm so far loving it



No doubt lots of questions will follow.

Best

Ade

Thanks for the welcome Steve

Had a poke about this evening to see what was under the tank.

Brake fluid level was ok.



Checked the air filter which seemed ok, carb float bowls had a few bits floating about, emptied them out and cleaned them and the floats with some liberal application of carb cleaner.

Disconnected the battery and had a look behind the front cover - I believe this is stock, can anyone comment? Would welcome thoughts thanks



Put it all back together and it fired up straight away (of course it did)...

Need to take it for a run to see if the interimittent fueling issues persist before I dive into a carb strip and fettle.

Irritatingly its forecast thunderstorms tomorrow and I've a new issue viewtopic.php?t=12254 to deal with...

Welcome! Looks like a fun project. Lots of archive information here.

Thanks dwerbil.

Came back in heavy rain, parked the bike outside the house to hose it down, wouldn't restart as the battery was dead... Not sure is this due to water or a couple of hours of low rpm urban riding with the lights on, not allowing the alternator to do it's thing. It pumps out 14v on the open road.

Dug out my battery optimate and hooked it up. (Glad I kept it all these years) Fingers crossed.

Fixed the dead neutral light, a spade connector had come off the gearbox sensor. What a masterpiece of accessible design....

A couple of observations...

The inside of the timing case looks stock... the condensor appears to be new.

The brush box on the alternator also looks newish.

You might want to check the length of the alternator brushes, they appear to be a bit worn looking at the amount of lead emerging from the top of the brush box.

Thanks Rob.

Currently waiting for the weather to make its mind up to go for a proper run and open it up.

First 2up ride this afternoon. It ran fantastically out of London and around the back roads of Surrey and East Sussex. Fueling was smooth with no hesitancy unlike my hill starts.

There is a random squeak from the front, wheel bearings are smooth and not running hot so I'm assuming it's either forks of discs..

Need to clean it now

A squeak! Could be anything. At least with the CS fairing I'm guessing there's less chance of amplification (RS fairing) of noises from goddamnanywhere. First thing that comes to mind is the alternator brushes. They might not squeak randomly though.
Brakes might squeal but usually at slower speeds coming to a halt. If so, a light clean of the discs with brake cleaner and steel wool/fine sandpaper can help, removal of the pads and deglazing and sometimes gooping up the back of the pads with brake/rubber grease even. My local mechanics were aghast when I did that though!
Bouncing the forks might illicit a squeak...give that a try.

No further fueling type hesitation? One habit of these bikes that needs occasional intervention is the diaphragms can split. Characteristically at speed eg 70mph (ymmv) the bike gets sluggish. Back off and it feels fine. Accelerate again and it won't want to.

What colour was the junk in the bowls? Red is tank lining, black is fuel hose. Looks like Karcoma taps. There should be an in tank filter sock over the inlets and an inline small filter in the fuel tap itself. It'd be worth emptying the tank, removing the taps and having a good look. Then you'll know they're good or not. # 4 & #12. If you loosen/remove #3 you'll be able to drop the small filter to check it. #12 needs the tap out.