BMW R80

Apart from the Guzzi, I also have a 1983 BMW R80RT which I've had for 12 years now (as of 2005). Here are some pictures of it...

As it was when I first got it, 1993 (yes it's ex-Plod!)...

Immediately after with touring panniers on...

somewhere in Wales 1993

Bit later with pattern dualseat and 'duck-bill' skirt/tail unit (notice not painted yet) and rear carrier (also notice no rear footrests – well the Police don't use 'em). Also Keihan stainless steel exhausts by this time (1996)...

Angelsey 1996

After tangling with a LDV Pilot minibus, 2001...

I don't have any pictures from when it consequently had a replacement metallic dark-blue fairing and orange tank! Not obvious from these pix but in fact most fairing seams were burst apart in the impact, even though it still held on afterward. Also headlamp glass missing (popped out and smashed). However new fairing (actually second hand from MotorWorks – thanks guys) is better than original; ditto tank in that filler cap tightens up properly without 'popping' the screw thread (worn).

Rebuilt 2005...

first outing May 2005

Note: new Grimeca discs, Smooth Hammerite painted lower forks (black) with added 'concertina' gaiters (which do work with the std fairing 'gaiters' [sealing skirts]); Hammerite painted hubs (silver), old-style pattern rocker covers. New HT leads with NGK caps. Modified sidestand with larger foot & 10mm thicker (grass is soft y'know).

foggy screen was replaced shortly (see below)

Apart from finishing cleaning up the bike post crash, about 5 years ago (about 2000) there arose an increasing problem of not being able to get LRP or 4-star petrol, and so for both reasons I hadn't used it for 4 years. So it's also acquired new (original BMW) cylinder heads (as 1985 spec.) with unleaded valve seats and pattern Swiss 'Intervalve' valves.

[new] tool box tray actually big enough to carry all my tools! Only bike I've had so far that can...

with new SecDem screen (French made pattern)

Fuel consumption was never very good at about 43 mpg. So I decided to rejet the carbs to the later 1985 sizes, only to discover they're already rejetted! However the atomizer tubes and air chambers for the needle jets were completely bunged up with black crud which might account for it (also mentioned in Mike Fishwick's hints & tips, BMW Club). I renewed the jets anyway (particularly the needle jet & needle which tend to wear). In addition I added a Fuel Economiser system same as the Guzzi is now using. Like the Guzzi, this even operates when shutting the throttles while changing gear. With these changes fuel consumption now seems to be a consistent 51 mpg! Tank capacity is 4.8 gallons (UK) so it can now go 200 miles before refilling.

Even in this pix long economiser hose to carb remains obscured behind fuel pipe ('T' junction is under tank). Other long hose (forward) is fuel filler overflow.

Jet Sizes
Idle jet:
Main jet:
Needle jet:
Jet needle:
Needle position:
Idle screws:
Throttle stops:

1985 – (1983)
45 – (50)
135 – (145)
2.66 (US); was 2.68 (UK) – (2.66)
46-251 – (46-231)
3 – (4)
2.25 turns*
0.75 turns*

* by default, 0.75 turns for idle screws & 1 turn for throttle screws, but this is only a starting value for setting up. In practice, the left-right cross connection of the intakes through the economiser hoses usually means the throttle stops are slightly lower than normal. On finding it rejetted already, I opted to reduce the needle jet to the 2.66 US spec. size. Also the floats were slightly lowered by about 2mm. Apart from the needle jet airways clagging up, other things that tend to afflict the Bing CV carbs are split diaphragms and leaking float valve needles. It's probably a good idea to carry around a spare float valve needle.