R80/7 question

[Wade Ogle]

Hello all, I just picked up a 78 R80/7. I recently had a K100LT but this my first boxer. It's a great bike but I wish it had a bit better throttle response. It's top speed is about 75mph which I'm fine with but acceleration is pretty tame. I'm told by a respected BMW mechanic that it runs as good or better than any R80 he's ever seen and that's about all I can expect. If that's the case, no sweat...but I keep thinking there's got to be an easy/low-cost way to get a bit more zip. Any input is appreciated.

[flash412]

but I keep thinking there's got to be an easy/low-cost way to get a bit more zip. Any input is appreciated.I dunno about the low cost part. But for easy... swap it for an R100/7.

[ChrisF]

I had my '73 R75/5 into triple digits (I think the statute of limitations has expired ;) ). A Motorcyclist Magazine review of the R80/7 from '78 indicated a quarter-mile top speed of 96.66 mph (13.68 seconds).

If the top speed of your bike is only 75 mph, I think there's something unusual going on.

[Wade Ogle]

"A Motorcyclist Magazine review of the R80/7 from '78 indicated a quarter-mile top speed of 96.66 mph (13.68 seconds). If the top speed of your bike is only 75 mph, I think there's something unusual going on."

-Chris, perhaps you're right. Being unfamiliar with the bike, I'm not sure. It does have 74,500 miles. It runs great though and as I've mentioned, both Bentonville BMW mechanics say it's sound as a pound (they've known the bike for a long time) and that's the norm for R80/7's. 96mph w/ a bit more zip would be damn nice though.

[srb]

While the R80 is not going to win too many races, 75mph is about 20-25mph too slow for the top end of this machine. I might look for a second opinion, preferable from a mechanic who knows airheads very well. Has there been a compression test done? It sounds like a good tune-up is in order (valves, points, carbs). I know guys who have R80s and jump right off the line, so their acceleration is not tame. Make sure you keep the revs up when you are expecting quick throttle respone (above 4K). Your K100 will have had much more power. Perhaps your throttle cables could use adjustment/replacement. Good Luck and enjoy your airhead in those Ozarks.

steve
'79 R100S
'74 R90S

[BeemoKat]

I have an r-80/7 that was none too quick, and last winter I changed the 32mm Flat-Top Bings for a pair of same size (32mm) Dome-Tops. It was a "direct-drop" replacement, and the bike performs much better now. Hope this helps.

[rocketman]

I'd have agree that 75 for a top end sounds a bit low for 800 motor, my 73 R60 can cruise all day at 75-80 at 5000-5250 or so and still has a bit more left (at least on a flat run :D). I should think an R80 should be able to at least match that.
If you want more punch, as was suggested, slip in an R100 motor, that will give more ponys easy.

RM

[Bob_M]

Shift into fifth gear :stick

[bprigge]

Something is way out of wack on your motor...or your speedometer. You
shouldn't need a shaking R100 motor to get snappy performance.

Bruce

[lkchris]

Top speed lower than what it should be is almost always bad carb diaphragms.

[Wade Ogle]

"Top speed lower than what it should be is almost always bad carb diaphragms."

-you nailed the problem. Thanks for the input.

[1505]

Hi Wade Ogle:
If you find out why your BMW does not have full power please let me know. I have been riding a 1978 R100/7 for the past 125K miles that is the same way. Runs very smooth and reliable but not the speed and power it should have. Did new pistons and valves etc right after I got it in 1996. Still ran the same. It has a DYNA III ignition.

Just bought a 1991 R100RT and although they are the same size and weight
the newer one has lots more speed and power.

Thanks
Ray BMWMOA #1505

[Wade Ogle]

Hi Wade Ogle:
If you find out why your BMW does not have full power please let me know.

-Bad carburateor diaphrams. $63 x 2 plus labor. I suspected carburateor problems but dismissed them because I bought the bike right after a full service etc... Good luck. -WO

[Wade Ogle]

Got the r80/7 back today. A HUGE difference. Proper throttle response. Bot sides working together. I was cruisin' 80/85mph and pushed to about 90+ or so. No problem. I'm not a speed demon but it's nice to have snappier response. Thanks for the input.