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Old 10-22-2013, 01:16 AM   #1
batoutoflahonda OP
Beastly Adventurer
Joined: Aug 2007
Location: Easton Wa
Oddometer: 1,386
R80 lost top end speed. Head scratcher.

Within the past week or so, my '81 R80G/S has lost it's top end speed. On a flat run it will hit 90 at 6K RPM, but that's it. Coming over my mountain pass
commute, best it will make is 80. It will hit red through 3rd gear, and the tach needle looks like the tach is "clipping" under acceleration (gets it's input from the coil), but just for a bit. Every where else the bike runs like a clock. No ping, knock, or oil consumption. Plugs are a nice tan. Fuel consumption is up, but I think it's because I am screwing with it. It pulls all the other hills fine and it used to pull the pass at 90+ (it's a nail biter on the WA freeways close to 100, so never got it past 101. The roads here have gone to crap since the shutdown.)

It has been converted to points with a dyna booster.

Been through the carbs, clean. Changed the diaphragms, no help.
Points are set. Carbs balanced.
Top ends/pistons done two years ago and valves are adjusted properly.
New spark plugs and the wires are good.
Fuel flow is around 400cc/min./side.

Really it acts like it just isn't getting enough gas, or has a major vacuum leak. The carb boots look good. Can't find any thing wrong with the fuel system.

So, I'm going to change the condenser thinking that my be causing the tach to clip, and maybe be my problem. If that doesn't help, pull the tank and ohm out the coil. I haven't done a compression check yet.

Am I headed in the right direction thinking it's electrical? Or is there some thing I'm missing? Any one have this problem?
It's eight and a half gallons of gas; and an engine. What more do you need?-- BMW R80G/S

Save lives. Legalize lane sharing.

Cow eyes don't glow.

batoutoflahonda screwed with this post 10-22-2013 at 01:32 AM
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