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jchen
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Joined: 07/07/2015
Posts: 17

My R75/5 generally starts well, especially in summer (I always initially start with choke open, let it warm up for a minute or so, then close and move on). Over the last two weeks or so, with the *inititial* 100-200 ft or so it bogs a lot through first and second gear. Then magically, it's smooth riding again and fine. Doesn't seem to be related to "cold" per se (it's like 70s here in the morning), as it happened yesterday in the heat of the day too. I'm hard pressed to imagine that I suddenly now in the summer need to let it warm up for 5 minutes. Twice in the last three months I've forgotten to turn the taps off at night and found the gas leaked a little and I wonder if it's related? Seems like a carb thing, but then why does it get better 200 ft into the ride?

RickR90s
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Farmington Hills, MI
Joined: 11/28/2016
Posts: 63
I think you mean by "choke

I think you mean by "choke open" that you're activating the choke?

But, taking you at your word, it will probably start and run ok without using the choke. (My R75/5 did), but since the motor is cold, it should bog until it's warm. Warmed up to an Airhead is more than a few miles.

FWIW: My R90s (with the big Dellorto pumpers) requires the enricheners to be set on a cold start, but they immediately have to be closed before riding away. It takes about four or five miles for the motor to feel lively and to pull strong from idle.

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RickR90s

jchen
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Posts: 17
Thanks! Yes, I mean

Thanks! Yes, I mean activating the choke-- I've found for whatever reason this particular bike won't turn over cold or hot unless the choke is activated. But then I completely close it before taking off in 1st gear. I'm guessing it's not a true carb thing since it seems to go away after the first short distance and then is very smooth, but I don't know if I'm fooling myself that somehow a higher gear is overcoming gummed up carbs? I would think that would always cause problem at lower gears and lower speed?

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6421
When is the last time you did

When is the last time you did a basic tune up? Be sure the valves are set correctly. Difficulty idling, starting could be tight valves. New set of plugs, new air filter. Get everything in good order and go from there.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

jchen
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Posts: 17
Roger that. Last tune up was

Roger that. Last tune up was about 10 months ago. New plugs are easy. I'm good to get it tuned up again though. Just rode her after about 4hrs of being parked and she started and rode like a dream at any speed, so hard to know....

mark_weiss
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Arizona
Joined: 11/17/2013
Posts: 171
choke use

Could you be letting the bike run, choke 'on', for too long? The time needed for warmup should be quite brief. In all but fairly cold temperatures, a half minute or less should be more than sufficient. When I would tune a /5, I would expect to use full choke for starting, then move to one-half within twenty to thirty seconds. By then it is ready to ride. If I am not able to lift the choke lever to full off within the first mile, I would judge the bike as needing a bit more adjustment.

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Mark
qualitycycleservice.com

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