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Surging at high rpm / accel?

Started by sebwiers, September 03, 2015, 05:34:55 PM

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sebwiers

What's this a symptom of?  Seems like most times when I whack open the throttle, at some point in the run up the engine will surge and the bike will jump forward very briefly instead of the RPM increasing gradually (but quickly).

My guess would be one or more slides sticking, and the surge being when that slide pops up?  Seems to have gotten worse over time, which is perhaps consistent with the slides getting dirty?  Has in fact become pretty common, although I'm not sure if that correlates with more surging, or more frequently whacking the throttle open.

balky1

Quote from: sebwiers on September 03, 2015, 05:34:55 PM
What's this a symptom of?  Seems like most times when I whack open the throttle, at some point in the run up the engine will surge and the bike will jump forward very briefly instead of the RPM increasing gradually (but quickly).

My guess would be one or more slides sticking, and the surge being when that slide pops up?  Seems to have gotten worse over time, which is perhaps consistent with the slides getting dirty?  Has in fact become pretty common, although I'm not sure if that correlates with more surging, or more frequently whacking the throttle open.

I think (only think) the reason for this often mentioned on forum is vacuum leak somewhere, most likely intake manifolds. Try spraying starter fluid around it to see what happens?

Other guys will know better.


FJ 1100, 1985, sold
FJR 1300, 2009

sebwiers

Looks like one of my K&N Pod filters came off again.  Evened out a lot after I got it back on.

movenon

Quote from: sebwiers on September 06, 2015, 09:41:25 AM
Looks like one of my K&N Pod filters came off again.  Evened out a lot after I got it back on.

K&N's  :dash2: :dash2: :dash2: :dash2:
George
Life isn't about having the best, but about making the best of what you have...

1990 FJ 1200

Pat Conlon

George, my thoughts exactly.....

Sebwiers, RE: checking and reattaching those K&N's, get used to doing that, and when the fuel mist from your carbs washes away the paper filter oil, letting dirt in your engine, don't say we didn't warn you.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3