Sputtering, loss of power and an ocasional stalling?

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E6420
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Sputtering, loss of power and an ocasional stalling?

Post by E6420 »

Hello! :)

Last year bought my FZR 600 and i've been really happy with it so far!
Got a couple of issues with it thought...i hope someone here can help me shed some light on the situation.
Here's the deal:
At hig revs, say from 8000 to 9000 rpm, there's a loss of power.
The acceleration diminishes significantly but the power comes back just after 9000rpm and from there on it's fine.
Also on when you let go of the throttle it occasionally stalls, this has only happend twice and it's ONLY on the overrun from high rpm:s, say 7000rpm+.
Yesterday it developed some sputtering/engine hesitation.
This occurs on at low revs, from above idle to 3k and then it runs just fine.


Now, i suspect that this might be the sparkplugs so i'm going to start with changing those to eliminate that possibility.
The engine hesitation is what leads me to suspect the plugs, it's exactly as when a cars plugs starts to go bad.
I doubt it's a carburettor issue since i thoroughly cleaned them last year and haven't used the bike since. Also i adjusted the idle revs and cleaned em up this year so hopefully they're not the issue.
It starts and idles just fine, no problems at all.
What makes me doubt that it is the plugs is the lack of starting issues and the pwr loss on high rpms.

Any thoughts? :D Would be greatly appreciated! :)


Edit: It's a 1991 model ;)
Edit 2: Also synced carbs last year
Yamaha FZR 600, 1991
M in KC
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Re: Sputtering, loss of power and an ocasional stalling?

Post by M in KC »

After your carb work last year did you sync the carbs? Simply setting the idle after a thorough cleaning will not optimize their performance.

You are saying you notice a loss of power between 8 and 9K rpms, but the power returns above 9K rpms? or it returns below 8K rpms?
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pnbell
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Re: Sputtering, loss of power and an ocasional stalling?

Post by pnbell »

Sounds like you are running rich. Check Plugs and Air Filter first.
-Pete
Current Toys
1995 FZR600
2002 Ducati 900ss
2008 Versys 650
1991 CB250
1978 CB350
Past Bikes
1981 CM400t
1981 GS650
1998 FZR600
1994 VS800
2004 SV650
E6420
Site Newbie
Posts: 2
Joined: Thu Jul 12, 2012 4:57 am
Location: Sweden

Re: Sputtering, loss of power and an ocasional stalling?

Post by E6420 »

M in KC wrote:After your carb work last year did you sync the carbs? Simply setting the idle after a thorough cleaning will not optimize their performance.

You are saying you notice a loss of power between 8 and 9K rpms, but the power returns above 9K rpms? or it returns below 8K rpms?
The carbs were synced.
The engine runs as it should above 9k and below 8k. It's between 8k and 9k (or at least in that range) the power loss occurs.

Yup, plugs and filter is on the list.
Filter is probably fine though, inspected it when i adjusted the idle speed a couple of weeks ago.
Yamaha FZR 600, 1991
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