Need help!

charlesneeson · Derestricted Danger Joined: 25 Sep 2011 Karma :

Hi all I'm hoping someone can help me, I was out on my bike yesterday, its a 1991 zzr 400. I broke down quite a few times and had to hide the bike and get a lift off my mate.

The problem- i had the throttle open and the revs were climbing gradually when all of a sudden it stopped climbing and I very slowly started to lose power i switched down a gear to try and get the revs up but they continued to fall so i had to pull over. After i waited about 5 minutes the bike started again fine and i made it to my destination but on the way back it started to happen more frequently. An old boy pulled up and told me that i was running on three cylinders when i got it started and when i was driving along and i started to lose power it was as if i had lost another one but it was trying to start again because the throttle was open and the bike would jerk forward as if trying to fire up again. I have tryed to explain this as well as possible and hope someone out there can help!

cheers

Charles

Paxovasa · World Chat Champion Joined: 25 Apr 2010 Karma :

Check all four spark plugs are working.
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Suzuki GSF600 K3 (in the fastest colour, black).

LongJohn22 · Trackday Trickster Joined: 16 Jul 2010 Karma :

The next time it happens, remove your fuel cap and listen for air being sucked into your tank, it could be your tank breather is blocked and starving the engine of fuel, after replacing the cap, the bike should run normally for a while until the vacuum builds up again.

temeluchus · World Chat Champion Joined: 01 Oct 2008 Karma :

after checking the fuel cap, drain the float bowls in case water has found a way in. give the ht leads a dose of wd40 and inspect the ht caps for corrosion.

after that the vacuum hose to the fuel tap, the tap itself need to be checked.

it may be also worn float needle causing it to flood.
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Some shite cruiser. Now with guns and FREEDOM!

Silentwalker · Two Stroke Sniffer Joined: 14 Sep 2011 Karma :

I would certainly support LongJohn22 and Temeluchus on their suggestions. Reads like a classic fuel vacuum blockage to me.

The sparkplugs might be a second problem, so don’t discard checking the spark when sorting out the petrol tank.

charlesneeson · Derestricted Danger Joined: 25 Sep 2011 Karma :

I changed the spark plugs and found that one of my ht leads had snapped indise the cap. I have still to check out the other suggestions. Thanks for your help guys!
On another note would any of you know if zzr600 caps would fit into the 400 as i have heard they are pretty much the same bike just the 400 has a sleaved in engine ?

temeluchus · World Chat Champion Joined: 01 Oct 2008 Karma :

charlesneeson · Derestricted Danger Joined: 25 Sep 2011 Karma :

ok so I think the problem is the carbs can anyone give me an estimate on how much it would be to get them cleaned and balanced ?