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+--- Thread: High revving engine (/showthread.php?tid=83863)
High revving engine - DaveF - 04-10-25
Hi, I'vm new to this forum and would welcome some advice/ help on the following issue.
I have a 2004 Fazer 1000 with 20k on the clock and live in the Costa Blanca region of Spain.
A couple of months ago I started having problems with increased idling revs with the throttle off. This would occur after about an hour of riding - the revs would only drop to around 2.5k with a closed throttle - which affected changing gear and mak engine braking at slower speeds difficult. When coming to a stop I could get the revs down to the correct idling level if I let the clutcn out briefly, moved forward slightly and then dabbed the front brake. The issue would then return again once moving.
If I stopped for fuel the issue disappeared for a bit then returned again after about 10 mins of riding. I had the plugs, air filter, chain/sprockets and lubricants changed recently and the problem seemed to have been sorted. However, I went out for a long ride this week and the issue has returned ?
I assume it's a heat related issue...maybe the TPS but I'm only no expert and only guessing, so would welcome any opinions or thoughts on this issue. Many thanks.
RE: High revving engine - Trebus - 05-10-25
Possibly an air leak somewhere. Worth checking the carb intake rubber caps are fitted correctly on the balancing points.
RE: High revving engine - unfazed - 05-10-25
Up to last June I had the very same problem on my 2005 model FZS1000 and it drove me nuts trying to diagnose it. It would stay reving up to 2500 revs when changing gear and when I would stop and eventually drop back to a slightly unstable tickover. I replaced the vacuum take off caps as one had a crack, checked the O-ring under the diaphragm cover, the diaphragms and the vacuum vents for the the diaphragms and they were chear. No cracks anywhere on the Intake manifolds. Eventually took the carbs off and opened the float bowls and everything in there was spotless. Took out the main jets and the O-Rings fell apart, removed the float valves and they look ok. Changed both of O ringson all the carbs and the float bowl seals as I had them off. Put the carbs back on and took it for a spin, running perfectly. Came home and checked the carb balanced which was fine. The O-rings in the Main Jets were only issue I found and was most likely bleeding excess fuel into the system. 2 months later I had a lot of surging when riging in traffic or touring around the back roads. Thankfully this turned out to be a dodgy TPS. Replaced that and had no issues since.
RE: High revving engine - DaveF - 06-10-25
(05-10-25, 02:26 PM)Trebus Wrote: Possibly an air leak somewhere. Worth checking the carb intake rubber caps are fitted correctly on the balancing points.
Thanks for the advice. Just had a look and one of the hose clamps looks a bit askew so it could be leaking air. I'll have a look at it this week and see if that sorts the issue - hopefully, it will. Many thanks
(05-10-25, 03:23 PM)unfazed Wrote: Up to last June I had the very same problem on my 2005 model FZS1000 and it drove me nuts trying to diagnose it. It would stay reving up to 2500 revs when changing gear and when I would stop and eventually drop back to a slightly unstable tickover. I replaced the vacuum take off caps as one had a crack, checked the O-ring under the diaphragm cover, the diaphragms and the vacuum vents for the the diaphragms and they were chear. No cracks anywhere on the Intake manifolds. Eventually took the carbs off and opened the float bowls and everything in there was spotless. Took out the main jets and the O-Rings fell apart, removed the float valves and they look ok. Changed both of O ringson all the carbs and the float bowl seals as I had them off. Put the carbs back on and took it for a spin, running perfectly. Came home and checked the carb balanced which was fine. The O-rings in the Main Jets were only issue I found and was most likely bleeding excess fuel into the system. 2 months later I had a lot of surging when riging in traffic or touring around the back roads. Thankfully this turned out to be a dodgy TPS. Replaced that and had no issues since.
(05-10-25, 03:23 PM)unfazed Wrote: Up to last June I had the very same problem on my 2005 model FZS1000 and it drove me nuts trying to diagnose it. It would stay reving up to 2500 revs when changing gear and when I would stop and eventually drop back to a slightly unstable tickover. I replaced the vacuum take off caps as one had a crack, checked the O-ring under the diaphragm cover, the diaphragms and the vacuum vents for the the diaphragms and they were chear. No cracks anywhere on the Intake manifolds. Eventually took the carbs off and opened the float bowls and everything in there was spotless. Took out the main jets and the O-Rings fell apart, removed the float valves and they look ok. Changed both of O ringson all the carbs and the float bowl seals as I had them off. Put the carbs back on and took it for a spin, running perfectly. Came home and checked the carb balanced which was fine. The O-rings in the Main Jets were only issue I found and was most likely bleeding excess fuel into the system. 2 months later I had a lot of surging when riging in traffic or touring around the back roads. Thankfully this turned out to be a dodgy TPS. Replaced that and had no issues since.Thanks for the help. I had the float bowl seals and o rings done not so long back so I'm hoping they are still good. I'll start with checking if it's an air leak and go from there. It's good biking weather now so hopefully J dan get it sorted quickly. Thanks again.
RE: High revving engine - Gaz66 - 06-10-25
DaveFHi, I'vm new to this forum and would welcome some advice/ help on the following issue.
I have a 2004 Fazer 1000 with 20k on the clock and live in the Costa Blanca region of Spain.
A couple of months ago I started having problems with increased idling revs with the throttle off. This would occur after about an hour of riding - the revs would only drop to around 2.5k with a closed throttle - which affected changing gear and mak engine braking at slower speeds difficult. When coming to a stop I could get the revs down to the correct idling level if I let the clutcn out briefly, moved forward slightly and then dabbed the front brake. The issue would then return again once moving.
If I stopped for fuel the issue disappeared for a bit then returned again after about 10 mins of riding. I had the plugs, air filter, chain/sprockets and lubricants changed recently and the problem seemed to have been sorted. However, I went out for a long ride this week and the issue has returned ?
I assume it's a heat related issue...maybe the TPS but I'm only no expert and only guessing, so would welcome any opinions or thoughts on this issue. Many thanks.
......................................................................................
Hi Dave.
Did u gap the new plugs? won't affect idle, but it'll run better if correct.
which brand of air filter is fitted? some are loose & you get poor filtering, won't affect idle, but something to check.
Weird that you can restore idle by doing a partial stall via clutch lever.
Any idle issues always assume it's a carb issue 1st.
A few things to try.
Check all 4 choke plungers are fully in, choke lever in off position.
Check high idle isn't caused by an over tensioned throttle cable, or frayed cables, fully back off all throttle cable adjustment at bar end of cable, this should give you a load of slack at twist grip, cables may have split/frayed internally & be stopping idle dropping?
Back off the idle via the adjuster cable knob on left side of carbs should allow you to fully drop the idle till motor stalls, beware to not fully unscrew it or it'll come out the carb body & you'll lose the washer & spring on its cable end.
Lift tank & eyeball where throttle cables wrap around the cam between carbs, check cables are fitted correctly & not frayed/snagged up in any way.
While tank's up, check carb vent filter aren't blocked, 2 hoses exiting between carbs 1&2 & 3&4, there's a bulbous plastic housing on each hose (wire gauze filter inside) carefully remove these & wash em out with brake cleaner, if these are blocked, you lose all idle control.
Methodically use little squirts brake cleaner around carbs mounts, if idle changes, you've an air leak, fire risk, so be careful.
Unlikely a TPS problem, you'd normally see a fault code displayed via rev counter.
You can meter test TPS but it's not conclusive, some test ok, but fail in use when hot, it might idle poor/erratic, won't cause a high idle, idle is all mechanical.
Good luck?