pulling away issue on mk1 fazer

[ghostbiker]

Frustrated!
Fazer 600 with an issue pulling away.
As you pull off the revs rise smoothly to approx 2500 - 3000 then drop like a stone to 500 then slip clutch to stop stall and she pulls fine. Bike rides like a dream. Tps set per manual. Carbs ballanced. Full service with plugs gapped. Clean air filter (KnN), oil and filter changed.

Bike was stood for a while so I'm now thinking gunked up pilot yet? Seems to be about where it swaps from pilot to main I think.

The carb balance did make it better, it's less agressive when it happens but it's still there.
Grrr

[His Dudeness]

Strange to have such a dramatic drop in revs. Almost sounds like an electrical problem but it's probably something gunked up in the carbs. I doubt it's pilot jet though. If it was I'd say your idle would be rough

[ghostbiker]

The tickover is smooth as a babys bottom.
Rev out of gear and it lifts clean and drops back to tickover fast and smooth.
Once pulled away it rides like a dream. One of the best Fazer 600 engines I have heard.
Its just that initial pull away or even once hot and waiting at lights etc same issue.

Adjusted throttle cables, no change
Lubbed cables and linkages.
Tried a 2k tick over, but just the same. Now back to 1.5k I know manual says 1.4 but felt better.

Ran some Red x stuff through before but might do another bottle before giving in and trying a garage.

[darrsi]

Bit more expensive but try STP Complete Fuel Cleaner, it's the only one that's ever worked on any of my bikes before with a noticeable difference, just lob the whole bottle into a full tank of fuel.
Make sure it's only this one though, as there are a few different ones. I've never noticed any change at all using Redex before.



http://www.halfords.com/motoring/engine-oils-fluids/fuel-oil-additives/stp-complete-fuel-system-cleaner-petrol-400ml


If it was bogging down i would've suggested an air leak but you're saying it's a sudden drop, an air leak would cough and splutter.
Are your plug caps okay, are they OEM or have they been replaced before?

[Bretty]

It's difficult to diagnose from what your saying.
Do you think...
The engine is down on power?
If you slow the bike down in 1st or 2nd and with the clutch out accelerate, does it pull through the whole rev range?
Is the issue with the clutch biting?

If it's been stood for a long time, could the steel clutch plates have rusted, making the clutch very grabby?!

[ghostbiker]

Power is good. If I slow to almost tick over and pull away again it's the same issue as pulling away from standing start. Less noticable as the bike Has momentum.
Not a clutch issue I'm sure.
Everything's operating smooth and clean other than that specific rev range.
You only really notice it in first as there is no momentum to the bike so a drop in revs almost stalls the bike. Once moving it is still there but only just noticeable if your looking for it and that low in the revs.
Plug caps are OE as far as I know

[Jules-C]

Can I throw carb diaphragm into the list of possible problems?

[His Dudeness]

Could possibly be losing spark through the plug caps. That'll show up as a clean idle, then a hesitation just after idle and then clear up as you get up the revs and the symptoms will get worse if it rains. You could try running the bike at night and look for small sparks around the plug caps or take the plug caps off and look for very small chips off the inner edge of the cap. Even if you don't see anything there's a set of ngk plug caps for less than £10. Get them and even if it doesn't fix the problem you can rule the plug caps