Bogging down after 4k rpm

My YZF600 again is playing up.

Previously it would bog down after giving it some revs i could give it full throttle and it will bog down and struggle to reach 50-60 .

The last few days when it done this just gave it the beans and then it would all of a sudden go like the clappers as if somthing was dislodged, but it is now continuously doing it

Any suggestions on what this is my thoughts as a very amateur mechanic is something stuck in the carb and needs cleaned out or the fuel filter needs looked /cleaned or the airbox needs cleaning?

any thoughts?

Could very well be carb icing - these bikes (and many carb bikes of the same era) are prone to it in the right conditions (cold and damp). See how it goes in warmer weather to rule this out (or put some fuel treatment in to help in the cold).

What temps are we talking about as it has been 1-2 °C

if this is enough what do i need to get to add to the fuel will i get it from a garage?

Also if i add this to the tank will it take immediate effect?

Just above freezing is the perfect recipe for icing - as the air is drawn through the venturi in the carb is is cooled and any moisture in the air freezes as ice particles, which block the jet and cause poor running. Often when you stop a little bit of heat sinks into the carb and melts the ice crystal and you're away again.

Wynns Dry Fuel is as good as any - should be able to find it in Halfords. It's a small drop in every tank and should work immediately.

The big question is how does it sound? Does it start to sound like a twin?

Does the bike start and run fine but this happens intermittently while riding?

On mine it was a case of riding along then it would just feel gutless and sound like a twin, I'd then have to rev it to keep the power up and then the power would kick in again.

Wynns additive and super unleaded helped in this case but didn't stop it for me.

Well it starts up and idles okay and i can rev it with no issues

However when running when giving it a bit of throttle from 20mph and above it bogs down sounds like it is getting far too much fuel and you can hear it backfire aswell

Not sure what i am listening for being a twin

When it bogged down i would give it the beans and it would make very little difference.

Anyway sun is coming out and the snow is starting to melt so will pop up the the local garage and get some additives to try

The air filter not dirty?

Sounds like you do have the conditions for carb icing, but that usually starts after a while maybe 20 or 30 miles. I use IPA in mine, cheaper and seems to work.

well placed some dry fuel in it the day , been snowing the last 2 days but running 90% better still the occassional splutter but all good

Does sound like carb icing.. I remember the first time I had it and the symptoms were exactly the same.. As all above have said the conditions are right for it, it'll be fine when it warms up a bit.

well hope it does still snowing here

And here!

Well so far so good after adding the dry fuel appears to havecleared

stretchie_ wrote:The big question is how does it sound? Does it start to sound like a twin?

Does the bike start and run fine but this happens intermittently while riding?

On mine it was a case of riding along then it would just feel gutless and sound like a twin, I'd then have to rev it to keep the power up and then the power would kick in again.

Wynns additive and super unleaded helped in this case but didn't stop it for me.

I currently have symptoms very similar to this (posted in the tech section).

Have you managed to get to the bottom of it yet? im going to add some Redex or similar to help clean the carbs, but id love to find out exactly what the problem is.

Well i has a 300 mile trip to inverness a few days ago at 0 degrees at points and it never missed a beat ran perfectly , i stuck in a whole tin of Dry Fuel in it .

But the next few days and today back to the same problem , even now i have placed some Pro FST in it appears to have made any difference.

I can still get a good speed but take 3 times as long to get there and the sound is sort of throaty if that makes sense sounds like it needs a good cough to clear some sh*t out.

So now I am in the process of ordering new spark plugs and an air filter, so planning tomorrow when finished my night to take it for a run see how it runs then place new spark plugs in then take it for a run see if there is any difference and if none then replace the filter and try again so i can pin point it.

Next step if that fails is carb clean up/tuned

The air filter is designed to be cleaned & reoiled not replaced. Use hot water & washing up liquid to clean it,leave it to fully dry out then reoil it with clean engine oil. Wipe of excess oil with kitchen paper.

Thanks for that I will do that with the filter saves me £20

I orders a set of spark plugs and will replace them the morrow.

I noticed the plugs I have already in a mix of normal ones and irridium ones so may see some difference when i put the new ones in will let you kn0w

Well here are the results

I took the tank off and checked the filter and it was mint no problems there, checked the oil filter all okay.

Put it all back and forgot to turn the tap back on Dohh!

The the postie came with my NGK spark plugs and put them in , started it up it ran without any choke , it reved well.

Took it for a run OMG put a smile back on my face ear to ear its like night and day so Panthro give it a try for the sake of £15 for a set of plugs

Thanks to everyone else for the help , just hope the weather is good the morrow off for a run

just back from a quick run and even at idling / under 3mph it so much smoother as well , where before i had to do a lot of clutch work to keep the speed in check

Nice one mate well done.

timboellis wrote:just back from a quick run and even at idling / under 3mph it so much smoother as well , where before i had to do a lot of clutch work to keep the speed in check

Great job! thanks for the tip, fingers crossed its as simple as fresh plugs.... surely we cant both be as lucky?..

Well hopefully it is, the plugs i took out looked fine as well, let us know how it goes.

For reference these are the ones i got and they done next day delivery

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you stuck a whole tin of dry fuel in wow
i only put in 5 caps full on mine never a full tin
& ive been told never use redex on a bike engine
pete

Just bought a cat last night and noticed that it is struggling for power a bit then all of a sudden gets it, then goes again etc, sounds same as this and a few other instances on here.

I have ordered a set of plugs, will get some dry fuel too and hopefully this will help so thanks for the advice from all that have posted. Obligatory oil and filter change will also be done.

What I have also noticed is idling revs very low, can someone advise roughly where the idle rev should sit please. Was causing a few issues when moving off from lights too as stalled a few times - or was that me just getting used to the clutch hehe.

The bike has been stood all winter so this was its first proper run. When it did clear it was bloody quick (well compared to my old Divvy 600 anyway) so hoping that the cobwebs just need blown out so to speak.

Well mine sits at 1,000rpm after warming up for 3 mins or so.

I only used dry fuel as i could not get my hands on any Pro FST had to order it online

Idle should be set between 1200 to 1400 at running temperature.