Hi Krew

Now, until a few days ago I had not noticed this issue....


For the last few rides Ive been on, the bike has a shudder/surging/missing thing going on until the engine is pretty much HOT. then it seems to go away and everything runs fine. But until then, for say the first 10mins of the ride it will surge like its got low fuel in the tank, most noticeable between 3 - 4.5k revs.

Does any one else experience this?

What may be the cause?

You could check if the blanking plugs and the pipe are on the injector vacuum take offs.
Had a similar problem when I put one of the rubber blanking plugs onto one of the butterfly adjusters by mistake. 
Wasn't the only one to do it on this forum.

Hey, I resemble that remark. My tip is wear your glasses Magoo.

They do say confession is good for the soul.

Comberjohn wrote:You could check if the blanking plugs and the pipe are on the injector vacuum take offs.
Had a similar problem when I put one of the rubber blanking plugs onto one of the butterfly adjusters by mistake. 
Wasn't the only one to do it on this forum.

Thanks mate. Just had a poke around and all is as it should be in that dept.

Last night I pulled the plugs to have a look and they are all fine.

Took the bike for a ride to check the surf just now and it ran 95% better than yesterday and Ill I did is listed above. 

Still exhibited this surge thing but faaaaar less (only felt it 4 or 5 times instead of constantly for 10 mins) and when it did do it, it was significantly less violent and much gentler. 

I recently resprayed my tank and just masked off the fuel cap. During the wash downs after sanding between coats there is a chance water got into the tank. When I finished the job and went to the servo to fuel up, about 50-60mls of water was sitting under the fuel cap and when I opened it, it all ran into the tank......

Would this cause these symptoms?

Could be.
What you need to watch out for is water collecting in the bottom of the tank.
It generally gathers around the fuel pump and it will corrode through the tank. Been there twice myself.
Has also been known to rust through on the other side, too.
First signs are a whiff of petrol and/or bubbles in the paint.
Common enough problem.
Can be fixed but it's going to get more difficult to get good tanks as time goes on.
To prevent it, make sure that the filler cap is the right way around. There's a drain to take any water away but the cap has to be fitted so that the lid opens towards the rider.

That is the symptoms my car exhibited when I got water in my fuel from a local servo.
I called the RACQ (auto club) and got it towed to the to the RACQ garage and when he asked where I got the last tank of fuel I said here right at that pump and they were very nice and fixed it right away. I thought they would and when I saw him later in the week he said they had 4 more just like me. Apparently not many people use 98 in cars.

Im now pretty convinced its water in the fuel.

I replaced the coils today (was going to do this anyway) with the later style orange stack ones. (not saying this had anything to do with the surge, just mentioning it).

Noticed that the coil end of HT leads 3 and 4 was green with moldy corrosion. I recall de-oxiting all of these, so that corrosion has come in 3 months. but maybe i didnt de-oxit them. anyways, they are clean now and the bike runs nicely. Is this caused by loose connections?

But the surge thing is still there. so back to water in the fuel.

So, as the bike gets hot the issue mostly goes away or becomes un noticeable. I suppose this could be consistent with a very small amount of water in the system?

After letting the bike sit for several hours after a long ride yesterday, it was then very very difficult to start and ran like a dog for a few mins. This may be consistent with water sinking to the bottom where the fuel pump in take is and then this water being drawn up first when I tried to start the bike.

The problem is getting less and less, perhaps consistent with the water being expelled. 

Will drain the remainder of the tank and report back.

Put 50ml of metho in the tank it will absorb the water and go into suspension in the petrol and the water goes through the system and out the back.

RicK G wrote:Put 50ml of metho in the tank it will absorb the water and go into suspension in the petrol and the water goes through the system and out the back.

Thanks Rick, good idea.

In your opinion (and anyone elses) would 50-100ml (it could be more I guess but if it is water its not enough for me to be able to see it in the bottom of the tank with a torch) be enough in a full tank of fuel to cause noticeable issues?

Only a small quantity of alcohol will mix unless you have the right stuff to keep it in suspension. So 50ml to a tank is about all that will stay there else it mixes with the water and also sits in the bottom of the tank. You could go to 100ml if you put 10ml of acetone in it as well.

possibly an idea might be to remove the fuel filter and drain it Floyd

they have a tendancy to trap water fairly well and not let is pass through well

whilst your in there I guess.,

hint if you can remove it without dumping the excess in the tank ...you should be able to drain it into a bowl and see the consistency ...

just a thought

RicK G wrote:Only a small quantity of alcohol will mix unless you have the right stuff to keep it in suspension. So 50ml to a tank is about all that will stay there else it mixes with the water and also sits in the bottom of the tank. You could go to 100ml if you put 10ml of acetone in it as well.

would the ethanol in e10 do the same?

no .....not the same at all

reports of ethanol in old lines turning to gell abound

from the interwebs:


Methylated spirits is sometimes also called denatured alcohol. Basically it is ethanol (the same stuff as in the 'E' in E10 blended petrol and also wine, beer and spirits). However, it also has a small proportion of other chemicals added make it poisonous, and very bad to taste/smell.  This is done to stop people drinking it recreationally.
It is generally used as a solvent and can be used as a fuel for burners and camping stoves. It's a common household solvent. The main additive is about 10 per cent methanol (which is the next most common alcohol - but a deadly poison, which also causes blindness). The use of methanol in the mix gives rise to the term 'methylated' spirits. Methanol is also a common fuel in racing cars, especially drag racers. Other chemicals found in methylated spirits include isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and denatonium.
None of these chemical additives alter the ethanol in the mix. They're just there to make it unpalatable, poisonous and undrinkable. They also make it almost impossible to distil the blend to extract the ethanol and drink it subsequently. 
In other words, 'metho' performs like ethanol for basic chemistry purposes.
One of the salient features of alcohol (ethanol/methanol, etc) is that water mixes with it. The chemical term for this is 'miscible'. Water doesn't mix with petrol. But alcohol also is miscible with petrol. So, when you add water, ethanol and petrol, you get a miscible solution of all three liquids. 
In other words, the water dissolves in the alcohol, which itself is dissolved in the petrol. (Industrial chemists prefer to say 'miscible' - but you get the point.
A small amount of metho in the tank, occasionally, can get rid of a very small amount of water trapped down the bottom.
If you have a 50-litre tank, I'd have no hesitation in putting a bottle of metho (call it one litre) in the tank. Effectively, this would be a do-it-yourself E02 blend. That would take care of some moisture trapped in the bottom of the tank.
However, a simpler solution to the problem would just be to fill up occasionally with E10 fuel (provided the car is compatible with that fuel). More ethanol equals more opportunity to dissolve more water and eliminate it by ingesting it into the engine.

When we were in France a lot of the time the only petrol available was that E10 and E85 stuff. It did afftect my RT quite noticeably and we were warned off the E85 altogether. Apparently the E85 eats seals etc for dinner and causes very bad running!!

floyd wrote:

RicK G wrote:Only a small quantity of alcohol will mix unless you have the right stuff to keep it in suspension. So 50ml to a tank is about all that will stay there else it mixes with the water and also sits in the bottom of the tank. You could go to 100ml if you put 10ml of acetone in it as well.

would the ethanol in e10 do the same?

I have used E10 to get rid of water but the octane rating isn't high enough to use it all the time mainly because the Nicasil bores don't like detonation one little bit and deteriorate rapidly if ridden hard.
I usually use a tank full of 50/50 E10 and 98 which works OK then put a few more tanks of 98 through to get rid of all the E10 because as Charlie said it gets into the lines and sort of melts them.
Water in the filter is very likely and also the pre filter under the pump from what I can find is a 6 micron filter and water needs 8 microns to pass but it does seem to get through a bit.

floyd wrote:from the interwebs:


Methylated spirits is sometimes also called denatured alcohol. Basically it is ethanol (the same stuff as in the 'E' in E10 blended petrol and also wine, beer and spirits). However, it also has a small proportion of other chemicals added make it poisonous, and very bad to taste/smell.  This is done to stop people drinking it recreationally.
It is generally used as a solvent and can be used as a fuel for burners and camping stoves. It's a common household solvent. The main additive is about 10 per cent methanol (which is the next most common alcohol - but a deadly poison, which also causes blindness). The use of methanol in the mix gives rise to the term 'methylated' spirits. Methanol is also a common fuel in racing cars, especially drag racers. Other chemicals found in methylated spirits include isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and denatonium.
None of these chemical additives alter the ethanol in the mix. They're just there to make it unpalatable, poisonous and undrinkable. They also make it almost impossible to distil the blend to extract the ethanol and drink it subsequently. 
In other words, 'metho' performs like ethanol for basic chemistry purposes.
One of the salient features of alcohol (ethanol/methanol, etc) is that water mixes with it. The chemical term for this is 'miscible'. Water doesn't mix with petrol. But alcohol also is miscible with petrol. So, when you add water, ethanol and petrol, you get a miscible solution of all three liquids. 
In other words, the water dissolves in the alcohol, which itself is dissolved in the petrol. (Industrial chemists prefer to say 'miscible' - but you get the point.
A small amount of metho in the tank, occasionally, can get rid of a very small amount of water trapped down the bottom.
If you have a 50-litre tank, I'd have no hesitation in putting a bottle of metho (call it one litre) in the tank. Effectively, this would be a do-it-yourself E02 blend. That would take care of some moisture trapped in the bottom of the tank.
However, a simpler solution to the problem would just be to fill up occasionally with E10 fuel (provided the car is compatible with that fuel). More ethanol equals more opportunity to dissolve more water and eliminate it by ingesting it into the engine.

bit like saying  "teachers scotch" is the same as "glenfiddich "  . similar effects can be noticed ....but there is a difference

Thanks gents.

Problem solved and bike running great.

There was only a couple of L of fuel in the tank so I pumped it out, removed the filter and drained it, broke a wire to the fuel pump so fixed that....had to push it to the 7/11 down the road to fill up. Some minor up hill sections made that fun. Filled her up, hit the starter, a cough and a splutter but no go. I mess around for a bit, determine the injectors are not opening...the usual suspect is the under tank FI loom connector. It comes loose fairly often. Will have to replace it. Re-plugged it and off she went. 

Do the early model K's have the pre filter basket around the pump? I dont and it didnt when I stripped it down. I have one of the 86 model but it wont fit.

Anyways, bike is running great now, thanks again.

Runs a tad smoother through the rev range with the cleaned up leads and new (old) coils according to the butt dyno.

Hi, good sorting that. All K's had the basket filter, the early ones without the connection for the 'breather hose' Difficult to find....

EME have the prefilter for the very early models.