Carb Issues..

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Carb Issues..

Postby Mick88 » Thu Jun 01, 2017 9:45 am

To start I don't know much about carbs so this is my first attempt. Recently had a stator issue which seems to be solved now. The bike was running a bit odd and I had summed it up to the stator being the the cause. It was the cause of other problems but not this one.

Symptoms:

Started when I noticed the bike would drop in rpm when at idle sitting at a light and I had to give it a little throttle although it never actually stalled. While at speed didn't really notice anything.

Carb visibly leaking from what I guess is the overflow. I have pics, will post later but basically a hole visible when lying on the ground looking up at the carbs while they are still on the bike. The second one if starting at the left. Its a very slow leak, not even drops more like a very slow trickle. The stuff coming out looks kind of grimey, old gas residue looking stuff.

Gas in the oil, like a lot :( oil is at the top of the sight glass. (checked to make sure it wasn't the coolant.. that already happened once :( )

Gas mileage went down a lot. Do mostly city riding and was getting about 100miles til reserve(3gallons, with 1.8 left over of the 4.8g tank). 27-33mpg. I filled up today I think 64miles on 3.4 gallons. I could swear as I was riding to the gas station I could see the needle moving down o.O. Definitely running on 4 cylinders no weird vibration or anything.

What I think is going on:

Stuck float or dirty needle valve/seat causing fuel to overfill the bowls draining a bit out the overflow and the rest down into the engine. I don't even know how long I was riding with that much gas in the oil. I'm guessing its happening while the bike is off because I don't have a misfire or backfire although the exhaust did smell a bit like unburnt fuel. I always turn the petcock to off while the bike is parked unless its a quick stop. I don't think this is a petcock issue because only carb #2 looks to have a outside visual leak. I would imagine if the engine is running the unburnt fuel would go straight out the exhaust and when off the only amount of fuel that could drain into the cylinder would be the leftover fuel in the tube after the petcock/the bit overflowed already in the carb. Possibly I had parked the bike without closing the petcock and since the needle/float is messed up gas tricked in for a few hours? Long ago I had left the fuel on for 2 weeks or so and I had some pretty nasty backfires and starting issues, bike had a lot of problems back then. Battery was near dead spark plugs were all fouled and air box filter was old as heck.

My plan is to remove the carbs, clean #2 first and check to make sure the float doesn't have holes in it and make sure the needle valve and seat are clean. Hopefully wont need parts. Want to fix it by the end of this weekend. If it looks visibly damaged I'll order parts found some ebay rebuild kits http://www.ebay.com/itm/4x-Carburetor-C ... Uy&vxp=mtr

Of course going to change the oil. I'll know if the petcock is leaking when I remove the gas tank ROFL2

Never done this before we will see how it goes. Tips appreciated :) By the way I am reading other threads and I'm seeing a lot of people with similar issues. Just like to keep a thread so I can have a go-to to see where I'm at in the project.
Last edited by Mick88 on Thu Jun 01, 2017 10:21 am, edited 3 times in total.
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Mick88
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Re: Carb Issues..

Postby Mick88 » Thu Jun 01, 2017 10:02 am

Image
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Re: Carb Issues..

Postby GreenMagicMan » Thu Jun 01, 2017 1:41 pm

I'm gonna help ya on this one. How long has it sat generally not riding it?
Continue to always shut off the petcock when not riding as a precaution for leaking fuel into the engine.

This is important to do so fuel cannot leak through the carbs into the cylinders and past the piston rings (oil seal) into your oil. So yes, you need to change that oil out right away.

Carb cleaning is very easy. There's a superb write up for our Keihin carbs with great pics. Made by another guy, another forum but they are our carbs! I added a few notes to his excellent write up here:
viewtopic.php?f=2&t=15998&hilit=+carb+clean thumbup
I sort of enjoy cleaning our carbs, I do in fact. I don't like getting TO them (needless p.i.t.a. I say), but if I was around and you handed me your rack of four I'd have been happy to do them for you, with you or show you how.

The best product to get for effectiveness, cost and availability is Evinrude "Engine Tuner" which can be found at most marina / boat yards. I specifically easily found a can of it for $13.15 in Oakland:
Outboard Motor Shop
#333 Kennedy St., Oakland
I'm sure there are many places close to you you can find it at. (Don't think West Marine carries it, but could check).
Brake cleaner is needed, and gloves to avoid skin contact with engine tuner product. Air compressor they say is needed but I've cleaned mine without that. I just shoot brake clean thru it all and call it good.

Clean out all four carbs. Leave them bolted together to eachother - each carb assembly and clean all 4 at same time! Don't just clean out #2. Won't take much extra time.
I don't believe you have a leak / hole in #2 float - that seems ultra rare. I don't think it's 'waterlogged' with fuel and causing the problem.
Since you say your fuel looks dirty then it IS. It's likely ethanol gunk build up and making a huge mess of things, so it's almost certainly completely gummed up your float needle. That is a little needle that rises up with the float, and cuts off fuel delivery in it's 'needle seat' (female part so to speak). There's likely gummy varnish from ethanol there and / or little debris in there preventing the needle from sliding up. If the needle cannot seal the seat fuel can just keep flowing and flowing... and out that overflow.

How old are your fuel lines? Take a look closely at your fuel filter while under the tank. Are there any black pieced of debris in there (fuel hose disintegrating).
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Re: Carb Issues..

Postby Mick88 » Fri Jun 02, 2017 6:35 am

Thanks, the bike only sits a couple days between rides always with the petcock to off. Ride almost every day year round. I gathered up the materials tonight for the clean. Got Oil/filter carb clean and brake clean. I don't have a compressor so closest I can get is compressed air cans.

Pretty sure my fuel lines are old but not so old they are falling apart. Will double check anyway. Last time I changed the fuel filter which was about 4-6 months ago it was yellowed with age but otherwise worked pretty much as good as the new one I put on there. Doesn't seem super hard just need to look up how to reset the floats and a good way to remember the amount of turns on the pilots or jets or what not. If you wanna help I'm free all weekend lmao

Btw stator cover is still yours but check my thread about the charging issues and view the scraping that was going on inside the generator. The allen screws weren't backed out so I think the cover was dented inward causing the allen bolts to rub a bit. Not 100% sure.

I also don't know if I want to drain the oil before or after the carb cleaning. I was thinking to clean the carb first then run the bike just enough to warm it up a bit then do the oil change. I was thinking if I drain it and put new oil in then put the carbs back on and problem is still there then contaminate the new oil etc..
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Mick88
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Re: Carb Issues..

Postby GreenMagicMan » Fri Jun 02, 2017 2:31 pm

Well I recall you did a pretty well researched cleanout from the coolant oil mix. What process did you use for that?
I doubt the gas in the oil is as bad, but your method was thorough.
Not sure if I'd warm up that oil first or not. In the meantime you can clean the carbs and reinstall them anyway.
I'm on the east coast right now.
Due to smashing my bike into the ground, I had to go east to get surgery as my medical insurance only covers me there beyond ER visits.
I'm also kind of like a cat with my leg stuck over my head almost all day - trying to reduce the swelling from the surgery on my ankle.
And yeah compressed air can is perfect. But I didn't even bother with that 2 of the 3 cleanouts I did. The brake cleaner evaporates anyway - so I don't quite see the point unless one is paranoid there is debris left in there somehow (but that's why you shoot plenty of cleaner through all the openings, and check the spray is of similar volume on the same hole in a different carb body anyway).

Big thing is in your case, make sure to pull all your float seats out and make sure they are super clean. pull all the float needles and inspect the tip of them carefully. I have not bothered to buy kits to replace the seats or the float needles. But I also have two spare carb racks with almost all the parts, so I've been able to pick n pulled better looking parts from the spare set(s).
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Re: Carb Issues..

Postby Mick88 » Wed Jun 14, 2017 7:15 am

Image

Alright well I took the carbs off the bike over the weekend and opened them up, everything was clean inside there. the float seat had "crust" around it and the o ring was in tact but could probably use replacing. I cleaned off the crust and put it back together and made sure the floats were all functioning and not stuck. The needle did have a ring on it but it wasn't indented a lot, put it back together and it seemed to run good for a bit...

After riding a while the same issue came back. Bike runs as normal except low mpgs(same as before carb clean). Only problem is at idle the rpms will continue to drop while the throttle is closed until the bike almost stalls, opening the throttle keeps it alive and while at any rpms above idle I don't notice an issue. Can smell fuel in the exhaust, it always ran a little rich but not like this.

Some things I don't know.

What exactly is circled in #1? It looked like gas was leaking from that area but when I took it apart it looked like that hole is not actually connected to anything? Was a bit confused by that.

#2 is the throttle spring(I think?) but fuel seems to be leaking from this area when turning the throttle(some drops come out when turning the throttle while the bike is off). I had to have a second person turn the throttle while I looked under the bike.. I am guessing no fuel is supposed to actually be in this area? its just a mechanical linkage that controls the butterfly flap?

Image
This is a picture I got off ebay but now I'm guessing for some reason the inner left carb is overflowing/constantly dripping fuel and thats landing on the butterfly flap and leaking out the spring area? And in turn thats causing my rough idle/idle drop to stall? So every time the bike is parked the remaining fuel in the line after the petcock is leaking into the engine and if the petcock is left open its just dumping in there..? Love the bike but its starting to be one thing after another D'oh . The inner right carb boot has a bit of fuel/oil or something on it too(similar to the inner left carb boot pictured).

Basically have to pack and move just about every weekend this month, want to nail this one on the head. I don't think the fuel line linkage between the carbs is leaking, so its got to be the carb internals? Rebuild kit time? Or is it simply the float height is incorrect? Is that just something that changes over time? For example the bike was running fine and carbs were untouched and then this developed...

https://c1.staticflickr.com/5/4269/3513 ... 6786_k.jpg

https://c1.staticflickr.com/5/4207/3449 ... d8f0_k.jpg

^^^What it looked like inside..
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Re: Carb Issues..

Postby Mick88 » Wed Jun 14, 2017 9:54 am

Got a rebuild kit coming in the mail. http://www.ebay.com/itm/311879006058

Just going to redo all 4 while I'm at it. Don't want to be taking it apart every weekend.
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Mick88
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Re: Carb Issues..

Postby GreenMagicMan » Fri Jun 16, 2017 1:04 am

Some of the 'holes' in the carbs have little ball bearing looking things wedged in them. If they are not connected to anything those are bore / drill holes to get into something beyond it, and then they press those little balls in to seal the hole they made manufacturing the carb body.
IF it really is something like that, and if it was actually leaking I would guess the fix would be a replacement carb body.
That's underneath front side of carbs you're pointing to in #1 right? I think I need some pics of my carbs to orient myself a little better there first to try to see what that is.

If that is in the float bowl part itself, then you're right, it goes to nothing. If there is somehow a leak there, then replace the float bowl.

If you would need a float bowl I have spares.
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Re: Carb Issues..

Postby Mick88 » Fri Jun 16, 2017 4:06 am

Image
Middle finger is on the drain, the other thing is where it looked like dripping was coming from. After I put it back together I haven't seen it wet there again..

Image
Also this is what my needle looked like.

I'm wondering if it dripped down from somewhere else and gathered there or something..

My plan right now is to replace all the needles and seats(only one is leaking but I have 4 rebuild kits..) and check all the float heights to make sure they are similar. I believe in the service manual it says 9-13mm is in spec, not sure what to aim for exactly though.

Image
More pics never hurt..
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Mick88
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Re: Carb Issues..

Postby GreenMagicMan » Fri Jun 16, 2017 2:46 pm

Correct 9-13mm range for float height. I've gone to the high side range of mine.
Which a friend might have said perhaps I should go more towards the smaller number side.

I sometimes have a 'carb flooding' issue too after the bike sits awhile. It's very sporadic and didn't happen at all this last item around after sitting for 6 months.

Unless you can see a crack in that float bowl it must have simply trickled down from somewhere else and that's the low point so it dripped off that. Gas leaks like that can be deceiving.

There's low / no pressure in there. Test the bowl. Fill it with any liquid and see if it can actually get through that spot. I doubt it will - unless it's cracked.

Your needle tips look a little dented / detented... but so did mine and I didn't bother to replace mine with new either. Here's a pic of my parts removed:
Image
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