Alternative Carbs ?

[Ninjinsky]

Okay I left it standing for a couple of weeks and now, as usual, it will only run through the choke circuit because the idle circuit has a smidgeon of oxide in it so will have to be stripped for the (double figures) time.
It is beginning to feel like a Wile-E-Coyote Acme bike

Anyone fitted alternative carbs to the Keihin CVKs that make it behave like a normal bike instead of clogging every time it stands for more than a week. Everything else about the bike is fine but the carbs are a real achilles heel.
No its not that I haven't cleaned them well enough it is always running just fine before standing. And every time it stands it is stuffed,
I'm contemplating a nice simple pair of these secondhand with K&Ns to get rid of the PITA airbox hassle too.
http://www.ebay.co.uk/itm/Mikuni-VM3...3D171258821631
It is going to be that or part it out because I need this hassle like a leaky biro in a white suit.

[alex.s]

have you checked the inside of your gas tank for rust?

whats the status of the fuel filter

[jkv45]

In a couple of weeks of sitting you can get a fair amount of condensation built-up if the tank is not close to full.

Gas with ethanol can go bad quickly, and you never know how long it was in the storage tank before you bought it. Can you get "Regular" (or anything) without ethanol? Higher octane than necessary can cause hard starting.

Drain the floatbowls and look at what comes out. I'd also run a fuel system cleaner once a season, or more if you think you have some deposits that need to be removed.

I really don't think a different set of carbs would help.

[alex.s]

direct fuel inject would probably solve the issue though

[Ninjinsky]

Originally Posted by alex.s

have you checked the inside of your gas tank for rust?

whats the status of the fuel filter

There is a little but it has an inline filter which is clean and replaced recently. The problem effects both carbs equally, It's not like it runs on one cylinder. Fuel flow is good.

JKV: appreciate that but once the idle circuit has been cleaned that fuel is fine.
I will drain them completely tomorrow in case there is water and to give the float bowl a completely fresh charge, but have never seen water in there.

[jkv45]

Originally Posted by Ninjinsky

JKV: appreciate that but once the idle circuit has been cleaned that fuel is fine.
I will drain them completely tomorrow in case there is water and to give the float bowl a completely fresh charge, but have never seen water in there.

Are you running fuel with ethanol?

The Pilot jets may have corrosion internally, made worse by ethanol. You could try replacing the Pilot Jets and see what effect that has - and run fuel without ethanol.

[Ninjinsky]

Originally Posted by jkv45

Are you running fuel with ethanol?

The Pilot jets may have corrosion internally, made worse by ethanol. You could try replacing the Pilot Jets and see what effect that has - and run fuel without ethanol.

Apparently varies 0 to 5%

http://www.tescopfs.com/our-fuel/specifications

[250rr]

I prefer vegan bread.

[garth285]

Convert to ninja 300 fuel injection? lol

[dcj13]

Ever consider adding a bit of fuel stabilizer every time you gas up?

[Motofool]

Originally Posted by Ninjinsky

........Anyone fitted alternative carbs to the Keihin CVKs that make it behave like a normal bike instead of clogging every time it stands for more than a week............

Those carbs would perfectly work, but the jets would get clogged as soon as the ones in the original carburetors.

The main difference is diaphragm versus slide; the passages for air and fuel are equally small; both types work with the same clogging gasoline.

I have had my Ninja out of operation for more than a month when I had gone to work out of the state and it has started right away.
My trick: draining both bowls completely before storage and filling up the gas tank up to the cap.

[Hero Danny]

Originally Posted by alex.s

direct fuel inject would probably solve the issue though

Fuel injection was the main reason why I ditched my 250. I miss the hell out of it, but I feel like my bike runs more reliably now, just push the button and you're good to go.

[alex.s]

Originally Posted by Hero Danny

Fuel injection was the main reason why I ditched my 250. I miss the hell out of it, but I feel like my bike runs more reliably now, just push the button and you're good to go.

port fuel injection runs fairly low psi and still has issues with clogging.

direct injection runs much higher psi, more like a diesel works. but obviously nowhere close to the levels that a diesel runs, otherwise the gas would explode in the injector.

direct injection doesn't clog because you're talking about a piezo hammer bringing it up to around 5000psi (diesels go all the way up to 30-50k psi depending)

[Ninjinsky]

Originally Posted by Motofool

Those carbs would perfectly work, but the jets would get clogged as soon as the ones in the original carburetors.

The thing is That I have had maybe 12 cars and 10 bikes, some of them pretty ragged and none of them has exhibited this behaviour, Only the CVK's on the ninja.

[Motofool]

Originally Posted by Ninjinsky

The thing is That I have had maybe 12 cars and 10 bikes, some of them pretty ragged and none of them has exhibited this behaviour, Only the CVK's on the ninja.

I see.
I don't know of an evident cause in this specific type of carbs.
Again, mine never get clogged: sometimes I ride daily, sometimes I must stop for several days.
The poor thing sleeps in a hot and humid garage.

Respect to the other bikes, has any other thing changed other than the Ninja?
Fuel (ethanol, octane, additives)?
Location (climate, height, air humidity)?
Storage conditions (fluctuations of temperature, humidity)?

[alex.s]

are you sure its the carbs causing the issue?

i know the problem goes away after you clean the carbs... but maybe its a distraction... maybe you have a really bad vacuum leak that develops after the carbs have been seated for awhile? and when you reseat the carbs its fine for a bit until they come out again? just spitballing.

[Ninjinsky]

Xemilin's video from a couple of threads down is the typical experience.

Link to original page on YouTube.



I have decided it is going, life is too short so a VX800 is probably imminent
I will soon be in the ex ninjetters lair

I will take some pics and offer it here at sensible money given the carb issue first if any one wants a crack at it.(Cambridgeshire UK) It goes like a bat out of hell when it's running.

[Ninjinsky]

Originally Posted by alex.s

are you sure its the carbs causing the issue?

i know the problem goes away after you clean the carbs... but maybe its a distraction... maybe you have a really bad vacuum leak that develops after the carbs have been seated for awhile? and when you reseat the carbs its fine for a bit until they come out again? just spitballing.

Thanks, yeah I have probably been through every idea over the past few years from Is there gas in the tank? to potatoes growing in the airbox
Sometimes in life one just has to say "beats me" and move on.

It has been apart many times and I have 2 sets of carbs, changed ICU and coils The head was off recently for a seeping gasket so pretty complete strip with all items/ plumbing checked but the problem remains the same.
So as I said above I think I will spares or repair it.

[alex.s]

that interceptor 800. she be a good bike.

[Ninjinsky]

Originally Posted by alex.s

that interceptor 800. she be a good bike.

True but I can't afford one which is why I said VX800 Suzukis neat semi custom v twin
http://www.suzukicycles.org/photos/v...Bruce1_640.jpg

[Hero Danny]

Originally Posted by alex.s

port fuel injection runs fairly low psi and still has issues with clogging.

direct injection runs much higher psi, more like a diesel works. but obviously nowhere close to the levels that a diesel runs, otherwise the gas would explode in the injector.

direct injection doesn't clog because you're talking about a piezo hammer bringing it up to around 5000psi (diesels go all the way up to 30-50k psi depending)

You're speaking another language to me. All I know is, I get out of class on a cold night and I turn the key, push the button and "cli...cli...cli...vroom"

[Motofool]

Originally Posted by Ninjinsky

Xemilin's video from a couple of threads down is the typical experience.
............

Carburetors may be bad, ......... but you have terrific battery and starter !!!

Unless you are smelling or seeing overflowing fuel while cranking, the bowls of your carbs are dry like coconuts !!!
I would check for plumbing problems instead, such as vacuum in the cold tank or lack of it in the petcock.

What that video shows is far from normal; my bike never needs more than three attempts after weeks in storage.
If your hose delivers less than 2 c.c. per second, there is a plumbing or vacuum or filter problem.
Check the mesh filters inside the tank and inside the end of the hose.
Try cranking with the petcock in reserve as well.

Also, do not crack the throttle open while cranking, you are killing the vacuum for the idle and choke circuits that way.

I fully agree, life goes away in a heart beat.

[alex.s]

Originally Posted by Motofool

life goes away in a heart beat.

it's the sad truth about life. it's over in an instant. and it comes from every direction.

[Motofool]

Originally Posted by Hero Danny

You're speaking another language to me. All I know is, I get out of class on a cold night and I turn the key, push the button and "cli...cli...cli...vroom"

I thought that you wanted to learn about engines.

After reading this, could you tell us what system is in your bike?:

http://en.wikipedia.org/wiki/Fuel_injection

[Ninjinsky]

Originally Posted by Motofool

Carburetors may be bad, ......... but you have terrific battery and starter !!!

Unless you are smelling or seeing overflowing fuel while cranking, the bowls of your carbs are dry like coconuts !!!

That wasn't my video, it was posted by another ninjetter "xomilin" having the same problem a couple of weeks ago.
https://www.ninjette.org/forums/showthread.php?t=202942

[jkv45]

Originally Posted by Ninjinsky

That wasn't my video, it was posted by another ninjetter "xomilin" having the same problem a couple of weeks ago.
https://www.ninjette.org/forums/showthread.php?t=202942

I remember that.

It was suggested that he crank a bit longer before letting up on the button, and try backing the choke off some and/or opening the throttle while cranking.

Not sure if that solved his problem or not.

[alex.s]

when was the last valve adjustment done?

[Yarhj]

As a fellow sufferer of carburitis, I feel your pain. My bike has trouble starting after sitting for two weeks, and past three weeks its almost impossible to start (yes, I'm a terrible motorcycle owner). I've had success with rolling it into some sun, cranking for short bursts (about 5-7 seconds) with full choke until it starts to fire and stall (with 30 second rests between each round of cranking), and then feathering the throttle verrry lightly while cranking, until it eventually runs with choke. As soon as it will run with choke, put it in gear and putter around for 5 minutes

Instead of ripping out the airbox, consider n4mwd's airbox mod -- it really simplifies the process of getting the carbs on and off. For me it changed the process from a 2 hour ordeal with lots of cursing to a 20 minute project (with recreational cursing).

Good luck, fellow carburhater! May the force be with you.

[Ninjinsky]

Originally Posted by Yarhj

As a fellow sufferer of carburitis, I feel your pain. My bike has trouble starting after sitting for two weeks, and past three weeks its almost impossible to start (yes, I'm a terrible motorcycle owner). I've had success with rolling it into some sun, cranking for short bursts (about 5-7 seconds) with full choke until it starts to fire and stall (with 30 second rests between each round of cranking), and then feathering the throttle verrry lightly while cranking, until it eventually runs with choke. As soon as it will run with choke, put it in gear and putter around for 5 minutes

Instead of ripping out the airbox, consider n4mwd's airbox mod -- it really simplifies the process of getting the carbs on and off. For me it changed the process from a 2 hour ordeal with lots of cursing to a 20 minute project (with recreational cursing).

Good luck, fellow carburhater! May the force be with you.

Thank you so much for that, so obvious once you think about it. It is going to happen tomorrow
I notice yours is about the same age as mine and shows the same characteristics. I will go through the fine specs and see if anything changed in the jetting or plumbing after our model. Since newer bikes regardless of mileage seem better reading the carb threads on here.
I am also going to lift the needles 1.5 mm
I have removed the carb heater plumbing but that obviously doesn't affect starting because the coolant is cold at that point anyway
Meanwhile the carbs are off (the hard way) and I am summoning up the will to strip them again
Alex.s Yes mate, I completely went through the valve clearances when I did the head gasket they are fine.

[Yarhj]

The pictures in n4's thread don't seem to be loading for me, so here's a link to a similar mod, so you can see what's actually being done. In this version they actually remove the airbox from the bike before sawing the battery box off, which just adds way too much hassle -- using string or steel wire is way faster.

[agentbad]

Originally Posted by Ninjinsky

The thing is That I have had maybe 12 cars and 10 bikes, some of them pretty ragged and none of them has exhibited this behavior, Only the CVK's on the ninja.

Yeah I feel you on that. If I sneeze wrong my carbs get clogged but it's almost always because I run the tank too low. Fortunately I have pods so removing the carbs takes 5 mins.

[Motofool]

Originally Posted by Ninjinsky

True but I can't afford one which is why I said VX800 Suzukis neat semi custom v twin
http://www.suzukicycles.org/photos/v...Bruce1_640.jpg

Did you fix the carbs of the Ninja 250 or did you buy that VX800?

[Ninjinsky]

The ninjette is currently stored in friends shed 200 miles away with the carbs off since I didn't have time to work on it during the house move.
I will get it running soon and take it to a dealer friend to sell for me. then I will join the ex ninjetters forum with some kind of V twin in the 500-800 bracket.