splutter

[hellbound]

Suzuki GN250

every now and again I loose all power on the bike, it idles but when I try and accelorate it splutters and backfires, it will do this at random times usually when I try and pull away after riding at 20 to 30 mph.

the only way I have found to cure it is to leave it to idle and try it every now and then or pull the choke out which then makes its splutter and eventually rev up.

Carb has been cleaned several times, it has a new spark plug and it doesn't matter how much fuel is actually in it.

Ideas?
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May you always see the road rising up to meet you and your enemies defeated in the mirror behind.

[neil.]

Air filter dirty or damaged or blocked? Carb inlet rubber (the big bit that connects carb to engine) cracked/damaged, meaning more air from outside getting sucked in?

[hellbound]

Air filter has been replaced

Didn't think of carb rubber but then thought it would do it all the time not once or twice a week, or then be fine for a few months then start again.
____________________
May you always see the road rising up to meet you and your enemies defeated in the mirror behind.

[neil.]

What about fuel filter being clogged? Depending on the bike, you might have one in the fuel tap and a strainer in the tank, as well as an in-line one somewhere.

Edit: the breather in the fuel cap might also be blocked which creates a vacuum in the tank and restricts flow.

[Martay]

Is it points ignition? Sounds a bit like worn contacts?
____________________
Eat well, poo hard
Drives: Cavalier 2.0 16v
Rides: Slightly ratted Honda City Express

[N cee thirty]

quite a few bikes i've ridden do this on start up,have the choke on for about 5 mins of riding and then it should be fine
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[Ichy]

[hellbound]

[cb1rocket]

fuel tank vents blocked possibly, next time it looses power open the filler cap and ride to see if it cures it

[hellbound]

I have done this too...had the same problem on the c90, cured it on that...not this time though
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May you always see the road rising up to meet you and your enemies defeated in the mirror behind.

[cb1rocket]

Is the GN250 a CDI ignition? I think it is, but not sure as I don't have the haynes. If so unlikely to be ignition related.

How did you clean the carb? Thats the bit I want to know. Did you actually take out the jets and clean them?

Also possible water in fuel tank

[fiery tupp]

Float hight adjustment too high , getting starved of fuel occasionally ?
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If you can't fix it with a hammer , use your head .

[HD]

When my carb rubber split it made the bike tick over excessively high. Well not just tick over but rev everywhere really high.
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Rusty '02 Vito Camper + CBR600F3

[hellbound]

[cb1rocket]

check for air leaks, also the float being set too low is another possibilty as been said

Since you mentioned the bike idle fine, it could well be the floats.

Whats the history on the bike? Has it recently started doing this? Or did you buy it like that? If not have you done whatever xxxx miles without problems?

[hellbound]

It started doing it about 6 months ago, I do about 300 miles a week to and from work.

I also have to switch the fuel tap off or it stinks of fuel after ten minutes.
____________________
May you always see the road rising up to meet you and your enemies defeated in the mirror behind.

[cb1rocket]

ahhhh, you have a float valve/float issue. Its simple as the carb is flooding itself with so much fuel that it starts to smell.

Get hold of another carb if you can, or strip the carb again and REPLACE the float needle and adjust the float height according to the haynes.

It def a carb issue. Maybe you should of left it alone!

[cb1rocket]

had a look and found this

https://cgi.ebay.co.uk/suzuki-gn250-carburetor-gn-250-carb-/150419103430?pt=UK_Motorcycle_Parts&hash=item2305ad5ec6

didn't even know it was CV type carb! Did you even disassemble the CV/ diaphragm? Its quite easily to split/damage the diaphragm rubber and if so the vacuum will be lost, and the lost of constant velocity air. These carbs are quite delicate.

Anyhow still cheaper to try the new float needle route first, if not its time for a new/different carb.

[Ichy]