What is wrong with my GN250?

[ABBA]

I recently purchased a 2007 GN250E with 2000 k's on the clock for commuting to work. I got a friend to look at it for me as I was out of the country at the time and didn't want to miss out on the deal. When I got it I found it has a problem, it sort of dies/surges and plays around when taking off and dies/surges a bit when cruising along at normal around town speeds. I have pulled the fuel tap out of the tank and cleaned the filters etc there, pulled the carb off and fully stripped it down and blown it out with compressed air and checked and cleaned both the the air cleaner and spark plug (also checked plug gap), I've also checked for leaks in the all of the seals going from the air filter box to the carb and then to the head. Nothing I have done has fixed the problem, it has only made it a bit more rideable. Has anyone out there had similar problems/issues with their GN??? Help!!!

Stephen

[Hiflyer]

maybe its the oil? my hyosung had the same problem for a bit but thats cos there wasnt any oil in the tank haha, not something that was on my checklist. so yea, might just be something you didnt think shold need checking?

[ABBA]

Hi, thanks for that...no not the oil sorry, that was one of the first things I checked before my first ride...Cheers

[rogson]

Check the mixture screw (top/front of carb under a rubber plug) - should be 4 turns out.

[ABBA]

Thanks for that, I've got it set at one and half turns out. Is that the specified setting? I'll try that out tonight and let you know how I get on. Cheers

[rogson]

Don't know what the spec setting is. See below for how I got to 4 turns.
http://www.kiwibiker.co.nz/forums/sh...friendly+GN250

[Racin Jason]

All of the new GN250's have this problem.
The mixture is not set right for Zealand conditions and it runs lean, causing a miss or splutter at low rpm and needing a long warmup period with the choke on. this cannot be fixed by simply adjusting the mixture screw.

when new, Suzuki dealers are "supposed" to correct the problem by fitting a larger pilot jet. But i believe these are no longer available. however since then some dealers have been drilling the original pilot jet to the correct size.
All Suzuki dealers should know all about this.

Also make sure the fuel hose from the tank isnt kinking - common problem

[ABBA]

Jason, thankyou so much for that information. As much as I hate to do it, I will contact the local Suzuki dealer and see if I can get this issue sorted. I will let you know how I get on. Thanks again!

[ABBA]

Hi Jason, well I rang the local Suzuki agent and they had no knowledge of the issue with the pilot jets at all. Can you let me know the name of the Suzuki dealer that you know of that has delt with the problem and I will contact them.

[idb]

Check that the fuel tank vent is clear.
The way I would do this is to disconnect the hose from the tap and run it into a container, after 30secs or so open the fuel cap and see if it increases in flow.
Make sure your bike is cold when you do this just in case you splash some about!

[Bass]

Hi Jason, well I rang the local Suzuki agent and they had no knowledge of the issue with the pilot jets at all. Can you let me know the name of the Suzuki dealer that you know of that has delt with the problem and I will contact them.

My wife's GN had the same/similar problem from new. Basically the idle jet/passages were blocked and they are quite tricky to get at with the compressed air. In the finish, we took it back to the dealer and told them what we had done (I asked them first before I got stuck into it as I didn't want to void the warrenty). Basically, I had done everything that they would have and so they just replaced the carby.
The problem returned again shortly afterwards, but cleared itself after a short while.
It happens again every time the bike is left standing for any length of time but usually clears again within the first km or 2.

I can only suggest that you try the compressed air again but concentrate on the idle passages. They take a bit of tracking and they emerge as 3 or 4 tiny holes just where the edge of the throttle butterfly contacts the barrel wall when the throttle is closed.

There is an idle jet insert in there, but it takes some finding.

[ABBA]

Hi, thanks for that advice...I spent quite some time with blowing out those passages you spoke of, plus every other passage again tonight with no further success...I do wonder if a prior comment was correct about the pilot jet as it is very small (it has the number "38" on it). If anyone could give me the correct size for this jet and where to get one it would be much appreciated, Cheers!

[kiwi cowboy]

Hi, thanks for that advice...I spent quite some time with blowing out those passages you spoke of, plus every other passage again tonight with no further success...I do wonder if a prior comment was correct about the pilot jet as it is very small (it has the number "38" on it). If anyone could give me the correct size for this jet and where to get one it would be much appreciated, Cheers!

Just blowing it may not do the trick.
You may need to soak it in white viniger and then wash in hot soapy water ,rince ,dry and blow with comprested air

[Conquiztador]

Visit a local bike wrecker, get a s/h GN 250 carbi from one of the Jap models (not the Chink ones!!!) and swap. Problem solved. Cost you approx $100 - $150. Good luck.

[LBD]

The mixture is not set right for Zealand conditions and it runs lean, causing a miss or splutter at low rpm

Sorry mate, dont know where that came from but its Bollocks....Air fuel mix (Lean ness) is not geographical except where altitude comes into play, (2000m plus) Sea level in NZ, Japan, New york or london all has the same atmospheric pressure (and air density) Temp can also play apart, but NZ is not the hottest or coldest.

If you remove the fuel line off the carburetor and open the fuel valve, a steady stream of fuel should flow.

Then check the float level that controls the availability of fuel to the jets, going by the symptoms, to me it sound like it is to low.

Cheers