Carburator tuning - Christchurch

[schrodingers cat]

Help!
I have a Suzuki GS1200SS
I've replaced the airfilter with a K&N and fitted a freer flowing muffler.
As expected the bike now runs really quite lean - massive flat spot at 4500rpm under hard acceleration


Having spent lots of time trawling the web for info, none of this is a surprise.
I shimmed the needles up but that only lifted the flat spot 200 rpm...

I have two questions:
Can someone recommend a capable person in Christchurch to undertake the re-jetting/tuning?

If anyone has been through this exercise themselves, can you share your 'fix' i.e. where you got the jet kit from, sizes etc?


To be clear - the issue is definately jetting. The fuel, fuel filter, CDI, Coils, Plug etc etc etc have all been checked. Its not caused by the speed limiter.
In fact if the standard filter is refitted, all is fixed.
I just want a bit more out of the thing (up to the limitations of the carbs/cams)

Cheers

[mulletman]

Dont know where or what size jets you need but would recommend Duane (Duanes bikes n skis , waterloo rd Hornby) to do the job, he'll prolly know what you will need , ring or see him and have a chat.

[mulletman]

http://www.kiwibiker.co.nz/forums/showthread.php/176133-GS1200SS-fuel-and-exhaust

[husaberg]

Help!
I have a Suzuki GS1200SS
I've replaced the airfilter with a K&N and fitted a freer flowing muffler.
As expected the bike now runs really quite lean - massive flat spot at 4500rpm under hard acceleration


Having spent lots of time trawling the web for info, none of this is a surprise.
I shimmed the needles up but that only lifted the flat spot 200 rpm...

I have two questions:
Can someone recommend a capable person in Christchurch to undertake the re-jetting/tuning?

If anyone has been through this exercise themselves, can you share your 'fix' i.e. where you got the jet kit from, sizes etc?


To be clear - the issue is definately jetting. The fuel, fuel filter, CDI, Coils, Plug etc etc etc have all been checked. Its not caused by the speed limiter.
In fact if the standard filter is refitted, all is fixed.
I just want a bit more out of the thing (up to the limitations of the carbs/cams)

Cheers


Google dynojet jetting kit or ask Grumph if he is interesting in helping in return for money if he obliges suggest he uses said money to shout himself broadband internet.

[AllanB]

Filter is the issue without tuning.

Honda Hornet 900's don't like K&N's much without a Power commander tune. Somewhere I have info from testing in the USA on the Hornet with stock filter and K&N. Stock won. HOWEVER this is very bike specific.

I owned a GS120ss before the Hornet - it came factory with the Yoshi titanium headers and alloy can. Fantastic pipe, beautify welds and bends. Stock jetting. Ran sweet. A mate had one with a Neptune can on the stock headers - no other mods. Ran great.

Duane has been around long enough to remember cards - shit he used to work on my Kawasaki's back in the early 80's at Norjos.

[schrodingers cat]

Thanks all.
I did find that other post mulletman, after I had posted...

Thanks tho for the recommendation to do the work.
It's grief I don't even want to try and put myself through.

Allan, you are right I could stay with the standard air filter. More airflow matched with more fuel equals bigger smiles tho!

[fokky]

Just done it all with mine, though retained air box. Lifted needles 1mm put #120 main jets. Apparently the carbs dont like K&N filters as there not enough restriction on airflow for vacuum slides to function properly. Can try putting foam sleeves like on lawnmower engines over K&N's to increase resistance (apparently)

[SVboy]

Putting it on the dyno at Ashburton Honda would be the accurate way to go, but the cost would mount up, dyno run, strip, rejet, dyno run etc etc. when I de restricted my gsx1200 (same carbs as a gs1200s?)a gentleman on here told me what needles to run, what mains, what clip height and pilot settings. I followed this and the bike fuelled perfectly. I suggest looking closely at TRW,s posts. He has a lot of knowledge and experience with these bikes.

[T.W.R]

Dont know where or what size jets you need but would recommend Duane (Duanes bikes n skis , waterloo rd Hornby) to do the job, he'll prolly know what you will need , ring or see him and have a chat.

As long as Duane works on the bike himself :msn-wink: one of his minions leaves a bit to be desired.


Putting it on the dyno at Ashburton Honda would be the accurate way to go, but the cost would mount up, dyno run, strip, rejet, dyno run etc etc. when I de restricted my gsx1200 (same carbs as a gs1200s?)a gentleman on here told me what needles to run, what mains, what clip height and pilot settings. I followed this and the bike fuelled perfectly. I suggest looking closely at TRW,s posts. He has a lot of knowledge and experience with these bikes.

BP or Andy would have it 3 runs on the dyno.
I had the luxury of bouncing & exchanging ideas and gems off Richard (old KB member) who was campaigning a GS1200 in DYO drag racing here & aussie.
Actually my old girl is currently on TM in ChCh $4495 .....tempted to by her back but chasing the GT380, someone will get a good strong GS :niceone: