Carb Rebuild, O Ring sizes, no idle

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
Post Reply
Blaack3
Settled in member
Reactions:
Posts: 12
Joined: Fri Jun 17, 2016 11:19 pm
Carb Rebuild, O Ring sizes, no idle

Post by Blaack3 » Mon Jun 27, 2016 1:00 pm

So now that I got the engine running mint I really want to fix the idle problems.
It runs super shitty as you can see in this video:
http://sendvid.com/h9w24haw

It never ran great btw.. :D
If you let it sit for a couple of seconds it will drop down to 2k until it slowly dies. Sometimes the idle is at 2k, sometimes 2,5k, 4k, 1k. Blipping the throttle really changes it.
The carb is getting no false air from any leaks on the intake sockets.
With the throttle wide open the bike behaves as it should: quick throttle response, linear power build up, fast declining rpm when the throttle is released

The float valves almost look brand new.
The mixture screws have been set to 1 1/4 turns out.
I roughly tried to synchronize them, but it is impossible! The bike just constantly dies.
When I turn in the idle screw it rises up to 6k, half turn out --> dies.
The float height is on all carbs between 14 and 15mm.
Carbs have been cleaned with an air compressor.

Now my guess is that the o rings on the carb tops might be bad.
Does anyone have the exact sizes of inner and outer diameter (thickness)?
Do you have any more suggestions what might be wrong with the carbs?

SevenThreeSeven
Settled in member
Reactions:
Posts: 192
Joined: Wed Feb 26, 2014 4:45 am
Re: Carb Rebuild, O Ring sizes, no idle

Post by SevenThreeSeven » Mon Jun 27, 2016 5:52 pm

Here's your go-to solution, Blair (that's his name) at LiteTek.com will set you up with high quality Viton.

http://litetek.co/Carb_Kit_Suzuki_GSF400.html

Blaack3
Settled in member
Reactions:
Posts: 12
Joined: Fri Jun 17, 2016 11:19 pm
Re: Carb Rebuild, O Ring sizes, no idle

Post by Blaack3 » Mon Jun 27, 2016 6:22 pm

28€ is pretty expensive for some thai o-rings, isn't it?
So turns out, that the pre setting on the carbs was absolute shit.
I turned them 2 2/3 out and now that thing runs absolutely smooth.
It holds idle at 1300rpm and it does not get stuck at 4k anymore.
Weird... is it possible that it is fixed now?
Or should I still go for new carb o-rings while I'm at it?
I would like to change the carb top o-rings at least, because those already look a little messed up.
But still, thank you very much for the link.
I might get that kit like that.
But the fact that I can get a package of 50 o rings (German production) for a couple of bucks that are garuanteed high quality just makes me wonder.

ventYl
Settled in member
Reactions:
Posts: 44
Joined: Sat Sep 05, 2015 1:02 pm
Bike owned: GSF 400 Bandit
Re: Carb Rebuild, O Ring sizes, no idle

Post by ventYl » Tue Jun 28, 2016 8:51 am

Depends on your country, but quality viton O-rings are worth of about 10 euros / dollars all (float valve set, choke pickup set, top cover set, secret O-ring set). There's a little problem with a fact that Suzuki did not disclose the dimensions but IIRC there dimensions are written up in some thread here on forum (or maybe on banditalley?). While the pack is cheap you can also use trial - error approach, try to measure old O-rings and find nearest replacements.


Post Reply