Running slightly rich

[Damienga15de]

My bikes in gettin a valet and once over at the mechanics, he says it's running slightly rich and the floats need to be adjusted. The exhaust tip has some black soot on it but the plugs I pulled when I converted to coil on plug last week were perfect.

 

i bought the bike standard and have added a 4-2-1 Sebring exhaust system and converted to coil on plug. The bike runs strong and smooth apart from a slight flat spot around 4500-5500 I think , revs out perfect starts easily every time hot or cold.

I don't want to go through the expense of a carb service on a bike that runs just fine at the moment.

I think I will fit a high flow air filter instead which should lean it out a bit for now and get the carbs serviced in the winter if I still think it needs it 

Does anyone have any opinion/experience of similar ? And what is better for the gsxr K&N or a pipercross foam 

[Gixer1460]

Personally - if the bike is running how you want and you are happy with it - DON'T FIDDLE WITH IT!

Certainly don't fit a free flow filter to try and cure a minor cough / flat spot and then ruin it everywhere else!

It may only need the needle dropping or raising one notch or 1/2 a notch even.

[Damienga15de]

Won't be putting pods on it just a drop in filter in the air box. 

[Fula28]

Just check your carb needles, on 38,cvs they wear in the emulsion tube, causing poor fueling 3-5k area , NOT saying it's defo this problem but it's quite common.

If they are good condition and no polishing or small notches or marks , then try lower the needle one clip slot higher.(leaner) 

[Antman]

I always look at the plugs and make adjustments according to them.

The needles in Cv carbs wear prematurely around 5000 Klms as they flutter within the emulsion tubes so the sides get worn the emulsion tubes get ovalised as well.

All this creates a rich mixture.

If these have never been replaced then I would do it and while the carbs are out replace all the O - rings obtainable from most decent bearing shops.

Or if your happy with the plug colour then leave it as others have said.

[Oilyspanner]

My experience with drop in air filters - on a 1100N (fairly std) - full Akra, ign advancer and light head work..

I swapped a K and N  filter  for a PiperCross -  I wanted to see what another filter was like. The PiperX  filter is a bigger filter and has a 3 inch aperture (K n N has 2 inch), it made all my carb settings too lean - I bought a FactoryPro  config 3.0 jet kit, with some fiddling I got it  perfect. I'm very happy with the filter, as it seems to flow very similar to dual pod filters, but has the advantages of keeping the rubber velocity stacks and airbox - ie better/smoother bottom end and mid-range - 40mm carbs are next to impossible to get right without the airbox.

Maybe a K n N would be better in your case, the PiperX needed a jet kit to get the carburation right (although on an 1100) and the K n N would still flow better than std. 

[suzook12]

Most dyno shops set these slightly rich anyway, but sounds like you may well have worn emulsions, they wear oval after time as well as wear the needles. You're looking at around £225 for needles and tubes, or fit a dynajet kit.....

[Oilyspanner]

If your needle jets/emulsion tubes are oval, Allen's performance are great  - I bought a set  for £53/55 about 3 years ago.

Jonny1bump - sometimes on here, came up with a great solution, some shaped needle spacers that keep the needles vertical - as standard they are held at an angle, which over time wears the brass needle jet. I made a simplified version of the spacers, a 'D' shape that stops the step at the bottom of the slide from holding the spacer at an angle (the needle is meant to be perfectly vertical, a Suzuki oversight).

[suzook12]

Not so much a Suzuki oversight, or even a Mikuni oversight, think you'll find they're like that so they are level in the air stream when engine is running. What they really need is to be held more rigidly then vertical is spot on, but usually these types of needle are a pain when you want to do anything with them..... A set of RS's or FCR's is the best way forward, but not everyone can afford these....

Good call on Allens performance, didn't think to try them when I just rebuilt a set of BST40's. Although changing the tubes is a waste if you don't replace the needles, they wear as well.....

Edited May 14, 2017 by suzook12
Omission

[Damienga15de]

Was out today and I don't think the bike could run much better , had a few runs with a 03 cbr600rr and we were very similar his should make 117 bhp from factory and I'm probably 25kg heavier never mind the bikes weight . I'll get a K&N see how it goes as I probably do need a filter anyway. I have a s1000rr shock ordered though as my shocks acting funny