moved "choke" cable, how do i adjust?

[geoffluttrell@yahoo.com]

Hello, I read throught the archives, but couldn't find what I was looking for, so here goes. I put a Uni filter on my bike. It seems to have a lean surge at about 4000rpm steady. Can I richen the stock carb without buying a jetting kit? Thanks, Geoff

[Kurt Simpson]

I read throught the archives, but couldn't find what I was looking for, so here goes. I put a Uni filter on my bike. It seems to have a lean surge at about 4000rpm steady. Can I richen the stock carb without buying a jetting kit? Thanks, Geoff ______________ you can drill the pilot screw cover and remove it and then richen the pilot jet...you can also buy a KLX needle and shim it... Kurt

[richardm@gowinnt.com]

--- In DSN_klr650@y..., "Kurt Simpson" wrote:

>you can drill the pilot screw cover and remove it and then richen >the pilot jet

What RPM/throttle opening range is affected by the pilot jet? Off- idle? Mid-range? WOT? How much can you accomplish by adjusting ONLY the pilot screw? RM

[professor.jim@worldnet.att.net]

Geoff, Is the UNI filter properly oiled & fully seated without any air leaks at the filter's base? Is the lean condition at 4k rpm & above or just in a limited rev range? Did you change anything else? Inquiring minds want to know. Professor A9 Federal Way, WA. [USA] +++++++++++++++++++++++++++++ --- geoffluttrell@y... wrote:

> Hello, > > I read throught the archives, but couldn't find what I was > looking for, so here goes. I put a Uni filter on my bike. > It seems to have a lean surge at about 4000rpm steady. > Can I richen the stock carb without buying a jetting kit? > > Thanks, > > Geoff

[BCSavWill@cs.com]

Hi, For an explanation of pilot, needle and main jet relationshipsand at what throttle openings which is controlling try this web site. Basically the pilot circuit controls 100% of the idle and 25% of the transition on to the needle. The needle cotrols mid range, by its taper and position, position having little or no effect below 3000 rpm and no effect on main jet. This is the hardest bit to get right ( the needle taper and shape) and is what you pay for in R&D. Another factor is float level, this will also have an effect on mixture from idle to mid. www.knpowersports.com/test/powerkit.html Brian A14 TE 410E Honolulu, HI [Non-text portions of this message have been removed]

[geoffluttrell@yahoo.com]

Hello All, The filter is oiled as specified in the manufacturer's recommendations, with Uni filter oil. I do not believe there is a gap at the base, as I moved it around before tightening the screw to make sure the filter was seated. The lean condition is around 4-5K at steady throttle cruise. It is not terrible, just a slight surge. I applied a bit of choke while cruising yesterday, and it picked up considerably. If it can be fixed by adjusting the pilot, fine. If I have to get a kit, fine. The problem is, I have been a professional mechanic for too long, and can't leave it alone. The other problem is I don't understand the way the choke operates. Does it lower the jet? Does it open the butterfly further? If it only lowers the jet, then I know I just need to richen the mixture somehow. I appreciate the help learning my way around my new machine. Take care, Geoff

--- In DSN_klr650@y..., professor.jim@w... wrote: > Geoff, > > Is the UNI filter properly oiled & fully seated without any > air leaks at the filter's base? > > Is the lean condition at 4k rpm & above or just in a limited > rev range? > > Did you change anything else? > > Inquiring minds want to know. > > Professor A9 Federal Way, WA. [USA] > > +++++++++++++++++++++++++++++ > --- geoffluttrell@y... wrote: > > Hello, > > > > I read throught the archives, but couldn't find what I was > > looking for, so here goes. I put a Uni filter on my bike. > > It seems to have a lean surge at about 4000rpm steady. > > Can I richen the stock carb without buying a jetting kit? > > > > Thanks, > > > > Geoff

[Ted Palmer]

Geoff wrote: [...]

> The other problem > is I don't understand the way the choke operates. Does it lower the > jet? Does it open the butterfly further?

The Keihin CVK is like an enhanced SU (or Stromberg CD, since the CVK uses a rubber diaphragm to seal the CV piston vacuum chamber). The CVK has a separate idle circuit using its own pilot jet and slow air jet. A pilot screw controls the amount of idle air/fuel mix into the throttle bore. I guess the idea is to make the idle mix more precise. The choke system is just another fuel circuit into the throttle bore, but it is cruder than the idle circuit. There is no mechanical link between the choke plunger and the throttle plate. In theory, the extra air and fuel through the "choke" system should be enough to create a faster idle, although in my experience this fast idle has not worked on my bike for years. My choke works ok and the bike idles ok, just not much over normal idle speed. Something else the CVK does that an old SU does not is richen the mixture on overrun. The CVK opens up an additional fuel port when the "manifold" pressure gets below a certain point. If that isn't enough yet, the CVK uses a main jet at the base of the needle jet to control max fuel flow into the emulsion tube. The main jet system also uses a main air jet to feed the emulsion tube. You can still juggle needle profiles a bit to influence midrange and transition mixtures, but the range of needles for a CVK is only a tiny fraction of what is available for small SUs (about 300 for the 1.25" and 1.5" SU AFAIR). Mister_T (ex SU tuner)

[BKGADGET@aol.com]

Wish I had you around years ago when I was racing a Mini Cooper S to help tune the carbs. Inspector Gadget A15 VFR800 [Non-text portions of this message have been removed]

[Greg Paul]

All I can say is it's "GREAT" to have access to so many geniuses on here! ))))))) Greg in Dallas

--- In DSN_klr650@y..., Ted Palmer wrote: > Geoff wrote: > [...] > > The other problem > > is I don't understand the way the choke operates. Does it lower the > > jet? Does it open the butterfly further? > > The Keihin CVK is like an enhanced SU (or Stromberg CD, since the > CVK uses a rubber diaphragm to seal the CV piston vacuum chamber). > The CVK has a separate idle circuit using its own pilot jet and slow air > jet. A pilot screw controls the amount of idle air/fuel mix into the > throttle bore. I guess the idea is to make the idle mix more precise. > The choke system is just another fuel circuit into the throttle bore, > but it is cruder than the idle circuit. > There is no mechanical link between the choke plunger and the throttle > plate. > In theory, the extra air and fuel through the "choke" system should > be enough to create a faster idle, although in my experience this fast > idle has not worked on my bike for years. My choke works ok and the bike > idles ok, just not much over normal idle speed. > > Something else the CVK does that an old SU does not is richen the > mixture on overrun. > The CVK opens up an additional fuel port when the "manifold" pressure > gets below a certain point. > > If that isn't enough yet, the CVK uses a main jet at the base of the > needle jet to control max fuel flow into the emulsion tube. The main > jet system also uses a main air jet to feed the emulsion tube. > > You can still juggle needle profiles a bit to influence midrange > and transition mixtures, but the range of needles for a CVK is only > a tiny fraction of what is available for small SUs (about 300 for the > 1.25" and 1.5" SU AFAIR). > > Mister_T > (ex SU tuner)

[geoffluttrell@yahoo.com]

Hello All, I was complaing of a lean surge a couple of weeks ago. I put a washer under the needle and it went away. Have not done any mileage calculations at this point. That little washer was sure cheaper than a jet kit. Take care, Geoff