TOPIC:

Ok I have a 78/79 Kz Sr650 with the stock mikuni carbs with accelerator pump and I have been here before to ask about my high idle. I pulled apart my carburettor before and I did open the section of the accelerator pump with the diaphrapm and I did notice the diaphrapm was a little lumpy. I would guess that that would be bad but would it cause my hig idle and blippy, hesitant throttle when I first go to start off from 1500 rpm and up?Also the guys often say that I should check for an air leak with wd40. Is that safe for the rubber manifolds? Is there anythingelse out there I can use?

This posting has been here for I think almost 2 weeks and I have no answer. I saw the accelerator diaphrapm cost like 60 something dollars. Does anyone know where I can get one cheaper?

kzwolfsr wrote:

Ok I have a 78/79 Kz Sr650 with the stock mikuni carbs with accelerator pump ..........Also the guys often say that I should check for an air leak with wd40. Is that safe for the rubber manifolds? Is there anythingelse out there I can use?

It has been said to take a propane bottle and let the gas flow around the manifolds. Unlit, of course.

If the idle changes when doing this you have an air leak. And the wd40 will not harm the manifolds.

What was the reason for pulling the carbs apart? If it was to clean them, you need to know some carb cleaners are very bad for rubber parts, like o-rings and diaphragms. Unless all the rubber was removed prior to cleaning, some of them may be wasted now.

Post edited by: OKC_Kent, at: 2006/11/10 09:59

also, double check your air screws. I have a Honda that a heck of a hesitaion off of idle. Turns out the air screws were just out of adjustment. Set tham all back to stock (with a little extra for my pod filters) and the hesitation was gone.

Z1 enterprises has the complete rebuild kit (both diaphrams, springs, etc)for $25.

geez thanks for all your info guys. I took apart the carbs too clean them but I didnt use that aerosol carb cleaner, I use the in tank GUMOUT carb cleaner that cleans the valves and such the same time and as for the air mixture screws, a guy made some adjustments to those and I find I have a better start now, but it starts then stops, so I have to keep kick starting it( my starter switch is in the bathroom rite now) and its cold so I guess the oil is just still to heavy for it to fully start up, so I guess no problem there. Thanks for the info on where I can get the diaphragm. I never think of that site or never remember it. Thanks guys

kzwolfsr wrote:

...but would it cause my hig idle and blippy, hesitant throttle when I first go to start off from 1500 rpm and up?...

This sounds like you have a lean condition. the wd40 test is great for checking for crusty, cracked, or loose manifolds, which might cause a lean condition. Checking your plug color is another way to determine if you're running lean; you want a nice tan color (white is lean, black is rich). Lean conditions can also be caused by improper float level and mis-adjusted pilot screws.

...boy, I'm starting to sound like I know something, but I assure you I don't...

I havent checked my plugs since, not in the light that is...lol I used to have this hard start prob and I always used to check them when I check the bike for spark but now I haven't had that problem so I haven't seen them recently

You posted this weeks ago and didn't get an answer? Hmmm never saw it. The problems are:
1. hard starting
2. high idle

They may be related or totally different causes. I suspect that if you properly bench sync'd the carbs (per a factory manual), the high idle would go away. The hard starting is likely due to insufficient cleaning of the choke and/or pilot circuits. If gas is a bit obstructed when the bike is cold, the lean condition will make starting a chore. What is your current airbox/pipe set up and what is the jetting and mixture screw setting? Last, spraying WD40 on rubber doesn't do any harm at all.

I never had to sync the carbs, they looked fine to me and my main jet is like 56 I cant remember the rest and I dont know my air mix settings. Can I tell there settings by just looking at them or would I have to screw them in or out to check. Air box is stock with brand new manifolds and I just put zip ties on them to cut off the supposed leaks on that side. Your choke assumption sounds rite. I dont know how to clean the choke and I tried starting the bike and it is a chore this morning. Its 28 degress and I was sweating till I had to change my skirts and jacket, Plus I managed to thaw off the ice on my tank with sweat

Take the carbs off the bike and take off the bowls and remove both a main and pilot jet and read the numbers. The 56 number you noted made little sense to me...

I will try and do that when my bike goes into a small sleep. I will get back to you on that, sorry for the delay.