High Idle, any ideas?

[infinity999]

I have an '03 Max and for the last couple of years it would tend to ide a bit high and then settle down to 1k. Now it will be idling at 1k and then on its own idle up to 3k on its own and stay there. It has also recently starting surging on the freeway. I bought carb rebuild kits on Ebay, (big mistake since one of the gaskets was incorrect) and opened up the carbs last night to find that they are very clean linside. I replaced the needle valves and put them back together. Bike still has the strange idle problem. Once you get moving past the high idle the carbs are no longer surging and runs great at highway speeds. A freind of mine thinks one of the diaphragm's is bad since it doesn't seem to respond as quickly as the other three. Would this cause a high idle problem? Also, the choke linkage seems to be working perfect also. I personally think it might be a vacuum leak and will try spraying some carb cleaner around it tomorrow and see what happens. I have already checked the thottle linkage and it's not sticking. I want it fixed, but I don't just want to throw money at it trying to "guess" what's wrong. Any help is appreciated! Thanks!

 

[gamorg02]

sounds like the slides might be sticking. def check for a leak first.

 

[infinity999]

I used some WD-40 on the slides and they are moving freely as far as I can tell. The diaphragms all looks good to me also. Is it possible there can be a leak where the diaphragms are attached to the slides? Will a leaking diaphragm affect the idle dramatically?

 

[satariel666]

Check your choke mechanism, this also can be sticked.

You have air leak or too much fuel somewhere, it you're refering that diapghrams are ok and the slides moving preatty ok so you may check the carb and v-boost boots for leakings.

Tell me, if its idleing about 3k you have black smoke comming form exhaust?

 

[gamorg02]

you *could* take the airbox lid off and in your driveway try to reproduce and see if u can see the slides sticking or something. not sure if its safe with stock setup tho, may cause it to run lean as fuck

 

[richwrench]

I know you said your linkage isn't binding, but I've found that if the throttle cables are adjusted too tight the idle speed will "hang" sometimes. Worth a look anyway - cost is free. :biglaugh:

 

[infinity999]

I have checked the choke and it moves everything moves freely and together.

Throttle cable has been adjusted and is not binding.

No black smoke coming out at 3k...

I am really leaning toward he vacuum leak and hope that is the problem. Will try the carb cleaner trick later today.

Can a leaking diaphragm affect the idle?

 

[naughtyG]

When was the last time you sync'd your carbs? I've seen some idle crazy high and not come back to normal idle speed just because the carbs were so out of sync.

 

[infinity999]

Good idea, I'll try to sync them tomorrow. I thought it would be better to get the idle speed right before synching, but I guess if you can't get it to idle right you have to sync first. Maybe one of the carbs is open quite a bit more than the others.

 

[zippo6]

Good idea, I'll try to sync them tomorrow. I thought it would be better to get the idle speed right before synching, but I guess if you can't get it to idle right you have to sync first. Maybe one of the carbs is open quite a bit more than the others.

Just be careful with your synch tool. Depending on model of course. If the rev's creep up during the synch and you are using a mercury tool, you could end up drawing it into the carbs.

 

[infinity999]

Well I tried syncing them and it was just all over the place, so I got tired with messing with it and took it into a local shop to have them taken apart and cleaned. Here is where it gets interesting.....

I bought this bike from a good friend of mine who took it to this same shop back in '03 to get a stage 7 jet kit and a kerker 4 into 1 exhaust. The full stage 7 wasn't installed on the recommendation of the owner because it isn't very "streetable". Instead the exhaust was installed and the carburetors were supposedly re-jetted. A couple of days ago the shop calls me and asks who re-jetted the carbs because the main jets and all other parts that would be changed are completely stock. I told them "you did" and faxed them copies of the invoice for the work and the dyno sheet. What I suspect happened is they probably tried a series of different combinations and found that the stock jets were best and still sold my buddy the jet kit anyway since they were stuck with it. I hope I am wrong about this because this shop has been in business for 15 years and is known as one of the best in Las Vegas. WOT always seemed fine to me and so did the acceleration. Should the bike run right with the stock jets and an aftermarket exhaust with a single K&N filter? I would think it would be running very lean, but I'm not expert. In '03 they also removed the "air bridge" from the top of the air box and the mechanic they have now was asking where it was. I told them, well you guys removed it and I have it at home... He told me that there will be a dead spot in the thorttle without that air bridge. Seems that everyone has a different opinion on what is correct and what's not on these bikes.... sheesh! So now they are going to put it back together with the stock jets, dyno it, and check the a/f mixture for free and see how it is running. Guess if it needs re-jetting that will be another deal all together.

The bike was in one other shop about two years ago to replace a couple of gears in the transmission. The only other thing I can think of is they guys swapped my carbs or stole my aftermarket jets, but who would do that? Bike seemed to run the same when it came back.. Any ideas? Thought I would share this interesting tale.....

 

[KJShover]

I'm at 440ft. I'm actually running a leaner-than-stock 150 main jet with my Kerker, and I can prolly go down to a 147.5.

 

[infinity999]

Well I think Vegas is that 2200 feet or so. If they didn't even re-jet the bike and still sold him the Stage 7 kit for $225, that isn't a very honest business practice if you ask me.. At least I'll get a free dyno sheet out of the deal. Good thing that work was done under my friend's name. That got them to basically admit that they didn't really do anything to the carbs. When I brought the bike there I told them they installed the jets and the exhaust. They were baffled because they couldn't find the order under my name.. oops.. The owner has been very good about dealing with the issue. Maybe they had some dishonest mechanics and or employees in the past.

Does anyone know what a stock V-Max is supposed to put down at the wheel? I am not sure what my stock numbers were, but when the work was done the bike made 78.9 torque and 114.1 hp, and like I said, I believe Vegas is at about 2200 ft. alt.

 

[KJShover]

Some dealerships are pretty ballsy about ripping off people. I would have loved to see thier faces when you popped the invoice on them.

Generally, you don't need a carb kit with eftermarket pipes. A kit, like Morley's or a DJ stage 7 will help you get the most out of your engine with the pipes.

I'll get corrected if I'm wrong. But, I'm pretty confident that when you add a good system to your bike, be it a Kerker, Marks, DW's your bike will actually richen up.

I'm running basically the same setup as you (Kerker 4-2-1, and K&N). My bike runs like a raped ape and all it took was a little jet reduction, A/F screw tweaking and a good sync.

Ya might want to hit up Sean, or Maleko for some tips on jetting for your elev. I'm thinking 150, the stock 152.5 should be about fine for your area. From what you were saying about the dealership, I'm thinking they really didn't do a whole hell of alot to the carbs, and they may need a good sync and idle speed screw adjustment.

How does your plugs look?

 

[infinity999]

Well I never did look at the plugs, probably should have..... Yeah I should have brought the invoice there in person instead of faxing it to them. The bike is still there and should get it back on Tues. or Wed. I guess if they had worked on a V-Max in the past they probably wouldn't have bothered selling my buddy a jet kit, but who knows? Guess I'll find out how much they know since they have torn the carbs apart and have cleaned them. I stopped by there the other day and saw my carbs split apart on the bench so at least I know they have done that much. Like I said I am dealing with the owner and he seems to be very cooperative about doing the right thing and getting bike running correctly... I think when I leave I'll tell them they owe my buddy the labor for installing the kit . Seems that all they did was bolt on an exhaust and dyno it. I could have put the exhaust on.... This is the reason I try to do my own work whenever possible. If anything happens to the carbs again I think I'll take them apart next time... Tired of dealing with shops and all their bs.