Author Topic: holeshot kit - 1 cylinder too rich (Read 4165 times)

rider123 · « **on:** September 06, 2007, 09:57:04 AM »

Hello I have a holeshot stage 1 kit and I seem to be having a problem with 1 cylinder and I was wondering if you could help. Number 2 cylinder is too rich. I have 1 less shim on there, and the mixture screw is 1/4 of a turn in than the other cylinders but it's still too rich.

The plug has a fairly clean tip however halfway down on the the ceramic centre post is very black, as is the ring around the bottom of the plug threads and at the bottom of the ceramic post. This leads me to believe that it may be that I still need to take another shim or two off. Any thoughts? I believe when the tip is black it's more to do with mixture screw settings but I may be wrong. If I turn in the mixture screw any more it starts losing power.

pmackie · « **Reply #1 on:** September 06, 2007, 12:18:15 PM »

I would look to make sure that the float level is not off. Also, check the float needle and seat.

And, it there any chance that the cylinder is burning a little oil? Maybe that one cylinder has a bad oil ring or valve seal. Does the plug look "sooty" (fuel rich) or "oily & carbony" (oil).

Double check the float level and needle valve first.

rider123 · « **Reply #2 on:** September 06, 2007, 12:53:47 PM »

Its slightly sooty, it only has 15000 kms on it. Float height and needle seat was checked a month ago. It could be that it just needs alot less fuel in that cylinder. I just need to know if its a mixture screw or a needle height problem.

Nitro · « **Reply #3 on:** September 06, 2007, 06:27:03 PM »

Were the plugs new? If not, you might wish to replace that one, or all 4 and get a fresh reading.

rider123 · « **Reply #4 on:** September 06, 2007, 08:42:40 PM »

Yep they were replaced a month ago. I'll try for shits and giggles turning the mixture screw in half a turn and see if it helps. Another trick would be to scrub the plug clean, then pop it in there and let it idle for a minute or two then pop it out and see what the colour is. I guess if its already starting to darken quickly it may just need less mixture screw, however if it's reletivly clean still I guess it needs less needle.

I guess I'll just go and swap the plug with a clean one and try an idle test first. I doubt highly that it's an oil ring after only 15000 kms and regular oil changes with semi-sythetic oil. I havent even gone past 8500 rpm. But the plug idea is good, you never know maybe it's just a shitty plug, its not impossible.

okbandit · « **Reply #5 on:** September 11, 2007, 01:07:24 PM »

I am a little late geting in on this one, but I think you have a carb sync issue there. That will cause what you are describing with one cylinder being off.

rider123 · « **Reply #6 on:** September 11, 2007, 03:49:53 PM »

Thanks for you're suggestions guys. But what I did was turn in the mixture screw some more and it's getting alot better. It's strange its almost 3/4 of a turn from the other ones but it's not unheard of. Some guys on this board saying that out of the factory some were as much as 2 turns difference between the carbs. I guess that's just how the bike likes it. As far as syncing goes, I just had it done last month so it's not the smoothness I'm worried about. It's smoothed up even more now that I turned in the mixture screw a little more than 1/8th of a turn. I just think I'm losing power in the midrange slightly which may be because I took a shim off that cylinder.

I've been hearing out there on the grape vine that some other guys have a rich # 2 cylinder on their bikes as well. It seems rare, but maybe on some bikes #2 cylinder is getting slightly more fuel pressure than the other 3 as the fuel line is right next to number 2? Who knows? at least you can turn in the mixture screw to correct it.

okbandit · « **Reply #7 on:** September 11, 2007, 05:58:39 PM »

I am glad that is working for you, however, what you are describing does not sound normal. If you are using a special setup for just one carb you most likely have a problem. Some inline 4 bikes will run hotter on the center jugs resulting in the center plugs looking lean compared to the outboard 2. What you are describing sounds like a specific carb problem so I would watch that one in case it gets worse. Mixture screw will only effect the small throttle (1/8th) and idle settings, with little or no effect on any other throttle position.

rider123 · « **Reply #8 on:** September 11, 2007, 09:36:14 PM »

Yeah thanks. On the idea that it may possibly be a bad plug I'll replace it tomorrow put all the mixture screws the same and re-check. It never used to do that before. Also it gets less mushy when it heats up so theoretically since I've been making lots of small jaunts lately it maybe that it hasn't got up to it's proper heat range. It's been cool and rainy here lately. I'll take a look tomorrow. I put the screw to 1/4 of a turn less than the others and it does have more power, so I'll have to figure it out. What a bummer though I had the floats checked and the needle valve checked a month ago when I got synched and it all was fine. The only other theory I have is that a jet is slightly loose and it's leaking ever so slightly past the threads when there is low vacuum through the jets when it's idleing. I should have had them to make sure all the jets were tight. When I got it back from the shop the mixture screws were as follows:

1: 3 1/4
2: 3 1/2
3: 2 3/4
4: 3 1/4

So number 2 out of the shop was 1/4 turn MORE than the others and the plug was fine. They seemed to have really filled the oil up to the top, to me a little too much and that could have been a problem but it hasn't really dropped at all from where it was. The only other thing I can think of is that they said one of the valve cover bolts was cross threaded and they wouldn't fix it under warranty(I dont know why?)So I said forget it as it was in a non critical position. I'll fix it next valve adjust. So theoretically I could have leaked some oil in there but I doubt it there is absolutely no oil on the outside, although I guess they're could be a leak internally but like I said the oil has barely dropped at all. Maybe, as I'm leaning it out more, oil than fuel is burnt so it could theoretically blacken the plugs more than if the gas which breaks down oil is in there. I don't know. I think what I'll do is put the shim back in there, set the mixture screws the same at 3 1/4 turns out and go for a really long highway ride. That should clean out anything that is in there and then I can do a plug check at the end and see whats up.

Alternatively, if I lean it out more the cylinder is heating up more and maybe that's why it drives slightly smoother because it's burning the excess oil out of there. I'll experiment and let you know. I was thinking that if it gets better as it heats up is maybe the tolerences tighten up a bit and seal better in case I am leaking a little from the gasket or whatever.

okbandit · « **Reply #9 on:** September 12, 2007, 08:51:33 AM »

The center jugs will appear rich* (correcting myself there). Dale is very good at standing behind his product. I would call the man and see what advice he can offer you. I assume you had a shop do the work but it sounds like you are familiar with the settings and a short talk with Dale can save you a lot of time.

rider123 · « **Reply #10 on:** September 12, 2007, 07:20:18 PM »

Nope it seems like it needs at least 3/4 of a turn in to be semi-close to being what the other cylinders are. At least I know it's the down low/mixture screw part and not the mid-range. So I have to put the shim back on there. In case I just counted the turns wrong I'll re-count. If you put it at where the others are you can smell it in the exhaust and it gets mushy. I really hope I just mis-counted the turns because I can't see this thing happening overnight. It must be what's wrong.

rider123 · « **Reply #11 on:** September 13, 2007, 11:42:43 PM »

Well I figured it out I must have mis-counted the turns, Arrrrgh. Oh well at least it only cost me a few days and a few twists to fix. Remember to go over your work if it goes wonky. I put the shim back in there and all seems well. In fact it's a little too well this thing is scary fast now.