Mad Mos Still Sta..Sta..Stutters!

[Da-Bubble]

Check out how outta whack my carbs are!!! I pulled the plugs on the Mad Mos for the first time since I started riding it and this is what they looked like. They are in order from left to right cylinder #1,2,3,4.



What does it all mean bazzle? (Austin Powers) Anyway, is the brown color on cylinder #3 the color I'm looking for? I know one and two are way rich. I did not sink the carbs since the bike runs fine. What should I start changing first?

[prometheus578]

Need to know if this is occuring at idle or at speed.
Easiest thing to play with would be the idle mixture screw.

[Da-Bubble]

Well this is after riding it at all RPM's. I will clean them then let it idle and check them again.

[mro]

wouldn't hurt to synk em
might be surprised how much different it will run.


mro

[randy]

I'm with mro, trying to correct the problem without synching is like trying to herd cats.

[Shuriken]

Your #4 looks the same color as all 4 of my plugs at 5700ft elevation with ZRX carbs.

[Da-Bubble]

Hey I tried to PM you! I was asking about the throttle cable clamp on the ZRX carbs. I have not tried them on yet, but what do I have to clamp? It looks like I could just use my stock cable? If not, what did you do as a permanent fix?

Instead of messing with my XS carbs (again) I'd like to install the ZRX's on there...OH! my other question was the choke lever...how'd you rig yours up?

[red bandit]

This is a 95 GSXR 1100 carbs that I was going to put on my bike, but now I have a set of ZRX carbs so I will be selling these GSXR's if anybody wants em. This pic is to show the cable hook up that is basically the same on the zrx carbs.


The stock inner cable on the xs isn't long enough to work on either the gsxr or the zrx carbs, so I modified a xs to a zrx cable holder.






As far as the choke hook up, if you have a handlebar control it should be a plug and play. I was going to use a manuel choke cable from a car. The hook up is at my 2 fingers.




FYI, the xs bore at the butterflies measures 1.345", the gsxr- 1.420", zrx 1.440". I am hoping I will get to try the zrx carbs out this weekend, weather permitting.

[XSPastor]

Da-Bubble,
#3 looks like what you want. Obviously, 1 and 2 are rich and 4 looks a bit lean to me. (I'm assuming that all the plugs were installed new at the same time.) I'd check to see if all the other floats are set like #3, then I would set all the mixture screws like #3, clean the plugs, sync the carbs and see what they look like after a ride.

If you still see major differences like the picture, I'd tear 'em off and give 'em a good cleaning. I guess you'll have to tear 'em off anyway to check float levels so you may as well clean them then. Make sure that they are all jetted the same while you're at it. (Maybe a P.O. mismatched the main or pilot jets?) Also check to make sure the slide diaphragms are in good shape. I'll assume the float valves are good because you didn't mention anything about fuel leaking out of your air box...

If you've never sync'ed the carbs before, you're not gonna believe how much smoother the bike will run! Good luck!

Tim

[planedick]

Herding cats..

Looks like a classic case of herding cats. You can't do anything about the mixture if they're not synched. Synching is the last thing you do to the carb bank, but it's probably the most important.

[XSPastor]

Good point, planedick. By all means, sync them first. Doing that will smooth out the engine and make it run more evenly because all the cylinders will be pulling the same. You'll still need to at least check all the other things I mentioned though because 1 and 2 are rich and 4 might be lean. The lean/rich combo problem is not being caused by carbs being out of sync.

Tim

[randy]

When I sync, I am adjusting the mixture as well. I synch, then adjust mixture across the bank for highest rpm, then synch again. It helps if you have an external tach so you can read the small rpm changes as you adjust the mixture, the dash tach isn't a very finely tuned instrument.

A have a SUN tach, set on 4cyl LOW, the scale can read increments of 20 rpm.

[randy]

The lean/rich combo problem is not being caused by carbs being out of sync.

You're right, but the lean/rich combo problem may have been created by trying to use the mixture screws to compensate for an out-of sync condition. BTDT

[XSPastor]

Hmmmm, adjusting sync and mixture at the same time? I'll have to try that next time. Thanks for the tip!

Tim

[DiverRay]

Tim,
You adjust the sync, then adjust the mixture, and then READJUST the sync! I can usually get it done in about 30 to 40 minutes. DO NOT forget the FAN to keep the engine cool while doing all the adjustments!