2000 1200S Clutch problems, carb problems, etc.

[rider123]

A sooty base ring is a sign of a rich condition, but now we have to figure out where. I know for the gen1 the recomendation is to actually go down one on the pilot while having a rich mainjet to make up for it. What is the condition of the electrodes? are they super white, also look way way down at the base of the electrodes. How large is the hole? I believe on the gen1 it should be 2 inches instead of 1.5 on the gen2. With the new pipe is the baffle in or out? Can you post a pic of the plugs?

[mpatrick]

The hole is 2 inchish. The drill slipped on me whilst doing it. I'll post pics when I get back from lunch, I just taped the hole up a little bit to see what would happen. Oh the baffle is in.

It just seems lean to me because of the surging at little throttle input, and the decel pop I don't care about the pop so much as the surging.

[rider123]

Well it could be rich up top with the baffle in like that(sooty base ring), maybe for fun take it out and go on a highway ride and see how the plugs turn out.

[mpatrick]

The lunch run was better with the hole taped up some felt a lot smoother.


heres some pics

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[rider123]

Definately way too rich. If you notice, you see that about halfway down the electrodes they are totally black halfway down to the bottom. THat indicates that over half throttle to full throttle is way too rich. Down low where the white part is showing it's actually not too bad. I believe the "surging" is probably caused by the mainjet, or too many shims dumping fuel abruptly when you start climbing in rpm levels. It's like you're going from nothing to like full throttle then closing the throttle and going back to nothing again. The transition is too crazy so it bucks like a horse. THere are only 3 there but I'm assuming the other plug is the same. For fun take out the baffle to see if the plugs clean up a bit. How many shims do you have on there? Do you have a K&N filter on there? You're supposed to, if you have a stock it will look like that, way too rich. Also the tips look a little sooty as well but the top end is so rich it may just be overflowing into the pilot circuit fueling area as mains will affect down low as well slightly. For now I wouldn't adjust the pilots just yet I would concentrate on the problem area with is the mainjet, needle position. If you have a stock filter, get a K&N quick and take the tape off!

[mpatrick]

stockish filter. I have a k&n coming. I've got .04 worth of shims. Damn Im pretty terrible at reading plugs I thought that looked good.

[rider123]

Ok for now temporarily take the tape off, take a shim off so there is only one, and maybe take the baffle out. That will at least get you closer and not such crazy transitions between fueling circuits. That will probably help alot with the crazy bucking, also the plugs will clean up a bit especially if you take the baffle out of the pipe. I know it might be annoying but it's only temporary, you'll also get way more power. You may have to turn the screws out a 1/4 a turn to make up for some lost needle but you have so much mainjet its kinda crazylike. When you get it close with the K&N, baffle in or out, mixture screws, all that stuff then you can fine tune for smoothness.

It's probably running better with the tape on because its now richening up the lower throttle inputs so now it's drowning down low so the transitions wouldn't be as abrupt and it retarding combustion so the power is down as well. Also you'll notice the mixtures are all different which doesn't help the bucking, but down worry about that for now, once you get close to where it should be carb syncing will unitize the cylinders and it'll purr like a kitten. You may want to turn the mixture screws out 1/4 a turn AFTER you take the tape off, reduce a shim, blah blah blah.

Another alternative which is the easiest is take the tape off and the baffle out(increasing airflow) and turn the mixture screws out a 1/4 turn or just leave them. 3 and a half is probably where you should end up once the airflow issue is dealt with so you can go there now if you like it will reduce the transition abruptness a bit.

[mpatrick]

baffle out, no tape, 3 1/2 turns out. 15 miles or so on the freeway home. All the plugs are pretty much the same.

[rider123]

Way better! Still rich but getting there for sure. Same number of shims? It think you said 2? Once the K&N comes in it may clean it up completely. If you look at the second plug you see that ring that goes around the base ring? Its a full turn of that light colour but kind of gets sooty once it goes around the towards the ground strap. You should be shooting for a full turn of the lighter colour on that base ring. If it doesn't go all the way around one full turn you are too lean. It seems that you are good, maybe a little light on the needle, but the rich mainjet is making it a bit hard to read. But 100% better just look at them compared to the first set. Did you notice any more get up and go? You'll notice that once the engine breathes a bit better the plugs are starting to come together and not look so far apart jetting wise as any bottlenecks are disappearing the engine can now breathe better.

Now if having the baffle out is too much of a bitch or obnoxious, you can pop it back in once the K&N comes but you're probably going to have to go one notch leaner on the mains to 125's or whatever but see what happens when the K&N comes, better to err richer than leaner. You can always compensate slightly by going a little leaner on the mixture screws, lose a shim, etc, etc so at least its good for like %90 of what you're going to be doing with the bike, it's up to you. Those K&N's really breathe well so it might be fine with the filter popped in there, only one way to find out. To be honest with the baffle out it only really starts getting loud over 1/4 throttle which on this bike is pretty damn fast acceleration. Any normal type driving it's not going to be that much louder. That's why I went with a 17" can so I wouldn't have to worry about jetting around baffles with the loss of power, etc. To keep the noise down.

Also if you like you can really repack that can which will really quiet it up. Mine was kind of light on the packing from the factory. It's basically fiberglass insulation so it's easy to get, just stuff the hell out of the end can like I did and it really helps a lot. Of course you can get the "official" repacking material but even thats cheap. All you do is drill the rivets out, take of the end cap, stuff the shit out of it, I stuffed so much after wrapping it around the insert I had to tap it in with a rubber mallet. Don't worry too much about over stuffing it slightly as the heat and the pressure of the exhaust will shrink it down. The first time I re-packed mine after a few years, the stuffing looked like a tattered rag and the pipe was basically just a hole it wasn't even suppressing any noise at all. The packing material lost so much even over those few years that the insert was vibrating in the pipe. Also the bike leaned out quite a bit with almost no back pressure.

The best one is probably number 3, you can see it's starting to lean up a bit and the sootyness is starting to break up. What your shooting for is the lightest part of the base ring all round. If possible use that shooting angle and try to shine a light down to the base of the electrode so I can see how dark it is down there.

[mpatrick]

Only took a month but I got them.



I know what I'm doing tonight.

Back to the questions at hand. The ride home last night and this morning felt pretty good, a noticeable increase in power. There was very little bucking once fully warmed up. I'm going to do the rebuilds tonight and ride it without changing anything else and check the plugs again. I know that some o-rings are bad which I assume is gonna make it run rich as well. I should also have the K&N by the middle of next week. I think we are close.
 
I feel like I should send you some money rider for all the help. 

[rider123]

Just drink some beer for me! The reason it was bucking was that there was too abrupt a change between the circuits. It's like trying to drive around normally at closed throttle then full then closed then full, a little exagerated but you get the picture. When the K&N comes it will probably get even better, see how that smaller pilot jet works out for you. I'm not sure why they would want you to go to a smaller pilot which affects smoothness at cruise. If it's only at 3.5 turns you probably have to about 4 turns before thinking that you may need to pop the stocker back in there but if the jetting calls for it test it with the default settings until you get a feel for it. Once the K&N goes in there you may have to bite the bullet if you go past 4 turns but I'm sure it will be fine at 3.5. All the circuits overlap a little bit so even if you had normal pilots in there and some super huge honking mainjet it would still spill over down low. Same with the needle, If the needle is super high and rich, even at idle it's going to spill a bit over into the pilots circuits area a bit. What you're shooting for is a smooth transition between pilots, needles and top end. Now with fuel injection you just set a variable in a computer so it's more precise. With carbs, its all black magic!!! Good to hear its coming together for you. With the rebuild and K&N it will be even better. Are you starting to feel the love of the Bandit??  

What you were doing before is compensating for a rich mainjet by leaning out the pilots too much. I've done that myself for testing purposes. For example yesterday, after looking at my plugs I figured my mid-range looked a little rich. So instead of wasting time with pulling the carb caps for possibly no purpose, I turned my mixture screws in a 1/4 turn artificially. I was popping all over the place and down low was weak but my mid-range got stronger. So today I put my mixture screws back and this weekend I'll take one shim off. As when the overall mixture was leaner, mid-range was better but top end fell off a little as the overall mixture was leaner. So obviously I'm going to have to take a shim off to preserve the low end and the top end goodness. However that being said. If taking off the shim at mid-range makes it even just slightly too lean in that area I'll put it back on as I said before better slightly rich than lean. Of course I could always have it at 4 shims for the summer and 5 shims for the winter but I'm lazy so if 4 shims isn't perfect all the way around I'll stick to 5 and just be slightly rich.

Maybe after the rebuild do a poor mans sync because if one cylinder was a little leaky it's going to change the jetting a little, some very small adjustment on the throttle sync screws may be warrented. Maybe while the carbs are off even redo all the mixture screws as well to 3.5 just to make everything 100% and set the float heights so you can start with a fresh clean slate. If some of the carbs were a little leaky it wouldn't help the smoothness any either so afterwards it may be running alot smoother, especially after a sync.

And remember, the most important part of any job: beer.


What your shooting for in the plug colour on the base ring is see that lighter area on the base rings? It should be that colour all the way around the plug, if it doesn't go all the way around then its too lean. Now this only shows overall jetting there are other signs that are there but this is the most important to get you close. Just as a note I'd say the first plug of the lot is probably the slightly leaky one as the tip of the electrode is noticeably darker. Some extra fuel is getting in there at low rpm and throttle ranges which is making that cylinder slightly richer than the others which doesn't help the smoothness any. If you wanted to save a buck or two just rebuild that carb, but it's better to rebuild them all at the same time and readjust them all even for the sake of knowing when they were all done a few years down the road. Good luck!

To think this thread started out because you had a slipping clutch! LOL

[rider123]

Well I must say 4 shims worked out quite well for me, definitely a boost. But if you notice pmackie I haven't changed the overall mixture of the bike I'm just changing the curve in which it's delivered. For example. I went with the 110's originally in my holeshot kit and the 17.5's and it drove like shit. Horribly rich down low and lean at the top. I know it works for like %90 of the people out there but for me it didn't. Ok so what I did is move the extra 2.5cc's of fueling up top where it belongs and instantly the bike drove better. However the original 5 shims(which is alot) was tailored towards the leaner mainjet. Once a larger mainjet is installed it's just too much needle, as the fuel curve is more situated at the top so too much fuel comes on too soon. So I went one down on the shims to reduce the amount of fueling at the mid-range and over 1/4 to under 3/4 throttle inputs so now not only do I have more power but the bike is driving a little smoother as well because the transitions between the fueling circuits isn't so abrupt. I may even go down one more shim to see if there is more improvement but if its good only when super hot, then I'll stick with the richer needle setting so I can set and forget. That way when winter rolls around I won't be adjusting needles to keep the power on. Here is a little chart of what I've done that may help you out on your bike:

Ok I first had:
110 mains
17.5 pilots
5 shims
total fueling 127.5cc's per min max
too rich down low, heavy needle to compensate for lean mainjet. Crap pickup especially when hot.

Now:

112.5 mains
15 pilots
4 shims
total fueling 127.5cc's per min max
Richness down low gone, nice and crisp throttle. Getting scared past half throttle.


As you can see the total amount of fuel is the same I'm just moving it to where it's needed.

So lets take a look at your bike. It's kind of hard because I'm not riding it but based on the plugs and what you've told me so far:

Your settings as I understand them:

Baffle now out(thank god)
127.5 mains
35 pilots
3.5 turns out
2" extra hole in airbox
stock filter
2 radio shack shims(4 holeshot equivalent)

My GUESS<<<<-----important

pilots good or maybe a touch lean, not enough airflow to justify mainjet size, because of larger than normal mainjet, too much needle for mainjet. Cause abruptness with fueling circuits. Possible o-ring induced leakage on number 1 cylinder due to sootier electrode tip.

Conclusion:
More airflow or leaner jetting needed. Richness is robbing power especially over 1/4 throttle. Lethargic mid-range and top end due to fueling coming on too much and too soon.

Solution A:
Increase airflow(K&Nfilter)
Repair fuel leak and re-adjust float heights and mixture screws.
Adjust needle for increased airflow, should be ok with current setting, re-evaluate after airflow issue dealt with.
pilots seem ok at current setting re-evaluate after too little airflow issue solved


Solution B:
Decrease mainjet size, one possibly 2 sizes
decrease needle setting, one shim should be ok, or adjust based on mainjet size
repair fuel leak and re-adjust float heights and mixture screws.
pilots seem ok at current setting re-evaluate after too rich mainjet issue solved

So as you can see there is more than one solution here since we've already determined that you're going with option A(the better solution). Just hang tight until that K&N comes in then you can adjust as necessary. If you want to test before hand or don't want to wait. Try taking 1 shim of the needle, that will at least help below 6000 rpm and under 1/2 throttle inputs. If you have any questions while you're rebuilding the carbs just post here I'm too burnt out from this hell week to go out and party. I'll just stay home and dick around a bit on the internet I have it so the thread alerts me when a response comes up so I'll probably get back to you shortly if you need any help.

[mpatrick]

Damn I'm having a hell of time with the carbs. I put the kits in and did a test by filling the float bowls with gas and had a leak, so took them apart again fixed the leak checked the float heights again, what a pain in ass that is btw. Put the carbs on the bike gave it a good warm up it ran just ok. I then tried to sync them again they were off a hair, got everything pretty close. My idle is still a little jumpy 100-200rpm jump or so. While syncing I was getting a little fuel coming out of the overflow, so the damn needle valves still aren't working. I need to give it a good run to really see what's up with it, I am almost at the point of giving up though. It's just so frustrating the damn carbs are such a bitch to get out. I did pull the plugs and they are showing pretty rich right now but it was just sitting there idling with weird fuel flow, from the aux tank.

[rider123]

Ok I know its frustrating, lets step a few steps back shall we? 1 step at a time. Ok so you got the rebuild kits and they are 100% for the RF900 carbs correct? It is possible they may have sent you the gen2 carb rebuild kit by accident. I'm not trying to be condescending in the least, I'm just trying to figure out what exactly is going on. Ok so you put in the rebuild kit no probs as you obviously know what you are doing, so let's trace back. When you were replacing the parts one by one did you notice any differences in the parts going in and parts going out? Was it a part for part exchange or did you change the entire set all at once? Do you still have the old parts to compare as a comparison to what you've just popped in there? Did some parts "just not feel right" when they were installed? Sometimes the smallest detail is the most telling. Also with an auxiliary fuel tank the fuel is just pouring in there with no regulation from the vacuum petcock so that may not be the best test. What float height are you working with? Any gasket kit will need a little "burn time" to get the appropriate gaskets swelled up to seal properly so let's take it one step at a time so we can sort it out. The reason you're getting a 100 rpm small jump is that there is a gasket or o-ring in one of the carbs not sealing properly and basically it's letting a droplet of fuel through which is then sucked into the cylinder and increases rpm that tiny amount. Now that the gaskets are new they will need a little time to set to seal properly, it may not be as bad as you think. When they are exposed to gasoline the o-rings and gasket will swell slightly, as a time factor it's anybody's guess but I don't see it going over a day or two before everything is settled. What do the plugs say? Since they are new gaskets and haven't been broken in, as well as the un-regulated dumping of fuel from the axillary tank, they are going to read rich. Is there one cylinder that is richer than the others?

[mpatrick]

Well. The kits were definitely right, all the parts matched up. I did one carb at a time and everything went together just fine. I have put on about 40 miles or so since doing it and it seems ok i guess. The float height might be the culprit im thinking. I am using 14.7mm per fast larry's site. In the clymer manual I have it says from like 13.6-15.3, so the 14.7 must be what works for most people. I think i'll wait until I get the k&n before I pass anymore judgement. Ill get some pics of the spark plugs in a little while. Oh and to make matters worse I put new tires on yesterday so the bike feels a lot different now.