'96 F3.. Weird issues... misfires all around...

johnyquest · 07-13-2008, 10:02 PM

Hey everyone. First post here. Glad to find a resource like this for the CBR's. I've had my 96 for three years now, and never really did much to it besides the obligatory oil changes.

I was out riding a the other day with a few friends, and found a cool road where I could get a foot or two of air. It was a bunch of fun. Anyways, after riding the road a few times, I noticed that at low RPM, low throttle situations the bike sounded like it was running on only two cyl. Upon giving it more throttle and accelerating it seemed to clean up and run fine at any condition where the bike was under load.

Well, took the bike apart, realized it had come with a K&N, so I bought the recharge kit and recharged it. Replaced the plugs with what the shop sold me, which happen to be CR9EK's, which are a dual electrode plug but I have read they are compatible. Also replaced the fuel filter, and checked the operation of the fuel pump. I guess it only pulses when needed on the F3? Anyways, that's what it does, and I did read somewhere that that is proper operation for the f3's pump. Oh, also sprayed some carb-clean into the carbs while I had it apart.

Now the real weird: Not only did the weird part throttle / low load only running on 2cyl sound not get remedied, but now full throttle bit the dust. It seems like it's all going well, then at 8k+ rpm, nothing but broken up misfires in any gear. I'm perplexed.

Anyone have any suggestions? I've been staring at it for two days, I just really don't know where else to look. A tune up should have resulted in a better running bike, not worse.... no!?

Bike is stock besides K&N and Two Brothers slip on as far as I know. I've put 4k on it without issue before this.

Thanks for any help.

Matt

lanbrown · 07-13-2008, 10:38 PM

Did the bike ever get tuned for the filter and Two Brother pipe? The jets may neve rhave been changed. The K&N actually doesn't flow as good as a stock. Howw much oil did you put on the filter? After all the work, you could have a filter that doesn't as well and more fuel going into the engine.

johnyquest · 07-13-2008, 10:49 PM

Quote:

Originally Posted by lanbrown

Did the bike ever get tuned for the filter and Two Brother pipe? The jets may neve rhave been changed. The K&N actually doesn't flow as good as a stock. Howw much oil did you put on the filter? After all the work, you could have a filter that doesn't as well and more fuel going into the engine.

I re-oiled it until it looked pink again. I pretty much followed the instructions in the kit to the T. I am not sure if it was ever properly jetted, but this problem came out of the blue, so I'm not sure it's jet related, though I can't rule this out yet. Not impossible, but like I said, I myself have put 4k on this 21k mile bike since I've owned it and it's always been strong and reliable, only issue ever being the cam chain rattle that all these bikes have... The exhaust note changed when this started... then I did the tune up, and it's worse.

So confused.

Matt

lanbrown · 07-14-2008, 12:18 AM

You did sort of clean the carbs. Pull the plugs again and see how they look.

johnyquest · 07-14-2008, 2:28 PM

Quote:

Originally Posted by lanbrown

You did sort of clean the carbs. Pull the plugs again and see how they look.

Yeah but it was a little while before I got it back together and actually started it from the time i sprayed the carb cleaner. I wonder if it did more harm then good?

I'll pull the plugs later today if this rain lets up.

Matt

lanbrown · 07-14-2008, 3:26 PM

You either clogged one of the jets or the fuel flow better than the intake. Does it run better or worse if you slowly add the choke? We an see if it has too much or not enough fuel with this method.

johnyquest · 07-14-2008, 4:07 PM

Quote:

Originally Posted by lanbrown

You either clogged one of the jets or the fuel flow better than the intake. Does it run better or worse if you slowly add the choke? We can see if it has too much or not enough fuel with this method.

You know that's a good point. I did try that the yesterday and it seemed to clean up and rev higher without breaking up the more choke I gave it. I'm going to have to double check test it again today after work, but if it does as I recall and allows me to run it to redline give or take with the choke on, does that leave us at clogged jets?

johnyquest · 07-14-2008, 7:05 PM

Update:

Choke doesn't really change where it misfires much, pretty much the same thing but it sounds fatter...

The low end problem rectified itself now that I added some b12 chemtool to the tank. Maybe it was bad gas, water in the tank? Will post updates.

I noticed that that thing that's bolted to the aluminum plate under the seat on the right when you are sitting on the bike is getting hot as HELL. Is this normal? The frame gets hot around where it's mounted as well. Is that the regulator or the rectifier? And do all of yours get that hot? I wonder if it's related.

Still massive hesitation @ high (8k+) rpm, but the low end now feels better than it has in a LONG time (probably the new fuel filter / air filter / plugs doing their thing).

Any ideas, don't hesitate to throw them out there.

Thanks!

Matt

johnyquest · 07-15-2008, 10:11 PM

Also drained excess oil... looks like I was a quart over because I used to check on sidestand by screwing dipstick in. Bike shop gave me a set of the CORRECT plugs free of charges realizing their mistake, and installed them as well. Ran half can of sea-foam through the fuel line and let it do it's thing. Re-checked air filter and fuel filter, no problems (both new) Low end / part throttle accel feels better than it has in a long time. Full throttle, still same issue. Almost like a rev-limiter. Will not pull past 8-9k. Shut the bike down mid pull before I pulled the old plugs. Plugs were wet with unburned fuel. As I stated before, choke does not rectify the problem.

ANYONE!? I'm SO lost. I'm not half bad with motors and I don't know what else to look at.

Thanks.

Matt

lanbrown · 07-15-2008, 11:16 PM

If the plugs are wet, do you have spark? If so, then I think it is running rich. You have different jets, so the high speed is getting too much fuel.

johnyquest · 07-15-2008, 11:19 PM

They were wet, I beleive, because I hit the kill switch mid-full throttle run while it was mis-firing to check their condition. I'd assume carbs would continue to deliver fuel regardless of the kill switch, no?

Matt

lanbrown · 07-16-2008, 12:11 AM

The engine would need to pull the fuel in. How does the exhaust look and smell at the higher RPM's?

newfie1000rr · 07-16-2008, 2:13 AM

Did you check the exhaust header it could have got flated out and not flowing.

johnyquest · 07-16-2008, 12:29 PM

Yeah, I checked all the obvious stuff including the exhaust. Is there some sort of valve / solenoid / something that is supposed to change the way the bike breathes at high load / rpm situations? I feel like it's starving for air...

Matt

Charles486 · 07-16-2008, 1:01 PM

this was mentioned earlier, but it could be just too much oil on your k&N thats a common mistake, I see you said it was new, ignore this if that means completely new.

Also, check your vacuum hoses, both the routing and condition. these bikes are very very sensitive to vacuum changes

johnyquest · 07-16-2008, 6:05 PM

I will try riding it w/o the filter right when I get home. I did just re-oil it.

Thanks!

Matt

johnyquest · 07-18-2008, 2:09 PM

This bike is junk. Took the carbs off, cleaned the jets, Still have no high throttle. This is annoying as hell. Now it sounds like it's pinging. I guess i'm going to have to bring this to someone.

Thanks for all your help everyone.

Matt

Charles486 · 07-18-2008, 3:47 PM

Sorry for your luck man

1. you might find a cheap fuel pump, least likely option but a possibility

2. check your vacuum routing and hose conditions if you havent already. This is easy to get wrong and can have a big effect

3. where did you get the fuel filter? if the fuel filter is clogged/not right etc it could be starving your fuel out.

Good luck, sorry i couldnt be more help

lanbrown · 07-18-2008, 3:50 PM

If you still have the old parts, put them back on. Then replace them piece by piece and find the weak link. You did too many things at once.

johnyquest · 08-06-2008, 7:09 PM

Quote:

Originally Posted by lanbrown

If you still have the old parts, put them back on. Then replace them piece by piece and find the weak link. You did too many things at once.

I brought it to someone who has been doing this for years. I'll let you guys know because it's sure been bugging the HELL out of me!

Matt

Far2Sly4U · 09-10-2009, 8:01 PM

Quote:

Originally Posted by johnyquest

I brought it to someone who has been doing this for years. I'll let you guys know because it's sure been bugging the HELL out of me!

Matt

I had this issue on my old 250 Rebel, and tried Chemtool with no change. Then I tried 4oz of SeaFoam and the issue was resolved after around 55 miles of riding. I'm no having the same problem with my 500 Shadow, but SeaFoam doesnt seam to clear it up. Still you may want to try it.