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Go Back   FZ1OA Message Board > FZ1 & Fazer Owners Association > FZ1 Problems & Issues > Gen 1 Problems & Issues

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Old 05-01-2016, 12:00 AM   #1
Nagahota
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Solved: Rough low rpm misfire due to lean condition

I read a bunch of forums on rough idle and low rpm misfire. I just wanted to post my symptoms, diagnosis and solutions.
Summary: Ivanized (drilled and cut) 05 FZ1 GYTR slip on, stock air filter and intake. 55k miles. problem with low rpm misfire, uneven running condition. Cause was overly lean carb. SOLUTION, carb floats to 13mm (from 14mm) and idle mix to 5 turns out (from 4).

I have run three settings: 12mm float, and 4.5 turns. Ran fine, no misfire. Plugs were a little rich, always idled less than perfect.
14mm float and 4 turns idle mix. No good.
13mm and 5 turns, made the bike very happy. Back to being nice and scary fast. Surprised that it is so sensitive.

(note: my carb is clean and otherwise properly operating, valves adjusted at 36k)

When I went to 14mm my symptoms were slightly sputter idle, rough running. Consistant, but soft misfiring throughout power and rpm range. No audible backfiring. Ran with choke on, but didn’t change feeling of a miss. Bike still had power and would rev out. But had a soft misfire feeling at regular frequency. Not erratic frequency misfire.
Other symptoms. Boots between throttle body and carbs (backside of carb) on 2&3 cylinders push off slowly, even with clamps over tightened. White on spark plug after 200 miles.

The FZ1 TPS sensor specifications for resistance (ohms). Not the cause of my problems, but i replaced anyway. Mine would hit the 5k in calibration mode only if I pushed it a little past limit of adjustment. Bought new one from partszilla. Now it hits 5k calibration, no problem. here are my resistance numbers if you wanna check yours.
Blue to black three positions. Left middle and right: 5.64,5.64,5.64. new 5.13,5.13,5.13
Yellow to black Old 6.08,3.45,1.19 New 4.74,2.31,0.38

Other things to check if you have rough running condition. Fuel filter, plug wires and boots, TPS, vacuum leaks, valve clearances, ignition pickup resistance, and proper battery voltage. Compression/leak down for rings and valves. Check float bowl operation, by connecting clear tube to carb drain, push any air back up into carb, then place tube next to carb. See how high gas goes. Mine goes to the bowl seal/seam/joint. This can help you check your float valve also. (see if it goes on and off), obviously clean the carb jets.
Check white plug under tank for contacts. Unscrew plug wires from boots, cut off ľ”, spread wires and reattach if you have nastiness at contacts.

hope this helped someone. good luck. goes anyone else notice their throttle body boot clamps being pushed off?
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Old 07-16-2018, 10:08 AM   #2
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I realize this is an old post. I’ve currently got some idle hang going on and possibly misfire like behavior.

This post is useful, thank you. Various things mentioned that I could check some I’d not though of. On the air box to carb intake question I’ve not noticed that on mine but you could use different clamps or put a rubber strip inside the clamps using contact cement say and that would tighten that up.
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Old 07-16-2018, 10:25 PM   #3
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Airbox to carb connection isn't critical. Either way, air is going to get into the carbs on that side of the intake tract. Problems arise downstream if there's a leak between carbs and the intake boots, because now extra air is getting in to the air/fuel mixture and too much will cause lean running.
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Old 07-17-2018, 11:20 AM   #4
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Iím well aware of that thank you. What Iíd like to know is whether there is any significant air leakage through the intake boots once they are cracked? There seems to be an internal metal body inside the boots in the middle/main area of the boot. It does not go all the way back to the carb clamp and Iíve got cracking there too but the boots is thick and it does not appear that the cracks go through to the inside.

Iíve taken the carb off at this point done extensive cleaning and I had lubed my slides with moly grease eons ago. So the moly grease dried out and sort of caked my slides and the mating recesses. There was also a good deal of dark dust/slide wear dust or dried moly lube dust inside under the diagrams and that conceivably got into the air jet system partially blocking that which along with the dried moly lube buildup was probably a double whammy and the system dealt as long as it could then crapped? Iím hoping anyways.

I need to get to harbor freight and buy one of those lighted magnification goggles this little nuanced stuff I struggle now to see up close any longer. Maybe some reading glasses from down the store?

Anyways. My float jets are all pulled and my o rings arenít showing the cracking that others reported. They werenít falling out either. One has a gouge in the outer surface. Trying to decide whether to trip 30 miles to get replacements or just put it back together. I donít think itís leaking. Also wondering if other o. Rings should be replaced but I donít have the designations to specify such as fuel screw o rings.

One of my floats is goofy. Itís crooked. Probably faulty from new. I remember now dealing with it before and the two sides arenít even to the bowl surface. I ended up setting it the best I could .

Iím wondering about the choke circuit. Iíve not taken that apart and that looks like it might have sealing rings inside maybe it could be a source for air leakage. Although the shafts/plungers look clean and nothing is sticking. Iím wondering if that too should be disassembled and the passages blown out and any seals cleaned or replaced. Iíll look at the parts Fischer I guess and decide. The choke did work fine.

Fortunately, I think, the carbs can be put back in and clamps tightened and the machine started and run to see if the hanging idle issue persists before reassembling everything.

Getting carbs in and out on this bike is such a pita!
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Old 07-17-2018, 01:34 PM   #5
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I've seen literally thousands of FZ1 intake stubs, many severely cracked on the outside but none have ever let in air in my experience. Of course, as the bikes get older, then the chances of that happening will be increasing all the while. I'm sure you know the simple tests to see if you have an air leak on the intake side, though.

I wouldn't reassemble the carbs without replacing the float needle valve seat O-rings. They will fail on you soon enough, especially now you've disturbed them.

Putting molyslip on the slides wasn't your brightest idea but hopefully the crud hasn't worked its way into internal passageways.

Good luck with the rest of your diagnostics and overhaul.
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Old 07-17-2018, 05:15 PM   #6
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I will send you 4 needle o-rings if you pm me your mailing address.

Jim
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Old 07-23-2018, 04:44 PM   #7
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I appreciate the offer on the O rings. My supplier didnít have that particular size so I put it back together with my originals. I think some of the dried moly dust may have reduced air flow in some of the air passages. I cleaned it all out meticulously. All passages solvent treatment and blown out multiple times. Getting the throttle cables back on was a real pita and took a lot of time. In the process I discovered that the return cable was frayed out of sight inside the outer sheath.

Back together she started up fine and seemed to run great. I warmed her up blipping the throttle. Seemed good I shut her off.

An hour or more later I started her again and this time running on three cylinders! Grrr. Water spray on headers showed cylinder 1 not as hot. I removed the plug and checked compression. All I got was 180psi. Upon trying to remove the tester the adaptor stayed in the plug hole. Grrrr. So that stalled me up big time as it wouldnít come out. So I had to apply locktite to the threads and wait all day for that to for sure set. Uggg. It then came out. Engine now dead cold I checked the number 4 cylinder to compare which was 200psi. Maybe the number 1 cylinder had had gas soaked rings? I checked cylinder 1 again and was able to get 198psi but it didnít seem as apt to reach that psi as cylinder 4.

I popped the tank again and wiggled the coil connections. I also cut each plug wire 1/4Ē or so to freshen up the connections in case it was shorting there. Started her up again and she seemed to have got back the 4th cylinder again.

My hanging idle issue is still there not as bad as before. If I run the idle at about 1000rpm itís fine and falls back when blipped no issues. Iíve run her like that a fair bit now. She seems definitely to fuel more smoothly than before and the hesitation on 4500-5K rpm cruise which was previously mentioned seems gone.

There may be an intermittent coil issue.

Iím starting to wonder if the number 1 cylinder has a tight exhaust valve. My theory is when cold and valve not expanded(lengthened) the compression showed higher than when warm (but possibly gas soaked cylinder too when warm cause it wasnít running right....) and since that cylinder seemed slower to reach the 198psi reading cold Iím suspicious it might be leaking compression when cold too.

I could take a warm compression reading on cylinder 1. My cold compression reading hours later might have still had excess gas in those rings. Hmmmm.
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Old 07-24-2018, 09:30 AM   #8
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The right thing to do here is a valve adjustment check. I really donít want to do that. I also donít want to damage by neglecting to do the valve check. Pondering. I guess, like removing and cleaning the carbs, that Iíll wind up doing the valve check for peace of mind.
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Old 07-24-2018, 10:20 AM   #9
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valve check on a gen1 takes less than two hours. Easier than removing the carburetors IMO. Considering your miles and if you don't know if the last one was done in the past 30k its worth looking into.
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Old 07-26-2018, 08:53 PM   #10
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I know the valve check shouldn’t be too drudgery. But I also know there will be tight exhaust valves (suspect>>> based on recent experience going through 34K miles ZX9R = they were all tight) and that will make the process longer and more tedious. Doing it on the ZX9R was a nightmare which lasted and largely due to the “lack of availability” of shims and my mis ordering shims (wtf I actually ordered the wrong thickness of shims for god sakes seriously???) and I wanted them as close as possible to the largest gap so I could avoid doing them again soon and I ended up actually doing the valves 3X to finally get that right what a headache it was. So no, I’m not looking forward to that again but if I wasn’t so particular it would make the job easier. What sucked with ZX9R is I was using the hot cam shims and their shim to shim sizing is too big of a jump causing me grief. Adding to the misery was driving around to various shops trying to get the exact shims that I needed and there’d only have one that size or none that size off to the next shop. Btw... dealer was happy to order me the shims 10 day wait and $13 apiece...fracking robbers!). I finally and ultimately had success trading some shims back and forth to get close to the final clearances I wanted but that was the third time taking the cams out and 3X was necessary/it was necessitated by one valve having excess lash on final clearance check, which it should not have had based on my measurements and calculations but... it was too large a gap! It was a real gift that kept on giving and I somewhat expect similar grief (especially finding availablility of shims locally??) from FZ1. Really not looking forward to it but.. I’ll have to dig in. At least the AIS system is recently removed so that provides added space to work.
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Old 07-27-2018, 04:55 AM   #11
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if it helps, I needed 5 of the same size shim and was able to get a 5 pack from Amazon Prime, 2 day shipping for $6. A Shim kit wouldn't have helped me. as they give you 3 of each size.
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Old 07-28-2018, 06:42 PM   #12
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Any certain size range that's generally needed ? Usually there's a range that they seem to be prevalent in an engine family .
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Old 07-29-2018, 07:08 AM   #13
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Or just buy the hot cams shim kit. And sell it when you sell the bike. It’s what I did with my fz and yz
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Old 07-30-2018, 06:14 AM   #14
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Hot cams kit gives you a boatload of shims of sizes across the thickness spectrum. All of which (the shims) have their excessive sizing gap between designations, meaning fine tuning is limited unless you want to sand down shims yourself with glass surface and sandpaper(I tried doing so F that!). And~ You only get three shims of each designated size. I’ll let you consider the usefulness of ~that~, given that most modern machines are 16 valves.... So. In the case of the ZX9R for example. Every single exhaust valve of the 8 was tight... and each was tight the same not some tighter than others, but not just tight, but significantly tight probably never checked previously. Verge of problems tight. Now, your hot cams BIG kit gives you 3 useful shims cause the shims from Kawasaki we’re literally all the same thickness designation from the factory. This means you too will need 8 shims of the same thickness designation to set your valve lashes right. Your kit leaves you just 5 shims short. (****eroo). Add to that the (the fun of = NOT) shims sometimes not being machined accurately as in the marked size on the shim does not match the physical (measured) thickness and it’s a recipe for REAL aggravation. That last part is the actual reason I had to remove my exhaust cam a final time on the ZX9R as I was frustrated and hurried wanting the engine buttoned up already after this described process going on for like two weeks already and I just trusted the designated thicknesses without physically measuring the shims to make sure (Thank you hot cams I should not have to do this the shims should be in spec per their designated sizes not maybe but every single time...but they are not!) and that resulted in one valve being (“.001”) too loose defying my calculations and measuring and then I discovered the “too thin” hot cams shim. Are you seriously kidding me? Heh, it’s not a problem at all, I’ll just remove that cam, yet again, remove timing chain yet again, have to uninstall, reinstall, retorque, reset cam timing yet again... thank you hot cams for your shit quality control grrrr.

And.... as to your contention about buying the hot cams big kit... It will not serve your needs properly, it will leave you with tons of shims you’ll never need(>never ever need<) and it’s wasting money. It’s sort of like needing a few new pairs of underware briefs and the sizes you need are only available in a package of say 100 briefs of sizes from baby boy to fat man. Of course that’s a bad example isn’t it cause at least the extra underpants can be used as polishing cloths, shit wipes, shop rags or whatever. What will you use all these useless too small and too large thickness shims for?

Best option is just buying the 5 pack replacement shim packs online and hoping not too many fall too far from the designated size. My experience with this is you’d buy 2 five packs hoping for 8 right size per designation shims! Or should you buy 3 five packs just in case to be sure? LOL. Good luck finding them locally. You just won’t.

Of course, Kawasaki was to hit me (knock me out actually!) for $13 a shim. Great way not to secure future business from prospectives right there.
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Old 07-30-2018, 08:13 AM   #15
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Eh, I did two shim changes on my fz. And multiple shim changes in my yz

I and many others Never had an issue with the hot cams kit, you can play musical shims. You retain the factory shims you remove and you can reuse where needed.

You’re paying for the convience to be able to check the shimming, perform the shimming, and get back on the road in a few hours.

But to each their own.
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Old 09-25-2018, 09:41 AM   #16
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Iím back to having running issues.

I checked my valve lash adjustments and they were all at, or close to the minimum. I left them there as none were out of spec. I wasnít able to figure out where air is leaking into the intake. I finally got frustrated and turned my idle fuel screws out 1/2 turn. This seemed to improve things and the bike felt better. That of course increases fuel across the whole range, not just at idle.

My choke seems to operate pretty wonky. It functions as a choke as in you fully apply it and it helps with cold starts. But the wonky comes in when you try to gradually reduce the choke setting and it seems reluctant to adjust smoothly. As in, a small movement and it wants to drop too much. So, Iím wondering if thereís air getting in through that circuit... presumably O rings on those plunger shafts?

I canít see anywhere that intake air leaks can happen here except the intake boots or that choke circuit.....

Iíve developed a misfire again. Idle is not smooth and itís pretty erratic. Almost sounds like itís missing on more than one cylinder at idle!

Itís been a few months and I didnít post my results before but my hot compressions were all in the 195 psi range. I think the idle used to be a lot smoother. This is leading me to believe that I definitely need to get some coils and wires. My misfire was traced to the number 1 cylinder again, using water spray bottle on header and it seemed to be fixed by rotating the spark plug boot back and forth. Then, of course, it came back. But then it went away again.

The bike was running reasonable well with the 1/2 turn extra on the fuel screws. I was still running the idle somewhat low to deal with that hanging idle issue and just running it as it was if I had to wait at a light or whatever Iíd dial in a bit of throttle to hold 1300-1400 rpm in those circumstances.

Once itís hot/running it seems to run fine except for the idle issue mentioned. It idles better if I adjust the idle up to say 1200 rpm but then youíve got some hanging idle issues again. Even adjusted to that rpm it doesnít sound smooth at idle.

Has anyone experienced coils not working right at low rpm but no drivability problems in the revs? Coils are a bit of a mystery to me. Seems to me if they go bad they should just fail but I guess with age you could develop higher resistances or arcing. I notic3 some of the coil/wire sets on eBay the spark plug wires were wrapped with electrical tape at the cylinder head/spark plug boot end. Sellers claim the engine was running great but wire taped? Huh? LOL
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Old 09-25-2018, 09:59 AM   #17
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Quote:
Originally Posted by curvecrazy View Post
Has anyone experienced coils not working right at low rpm but no drivability problems in the revs?
So Gen2 coils are known for failing and that's exactly how they go out. They stop working properly at low rpms, especially while taking off, but would work fine at high rpms. So if that sounds like your issue, I'd suspect the coils
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Old 10-10-2018, 09:02 PM   #18
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You mention gen 2 coils, but mine is a gen 1. Are the coil failures similar? I put in some used gen 1 coils and it seemed to help smooth out the idle noticeably but still not smooth. Cylinder 1 still seems to be running cooler than the rest while at idle. I’m starting to wonder if the float jet O ring in the cylinder 1 carb float is leaking. It had a nick in it and I didn’t have access to replacements so I put it back in as it was. Some have mentioned that if so (leaking) that it can display as rough idle possibly coil problem! If that’s leaking fuel past then the float would remain closed longer with the float topped out and float needle closed but I’m not sure how that would affect running conditions would it run lean or rich? Would it be rich at idle resulting in the cooler exhaust header? It does seem to run better (smoother and more responsive) now in the revs. And when it’s revved to say 3000 rpm, the #1 cylinder exhaust header seems as hot as the rest. I noticed that the used coils had very similar readouts to my original coils but they had higher resistances in the plug boots than my original well used plug boots. Spec is listed at 10K ohms. These used ones measure 12K ohms. Disappointing because I was hoping the lower mileage plug boots would have less than 10K ohms resistance and along with that, I assumed improved performance.

This is getting really annoying with this rough idle. It seems to run pretty well when cruising backroads.
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