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Post by firmstools on May 14, 2021 20:09:31 GMT 1
Odd forum to post this on but I know there is a lot of knowledge out there!
My OW01 has had a running issue since I have had it.
Starts OK, as warms up the revs start to "hang high"
IE. Rev it up and revs drop to 3000rpm and stay there, if I wind tick over screw out nothing happens, wind it a bit more and still at 3000rpm, wind it out a bit more and.......300rpm and stall!
If I wind the tickover screw out several turns the revs rise and fall as they should but obviously it will not idle.
This is a classic Yamaha 4 stroke issue, I have heard of it on YZF750s, R6s and R1s with carbs. 99% of the time it is carb related.
All the classic signs of an intake air leak.
I have replaced (deep breath) inlet rubbers, all O rings and seals in carbs, diaphrams, O rings on inlet stubs, sprayed brake cleaner round inlets, new ignition pick up, cleaned and replaced all ignition wiring, tried 3 other sets of carbs, tried another ECM and problem still persists.
I have checked cam timing, compression test is good, as is leakdown test.
All the symptoms of running lean, except.........................spark plugs are black and sooty.
Runs like shite above 5000 rpm too.
My last thought is valve guides, if they are excessively worn will they allow air/oil mixture into the combustion chamber on the intake stroke?
Any thoughts before I spend even more LC money on the damn thing?
Thanks.
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Post by firmstools on May 14, 2021 20:12:13 GMT 1
And I have put copper washers on the cam cap bolts as they extend into the inlet tracts but still no change.
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Post by beardy on May 14, 2021 20:28:18 GMT 1
Are all 4 choke plungers returning? Thinking my zzr has a slide that pulls all 4 choke plungers. Only coz you say plugs are black.
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Post by tony2stroke on May 14, 2021 20:30:15 GMT 1
In my experience that is the classic sign of running rich, could be badly balanced carbs, with one being way out, could be a sticking choke plunger or damaged, wrong float height.
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Post by firmstools on May 14, 2021 21:04:16 GMT 1
In my experience that is the classic sign of running rich, could be badly balanced carbs, with one being way out, could be a sticking choke plunger or damaged, wrong float height. Forgot to mention that I balanced the carbs and checked choke plungers were returning ok. Yamaha don't do float heights on these, you have to measure fuel level with a running engine. Several burned fingers later they were all ok🖒 |
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Post by midlifecrisisrd on May 14, 2021 21:52:00 GMT 1
If it was the guides it would be Smokey from the burnt oil
As you say it gets worse as it warms you would have to leakdown test it hot which is impossible
Are all 4 plugs the same
If all 4 are black and sooty it suggests it's not a single carb issue
Did these crack blocks like the R1?
How many miles has it done?
My FZR1000 was rich as feck down low, would make your eyes water
I blamed it on the needles wearing due to the angle
Forgive the ignorance but do they have an exup valve, is it adjusted correctly?
Steve
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Post by tony2stroke on May 14, 2021 21:55:12 GMT 1
Problems like this are a real pain, when everything is in correct spec but still won't run right, very hard to find then, only by a process of elimination, sorry can't help any further, good luck with it.
It is classic rich mixture symptom though, for whatever reason.
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Post by midlifecrisisrd on May 14, 2021 22:01:37 GMT 1
Also, have you actually strobes the ignition and checked the timing
Timing way out will affect the way the fuel burns
I chased a poor running issue (on a 2 stroke mind) for months thinking it was way rich. Think stank when it ran. Turned out to be duff ignition
Steve
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Post by hoist1 on May 14, 2021 22:59:06 GMT 1
Looks like you can rule out carbs. Would look at inlet rubbers for the high tickover and the coils for the rest of it, have you a multimeter?
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Post by midlifecrisisrd on May 14, 2021 23:16:44 GMT 1
I'll also say any time I had problems with my Fazer 1000's woolly at idle and sh1te up top was coils
Steve
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Post by firmstools on May 15, 2021 8:36:46 GMT 1
If it was the guides it would be Smokey from the burnt oil As you say it gets worse as it warms you would have to leakdown test it hot which is impossible Are all 4 plugs the same If all 4 are black and sooty it suggests it's not a single carb issue Did these crack blocks like the R1? How many miles has it done? My FZR1000 was rich as feck down low, would make your eyes water I blamed it on the needles wearing due to the angle Forgive the ignorance but do they have an exup valve, is it adjusted correctly? Steve Some good points Steve, It has only done 5000 ish miles but it had been badly neglected when I got it (left outside for years by the look of it) , one of the things I replaced was the cylinder head as it had badly pitted valve seats , the rest of the motor was like new. The replacement head was cleaned and all valves lapped in but I never thought to check stem to guide wear. Ihave done a leak down test when hot ( piston on tdc compression, 80 psi in the plug hole) and all is good. IIt does make your eyes sting if you are too close to it and exhaust pipe is sooty. Ex up valve is set correctly Coils replaced Needles have no wear Carb rubbers and clamps new genuine yam. Bits of carbon in inlet tracts and on inlet valves The not revving down is classic running lean problem Everything else is classic running rich! |
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Post by firmstools on May 15, 2021 8:47:39 GMT 1
And to complicate things even further,
The std setting for the pilot fuel screws is 2.5 turns out.
If I set them to 7.5 turns out , making it very rich at idle the bike revs down and is crisp and responsive to the throttle ,idling at 1200 rpm solid as a rock, so I am compensating for a lean condition elsewhere.
Same with all carbs I have tried.
As we know from LC problems, replacing a suspected faulty 30 year old part for an untested 30 year old part is a gamble.
Thanks for the input guys.
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Post by Robbieben on May 15, 2021 9:48:52 GMT 1
I've had a similar issue to this before on a GS1000, in the case of that bike it was the ignition timing being too far retarded but still ok for it to run, effectively burning the fuel past TDC. Your symptoms are near on identical to those I had.
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Post by midlifecrisisrd on May 15, 2021 10:04:16 GMT 1
Are the pilot screws not air screws so 7.5 turns out is weakening it
Its highly unlikely an 0w01 has enough miles to wear the stem guides and as said it would be Smokey
If all the carbs had the same issue it's not them
Strobe the timing. Can only be that or something else you have disturbed is set wrong
Steve
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Post by firmstools on May 15, 2021 10:33:13 GMT 1
Pilot screws are fuel in these carbs,
General rule, if they are airbox side of carbs they are air regulators, engine side are fuel.
Really interesting that 2 of you have now mentioned ignition timing, I had discounted even checking as it is not adjustable,
Doesn’t mean something funny has not gone on!
I have checked the air gap between crank and pickup and it’s ok
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Post by zed1015 on May 15, 2021 11:53:07 GMT 1
Unless you have been unlucky and all four sets of carbs you have tried have the same issue you can rule out the fuelling.
Are you sure it's not just mal adjusted throttle cables ( especially an over tight return ) as too little slack will cause a hanging idle.
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Post by firmstools on May 15, 2021 15:24:04 GMT 1
Unless you have been unlucky and all four sets of carbs you have tried have the same issue you can rule out the fuelling. Are you sure it's not just mal adjusted throttle cables ( especially an over tight return ) as too little slack will cause a hanging idle. Would be lovely if it was as simple as the cables. I have even tried it with the tank propped up and cables disconnected! Was told a long time ago that 80% of carb running problems are non carb related! Think this is a case in point! Beginning to understand why the original owner left it outside and forgot about it  |
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Post by brigitte on May 15, 2021 16:54:45 GMT 1
Hello,
I once had similar problems with a 4-stroke twin with constand depression carburetors. Maybe the springs in the trottle valves have become weak. This would explain the rich mixture.
Brigitte
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Post by LC_BOTT on May 15, 2021 19:02:57 GMT 1
Just an idea, but is it easy to disconnect the choke system, guessing it's a common linkage, across all four, with single screw adjustments??
Are there any pipe from airbox to carbs that could be split/damaged (just sorted a very badly running BMW myself last week) and this was causing it, all good so far....
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Post by julianboolean on May 15, 2021 19:32:50 GMT 1
It sounds like an air leak, but could be ignition timing, I've had an ignitor box go and the bike would start lovely but not run properly because the timing was stuck at start-up timing. Have you tried talking to either Peter Day or Pete Beale about it, both know about OW01s I'll swap it for a running FZR400RR  |
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Post by rich on May 15, 2021 19:46:32 GMT 1
One thing you haven't mentioned is are the valve clearances ok?
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Post by firmstools on May 15, 2021 20:30:27 GMT 1
Just an idea, but is it easy to disconnect the choke system, guessing it's a common linkage, across all four, with single screw adjustments?? Are there any pipe from airbox to carbs that could be split/damaged (just sorted a very badly running BMW myself last week) and this was causing it, all good so far.... Done all that, all new hoses and clamps, and it still laughs at me! |
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Post by firmstools on May 15, 2021 20:32:58 GMT 1
One thing you haven't mentioned is are the valve clearances ok? Forgot to mention that, all set to mid tolerance and re checked several times since in case some had closed up, all good. Cam timing checked several times as I started doubting myself! |
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Post by firmstools on May 15, 2021 20:41:24 GMT 1
It sounds like an air leak, but could be ignition timing, I've had an ignitor box go and the bike would start lovely but not run properly because the timing was stuck at start-up timing. Have you tried talking to either Peter Day or Pete Beale about it, both know about OW01s I'll swap it for a running FZR400RR I agree 100%, ignition timing to be checked asap. I have spent too long on and off chasing an air leak that I think was never there. You and several more have suggested ignition timing that I had discounted as its a non adjustable system. Peter Day was as baffled as me last time we spoke, he was kind enough to lend me some carbs which made no difference. Think Peter Beal is more R1s these days. Thanks for the kind offer of the FZR400, I have given it due consideration and decided to decline your offer on this occasion.  |
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Post by steve63 on May 17, 2021 12:48:21 GMT 1
Did these crack blocks like the R1? Steve Is that not just the R6? I've not heard of it on R1's. To be honest I've not looked for it either. I have enough with the issue I have |
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Post by midlifecrisisrd on May 17, 2021 15:27:35 GMT 1
Did these crack blocks like the R1? Steve Is that not just the R6? I've not heard of it on R1's. To be honest I've not looked for it either. I have enough with the issue I have Not sure, it was just I was looking at a cheap R1 and it said it had a suspected cracked liner Steve |
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