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Old November 22nd, 2018, 07:12 PM   #41
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i have a factory pro pregen kit for sale. I can loan it to you for tuning if need be.
https://www.ninjette.org/forums/showthread.php?t=324987
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Old November 22nd, 2018, 07:32 PM   #42
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Quote:
Originally Posted by dodgerdad View Post
No, I can't isolate the problem to the carbs so I want to avoid the time & cost of sending it out only to put it back on and have it perform the same.

I've cleaned out the carbs and set them multiple times, this thing is as clean as can be, not to mention it wasn't too bad to begin with.

I'd prefer to rely on the shop because they can look at the whole bike. If they incorrectly diagnose it, they won't get paid for unnecessary parts/labor.
I wouldn't count on that.

In today's world, carb work is not something that most mechanics are familiar with. Even if they knew what needed to be done, chances are they would not have the proper tools to do it.

From you initial description, I would say chances are good the issues are carb related.

You'd be surprised at how much it would cost to bring your bike in and say "fix it". Having the carbs gone through by ducatiman would be much more reasonable and would get right to the heart of the problem.
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Old November 22nd, 2018, 09:26 PM   #43
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On top of that I can bet you any shop will tell you that what they fixed needed fixing whether it corrects your problem or not.

You can very easily end up spending more than your bike is worth having a shop chase down a problem (especially an elusive one on a cheap bike).

95% likely it's still a carb issue. Regardless of how clean you think you've made the carbs a spray can of carb cleaner simply doesn't do the trick sometimes. I'd also suggest taking a look at the parts breakdown online and make sure all your bits are accounted for and where they belong. I don't remember seeing it, you've set float bowls, tuned the idle jets and synced the carbs right? As well as done a compression test?
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Old November 23rd, 2018, 08:37 AM   #44
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Dealing with folks with problems after repeated corrective attempts, I am inclined to perform a wet test, as carbs are delivered, prior to any disassembly...does not eliminate teardown and the usual intense service...but the extra effort in testing can be revealing.

Here's a pic of a runaway float valve, EX500 carbs as received...(witness the way high fuel level, right up to the vent!) diagnosed minutes after unpacking. Provided the owner with an answer (and visible proof) as to why his leaking out the vent hose, extreme flooding condition.

Of course, successful service then went forward.

And re: shop rates...dealerships charge labor per hour, period. I don't think they'd be too receptive to bargaining. Dealers closely monitor that hourly labor.... and some choose to PAY their techs based on those hours, too.

I'd advise to call the service manager, discuss their hourly rate and get an estimate on time required to do an "on the bike" carb R and R, clean and setup. So you know going in...no surprises.
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Old November 23rd, 2018, 09:14 AM   #45
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H, If you suspect carb trouble I'd bet you'll be way ahead sending them to Gordon instead of a dealer or anyone else. And I don't get a sale commission for saying that.
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Old November 23rd, 2018, 04:48 PM   #46
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Quote:
Originally Posted by ducatiman View Post
@dodgerdad....

If you were to fully warm up the bike (as when setting the pilot screws) with choke lever confirmed in off position...what effect does slowly turning each pilot screw (not both at same time, but one side at a time) all the way IN have? (to lightly closed, not jammed shut)

As the screw is turned in...does it lower RPM from that cylinder? As it approaches closed position, does that cylinder continue to run? At closed, does the cylinder nearly shut down? But return the screw to 2 1/2 OR preferably the setting that achieves the highest RPM....THEN do the opposite side.

Does EACH side have the same, near approximate partial and fully shutdown results? Or radically different?

A cooling fan blowing towards the radiator/engine is a good idea....as are gloves or rags strategically placed to shield from burning your hands.

Please discuss your findings here, be careful, repeat test as necessary.
I did the fuel mixture test as you described. The right carb seemed almost completely unaffected. The left carb was impacted by screwing it in (seemed to SLIGHTLY improve the response when it was leaned out).

At this point I think my best option is to have the carb serviced, if that doesn't clear up the issue I can then take it to a local shop to have them look over the rest of the bike, knowing the carb hasn't any flaws.

I'll PM you. Thanks for the help.
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Old November 23rd, 2018, 06:09 PM   #47
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^ answered your PM, prepped to move forward.
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Old November 24th, 2018, 07:49 AM   #48
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Quote:
Originally Posted by maverick9611 View Post
i have a factory pro pregen kit for sale. I can loan it to you for tuning if need be.
https://www.ninjette.org/forums/showthread.php?t=324987
Thanks, really appreciate the help. I'll be shipping my carbs out to ducatiman this week and keeping my fingers crossed.
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Old November 24th, 2018, 08:12 AM   #49
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Originally Posted by dodgerdad View Post
Thanks, really appreciate the help. I'll be shipping my carbs out to ducatiman this week and keeping my fingers crossed.
Good call.

They will be better than new when you get them back!
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Old November 24th, 2018, 11:29 PM   #50
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Old November 25th, 2018, 12:10 AM   #51
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Here's some examples of ducatiman's most excellent work: https://www.ninjette.org/forums/show...php?p=1041052/
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Old November 25th, 2018, 09:27 AM   #52
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jeez, turning into an infomercial here.....I really do appreciate your feedback and support.

For fun...here's a pic of a little challenge I had on EX500.

A nightmare...rotted, corroded, intensely stuck pilot jets The broken off part of the pilot jet remained frozen in place, after the head broke off in (attempted) removal.....I was lucky enough to stumble upon a tiny EZE out in my tools...and got lucky.....saving the fella his carb body...NEW pilot jets of course, and a full service met success.
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Old November 25th, 2018, 09:40 AM   #53
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Wow, looks like it froze on at the body, not the threads!
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Old November 25th, 2018, 09:57 AM   #54
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And I've developed a safe, surefire method to replace diaphragms with new aftermarket on the plastic slide 250's. A good USA source for the new...but a tricky process nonetheless.....the factory uses a glued "cap" to ahem, capture and seal the diaphragm.
The rebuild requires removing/destroying the cap...while leaving the "2nd deck" (also plastic) intact.

Very carefully using a dremel with cutoff, I've developed a safe removal procedure, requiring taking them off piece by piece.

The well structured new diaphragm (not even listed for the 250!) has a center "tire" which replaces the cap and offers excellent sealing capability.

It is then glued and sealed, as was the factory diaphragm rubber.

Its a very tricky process, but effective as new diaphragm/slides are quite expensive.

So...within my service, I'm now stocking diaphragm rubbers for both EX250 and 500. Keep that in mind, folks.
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Old November 25th, 2018, 10:09 AM   #55
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Quote:
Originally Posted by dodgerdad View Post
Wow, looks like it froze on at the body, not the threads!
Even the threads were stuck tight...intensely corroded. I forget...bike was left dormant with unstabilized fuel for 5 or 6 years, if I remember correctly.

Using the right sized screwdriver for the pilot head... and just enough force to remove, meanwhile NOT damage the pilot head, carb threads or housing is the trick. It can get nerve wracking, frustrating and difficult...sometimes must resort to drilling. Ugh.

But quite rewarding when out...then further treatments...new pilot jets and the realization that you've saved them from the scrap heap. The owner (who had no idea it was this bad until i sent pics and described) was ecstatic. He understood the effects of the long dormancy.
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Old November 26th, 2018, 03:14 PM   #56
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back to topic-

I've received DD's carbs already...

Findings.....an immediate, as received wet test revealed a very high float level on the RH carb (ta-da!) I suspect worn float valve tab spring and/or poor setting by someone prior, I'll see when I replace the float valves and setup.

Various vac hoses very loose at 4 points....very possible source of vac leaks when hot.

Synch was slightly off, rail orings were flat...

I think the high float level in the RH carb is the bad guy here....the reason why adjusting his rh pilot screw had no effect, and the bike ran better when the LH side was leaned (the LH side right on the edge of being high, too.)

Otherwise will come out mint, in & out. All new orings, float valves, likely vac hoses, proper setup (where I'll make corrections) , stainless buttonhead screws icing on the cake .....we shall see.
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Old November 27th, 2018, 02:15 PM   #57
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I'll send you my carbs soon. I just need to recover funds from all the BF shopping.

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Quote:
Originally Posted by ducatiman View Post
back to topic-

I've received DD's carbs already...

Findings.....an immediate, as received wet test revealed a very high float level on the RH carb (ta-da!) I suspect worn float valve tab spring and/or poor setting by someone prior, I'll see when I replace the float valves and setup.

Various vac hoses very loose at 4 points....very possible source of vac leaks when hot.

Synch was slightly off, rail orings were flat...

I think the high float level in the RH carb is the bad guy here....the reason why adjusting his rh pilot screw had no effect, and the bike ran better when the LH side was leaned (the LH side right on the edge of being high, too.)

Otherwise will come out mint, in & out. All new orings, float valves, likely vac hoses, proper setup (where I'll make corrections) , stainless buttonhead screws icing on the cake .....we shall see.
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Old November 27th, 2018, 02:56 PM   #58
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ok
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Old November 28th, 2018, 08:39 AM   #59
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@dodgerdad carbs are on the way home
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Old November 28th, 2018, 08:49 AM   #60
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@dodgerdad carbs are on the way home
Eager to try them out. Thanks!
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Old November 28th, 2018, 08:49 AM   #61
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Old December 5th, 2018, 08:33 PM   #62
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Here's an update to my saga. I sent the carbs to ducatiman (while I adjusted the valves) and he found the sync to be a little off and bad fuel float heights. He did a complete cleaning and service and promptly shipped them back.

12/1/2018:
The good: The bike certainly benefited from the valve adjustment and carb tuning, it even sounds much better. I took it for a 10 mile spin on suburban streets and found the throttle response to be very smooth & crisp. Acceleration and overall cruising felt much more responsive.

The bad: It fired up fine but after about a minute I closed the choke and it idled pretty crappy until it was at FULL operating temperature. RPM's would hang a little on deceleration and rev's fluctuated a tiny bit. Once It got up to temp, I adjusted the idle speed to 1700. Riding around town I encountered the exact same issue from before where it would idle at 1700 or 1100, one or the other. The tach needle didn't fluctuate much but I'd be at a stop and SOMETIMES the idle would just drop to 1100. Other times I'd come to a stop and it would be at 1700, whereas other times I'd stop and it would be at 1100. I'd estimate a lower idle was present about 25% of the time, mostly it ran at the desired 1700.

I've only adjusted the idle and haven't touched the mixture or sync screws. It ran without stalling so I might have to learn to live with it though I'm worried about riding it in the local mountains where the altitude may exaggerate the symptoms. Ducatiman suggested a carb sync should help eliminate the ongoing problem.

Update (12/5/2018):
I planned to sync the carbs this afternoon but when I went to fire it up to ride/warm-up it took a good 5 minutes to get it started. It ran horrible. Instead of riding it I "helped" it idle until it reached operating temp. At that point it idled but the tach needle was fluctuating and when I gave the throttle a quick acceleration it either bogged down or it stalled out. Needless to say I I'm in the same boat.

I expect to have time Friday/Saturday to "aid" it to operating temp and attempt to sync the carbs. I must admit I'm almost at the end of the line. If The sync doesn't prove 100% I'll drop it off at a local shop for a diagnosis. If they can't track it down for a reasonable price my ninjette will be making an appearance on craigslist by year end.

To be continued...
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Old December 5th, 2018, 10:44 PM   #63
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Don't mess with carbs! They are now perfect and contributing nothing to issues. Look at and measure following areas:

- compression test, both plugs out, WOT when cranking

- little filter screen in fuel-inlet hose. Try running without it

- ride with gas cap open,any better? Do whistling gas-cap mod

- vacuum going to petcock. Make sure line isn't crimped when tank lowered

- use rubber-T and measure vacuum level at petcock

- petcock flow-rate. Aim fuel inlet hose into measuring cup. Apply at least 7 in.Hg
to pecock for 1-minute. How much fuel flowed into cup?
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Old December 6th, 2018, 06:51 AM   #64
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Are you certain the fuel is fresh? Is the tank perfectly clean? Any bad gas in the tank will continue to give you problems even if you add fresh gas on top of it. You may need to completely drain the tank and floatbowls to be sure.

Have you checked for vacuum leaks? Some of your symptoms suggest there may be one.

If everything else checks out, the only thing I would adjust on the carbs would be the idle mixture. Make a note of where they are now before making adjustments, but I wouldn't hesitate to see if that may cure the issues.

Checking the carb sync with vacuum gauges would be a good idea, but most likely they are close. If not, there may be other issues contributing to the problems.
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Old December 6th, 2018, 06:56 AM   #65
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Talk to Gordon and get his advice. He may suggest something simple like adjusting the idle a little richer.
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Old December 6th, 2018, 08:19 AM   #66
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Yes!

Quote:
Originally Posted by DannoXYZ View Post
Don't mess with carbs! They are now perfect and contributing nothing to issues. Look at and measure following areas:

- compression test, both plugs out, WOT when cranking

- little filter screen in fuel-inlet hose. Try running without it

- ride with gas cap open,any better? Do whistling gas-cap mod

- vacuum going to petcock. Make sure line isn't crimped when tank lowered

- use rubber-T and measure vacuum level at petcock

- petcock flow-rate. Aim fuel inlet hose into measuring cup. Apply at least 7 in.Hg
to pecock for 1-minute. How much fuel flowed into cup?
I think you're on to something in relation to the petcock. I've done some searching and have found many posts & videos which display the exact issue I'm having resulting from a bad petcock (diaphragm). Oddly, it seems more prevalent in Harley/twin cruisers but they describe the same symptoms (hanging idle at low rpm, running rich, bogging under rapid acceleration, inconsistent idle when coming to a stop, etc.). Recently when I've removed my tank I always find a decent amount of fuel in my vacuum line (I assume this is abnormal).

I don't own a vacuum gun/tester but I'm optimistic because the symptoms are identical to what I've found when researching this. I don't feel like messing with ordering parts and rebuilding so I'm going to see how cheap I can get a new OEM unt for, preliminary searches put it around $95. That's steep but if it brings my bike to 100% I'll pay for it with a smile.

PS I've experienced no hydro locking/whistling when riding and the stock fuel screen has been removed and replaced with a small inline filter.
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Old December 6th, 2018, 08:59 AM   #67
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Quote:
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PS I've experienced no hydro locking/whistling when riding and the stock fuel screen has been removed and replaced with a small inline filter.
That can also cause fuel deliver problems.

It does sound like you may have a problem with the petcock due to the fuel in the vacuum line, but because of the short fuel line from the petcock to the carbs an inline filter can often create a low spot that will cause flow issues.

Ducatiman usually recommends the stock filter inside the line at the carb inlet IIRC.
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Old December 6th, 2018, 09:24 AM   #68
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You don't need a vacuum gun, a gentle sucking with your mouth on the vacuum hose should open the petcock. They're made to stay open even when you open the throttle and there isn't much vacuum.
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Old December 6th, 2018, 09:27 AM   #69
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Quote:
Originally Posted by dodgerdad View Post
I think you're on to something in relation to the petcock. I've done some searching and have found many posts & videos which display the exact issue I'm having resulting from a bad petcock (diaphragm). Oddly, it seems more prevalent in Harley/twin cruisers but they describe the same symptoms (hanging idle at low rpm, running rich, bogging under rapid acceleration, inconsistent idle when coming to a stop, etc.). Recently when I've removed my tank I always find a decent amount of fuel in my vacuum line (I assume this is abnormal).
Fuel within the vac line indicates a torn, ripped, pinholed or otherwise damaged, unable to seal diaphragm (within the petcock). The diaphragm is activated by engine vacuum (on the back side of the petcock) and when activated, allows gravity fed fuel to flow (on the front end). The 2 functions are separate, the diaphragm should absolutely NOT be not allowing "leakage" between front and rear sections. I've also encountered them MISSING return springs within petcocks, lost or discarded? Gotta look inside.

Its a vac leak, but sucking unmetered fuel, air or an intermittent mix of both, whacking the mix in the LH cylinder out. MUST deal with this...may very well be the underlying issue.

Darn....now knowing fuel is present in the vac line...I wish you had sent it (the petcock) with the carbs.

Either a new, confirmed good used, or a rebuild of yours is definitely called for. And testing thereafter, can easily be done on the bench.

If you have any doubts doing, send it on, labor on me.
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Old December 6th, 2018, 09:35 AM   #70
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Thanks for the feedback & assistance. I'll repost after my next step.
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Old December 6th, 2018, 11:45 PM   #71
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Quote:
Originally Posted by Triple Jim View Post
You don't need a vacuum gun, a gentle sucking with your mouth on the vacuum hose should open the petcock. They're made to stay open even when you open the throttle and there isn't much vacuum.
i wouldn't do that if he's finding gas in petcock's vacuum line.

hand-operated vacuum pump will help troubleshoot leaking diaphragm. Pump it up to 5-7 in.Hg to get fuel flowing. Then watch gauge. If vacuum drops and you have to keep pumping to maintain same vacuum reading, shows diaphragm isn't sealing.

here's procedure for R&R
https://faq.ninja250.org/wiki/Rebuil...tcock/fuel_tap
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Old December 7th, 2018, 06:18 AM   #72
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Originally Posted by DannoXYZ View Post
i wouldn't do that if he's finding gas in petcock's vacuum line.
You're right, if there's gasoline in the vacuum line it would be obvious you shouldn't suck on it, and that the diaphragm is ruptured.

If there's no gasoline in the line, or for a bench test, I check them by sucking on the hose and then blocking the end with my tongue. After waiting 5 or 10 seconds, if it's still stuck to my tongue, it's good.

The operation of the valve, can be done by mouth with the petcock in place and gasoline in the tank.
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Old December 8th, 2018, 03:47 PM   #73
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Preliminary update 12/8/2018

I installed the new petcock valve this afternoon. Bike fired right up and ran much better. It wasn't 100% when cold but I attribute that to there still being some residual fuel in the vacuum system (though I tried to dump out what was in the hose).

Once it was fully warmed up there were no noticeable idle fluctuations or bogging upon acceleration. I was able to set the idle speed and it maintained itself nice and steady.

The bike never left my driveway but I plan on taking it for a short ride tomorrow and that will hopefully determine everything. I'm eager to see how it runs tomorrow morning when I fire it up cold.

I'll post back tomorrow.
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Old December 8th, 2018, 04:21 PM   #74
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Sounds promising. But may still benefit from a pilot screw adjust, now that its apparently stable.
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Old December 8th, 2018, 06:04 PM   #75
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Woo hoo!! Good job!!!
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Old December 8th, 2018, 08:05 PM   #76
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Glad to hear she's running better!
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Old December 9th, 2018, 12:47 AM   #77
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the spring in the petcock sometimes needs a little pull especially if it's been sitting along time. I have good silicone vacuum hose if u need some.
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Old December 9th, 2018, 07:52 AM   #78
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A weak or even missing spring would, in fact allow runaway gravity fed fuel flow, (yes, a spring "stretch" can correct this) but only a torn, pinholed diaphragm would account for fuel behind it..... into the vac section, allowing unmetered fuel/air sucked in by the engine.

that is (was) @dodgerdad stated condition, fuel in the vac line.

The 2 subsections of the petcock, the front end (fuel) and rear end (vacuum) are distinctly separate sealed paths....once violated, correction is mandatory.

In any case, many problems are associated with these vacuum type petcocks as the bikes begin to age, accentuated by long periods of disuse, ethanol fuel and even outdoor storage (open to atmosphere thus accelerating internal corrosion).
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Old December 9th, 2018, 02:00 PM   #79
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Conclusion 12/9/2018

I started the bike this morning (about 60 degrees) with the choke open and it ran at a VERY low RPM. I held the throttle open just a tiny bit for about a minute. Once I closed the choke it ran about the same.

I didn't stick around much, so I took off on a 14 mile ride through stop-and-go suburban streets. The bike rode nice and smooth with no bogging at acceleration from a stop.

Idle is not what I'd call perfectly steady but at this point I'm probably being too picky on an 11 year old carbureted 250cc bike. It may likely benefit from a carb sync but if the bike continues to perform as it did today, I'll be able to live with it, after all I bought it for cheap with the intent of entertaining myself with a low budget build/project.

I'd like to thank everyone who's offered up their help/ideas and would like to point out that this forum was what sealed the deal for me in choosing a ninjette when I was considering what type of bike to buy for a project. It's nice to find myself amongst friendly enthusiasts.
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Old December 9th, 2018, 03:59 PM   #80
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What is "idle not perfectly steady"? To what degree? Was there actual improvement after petcock renewal?

I'll still submit further tuning, an accurate carb synch followed by setting the pilot screws with the bike hot will nail it down further.

Going forward, monitoring the fuel consumption a good indicator of overall system "tune" as well. And using an ethanol additive/stabilizer in every tank will keep the carb circuits truly clean. I've had really good results with the Stabil 360 Marine (as I've raved about before)
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