bike acts up low rpms but only when clutch pulled out

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have an issue sometimes with the bike where ill be riding and from a stop or just riding in low rpms id say below 2000 my bike will misfire i believe, maybe its spark detonation but im not sure if something like that constantly happens or can be intermittent as in not every time i take off. i will say if i have the clutch at its friction zone and i ride it for a bit the bike will be fine, but if i use the clutch correctly it will tend to act up, doesnt happen after i believe 2000 but i might have to take a ride to see where it stops. when the bike idles high id say 14-1500ish i will hear a misfiring thats very rapid but it does cut out sometimes, 1100 its perfectly fine.

with clutch pulled all the way in or neutral bike has no issue climbing up revs but when under load it will act up, doesnt always happen but it did today and i would like to get rid of the issue.

i believe my timing is fine as the bike doesnt have an issue climbing up every single time i go from a stop and the bike doesnt necessarily need to be warmed up for it to happen, but i have replaced 2 spark plugs since ive ran the bike more consistently and had to replace them both within 2 weeks of eachother, it was a different cylinder and not firing from the same coilplug but these spark plugs were very new, i always have ngk d8ea plugs in the bike.

can i do any tests without running the bike? i was thinking of a spark test but the thing with that is my bike runs on all 4 at idle and once im up past 2000ish all 4 are forsure back on, and i cant just run the bike on 3 cylinders to see how the sparkplugs act up climbing the rpms because the bike doesnt act up in neutral.

my only other thought was that i might be running lean but i believe im at 2 and a half turns out with my mixture screws and since i have a stock intake nothing probably needs to be upsized, the bike runs very smooth throughout with no flatspots or crazy jumps in how it accelerates. ill inspect the plugs to look for any damage and just to see how the colouring is.

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https://www.youtube.com/watch?v=Fob-w9CS-QI

video of plugs for yall to see

[Rob S.]

Right off the bat, I'd say 'riding below 2k rpms' is revving too low, even if it were an 1100. I would do zero pulling below 2k on a 650.

And I'm sure others will note that it's showing symptoms of an intake leak.

[tom203]

I’d ride it around in this 1500 to 2000 rpm somewhere safe. Then stop and pull spark plugs..have wrench and gloves….

my bike will pull fine at 1500 even in fifth without complaining. I cruise thru 25mph village zones regularly in fifth ….

[Rob S.]

I’d ride it around in this 1500 to 2000 rpm somewhere safe. Then stop and pull spark plugs..have wrench and gloves….

my bike will pull fine at 1500 even in fifth without complaining. I cruise thru 25mph village zones regularly in fifth ….

Stealth mode...I get it. Here's the thing: something gets in your space. You need two or more downshifts to get to escape velocity. Not enough time. After all, a 650/4 (or even an 1100/4) is not a 1670 cc V twin, which never seems to need a downshift.

[timebombprod]

im generally riding 45+ once im out my neighberhood so im usually up in the rpms a bit, havent rode yet will either tonight or tomorrow its basically dark at 6pm since the clocks had been turned back today.

is there any other locations a vacuum leak could happen other than the intake boots? theyve been replaced aswell as the o-rings twice. ive rode to school and back and it went straight back to 1100 everytime i pulled in the clutch and i tend to fool around a bit on the empty roads there and back so it doesnt seem to be because of simply going to 9000 having some airway open up causing a vacuum leak. could it be one of the engine gaskets? more so the valve cover gasket, i say that because if i had a bad headgasket my compression numbers should show that, and theyre all at 150.

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andddd its actually up to 2500 rpm not 2000, i believe my full advance is 3500 rpm and like i said the bike acts fine in neutral or riding the clutch but not on its own weight at those low rpms. i will have to do the ride at those speeds and check the plugs out but what i can say is it acts alot like if you have a faulty petcock that doesnt deliver enough fuel causing it to not want to move correctly, so maybe im leaning out at those rpms, not sure ill have to do the riding at low speeds and check the plugs to findout.

[pdqford]

If your 650 has a vacuum controlled peacock, perhaps lugging the engine down to low RPMs, it may not make enough vacuum to keep the petcock fully open?

How does it behave if you run with the peacock on prime?

[timebombprod]

If your 650 has a vacuum controlled peacock, perhaps lugging the engine down to low RPMs, it may not make enough vacuum to keep the petcock fully open?

How does it behave if you run with the peacock on prime?

ill have to try that tomorrow, maybe ill get an answer, good quick and easy way to check.

ill inspect the vacuum line aswell and make sure i get a tight seal going on.

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well, putting bike on prime didnt seem to fix it, thatd be nice if i just needed to secure my vacuum line a bit more but nope. however the bike acts fine when its cold but when warm that is when it acts up. i take 5 minute rides to the skatepark and ill be there about an hour or two, when i go to ride back that is when it definently acts up, and it generally idles a bit higher than it should. gonna have to ride those low rpms and check the plugs, i guess the issue is so small i havent been too urgent to solve it as i am able to ride anywhere anytime with just the downfall of sounding like i just started riding everytime i take off and ride my clutch a good bit. i guess if i keep doing this ill need to replace the clutch which will be an actual job so i should get to this sooner than later lol.

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did another quick test, and i guess that brings up a question, when the bike is fully warmed up should the fuel enrichment kill the bike when pulled out? if my bike is at idle fully warm i am able to pull the fuel enrichment rail out and the bike will climb up in rpms. im not pulling the rail out all the way as that does make it want to die out but id say i pull it out close to halfway and it will foresure rise the idle.

ugh this is gonna be a headache for a small issue, i have replaced the intake boots before so they are new, aswell as the o-rings, if i do a spray test on them i can almost guarantee that the idle will not rise as i have done this test plenty before, the breather hose is hooked up correctly and i have a stock intake so jetting should not be the issue. my mixture screws are atleast 2 1/4 turns out and they actually run good that way. if i try them at 1 1/2 turns the bike has a very slow, airy acceleration aswell as the deceleration. the bike will rev up no problem at all in neutral, but under a load it will act up to 2500 rpm. can a valve cover leak be a culprit?

my vacuum line for the petcock is hooked up just fine but i do not have any sort of clamp holding it down which i will be changing that soon but i dont know if that could cause my issue.

any suggestions? quick tests? i will go ahead and ride it around right now in the low speed rpms and see what the plugs look like, i will be back with an update soon.

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went ahead rode around 1100-2300 rpm, didnt go to 2500 to make sure i stayed in the range of where my issue is occurring, the plugs look just like they do in this video. i went ahead and did a spray test aswell just to fully ensure that i do not have a vacuum leak coming from the intake boots, and there was no idle rise at all when spraying each intake carb boot on both carb and cylinder side. i will say when riding at around 2000 rpm the bike will jerk a bit, its not violent but you definitely feel it and im guessing that jerk is a proper combustion, but i dont know it all. again i can rev in neutral all day long no problems but only under load the bike will act up at these low rpms.

i messed with the fuel enrichment again while letting it idle in the driveway and at 1/3 to about halfway pulled out it rises the idle up but if i pull it out anymore it will drop the idle trying to kill the bike.

https://youtu.be/Fob-w9CS-QI

[Rob S.]

A little too white and ashy (?),

a little too lean?

[timebombprod]

A little too white and ashy (?),

a little too lean?

if thats how they look in the video yes that must be it, but the thing is i have a stock intake i only added an exhaust, if i put in the next size up on pilot jets the bike runs way too rich even from half a turn out, on stock pilots i have to get it to about 2 1/4 to 2 1/2 turns out to have a nice throttle response. could it be something to do with fuel height? i had a shop set the float height for the bike and the guy said he weighed the floats and set the height but he didnt actually set it according to the fuel level itself.

i wouldn't say there's physical ash on the plug but then again i haven't really wiped my finger on them and seen what comes off.

edit: i should clarify that i do check how the plug looks when i was tuning the pilots on the bike so when i say it ran too rich the plug was completely fuel fouled.