Guest ArizonaRC36 Posted October 10, 2012 Share Posted October 10, 2012 A few months back, had posted on here my '96 VFR's running issues. The issues of not completely running smoothly when trying to maintain throttle at certain speeds, nearly always in the 1/8 throttle open or less. Last couple weeks, basically returned the bikes carbs back to OEM (had put in a jet kit). Bought new main jets and pilot jets and put them back in place of the jet kit sizes. New float needles as well. Carb was fully re-cleaned of course to make sure prior to bolting everything back together. New OEM air filter put in, instead of the K&N. Airbox with snorkel in put back in place of the de-snorkled. Fuel pump is NOT OEM though, as I had installed a Facet one (correct one to match required specs: model Facet 40171) Only have a Delkevic slip on exhaust. Fuel/air mixture screws are turned out 4 turns total. Yes, I know this is probably way too much... but if not, the issue seems even more noticeable if screws were turned out 2 1/2 to 3 turns. It's only is this throttle position is this what I am experiencing. Is there something I'm missing that might need replacing? I've pretty much replaced all the carb guts except floats and new diaphram/slides. Would there be a possibility that the (using the microfiche name description) part no. 16510-MZ2-650 VALVE ASSY., AIR CUT may need to be replaced or bad?? Can't think of what else is causing this. New carb boots, vaccum lines, new nipple end caps too. Checked fuel coming out of petcock... flows out really fast. New fuel filter, spark plugs are new again and from past post... pretty much all new everything electric, from stator, rec, pulse coils... you name it, it's been replaced new. Any suggestion for this possible low circuit issue or worse, would be greatly appreciated. Link to comment Share on other sites More sharing options...
NakedViffer Posted October 10, 2012 Share Posted October 10, 2012 Oh boy, seeing this just reminded me, I totally forgot to reply to your message. I had left it open just so I would remember to reply, and now that I think about it.. I'm pretty sure the computer had been restarted when I got back to it.. Sorry, dude! By the looks of the problems you are having, I'm guessing you had a DynoJet kit installed previously? You didn't mention if you put the stock jet needles back in? Link to comment Share on other sites More sharing options...
Guest Posted October 10, 2012 Share Posted October 10, 2012 Oh boy, seeing this just reminded me, I totally forgot to reply to your message. I had left it open just so I would remember to reply, and now that I think about it.. I'm pretty sure the computer had been restarted when I got back to it.. Sorry, dude! By the looks of the problems you are having, I'm guessing you had a DynoJet kit installed previously? You didn't mention if you put the stock jet needles back in? No worries man! No Dyno Jet kit, was a shop on Ebay that supplied larger main jets, larger pilot jets and extra shim for needles (retained stock needle) Link to comment Share on other sites More sharing options...
Member Contributer rangemaster Posted October 10, 2012 Member Contributer Share Posted October 10, 2012 Did you poke a .011 wire (guitar string) down at least an inch or so into the jet (pilot, idle, slow speed, whatever) that doesn't come out? Mine would surge around 3000 rpm with the throttle barely cracked open until I cleaned all the fixed jets. I used an eyedropper to put some Berryman's Chemtool in the jet to soften up whatever was in there. Runs great ever since. Link to comment Share on other sites More sharing options...
Guest Posted October 10, 2012 Share Posted October 10, 2012 Did you poke a .011 wire (guitar string) down at least an inch or so into the jet (pilot, idle, slow speed, whatever) that doesn't come out? Mine would surge around 3000 rpm with the throttle barely cracked open until I cleaned all the fixed jets. I used an eyedropper to put some Berryman's Chemtool in the jet to soften up whatever was in there. Runs great ever since. I can pull the carbs off again and give it another shot gettin' them all cleaned. We were pretty thorough... but never know. :D Link to comment Share on other sites More sharing options...
NakedViffer Posted October 10, 2012 Share Posted October 10, 2012 Ok, being the stock needle, its got a constant taper all the way down, so it shouldn't really cause the stumble you describe. I think Rangemaster may be on to something, a little piece of trash could be hung up in a passage somewhere blocking just enough of the low speed circuit to give you that part throttle problem. If you don't have a guitar string, you can find whatever copper wire, or I've even used a bristle pulled from a wire brush a couple times. Try and take particular care to blow compressed air, or carb cleaner if you have no air source, and blow through the pilot jet hole (jet removed), while probing the low speed holes with the wire. If you aren't familiar with my terminology, the small holes just under the bottom of the throttle plate are the low speed holes, and where the pilot jet squirts its fuel out. Link to comment Share on other sites More sharing options...
Guest Posted October 11, 2012 Share Posted October 11, 2012 Ok, being the stock needle, its got a constant taper all the way down, so it shouldn't really cause the stumble you describe. I think Rangemaster may be on to something, a little piece of trash could be hung up in a passage somewhere blocking just enough of the low speed circuit to give you that part throttle problem. If you don't have a guitar string, you can find whatever copper wire, or I've even used a bristle pulled from a wire brush a couple times. Try and take particular care to blow compressed air, or carb cleaner if you have no air source, and blow through the pilot jet hole (jet removed), while probing the low speed holes with the wire. If you aren't familiar with my terminology, the small holes just under the bottom of the throttle plate are the low speed holes, and where the pilot jet squirts its fuel out. Will do on those suggestions... The carbs sync was good... cylinders 2,3 and 4 were 21mmHg and cylinder 1 was 20mmHg Link to comment Share on other sites More sharing options...
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