Carb question.....

[motoman]

Hey Brant,

I know the VF500 coils are USED! I have the same/similar bike, 81 Special, or at least the same carbs!!!! Mine just have 45 pilots, and 117.5 mains because of my intake/exhaust mods and little big bore kit.

However, I am running very strong DynaTek Green 3.0 ohm coils that put out ~35kV of spark energy. I would think that the VF500's are still old stock at may only put out 15 or so KV, don't know for sure??? I'm running non-resistor caps and non-resistor plugs....ol AC/Delco stuff, but mine are nice and tan, no black sooty residue.

I also run E-10 fuel, premium with a splash of sea foam in the tank almost every time I fill up. The Premium fuel is supposed to burn slower, after my little big bore kit, with the mildly increased compression, and intake/exhaust mods, I didn't want to run the chance of detonation and holing my new pistons so that's why I started using premium. And with my helmet and slightly noisy exhaust, I don't know if I would be able to hear/feel if I were to experience any detonation IF I were to try to use regular, so I don't.

So....like you're saying, perhaps is still is an ignition problem....I know folks have reported good results with the VF coils, but do you really know how much spark energy (KV) they put out??

T.C.

Yup.....that seems to be the million dollar question.......but, its running GREATLY improved as opposed to the fading 3ohm stockers that were at 2.3ohms.......both the originals AND the extra set!

As far as detonation, trust me, you'll hear the tinging goin' on in the exhaust when it happens. Header pipe 'hammerin' will be more noticable pullin' steep hills under load seems to fist indicator, as it is when on the lean side pullin' grades.

Gettin' rally time, so don't wanna get too involved, but for grins I'll go back thru the main plug-in behind fuse panel(don't hurt to re-clean and dielectic lube anyways), timing lite and check TCI's mechanical advance funtion, and check other two units while at it. No reason to packin' around 4RO TCI's if their not fuctioning properly.

Today's test ride, bike functioned better with mid 90degree temps as opposed to the 102temp of the other day,(same rolling hill 65mph 4-lane). Removed plugs at home, and the lower RPM/speed TO there with no stops had the four plugs at a dark,dark choc. brown, with down inside and around the base still black. Same route home previously had electrode/ground strap black, so something improved....somewhere, unless it was just mother nature!
Out on the open rode, black down in around the inside of plug stays black with the electrode/ground going white.

BTW, the lean tinging in the exhaust upon take off with little throttle the other day was due to unrealized low fuel...........till it just flat died on me today on highway..........hmmmm, flipped petcocks to prime, immediatly restarted, went to reserve....all still good.......hmmmm, tinging/pinging went away upon take-off.

So, sorry for the pinging to turn out to be a mis-leading factor.

[TopCatGr58]

Hey Brant,

I know the VF500 coils are USED! I have the same/similar bike, 81 Special, or at least the same carbs!!!! Mine just have 45 pilots, and 117.5 mains because of my intake/exhaust mods and little big bore kit.

However, I am running very strong DynaTek Green 3.0 ohm coils that put out ~35kV of spark energy. I would think that the VF500's are still old stock at may only put out 15 or so KV, don't know for sure??? I'm running non-resistor caps and non-resistor plugs....ol AC/Delco stuff, but mine are nice and tan, no black sooty residue.

I also run E-10 fuel, premium with a splash of sea foam in the tank almost every time I fill up. The Premium fuel is supposed to burn slower, after my little big bore kit, with the mildly increased compression, and intake/exhaust mods, I didn't want to run the chance of detonation and holing my new pistons so that's why I started using premium. And with my helmet and slightly noisy exhaust, I don't know if I would be able to hear/feel if I were to experience any detonation IF I were to try to use regular, so I don't.

So....like you're saying, perhaps is still is an ignition problem....I know folks have reported good results with the VF coils, but do you really know how much spark energy (KV) they put out??

T.C.

[bikerphil]

The VM style has a different spray configuration and is no good in our carbs, even in the late type and XJ. The BS30/96 style also comes with no holes in the side.

[motoman]

See if you can shake gezzer off the couch for input. I know he hasn't been well of late but i'm sure he still lurks.
Are the plugs consistent across all four? I had a similar issue but thought it was one of my coils but turned out to be spark plug gap. I had swithced in resister plugs and the required gap is narrower unless you remove the resister caps.
My LH runs like a top at 3 turns out. If you do a roll on in 5 th from 2.5 k and it bogs at all it's too lean in the idles
Geezer can tell you what the TCI test is and as far as iginition goes, He's the guy!You have a hybred apparently, you two need to talk.
One question though, just to prove my ignorance, whats "stock 30/96 pilots"?my LH has 42.5 mikuni's. The pilot air and jet circuit is the only one in play not matter what the throttle plates are doing.Albiet to a lessor degree once the jet needles and mains come into play.

FWIW Mack, the BS30/96 pilots are the 2-1-2-1 six holed pilots(what's in yours too, 42.5's. The XJ uses smaller size, and are VM style(no side holes),so short of givin' you a 101 on BS34 II Mikunis, that's what that is all about

As for low rpm throttle roll-on.........no stumble or hiccup from less than 2K in fifth gear.
Stock plugs, VF500coils and new 7mm hi-temp SOLID core steel wire. BTW, no hybrid here. All original Venturer I bought new, cept for the 81Special carbs, same as yours. The 80-81Standard carbs had different metering rods/main jetting than the Special.

At this point, fairly sure there's a tiny secondary ignition issue, if anything at all. Gotta watch and diagnose carefully, cause 99.5% of the time, escaping of a tiny amount of all important secondary ignition 'smoke' WILL trick you into thinking a fueling problem. That's just 'old school' rule of thumb, and works wonders on these ole' scoots. That's why I will occassionally here tell someone their carbs are having electrical issues, if I have suspect it may apply.

[mack]

ignition

See if you can shake gezzer off the couch for input. I know he hasn't been well of late but i'm sure he still lurks.
Are the plugs consistent across all four? I had a similar issue but thought it was one of my coils but turned out to be spark plug gap. I had swithced in resister plugs and the required gap is narrower unless you remove the resister caps.
My LH runs like a top at 3 turns out. If you do a roll on in 5 th from 2.5 k and it bogs at all it's too lean in the idles
Geezer can tell you what the TCI test is and as far as iginition goes, He's the guy!You have a hybred apparently, you two need to talk.
One question though, just to prove my ignorance, whats "stock 30/96 pilots"?my LH has 42.5 mikuni's. The pilot air and jet circuit is the only one in play not matter what the throttle plates are doing.Albiet to a lessor degree once the jet needles and mains come into play.

[motoman]

Hey Brant, apparently I was typing while you were! Uh....don't you mean Vac. adv. is working, not cent. since it's programmed into the 4RO TCI? And my comment about adjusting the static timing....I didn't check/realize you were talking about the 81 model with the 4RO type TCI and timing plate which is sealed, non adjustable! I had thought about taking it off of mine and using my little mill to ream out a little channel where they filled it in, so that I could "play" with the static timing and tweak it a few(5) degrees more advanced!

As for the timing light, check the SPRING with an ohmeter, but I think it will show that it doesn't really have much resistance, and that it should work just fine in line with your spark plug wire and plug for your older timing light!

T.C.

May give it a try T.C..........least I could check all three units while I was at it.

Any other thoughts are welcome. At this point, I didn't, whatever is goin on with it to become a blubbering mess from the pilot circuit next week,.... if it gets the rally 'duty', which includes the 14K of PikesPeak.

[motoman]

Hey Brant,

Okay, plenty of FIRE. With enough turns out of pilot for no decel popping, you get bog and black soot. With less turns out you get better throttle response, better plugs, but a little decel pop.

Thinking about how we are using much crappier fuel than 30 years ago with the Ethanol, doesn't burn as hot, not as much power, and so even with good fire may not burn completely when in low rpms, but with highway speeds/rpms it's getting hot enough to burn completely=clean plugs.

Do you run any additives? Trying to wrap my head around what's happening in the combustion chamber at low rpms, the pistons are not moving quite a quickly, the valves aren't opening as quickly, and so theoretically there should be more time for the fuel to burn more completely before being expelled via the exhaust...so...why is there unburnt fuel being left on the plugs. At high rpms, things are moving much faster, less time for fuel to burn, but it is possibly burning in a hotter environment. The other thing I was thinking was at CRUSING rpm the vac. adv. is kicked in MORE, so the ignition timing is more advanced giving a sooner spark so more time to burn the fuel, and at cruising the F/A mixture is also a bit more lean so again less fuel to burn!? The throttle chop is done under LOAD, so it shouldn't really be running at as much timing adv. and also more fuel being sucked in!

SO...I'm wondering if advancing the static timing a few degrees might help with the plugs...more time to burn, however you may still have the decel pop. It may be the least of two evils that you have to pick from, decel pop or sooty plugs? I would pick decel pop...and you might also be able to reduce that with just a slightly higher idle speed setting so that when you drop the throttle the butterflies don't slam completely closed!

T.C.

T.C. looks like we're headed the same direction, with two different possibilities that are as of now seemingly timing related.
Can't do anything about the static timing(81)...............but ironicly, my original 4R1 numbers matching motor has adjustable timing marks both directions from zero....go figure. The motor I have in it now is also model/yr. correct, and only 82 in production numbers later than my original............but fixed timing.

[TopCatGr58]

One thing I've considered as the issue, since just riding it and noticing the head pipes reverberate a real 'twing' sound taking off if not up on the throttle a bit and it lugs a bit, is the TCI not doing it's mechanical advance job. Have three of the 4RO's, but wouldn't think all three would be bad. Centrifical is working perfectly watching it, and has stayed free and rotates easily.

Bout the only way I know off to check that on those TCI's would be disconnect vaccum advance and hook up a timing lite. Just haven't been sure if my old school lite not being inductive(fan ate my nice inductive timing lite a couple decades back) would cause any coil issues with the added resistance thru the spring connector that goes on the plug and into the plug boot?

Hey Brant, apparently I was typing while you were! Uh....don't you mean Vac. adv. is working, not cent. since it's programmed into the 4RO TCI? And my comment about adjusting the static timing....I didn't check/realize you were talking about the 81 model with the 4RO type TCI and timing plate which is sealed, non adjustable! I had thought about taking it off of mine and using my little mill to ream out a little channel where they filled it in, so that I could "play" with the static timing and tweak it a few(5) degrees more advanced!

As for the timing light, check the SPRING with an ohmeter, but I think it will show that it doesn't really have much resistance, and that it should work just fine in line with your spark plug wire and plug for your older timing light!

T.C.

[TopCatGr58]

Hey Brant,

Okay, plenty of FIRE. With enough turns out of pilot for no decel popping, you get bog and black soot. With less turns out you get better throttle response, better plugs, but a little decel pop.

Thinking about how we are using much crappier fuel than 30 years ago with the Ethanol, doesn't burn as hot, not as much power, and so even with good fire may not burn completely when in low rpms, but with highway speeds/rpms it's getting hot enough to burn completely=clean plugs.

Do you run any additives? Trying to wrap my head around what's happening in the combustion chamber at low rpms, the pistons are not moving quite a quickly, the valves aren't opening as quickly, and so theoretically there should be more time for the fuel to burn more completely before being expelled via the exhaust...so...why is there unburnt fuel being left on the plugs. At high rpms, things are moving much faster, less time for fuel to burn, but it is possibly burning in a hotter environment. The other thing I was thinking was at CRUSING rpm the vac. adv. is kicked in MORE, so the ignition timing is more advanced giving a sooner spark so more time to burn the fuel, and at cruising the F/A mixture is also a bit more lean so again less fuel to burn!? The throttle chop is done under LOAD, so it shouldn't really be running at as much timing adv. and also more fuel being sucked in!

SO...I'm wondering if advancing the static timing a few degrees might help with the plugs...more time to burn, however you may still have the decel pop. It may be the least of two evils that you have to pick from, decel pop or sooty plugs? I would pick decel pop...and you might also be able to reduce that with just a slightly higher idle speed setting so that when you drop the throttle the butterflies don't slam completely closed!

T.C.

[motoman]

Brant,

It's been too long, like, more than five minutes (Teflon brain, nothing sticks!) so I can't remember if we checked them or not but are the Pilot Air jets and passages clean with the right size #185 Genuine Mikuni air jets?

Same with the #140 Main Air jets but those aren't likely to have been changed -- ever! because they're pressed instead of threaded.

.

Yes, I had replaced those air jets two summers ago seeing they were K&L junk. As of now, ALL jetting is G.Mikuni.

One thing I've considered as the issue, since just riding it and noticing the head pipes reverberate a real 'twing' sound taking off if not up on the throttle a bit and it lugs a bit, is the TCI not doing it's mechanical advance job. Have three of the 4RO's, but wouldn't think all three would be bad. Centrifical is working perfectly watching it, and has stayed free and rotates easily.

Bout the only way I know off to check that on those TCI's would be disconnect vaccum advance and hook up a timing lite. Just haven't been sure if my old school lite not being inductive(fan ate my nice inductive timing lite a couple decades back) would cause any coil issues with the added resistance thru the spring connector that goes on the plug and into the plug boot?

[3Phase]

Brant,

It's been too long, like, more than five minutes (Teflon brain, nothing sticks!) so I can't remember if we checked them or not but are the Pilot Air jets and passages clean with the right size #185 Genuine Mikuni air jets?

Same with the #140 Main Air jets but those aren't likely to have been changed -- ever! because they're pressed instead of threaded.

.

[motoman]

Probable cause since it loads up on slow speed and RPM. Runs fine at High RPM. Just my $.02

Was one of my thoughts also since one of them has a bit of the coating wore off it, but it does mic out the same as others and mic. out round. Definitely a good thought, AND one least thought of.

[vedgar]

Worn needle jet ? Ovaled ?

Probable cause since it loads up on slow speed and RPM. Runs fine at High RPM. Just my $.02

[motoman]

.....and throw all the input you got at me........somthin' will stick.

As many know, I've be arguing with the Bentley over several yrs. now.....get irritated and park it under cover in the man-cave.

Carbs are 81Special with the 5GL16 metering rods, stock mains(110's), stock pilots(BS30/96).......stock everything on bike. Eight floats dead-on at .905in.(23mm).
idle mixes when set at highest in.vac. (3.25 turns out) are WAY too rich. Re-set .lean drop' methid put them at 2 3/8 out from seated. Smoothed it out substantually under slight throttle application in the 3K and under range. Plugs still showin' dusty black in the idle/low rpm range. Decel with this mix setting will ever so slightly give a muffled pop.....on occassion. 3.25 turns out, no pop, but a bit of a load-up with initial take off. Smooth and no loading up on take off 2 3/8 turns out.

Low voltage issue resolved previously between I and 3Phase.....12.9 @ battery........12.9@ coils(Honda VF500 3ohm), which included making up of new 7mm high-temp wire core wires.

Main circuit is happy with the stock 110's, other than I guess to expect a white plug after 20mi. of constant 70mph@100degree temps, and that crap that's still called gas. That was from a rolling hill ride@ constant 70mph/4600rpm, doing a throttle/kill switch 'chop'.
Come back down in the pilot circuit locally headed home, and pull plugs after, they are starting to soot up. Blacked up, amazingly it doesn't even hint at misfiring, so the Honda coils seem to be doing their job. On the good side, whatever the burn rate is, depending on circuit it's running in, all four plugs show identical.

Hopefully that's enough info for someone to decifer the possibilities that may correct it........IMO, at this point, it's gotta be somthin' simple I've missed, since overall bike is smooth soundin' out exhaust when on the slab, with same tone again as it had when new....the reconizable low decibel hum of an XS11.
Thanks again for any and all input......don't be bashful.