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Post by harleyracer59 on May 10, 2019 23:30:22 GMT -5
whats up y'all! so I have a weird issue: on my orange 84' aero/ tact, when at full throttle for plug chop (40-45mph) I hit kill switch and scooter accelerates. it goes faster for 2-3 seconds then slows down. at a stop idling switch works normal. but if accelerating on throttle switching the kill scooter almost seems to clear out and pick up speed. as if I shut fuel off on a race car. how they lean out before engine dies. that how this feels. except im not shutting fuel off, im supposed to be stopping ignition/ spark. it gets a few seconds of run on and actually starts pulling mph before it starts to actually die.... any one got an idea as to what causes this? is my spark plug too hot and glow plugging? it feels like im running rich. that was the initial reason for plug chop. then this situation occurred. so I turned around went back down street hit the kill switch again and same thing, except down hill it picked up 5mph. as soon as I let off throttle it dies and wont come back if throttle is given again.. I haven't held the throttle to see how long it will go but it seams the only stopping factor is I let off throttle. stupid part is if it ran like this glitch. I wouldn't be doing the plug chop... any ideas on this would be great. im stumped. never seen this before accept on an alcohol dragster when fuel is shut off at end of run. which is normal as the engine leans out. thanks  |
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Post by 190mech on May 11, 2019 4:04:37 GMT -5
Sounds like youve got preignition/detonation going on there,,compression too high,hot plug,sharp areas in combustion chamber,restrictive exhaust are a few things to check..It surely isnt good for that engine!I guess first would to check that the kill switch IS working at high revs(good contacts,grounds etc),,
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Post by oldgeek on May 11, 2019 5:16:31 GMT -5
Its too hot. glow plugging like you said!
Did that to my Vino one time during initial tune. I thought it was a tad lean, let my buddy ride it but forgot to tell him to take the short loop. He took the long loop and when he got back it would not shutdown!
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Post by harleyracer59 on May 11, 2019 13:02:57 GMT -5
this is what I figured. the plug is a bpr6hsa. it was a little on lean side but there was some chocolate brown mixed in with the little bit of whitish grey. and no specs of metal were found on insulator, like you usually see with preignition.
I wonder if its the raised center electrode the plug has? although I thought a raised electrode put the spark further into the combustion chamber and kept the plug cooler?
there was a weird popping heard out exhaust on longer full throttle pulls. never heard this before on any engine. timing is advanced but no ping or detonation heard.
I swapped the main jet from 110 to 120 last night. its a 20mm mikuni flat slide. ill ride to the auto parts store and pick up a couple plugs. ill get an 8 with the raised electrode and a 6 with the normal/ recessed electrode and report back with findings.
thanks guys!!!
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Post by 90GTVert on May 12, 2019 12:41:11 GMT -5
I don't know those engines, but 6 series NGKs sound really hot for a 2T to me. I use 8s in all of my stock and sport-ish stuff up to 110cc. Most seem to end up between 7 to 9 heat range NGKs... but again I'm used to Minarelli/clones. I've always used BR8HS, but some use BR8HSA or BPR8HS. Oddly enough, I took pics of my different plugs this morning, long before I checked this thread out. I bought a few to check out when I was fouling plugs, but then it turned out to be a CDI issue. I should also mention plugs with -10 suffix. I use those at times (BR8HS-10) if they're cheaper. They have a 1mm gap, so I just gap them where I want them if it saves me money. I check 'em anyhow.  |
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Post by ThomasTPFL on May 12, 2019 18:21:47 GMT -5
How does the ignition work on those? Is it points? CDI? TCI?
TCI I could see a possibility of it going off like the old points go-kart kill switch trick. That the stator ignition coil is pushing enough energy to fire the plug even with the signal grounded. It'd cause a change in timimg, but you'd still have a regular spark.
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Post by harleyracer59 on May 12, 2019 20:06:22 GMT -5
How does the ignition work on those? Is it points? CDI? TCI? TCI I could see a possibility of it going off like the old points go-kart kill switch trick. That the stator ignition coil is pushing enough energy to fire the plug even with the signal grounded. It'd cause a change in timimg, but you'd still have a regular spark. it has a cdi AC ignition. 5 wire, 6 port, single plug on the cdi. its only when running high rpm. if I do it while accelerating it will die. towards top speed, hitting the switch, the motor almost clears out and picks up more rpm. no pinging, no detonation on plug porcelain. and it will pull until I let off throttle. not sure exactly how long because at that speed I cant stay on too much longer without running out of road. thanks fotr the plug pics 90GT. the ngk 6 heat range is stock heat range. I run bpr 4 and 5 hs in winter on my Hondas with bbk and still oil injected with no problems. "they" say 8 range for extended wot rides. I think that cold a plug never heats up enough to self clean. I never foul plugs. lol I still have this issue going from a bpr5hsa, bpr6hsa, br6hs, I ordered 2 br8hs, I guess ill order a 9 and 10 and see what the findings are. ill report back  |
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Post by ThomasTPFL on May 12, 2019 20:47:28 GMT -5
I still wonder if at high rpm the trigger coil is still sending out enough to trigger the cdi even when grounded. How does the kill work on those? Does it just ground the signal to the coil or what? AC or DC cdi?
I know it’s harder to do, but what happens if you flip the key off?
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Post by harleyracer59 on May 12, 2019 22:52:07 GMT -5
its an ac coil. kill switch is to ground when in off position open in run. I want to turn the key off and see what happens, but it gets hairy at 45-50mph just flipping killswitch. it either dies and stops accelerating so nose drops. or it go go gadget rocket ships and youre waiting for it to die and engine brakes to a stop. but it doesn't till you release throttle then it shuts down like normal. no dieseling, no run on. it drags motor till clutch lets go then it coasts to a stop.
all plug heat ranges have no ping at wot or when accelerating. it does seem rich yet plug is a little on lean side. starts first kick no choke needed when cold or warmed up. idles great and when you let off throttle to stop at a light or intersection, it slows to an idle great. no stumble then catch up to idle like a rich condition
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Post by 90GTVert on May 13, 2019 10:55:56 GMT -5
thanks fotr the plug pics 90GT. the ngk 6 heat range is stock heat range. I run bpr 4 and 5 hs in winter on my Hondas with bbk and still oil injected with no problems. "they" say 8 range for extended wot rides. I think that cold a plug never heats up enough to self clean. I never foul plugs. lol I may be biased to sticking with 8s because it is not unusual for me to be WOT or near it for 10 mile straights. Many times I'm hard on it for most of a 70 mile (each way) trip to the beach and I live in a rural area with lots of back roads. That's the only way I've ever known riding. |
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Post by jackrides on May 13, 2019 11:09:20 GMT -5
If the signal isn't killed by the kill switch, make all connections in that circuit perfect. Crimped, soldered, tightened with dielectric grease. Then run a new ground wire from switch to every place it should ground to. Some kill switches ground to the handlebars which 'ground' thru the steering bearings to the frame and then let it find its way. Not nearly good enough.
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Post by harleyracer59 on May 13, 2019 18:05:45 GMT -5
thanks fotr the plug pics 90GT. the ngk 6 heat range is stock heat range. I run bpr 4 and 5 hs in winter on my Hondas with bbk and still oil injected with no problems. "they" say 8 range for extended wot rides. I think that cold a plug never heats up enough to self clean. I never foul plugs. lol I may be biased to sticking with 8s because it is not unusual for me to be WOT or near it for 10 mile straights. Many times I'm hard on it for most of a 70 mile (each way) trip to the beach and I live in a rural area with lots of back roads. That's the only way I've ever known riding. I wish I could roll wot for 10 miles straight! I might get 1 maybe 1.5 miles on a straight wot run. then theres a intersection or a street light. im not in the main city with sky scrapers and high rise buildings but the vacant patch of ground is few and far between. it would be fun to take a ride like you get to. im 15ish miles from beach. but other than taking the storm drain/ "river bed" theres atleast 25-30+ street lights from here to there. I too am a idle or wot type rider as well. I cant pin it as long as you get to. I jealous now... lol I swapped to a br8hs last night. today it actually shut down 2-3 seconds after hitting kill switch while holding wot. I was happily surprised. ill try to switch the ignition switch today and test if that changes anything. thanks again to all the ideas guys!! |
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