Hello everyone, this is my first post. I've been lurking for about three months now and the collection of knowledge here is awesome! I have owned a 02' M2 Buell cyclone and chopped 78' honda 500 twin over the years, but this is my first venture into the world of yamaha.
Ok, so I have been working on a buddy's 80 with the TCI ignition, he left it at my place since he already has a sportster he rides all the time. I get to ride it and work the bugs out, cool I haven't had a bike in a couple years. Should just be a carb rebuild and thrash it to work and back...it has turned into a real adventure.
PO already bobbed it and the harness was a butt connector mess. So first thing I did was re wire it to this schematic. I ran new wires from the coil back, cleaned all the male/female blades and soldered almost all the butt conectors up. It's just headlight, taillight and kickstart. I Did the basic check over stuff, timing chain and valve adjustment checked the floats for holes and cleaned the carbs.
I finally got it running decent after I replaced the tank (old one was rust city), petcock, gas cap, new manifolds, butterfly seals and rebuilt the 1975 bs 38's (127.5 main, 45 pilot, needle clip at 4th position), running down pipes and no air filters (cheap pods were choking the venturies so I ditched them). I had it die at idle waiting for a traffic light a couple times, no big deal...right.
Finished putting the new intake manifolds on and put new mains in the carbs so I went for a ride to a buddies. Ran good 1-4th but the bike felt like it was hesitating, or some one was flicking the on and off switch when I would get going 65 (5th gear) under throttle. Stopped and lowered the carb needles, jump back on the highway, same hesitation. 45 minutes at my buddies, before I headed back I lower the needles again. I got about 15 minutes down the road, still hesitating everytime I get into the throttle. Gets progressively worse, bike dies doing 65. Won't start back up even when I was popping the clutch. Headlight and tailight work, No spark, can't get 12v to coil, tow it home.
Next day I hooked the timing light up. Disconnect the reg/rec kick, kick. No spark. Hook reg/rec back up wiggle some wires...kick, SPARK! Stupid butt connector for reg/rec didn't get replaced, soldered that up. Soldered all the crimp connectors and re did all the grounds (battery to frame, rec to frame, ignition box to frame, new engine ground to frame, paint free and greased).
It was eating taillight bulbs like nobody's business, I figured it was the T shape license plate holder PO had welded on the swingarm shaking bulbs to death. So I cut that off and built a proper license plate holder and welded it onto the frame, installed a new trailer light. Put the carbs back to 4th needle clip. Go for a 20 minute ride before work..
It goes great until you get into 5th gear. Gets some hesitation again, more of a stutter or stamer when you get up around 65/70 in 5th. Bike feels good, doesn't pop or backfire, pulls hard. I get back to the highway after 15 minutes, start to head for work, doing 70 flat out for about 2 miles and it starts doing the ol hesitation, stutter thing again then dies. I manage to get it off the highway about a 1/2 mile from work. No headlight or taillight, just dead. No fluke meter on me, grab a wrench and slap test it. Nothing. Alright at least were getting somewhere, unplug the rec/reg turn it on, nothing, still dead. Plug them back in. Push it for 12 minutes or so then take a break, figure I would give it another try. Key on and I got power! Turn it off, unplug the rec/reg kick it over and limp it to work, hesitating, bucking won't really rev over 3k, rec/reg makes no difference. Sits all day, plug the rec/reg in and fire it up to head home eight hours later. Same crap all the way home, bucks hesitates, can't go over 3k or 35mph I had to feather the clutch in second all the way home.
So I start tracing 12v when I get home. 1 volt drop from battery to the coil, drops off at the ignition so I put a new keyed ignition in it. I went through the charging system next.
Readings at 200k:
-Cleaned the rotor slip rings, ohms at 5.6 inner to outer ring, infinite to motor.
-Replaced brushes
-Stator ohms .5 from any three white wires in combination, Infinite to ground.
-Rectifier pases diode test off bike.
•Black lead on black wire, white wires read 0.
•Red lead on black wire, white wires read .560-.580.
-Pick up sensor ohms .780 and .790.
-Jumped the green - wire at brush and the voltage just walked away 14.v, 15.v, 16.v so I shut it down.
-Replaced voltage regulator with 12v Fiat regulator.
-Replaced rectifer with 35 amp 100v 3 phase bridge rectifier from wind river.
Get that stuff installed, jump my ground brush and it regulates, woo hoo! Fixed you say? Nope.
Go to ride it and I can't even get to the end of the block, still bucking and hesitating. Ok, gotta be fuel, pull the carbs for the 8th time and put them in the ultrasonic now with a cup of mean green and distilled water. Blow everything out reassemble, fuel to the carbs, no change.
Unplug the new rec/reg, no change, still won't rev past 3k. Pull the ignition box apart and reflow the board, no change. Start looking for a voltage drop again, unpluged the power to the rectifier and acidently grounded the battery, pop the main 20 amp fuse. Replace that and now I'm back to no spark.
Load test battery at O'Reilly's, it passes.I have power 12.volts to coil, I get spark if I manually ground the coil...coil ohms at 2.7 primary, 29000k secondaries and infinte to ground. Shit, I think I just smoked the ignition box. I picked up a box from a forum member. Go through the harness again this morning, make sure all the grounds are good everything is hooked up right. Fire the bike up, advances ok with the new box, still hesitates and misses when I ride it to the end of the street, twist the throttle and it's 1-2 second delayed response before it accelerates, then the throttles falls on its face then comes back on. Pull the carbs off again, double check floats are at 24mm. Reinstall carbs and dead cylinder tune it, ground coil to fin via extra plug. The right bank is really hard to get a smooth idle out of it, seems like it has a miss then would die at a low idle or you have to idle it at 1300rpm to keep it running. Finally got them both to settle in about 1100, went for a test ride and there's a lot of hesitation 1st through 3rd (didn't drive it too far).
Off idle, through wide open. It will just fall on its face then come back on and try to spin the clutch it hits so hard. I really don't know what to look at next. My gut says the coil is having a heat related failure. It's the original unit as far as I can tell, the plug caps and secondary wires are all one piece. Even with the floats adjusted and the petcock closed I'll get a burp of gas on the floor after an hour or two. I put the floats in a gasoline filled jar overnight and they were still floating. Anyone have any insight, or see something I missed? Carbs or coil? I'm kinda stumped.
Thanks for hanging in there if you read this whole thing, just trying to be thorough.
Ok, so I have been working on a buddy's 80 with the TCI ignition, he left it at my place since he already has a sportster he rides all the time. I get to ride it and work the bugs out, cool I haven't had a bike in a couple years. Should just be a carb rebuild and thrash it to work and back...it has turned into a real adventure.
PO already bobbed it and the harness was a butt connector mess. So first thing I did was re wire it to this schematic. I ran new wires from the coil back, cleaned all the male/female blades and soldered almost all the butt conectors up. It's just headlight, taillight and kickstart. I Did the basic check over stuff, timing chain and valve adjustment checked the floats for holes and cleaned the carbs.
I finally got it running decent after I replaced the tank (old one was rust city), petcock, gas cap, new manifolds, butterfly seals and rebuilt the 1975 bs 38's (127.5 main, 45 pilot, needle clip at 4th position), running down pipes and no air filters (cheap pods were choking the venturies so I ditched them). I had it die at idle waiting for a traffic light a couple times, no big deal...right.
Finished putting the new intake manifolds on and put new mains in the carbs so I went for a ride to a buddies. Ran good 1-4th but the bike felt like it was hesitating, or some one was flicking the on and off switch when I would get going 65 (5th gear) under throttle. Stopped and lowered the carb needles, jump back on the highway, same hesitation. 45 minutes at my buddies, before I headed back I lower the needles again. I got about 15 minutes down the road, still hesitating everytime I get into the throttle. Gets progressively worse, bike dies doing 65. Won't start back up even when I was popping the clutch. Headlight and tailight work, No spark, can't get 12v to coil, tow it home.
Next day I hooked the timing light up. Disconnect the reg/rec kick, kick. No spark. Hook reg/rec back up wiggle some wires...kick, SPARK! Stupid butt connector for reg/rec didn't get replaced, soldered that up. Soldered all the crimp connectors and re did all the grounds (battery to frame, rec to frame, ignition box to frame, new engine ground to frame, paint free and greased).
It was eating taillight bulbs like nobody's business, I figured it was the T shape license plate holder PO had welded on the swingarm shaking bulbs to death. So I cut that off and built a proper license plate holder and welded it onto the frame, installed a new trailer light. Put the carbs back to 4th needle clip. Go for a 20 minute ride before work..
It goes great until you get into 5th gear. Gets some hesitation again, more of a stutter or stamer when you get up around 65/70 in 5th. Bike feels good, doesn't pop or backfire, pulls hard. I get back to the highway after 15 minutes, start to head for work, doing 70 flat out for about 2 miles and it starts doing the ol hesitation, stutter thing again then dies. I manage to get it off the highway about a 1/2 mile from work. No headlight or taillight, just dead. No fluke meter on me, grab a wrench and slap test it. Nothing. Alright at least were getting somewhere, unplug the rec/reg turn it on, nothing, still dead. Plug them back in. Push it for 12 minutes or so then take a break, figure I would give it another try. Key on and I got power! Turn it off, unplug the rec/reg kick it over and limp it to work, hesitating, bucking won't really rev over 3k, rec/reg makes no difference. Sits all day, plug the rec/reg in and fire it up to head home eight hours later. Same crap all the way home, bucks hesitates, can't go over 3k or 35mph I had to feather the clutch in second all the way home.
So I start tracing 12v when I get home. 1 volt drop from battery to the coil, drops off at the ignition so I put a new keyed ignition in it. I went through the charging system next.
Readings at 200k:
-Cleaned the rotor slip rings, ohms at 5.6 inner to outer ring, infinite to motor.
-Replaced brushes
-Stator ohms .5 from any three white wires in combination, Infinite to ground.
-Rectifier pases diode test off bike.
•Black lead on black wire, white wires read 0.
•Red lead on black wire, white wires read .560-.580.
-Pick up sensor ohms .780 and .790.
-Jumped the green - wire at brush and the voltage just walked away 14.v, 15.v, 16.v so I shut it down.
-Replaced voltage regulator with 12v Fiat regulator.
-Replaced rectifer with 35 amp 100v 3 phase bridge rectifier from wind river.
Get that stuff installed, jump my ground brush and it regulates, woo hoo! Fixed you say? Nope.
Go to ride it and I can't even get to the end of the block, still bucking and hesitating. Ok, gotta be fuel, pull the carbs for the 8th time and put them in the ultrasonic now with a cup of mean green and distilled water. Blow everything out reassemble, fuel to the carbs, no change.
Unplug the new rec/reg, no change, still won't rev past 3k. Pull the ignition box apart and reflow the board, no change. Start looking for a voltage drop again, unpluged the power to the rectifier and acidently grounded the battery, pop the main 20 amp fuse. Replace that and now I'm back to no spark.
Load test battery at O'Reilly's, it passes.I have power 12.volts to coil, I get spark if I manually ground the coil...coil ohms at 2.7 primary, 29000k secondaries and infinte to ground. Shit, I think I just smoked the ignition box. I picked up a box from a forum member. Go through the harness again this morning, make sure all the grounds are good everything is hooked up right. Fire the bike up, advances ok with the new box, still hesitates and misses when I ride it to the end of the street, twist the throttle and it's 1-2 second delayed response before it accelerates, then the throttles falls on its face then comes back on. Pull the carbs off again, double check floats are at 24mm. Reinstall carbs and dead cylinder tune it, ground coil to fin via extra plug. The right bank is really hard to get a smooth idle out of it, seems like it has a miss then would die at a low idle or you have to idle it at 1300rpm to keep it running. Finally got them both to settle in about 1100, went for a test ride and there's a lot of hesitation 1st through 3rd (didn't drive it too far).
Off idle, through wide open. It will just fall on its face then come back on and try to spin the clutch it hits so hard. I really don't know what to look at next. My gut says the coil is having a heat related failure. It's the original unit as far as I can tell, the plug caps and secondary wires are all one piece. Even with the floats adjusted and the petcock closed I'll get a burp of gas on the floor after an hour or two. I put the floats in a gasoline filled jar overnight and they were still floating. Anyone have any insight, or see something I missed? Carbs or coil? I'm kinda stumped.
Thanks for hanging in there if you read this whole thing, just trying to be thorough.
