The Toad... '78 Shovelhead
161 - 180 of 212 Posts
Joined
·
560 Posts
These are the things we've tried over the weekend...
after discussing the order in which to proceed, we decided to bench test the mag AGAIN, this time without any ground and without the power drill, just turning it by hand. It seemed to have good spark, but a little irregular maybe.
then we put it back on the bike and tried to get the spark to jump from the cable to the head or cylinder without the spark plug, like we just did on the bench. Won't do. We put the plugs on and got spark, but not the mightiest to be honest. Still, we got spark.
so then we decided to swap carbs first and see if we could kick start it with the freshly rebuilt Keihin Butterfly that used to be on the bike when it last ran. No success.
Then we pushed the bike outside and up a small bridge. We managed to get it running, but unfortunately the needle valve stuck open and the carb flooded, and since the magneto was retarded the bike spit flames and died.
at least it ran like a hundred meters under its own power. Lol. Looks cool though, and sounds awesome. I changed the needle valve and got the carb to work, but nevertheless, we did not really get it to run. Our suspicion is, that the spark is just too weak and gets blown out by the compression. Unfortunately we could not try and peg the bike with the SU, no time or breath was left.
we played with the gaps on the plugs, tried several different plugs, no effect.
So... Next step will be to put the oem ignition cone back on, temporarily wire a coil to the bike and see if it starts then. This is the most stubborn machine I have ever encountered...
after discussing the order in which to proceed, we decided to bench test the mag AGAIN, this time without any ground and without the power drill, just turning it by hand. It seemed to have good spark, but a little irregular maybe.
then we put it back on the bike and tried to get the spark to jump from the cable to the head or cylinder without the spark plug, like we just did on the bench. Won't do. We put the plugs on and got spark, but not the mightiest to be honest. Still, we got spark.
so then we decided to swap carbs first and see if we could kick start it with the freshly rebuilt Keihin Butterfly that used to be on the bike when it last ran. No success.
Then we pushed the bike outside and up a small bridge. We managed to get it running, but unfortunately the needle valve stuck open and the carb flooded, and since the magneto was retarded the bike spit flames and died.
at least it ran like a hundred meters under its own power. Lol. Looks cool though, and sounds awesome. I changed the needle valve and got the carb to work, but nevertheless, we did not really get it to run. Our suspicion is, that the spark is just too weak and gets blown out by the compression. Unfortunately we could not try and peg the bike with the SU, no time or breath was left.
we played with the gaps on the plugs, tried several different plugs, no effect.
So... Next step will be to put the oem ignition cone back on, temporarily wire a coil to the bike and see if it starts then. This is the most stubborn machine I have ever encountered...
Joined
·
1,835 Posts
Question is.. how did it seem when running, albeit for a few seconds? was it firing on both cylinders? if so, timing may be spot on. Which eliminates that. Sounds like the carb is good.. So it must be mag.. magnets may be weak.
Joined
·
1,746 Posts
It is very unlikely the magnets have gone unless it's been left disassembled for any length of time,
usually, if it sparks when turned by hand, there isn't a problem of losing spark under compression, unless the condensor is bad, it's about the only thing that can go wrong with them,
I have been using FM type magnetos exclusivly on all but 2 of my Harleys since my first in 1977 & never had a problem other than on one 30+ years ago which was cured with one of Morris's condensors,
the one thing is they MUST be in a perfect state of tune as at kicking speeds they need all the units working together as ANY state of the tuning being out will hold you back,
it's probably a good idea as you said to fit the std points system on to dial in the carb & when it's set 100% perfect then put the mag on, an untuned carb is a Magneto's worse enemy !!
when I built my 45Magnum it was an utter Bitch to start unless I had a very steep hill to bump it down, when it was running I dialed the carb in to as close as I could without a gas analiser, & when set it was a first kick bike & that one had a hell of a high compression ratio so it needed to all be spot on tune wise or you'd need a big hill in ya pocket to start it with
![Land vehicle Fuel tank Vehicle Automotive lighting Automotive tire]()
usually, if it sparks when turned by hand, there isn't a problem of losing spark under compression, unless the condensor is bad, it's about the only thing that can go wrong with them,
I have been using FM type magnetos exclusivly on all but 2 of my Harleys since my first in 1977 & never had a problem other than on one 30+ years ago which was cured with one of Morris's condensors,
the one thing is they MUST be in a perfect state of tune as at kicking speeds they need all the units working together as ANY state of the tuning being out will hold you back,
it's probably a good idea as you said to fit the std points system on to dial in the carb & when it's set 100% perfect then put the mag on, an untuned carb is a Magneto's worse enemy !!
when I built my 45Magnum it was an utter Bitch to start unless I had a very steep hill to bump it down, when it was running I dialed the carb in to as close as I could without a gas analiser, & when set it was a first kick bike & that one had a hell of a high compression ratio so it needed to all be spot on tune wise or you'd need a big hill in ya pocket to start it with
Joined
·
560 Posts
Gorgeos, I love magnum conversions.
what a trumpet on that thing, sucks the birds right out of the apple tree...
The magneto in question is one of those "to good to be true" 700something dollar units that used to be on the evil bay some years ago. I guess it sat unused for six or seven years now, other than that it is brand new on the inside.
what makes me so suspicious is the fact, that it shows such a weak spark on the bike. Shouldn't it be able to gap 5mm when mounted on the engine, just like it does on the work bench?
I will try and dial in my carb like you said.
The Hunt and Linkert setup I use on my flathead never gave me a whole lot of trouble. It's not a one kick bike, but it is super reliable and doesn't get a lot of maintenance... Lazy me. Bought the mag used from an ironhead sportster, put it on, set the points and never looked back. God knows how old it is. I think I cleaned the points one or two times as they tend to get a little oily, but that's that.
what a trumpet on that thing, sucks the birds right out of the apple tree...
The magneto in question is one of those "to good to be true" 700something dollar units that used to be on the evil bay some years ago. I guess it sat unused for six or seven years now, other than that it is brand new on the inside.
what makes me so suspicious is the fact, that it shows such a weak spark on the bike. Shouldn't it be able to gap 5mm when mounted on the engine, just like it does on the work bench?
I will try and dial in my carb like you said.
The Hunt and Linkert setup I use on my flathead never gave me a whole lot of trouble. It's not a one kick bike, but it is super reliable and doesn't get a lot of maintenance... Lazy me. Bought the mag used from an ironhead sportster, put it on, set the points and never looked back. God knows how old it is. I think I cleaned the points one or two times as they tend to get a little oily, but that's that.
Joined
·
1,835 Posts
As Pete has said, I had one with dead magnets, but I rebuild and move a fair few on, out of the 45+ I've built I had one magnet issue. Pete's nailed it with tune and condensers. Worth replacing points as well, stranger things have happened. You should be getting a fairly fat spark even turning by hand, and with a little kicking through. What's the spark like when you spin it with a drill? As Pete said, wall about speed you kick them.
I had a friend who had a similar mag on his cone shovel. I failed to ever get it running easily from kick. It ran fine, and ran well, was a stroker. But kicking it's 10+/1 compression was a killer. The mag I run on my knuck was also on my flatty and also on my pan. Never had to even clean it. Can't beat fairbanks in my humble opinion. I buy lots of parts whenever they come up on fleabay. Gold.
I had a friend who had a similar mag on his cone shovel. I failed to ever get it running easily from kick. It ran fine, and ran well, was a stroker. But kicking it's 10+/1 compression was a killer. The mag I run on my knuck was also on my flatty and also on my pan. Never had to even clean it. Can't beat fairbanks in my humble opinion. I buy lots of parts whenever they come up on fleabay. Gold.
Joined
·
560 Posts
Like i said, it's a mystery to me. I never had problems like this. Set the mag up and it would start somehow. That's why I love these, I always had more trouble with batteries and coils and faulty wiring and such...
I'll let you know when I learn more. Took the Flattie out for a spin today to deliver the cone and old ignition to the shop where the shovel sits at the moment... It just ran fine like always and I had a good time
I'll let you know when I learn more. Took the Flattie out for a spin today to deliver the cone and old ignition to the shop where the shovel sits at the moment... It just ran fine like always and I had a good time
Joined
·
1,746 Posts
the speed of the kick is a hell of a lot with magnetos,
45's and stock low comp bikes like Knucks Pans & Shovels are piss easy to spin over fast enough, but anything with compression above about 8.5:1 compression & ya start having to really learn to kick with greater input,
I cant kick my shovel with my hips being fecked, & it having Wiseco 9.5:1 pistons & with the Leineweber cam, I'm just glad I got a Lectron carb as they alone help make starting easier whatever comp ya go for, having a real choke system & not just an 'enrichment device' that basically just temporeraly puts ya carb outa tune in a hope it gives a sort of choke effect, & most fixed & adjustable jet ventury (butterfly type carbs= BOAT ANCHORS !!!) are a pain if used with a magneto unless used with low comp pistons or electric starters,....
45's and stock low comp bikes like Knucks Pans & Shovels are piss easy to spin over fast enough, but anything with compression above about 8.5:1 compression & ya start having to really learn to kick with greater input,
I cant kick my shovel with my hips being fecked, & it having Wiseco 9.5:1 pistons & with the Leineweber cam, I'm just glad I got a Lectron carb as they alone help make starting easier whatever comp ya go for, having a real choke system & not just an 'enrichment device' that basically just temporeraly puts ya carb outa tune in a hope it gives a sort of choke effect, & most fixed & adjustable jet ventury (butterfly type carbs= BOAT ANCHORS !!!) are a pain if used with a magneto unless used with low comp pistons or electric starters,....
Joined
·
1,835 Posts
Like i said, it's a mystery to me. I never had problems like this. Set the mag up and it would start somehow. That's why I love these, I always had more trouble with batteries and coils and faulty wiring and such...
I'll let you know when I learn more. Took the Flattie out for a spin today to deliver the cone and old ignition to the shop where the shovel sits at the moment... It just ran fine like always and I had a good time
Pete, I fully agree, some of the shovels come to mind I've been around and them + a mag that's not in tune or timed makes your life a living hell. I don't think any of the bikes I've owned have had over 6:1 compression, probably less. So mag with timing and tune = no issues. It will be something minor and you'll be HAPPY haha.
Joined
·
1,746 Posts
last year I dropped £2500 (now they are up to £3100 !!!) on a cannonball steath starter from W&W,
even when my hips are done, it will not be good enough to kick much more than a jap 4, as the smaller swept area even at 9:1+ doesnt feel as bad as a big twin,
being disabled I dont pay VAT on items to allow me to convert a vehicle for disabled use,
as my shovel didnt have a starter, adding a Cannonball starter is classed as a legitimate conversion,
so I got a nice cheque for £500 back from the vat man within 2 weeks of buying it !!
plus as I run a 3 inch Karata belt drive, I didn't want to have to change it all out for a narower belt drive with a ring gear on the clutch basket & have to fit primary covers for the starter motor ,Solenoid etc so it would work as factory, & the factory set up is shit, a bodged together load of 50's & 60's car or truck parts that when working are only just adequate at best, when I bought mine they used a 2kw motor that spins it so fast it starts with only the briefest press of the button, now they send them out with 1.4kw motors as thats all they really need, but glad mine is the 2kw one.
even when my hips are done, it will not be good enough to kick much more than a jap 4, as the smaller swept area even at 9:1+ doesnt feel as bad as a big twin,
being disabled I dont pay VAT on items to allow me to convert a vehicle for disabled use,
as my shovel didnt have a starter, adding a Cannonball starter is classed as a legitimate conversion,
so I got a nice cheque for £500 back from the vat man within 2 weeks of buying it !!
plus as I run a 3 inch Karata belt drive, I didn't want to have to change it all out for a narower belt drive with a ring gear on the clutch basket & have to fit primary covers for the starter motor ,Solenoid etc so it would work as factory, & the factory set up is shit, a bodged together load of 50's & 60's car or truck parts that when working are only just adequate at best, when I bought mine they used a 2kw motor that spins it so fast it starts with only the briefest press of the button, now they send them out with 1.4kw motors as thats all they really need, but glad mine is the 2kw one.
Joined
·
560 Posts
i uploaded the video of the last bench test to youtube. we spin the magneto over by hand, and it gaps 6mm with bright blue sparks.
Harley Magneto Bench Testing Part II
unfortunately, like i said, that changes when it is installed on the bike.
here's some pics from the day we push started it.
![]()
![]()
![]()
![]()
![]()
next step will be putting the old points ignition back on the engine and see if i can get it to start / find more things in the process.
in the meantime i will try and get a rare earth rotor (Morris P12) that fits my Burghardt unit. they are supposed to produce a stronger spark.
maybe that will help.
Harley Magneto Bench Testing Part II
unfortunately, like i said, that changes when it is installed on the bike.
here's some pics from the day we push started it.
next step will be putting the old points ignition back on the engine and see if i can get it to start / find more things in the process.
in the meantime i will try and get a rare earth rotor (Morris P12) that fits my Burghardt unit. they are supposed to produce a stronger spark.
maybe that will help.
Joined
·
1,835 Posts
i uploaded the video of the last bench test to youtube. we spin the magneto over by hand, and it gaps 6mm with bright blue sparks.
Harley Magneto Bench Testing Part II
unfortunately, like i said, that changes when it is installed on the bike.
here's some pics from the day we push started it.
![]()
![]()
![]()
![]()
![]()
next step will be putting the old points ignition back on the engine and see if i can get it to start / find more things in the process.
in the meantime i will try and get a rare earth rotor (Morris P12) that fits my Burghardt unit. they are supposed to produce a stronger spark.
maybe that will help.
Sir, that spark is purple so the mag is good. Is it possible it's earthing itself somewhere? I've had it happen. But looking at that spark, nothing wrong there.
Joined
·
560 Posts
here's a short update and temporary declaration of defeat/bancruptcy:
we changed the bike back to the old cone with points ignition setup and it fired on the first kick.
the ugly thing is, it is a lot easier to kick now, too. that is bad, because it means something inside the burghard drive is seriously NOT working like it should be.
something is binding and grinding in there, i guess, creating some serious friction. it is easy to disassemble and reassemble, i tried it, nothing obvious there,
but i can see wear marks on the magneto sprockets and there was a little bit of brass particle "fog" in the oil on the bottom of the cam chmaber when i pulled the
Burghardt housing. this has to be investigated, and i don't intend to give up on the mag yet, BUT...
it finally runs! that's a good thing, i guess
![]()
and here's my main man showing off the work lol
![]()
(sign reads "inspected - tended - dependable")
seriously it wouldn't be where it is right now without him, i'm super thankful for all the help i got here
we changed the bike back to the old cone with points ignition setup and it fired on the first kick.
the ugly thing is, it is a lot easier to kick now, too. that is bad, because it means something inside the burghard drive is seriously NOT working like it should be.
something is binding and grinding in there, i guess, creating some serious friction. it is easy to disassemble and reassemble, i tried it, nothing obvious there,
but i can see wear marks on the magneto sprockets and there was a little bit of brass particle "fog" in the oil on the bottom of the cam chmaber when i pulled the
Burghardt housing. this has to be investigated, and i don't intend to give up on the mag yet, BUT...
it finally runs! that's a good thing, i guess
and here's my main man showing off the work lol
(sign reads "inspected - tended - dependable"
)seriously it wouldn't be where it is right now without him, i'm super thankful for all the help i got here
Joined
·
53 Posts
There has been some problems with the gears of those Burkhart systems, I know a friend of mine machined lots of parts for his to run it.
Joined
·
53 Posts
Just readed his stories from 2016, he had too tight fitting between magneto gears and it resulted broken bolt at camshaft. He ordered new gears from Morris if I understood correctly.
Also had many other small stuff like multiple bad condensators etc.
Also had many other small stuff like multiple bad condensators etc.
Joined
·
560 Posts
thanks man.
actually that sounds A LOT like what i have going on here.
the tooth flanks of the mag drive gears are showing signs of wear already, even though the bike only ran for like 100m or so
(other than it was kicked over maybe 1000 times before that). there has to have been a serious load on something or some sort of bind,
since it kicks over much easier now. my guess is, you can seriously burn some energy with a bad worm drive, if the teeth aren't cut well enough
and don't fit, or if the two shaft centers are too close to one another...
the screw holding the drive gear to the cam on the engine side had become so tight that we ruined the allen head and had to weld on it to break it loose.
also it appeared that the split pin that should keep the gear from rotating on the cam was sheared off. so something was wrong there, that's for sure.
bad condenser rings a bell, too...
now i have to find out what gears i could use as a replacement, and carefully measure everything to find out what is binding in there.
actually that sounds A LOT like what i have going on here.
the tooth flanks of the mag drive gears are showing signs of wear already, even though the bike only ran for like 100m or so
(other than it was kicked over maybe 1000 times before that). there has to have been a serious load on something or some sort of bind,
since it kicks over much easier now. my guess is, you can seriously burn some energy with a bad worm drive, if the teeth aren't cut well enough
and don't fit, or if the two shaft centers are too close to one another...
the screw holding the drive gear to the cam on the engine side had become so tight that we ruined the allen head and had to weld on it to break it loose.
also it appeared that the split pin that should keep the gear from rotating on the cam was sheared off. so something was wrong there, that's for sure.
bad condenser rings a bell, too...
now i have to find out what gears i could use as a replacement, and carefully measure everything to find out what is binding in there.
161 - 180 of 212 Posts
Join the discussion
