Misc: Ignition Modern BTH Ignition

Albervin

Well Known and Active Forum User
VOC Member
Way back in 2002 or 2003 I decided to fit the new electronic magneto. The reason was less moving parts and wear and tear. In 2010 I had a coil failure and limped home about 5 miles to the rally HQ in Qld on my Rapide. The wonderful Greg Brisllus came to the rescue with a new coil and I had a great rally. Fast forward to 2020. The Rapide has been having a real hit and miss with starting; nothing to do with the great garage catastrophe. Finally I decided to replace the other original coil. First kick and she fired up. I stopped the engine and kicked a lazy kick and away she went again. After a couple of minutes on a fast idle it settled to a regular heart-beat. The question is, how many people are still using the original coils and complaining about a hard start or otherwise? Do the coils degrade from start cycles or just the hours they are working? This is about preventative maintenance and I think I should have replaced that coil two years ago. Opinions?
 

vibrac

Well Known and Active Forum User
VOC Member
I thought the new coils were mainly a mechanical improvement on the ignition lead fixing do I decern an electrical improvement as well?
 

greg brillus

Well Known and Active Forum User
VOC Member
I've not had many coil failures, that would generally happen from a HT lead not being connected at some point, like any HT system if there is no escape for the High tension spark, it will do some damage to the internal insulation on the secondary winding. This may happen at some point but not show up for some time down the track as it were. We recently had a failure of an earlier BTH mag that seems to have suffered a break in one of the internal wires. I could manage to get it to spark on the dead coil if I moved the wires, I could not replicate the problem, and it is too expensive to send for repair to the Uk, so it is resigned to the scrap bin. I have mentioned it on here before, but sometimes hard starting can be due to the outer end face of the internal pickup coils from getting a light coat of rust on here results in a poor pickup strength and that coil will fail to fire. A light buff to remove this coating will restore the mag to full operation again.
 

macvette

Well Known and Active Forum User
Non-VOC Member
Way back in 2002 or 2003 I decided to fit the new electronic magneto. The reason was less moving parts and wear and tear. In 2010 I had a coil failure and limped home about 5 miles to the rally HQ in Qld on my Rapide. The wonderful Greg Brisllus came to the rescue with a new coil and I had a great rally. Fast forward to 2020. The Rapide has been having a real hit and miss with starting; nothing to do with the great garage catastrophe. Finally I decided to replace the other original coil. First kick and she fired up. I stopped the engine and kicked a lazy kick and away she went again. After a couple of minutes on a fast idle it settled to a regular heart-beat. The question is, how many people are still using the original coils and complaining about a hard start or otherwise? Do the coils degrade from start cycles or just the hours they are working? This is about preventative maintenance and I think I should have replaced that coil two years ago. Opinions?
I put a modern BTH on my bike 5 or 6 years ago. After some initial issues, including interference via the cut out wire, it settled down. Last year, the tickover became irregular and acceleration from low revs hesitant. I replaced the coils and relocated them to the inside of the mag cowl retained by plastic coated terry clips. They were previously mounted on the BTH supplied bracket. The guy at BTH said they need to be separated but this is not possible with supplied bracket, hence the relocation.
This cured the issue but since I did two things at once not sure which worked.
Mac
 

erik

Well Known and Active Forum User
VOC Member
When I bought the BTH last year it didn`t work on both cylinders.When i looked closer to the coils I realised that on one coile the HT lead was not screwed in the HT exit of the coil in its soul.The woodscrew like pin was screwed in the insulation of the lead. Erik
 

Vincent Brake

Well Known and Active Forum User
VOC Member
Used up some ht coils yes
Than Binned 2.
Due to overheating in italy.
Looking inside it was a circuit board with much silicone on it. Making it even hotter.
These were from the previous bth owner.
Maybe better now.
 

Chris Launders

Well Known and Active Forum User
VOC Member
I've had one on ten years, changed coils as they were the old type with just push in leads and one almost pulled out, then a year or so ago I had one of the CDI units fail (possibly because of the wayward lead) on test they found one cylinder was 5 degrees out !!!, how could that happen, surely all the CDI mounting plates mass produced, anyway had a new correct mounting plate fitted but I keep wondering if mine was 5 degrees out are others !!!
 

Normski

Well Known and Active Forum User
Non-VOC Member
Used up some ht coils yes
Than Binned 2.
Due to overheating in italy.
Looking inside it was a circuit board with much silicone on it. Making it even hotter.
These were from the previous bth owner.
Maybe better now.
Mine is an earlier one from the previous owner of BTH, it failed on one cylinder earlier this year and the new BTH owner fitted all new internals to it. With this done it has still got a messy mass of black sealant/silicone in it (I think Vibrac posted a picture of the inside of one some time back)
I found after refitting it to exactly the same timing as previously using the same piston stop, that the bike didn’t run too well. I did the wrong thing and messed with the carbs (which Alyn may recall being a problem in Paris) but having now advanced the timing several degrees to about 37btdc the bike runs as it did before.
Notwithstanding this I like the BTH and the bike is a reliable starter and has never kicked back when trying to start which is a great benefit.
 
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