BT-H vs Pazon

Ian Watson

Active Forum User
VOC Member
Sorry if this is a well worn subject but I hear there were problems with the BT-H magneto which I'm considering for my Shadow and I wonder whether these have been fixed. I am told Pazon is good . I'm interested in reliability /which does the job best , as I'm fortunate in having an expert install for me. (I've only just learnt what a sprag bearing is .. I think ).
 

vibrac

Well Known and Active Forum User
VOC Member
If your Vincent is blessed with good reliable dynamo then you might consider Pazon. on a Triumph with an alternator what better could you get? but for me on a Vincent there is no substitute for a magneto and for a magneto I cant beat BT-H. from the moment I slid the locking bar and set my timing thinking why has no-one thought of this before? I knew it was for me.
Over the years all our racers twins and singles have had one including a Methanol engine which we were told would place an undesirable load on the electronics. My alphabet twin has one. the coils have improved mechanically although I still have an old one on our racing comet.
I don't have one on the cooking Comet because the Lucas is still working, but when it stops I know what I shall get. It is even match on what a rebuild of a Lucas to a new BT-H will cost. I don't have one on the Grey flash because that has a BTH (no dash)
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Sorry if this is a well worn subject but I hear there were problems with the BT-H magneto which I'm considering for my Shadow and I wonder whether these have been fixed. I am told Pazon is good . I'm interested in reliability /which does the job best , as I'm fortunate in having an expert install for me. (I've only just learnt what a sprag bearing is .. I think ).
I have been "trying" a Pazon on my Comet for the last 2 to 3 years and have NEVER been long term happy with it. My experience has been plagued with mis-firing issues despite the entire unit having been replace by Pazon and ALL of the wiring on my bike (including all of the Pazon lLT leads) having had extensive electro-magnetic shielding installed by me. I also went to the length of revising the complete electrical system on the bike ensuring a single earthing point and no earth "loops".

In my experience - I get to the point where the Pazon appears to be working OK then after just a small amount of use the mis-firing and general unreliability starts to reoccur and as time passes it gets worse and worse. I should add in regard to the Pazon system and installation that I have kept ALL of the low tension leads well away from the coil and the high tension cable. Likewise I have ensured that the control box, being mounted UNDER the battery platform, does not get heated by the motor, is well away from the HT stuff and gets plenty of cooling air. Of note is that the ignition pickup or sensor that mounts where the magneto would be does get rather hot through convection of heat from the motor.

I'm a slow learner - or I must be - because every so often I pull the Pazon out of its box and give it yet another try after I have implemented yet a further fix I have dreamed up - these fixes by the way all revolve around trying to shield the Pazon system from electromagnetic interference.

Having said all that my Comet is now a first kick starter, idles very smoothly and under all riding condition the motor is very sweet - How come? The Pazon is (again) on the shelf and I have the original, though rebuilt, Lucas magneto installed and a "new" ATD from VOC spares. Will I be reinstalling the Pazon again? I think not.

Were I starting out afresh I would look long and hard at the BT-H - and provided when you install it you make sure to keep the kill wire well away from the HT leads it should work as well if not better, than the original magneto. As a bonus, with a magneto, a flat battery will NEVER see you stuck on the side of the road.

Having said all that - I have found that if you have the original magneto rebuilt by a competent person, with modern hi tolerance capacitors used along with a ATD in good condition, you could not go far wrong.

In conclusion I do know of some folks who claim to have had great success with Pazon - I guess I must be jinxed.

Martyn
 

Goffy998

Well Known and Active Forum User
VOC Member
I have Francois Grossets electronic ign on my twin & I'm happy to recommend it. I had two different rebuilt magnetos & a series 'D' type distributer fitted at different times, but the bike never started so easily or runs as well as it does now. Patrick Godet uses this system on the bikes he builds. The only down side is that it's dependent on the charging system working properly, but an Alton was fitted at the same time and both are trouble free.
Paul Goff
 

Howard

Well Known and Active Forum User
VOC Member
With electrics, start at the generator, if there ain't enough going in, you won't get much out. I find the Pazon on my twin uses a lot of juice, but I run a 300 Watt alternator, and wouldn't run it with a dynamo. That being said, Pazon has transformed the engine (which was running points and coil ignition), it's smoother, easier to start and just feels right at any revs.
My Comet, on the other hand, has a BT-H (bought with it). I've only done 1000 miles on it so far, but it seems ok, and it's only got a dynamo, so the BT-H will not be changed. One niggle, it wasn't as easy to start as I expected, but I've just given it a once over (service) and we'll see if that improves when I get my chroming and painting back.

H
 

Howard

Well Known and Active Forum User
VOC Member
That reads strange. Chroming and painting obviously got nothing to do with starting, apart from it's difficult to start the engine when the cycle parts aren't around.

Re : Magnetos - In the last 50 years I've spent more time waiting for the recovery truck due to dead Mags, than all other problems put together, and I never want one on a bike of mine, ever again! Just my opinion of course. :)

H
 

bmetcalf

Well Known and Active Forum User
VOC Member
KVF FAN.jpg
My Rap -----
 

robert shennan

Active Forum User
VOC Member
I fitted a BT-H magneto to my rapide and it started easily first time, after about one month starting became progressively more difficult and on looking into the matter it was not firing on the front cylinder.
I contacted Peter at BT-H and he could not have been more helpful, he took the unit back and put it on his test bench, although everything appeared OK on test he changed all the components other than the stator and rotor. He aalso at my request fitted a longer earth wire to allow me to route the earth wire under the engine away from the HT leads.
The only thing he noticed was that the coupling was a little too thick and might not be locking on the tapered shaft.
Everything is now running fine and I cannot emphasize enough how helpful and friendly the service received was ( I have no ties to BT-H ).
 

timetraveller

Well Known and Active Forum User
VOC Member
A question for MartynG and not trying to teach you something you know already. Did you ensure that all your electromagnetic shielding was only earthed at one end?
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
A question for MartynG and not trying to teach you something you know already. Did you ensure that all your electromagnetic shielding was only earthed at one end?
As I said

" I also went to the length of revising the complete electrical system on the bike ensuring a single earthing point and no earth "loops".

There were and are no earth loops - all earth "leads" were and are connected at one end only - which is the main earth bolt at the rear LH side of the UFM.

As you may have gathered - I am at my wits end with this. And I know its not just me. A fellow Comet owner is having EXACTLY the same issues with his Pazon.
 
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