• Welcome to the forum website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Online Forum Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this forum website.

    If you have previously registered to use this forum website, you should log in now. CLICK HERE.

    If you have never registered to use this forum website before, please CLICK HERE.

Fitting BT-H Magneto

redbloke1956

Well Known and Active Forum Website User
Non-VOC Member
P1080182a.jpgHi to all, tonight I was trying to fit my new BT-H Mag, I purchased a BT-H fitting kit from the VOC spares and the result is as per photo, the same result was obtained with the original Mag ATD, the mag pinion goes too far into timing chest, therefore I can't get proper mesh.
I therefore suspect the BT-H shaft is too short? Anybody seen this before?

Kevin
 

davidd

Well Known and Active Forum Website User
VOC Member
Kevin,

I cannot say that the shaft is the correct length, but I installed mine some years ago on the racer and I used stock parts that I ordered from Coventry Spares. I say this because I assume the "Kit" that you purchased is an assemblege of stock parts for a manual advance ignition and not specifically designed for a new BT-H. ET 223/1 determines the spacing as the gear is sandwiched between it and ET238 held together by the four bolts. If the stock ATD that you removed has the same issue, then the shaft is too short. It seems to me that the BT-H shaft length is the same as the Lucas you removed. All the parts should be interchangeable.

David

David
 

BigEd

Well Known and Active Forum Website User
VOC Member
VOC Forum Website Moderator
A long shot but is there a shim, gasket or packer on the three fixing studs that is stopping the new magneto going fully home? Can you put the old mag back on and try the new pinion kit on that?
 

Hugo Myatt

Well Known and Active Forum Website User
VOC Member
I'm not sure from the photo but it looks to me as if you could have fitted the spiggotted part to the wrong side of the pinion. When I bought mine from the Spares Co. it was missing the outer plate. I puzzled about how to fit it for a long time before I realised there was a part missing.

Hugo
 
Last edited:

davidd

Well Known and Active Forum Website User
VOC Member
Hugo may have a point. I do not think that ET 238 was available when I put mine together. I took two washers and edge welded them together to get the right thickness. It is best to check your parts. If you do not have a diagram of the bits, I have one scanned in. Send me an email if you need it. daviddunfey@aol.com

Eddy, the installation uses an "O" ring, so it should not be an issue. By the way, it was not sufficient to supply a ground on my bike, I ran a separate ground strap to get spark.
100_2691.jpg

David
 

redbloke1956

Well Known and Active Forum Website User
Non-VOC Member
P1080186a.jpgHi Guys these are the components from the VOC,
Hugo, I am pretty sure they went on the right way because the spigotted part (far left) can only go on one way due to the internal taper?

Big Ed, there is no spacer between the BT-H and the case.

David, the parts I received were specifically for the BT-H (PR22/BTH/Drive)

However, I have just checked my original mag in place and it has the same issue (hadn't noticed it when I first stripped down the very messy timing case) So this has me perturbed:
With the original mag and ATD, the gear sits too far into the case,
The new BTH and old ATD sits in roughly the same place,
The new BTH and new pinion assy sits in roughly the same place
I don't have a diagram with a parts breakdown of the maneto and drive pinion so can't determine what is missing if anything?

Kevin
 

BigEd

Well Known and Active Forum Website User
VOC Member
VOC Forum Website Moderator
Dear Kevin,
Below (I hope) is a picture of the kit I got from the VOC Spares company when I fitted my magneto. This was probably 2008 so the gear is fibre rather than nylon as shown in your picture. You can find the same picture at: http://www.bt-h.biz/timing_pinion_conv.htm and links to more fitting pictures and tips.

You say your gear misalignment seems to be the same even with your original magneto fitted. I previously suggested there might be some kind of spacer/shim on the joint face that would put the magneto further towards the centre line of the bike giving you the gear misalignment. If as you have stated there is no shim/spacer then could the casting where the the magneto flange fits be thicker than normal?

Is it feasible to put a thin spacer between the ET223/1 and the gear to move the gear better into alignment?
BT-H_mag_pinion_kit.jpg

Hi Guys these are the components from the VOC,
Hugo, I am pretty sure they went on the right way because the spigotted part (far left) can only go on one way due to the internal taper?

Big Ed, there is no spacer between the BT-H and the case.

David, the parts I received were specifically for the BT-H (PR22/BTH/Drive)

However, I have just checked my original mag in place and it has the same issue (hadn't noticed it when I first stripped down the very messy timing case) So this has me perturbed:
With the original mag and ATD, the gear sits too far into the case,
The new BTH and old ATD sits in roughly the same place,
The new BTH and new pinion assy sits in roughly the same place
I don't have a diagram with a parts breakdown of the maneto and drive pinion so can't determine what is missing if anything?

Kevin
 

redbloke1956

Well Known and Active Forum Website User
Non-VOC Member
Dear Kevin,
Below (I hope) is a picture of the kit I got from the VOC Spares company when I fitted my magneto. This was probably 2008 so the gear is fibre rather than nylon as shown in your picture. You can find the same picture at: http://www.bt-h.biz/timing_pinion_conv.htm and links to more fitting pictures and tips.

You say your gear misalignment seems to be the same even with your original magneto fitted. I previously suggested there might be some kind of spacer/shim on the joint face that would put the magneto further towards the centre line of the bike giving you the gear misalignment. If as you have stated there is no shim/spacer then could the casting where the the magneto flange fits be thicker than normal?

Is it feasible to put a thin spacer between the ET223/1 and the gear to move the gear better into alignment?
View attachment 1152
Hi Big Ed, thanks for the time and effort you put into replying mate, I cannot yet think of any other explanation to this conundrum except that as you say, the thickness of the casting. This is my first Vin so I don't know if this sort of thing happens from time to time, I would be surprised though considering the relatively high quality of manufacturing that Vincents seem to be renowned for.
Until I make some proper measurements, my estimate would be that the casting would have to be at least 1/4" thicker than normal if that is indeed the issue.


I just found a photo that I took of the timing case before I dismantled everything (it was a mess) and the angle is not good but it looks as though the original mag pinion did mesh so I must have stuffed something up?........AGGHHH!!!!
Why is it that nothing about a Vincent is ever simple!!!!!!!!!!!!!!!


KevinUntitled-1 copy.jpg
 

vincenttwin

Well Known and Active Forum Website User
VOC Member
Is the Bth fitting flush on the mounting studs ,mine would not pull up flush on my B I had to grind a little off the case cheers peter allen
 

BigEd

Well Known and Active Forum Website User
VOC Member
VOC Forum Website Moderator
That is worth a look to see if the casting is too full in that area. When the new BT-H magnetos were first made there were a few instances of the clearance being a bit close due to the thickness of the casting in the unmachined area near the magneto. ( The bare crankcases of my "B" twin seemed to weigh a ton despite them being aluminium so there was certainly plenty of "meat" in them.:D)
My magneto however went straight on without any metal being removed. I haven't heard of this being a problem with a Comet but that doesn't mean it is not a possibility.

Is the Bth fitting flush on the mounting studs ,mine would not pull up flush on my B I had to grind a little off the case cheers peter allen
 
Warning! This thread is more than 11yrs ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Photos from the 2022 North American Rally

Photos from the 2022 Annual Rally

Photos from the 2022 French Rally


Top