A65 rebuild

[Bess]

Hi,
    In this thread Bill Nelson is aware of your issue and mentioned a place that sorts it out. Worth having a conversation with him or the engineering firm he recommends.

Best wishes...

[MITCHELL]

Hi, of course, will make that call thanks Bess...... and Bill.

[Bess]

Hi Mitchell,
                Looking back over your crank images I cannot see a timing slot or hole in your flywheel, it should have one on the later assemblies. I can see the number for calculating the shim size at TDC so guess the flywheel is in the correct orientation. Its worth checking to see if your crank and flywheel is a mix and match, it looks like you have a later crank and an early flywheel. Unfortunately there's a choice of 6 flywheels so it would be prudent to have it balanced on completion.

Have you considered getting the correct crank, I have seen some on the internet, maybe stop these issues, easier and cheaper option?

Hopefully you can now go forward and please can you send some pics on progress? I am interested to see how this turns out.

Best wishes...

[Mike Farmer]

 

I had this problem as I posted earlier. SRM machined mine by X thou to run smoothly. At least I think it was SRM it may have been T&L I cant find the invoice.

Mike

[Gup holland]

I took Some mesurements, the crank i want to put in is pre 66. Engine is 62.  There was a 734 crank in, the same dimensions as post 66. In my case of 62 there was no machining done , i suppose , bearing dept same as bess said. TS flange same as Mitchell.
According to the story off CBS (small cranks/long cranks) it's shouldn't by easy to fit. I'm running around for over 35 years now with that engine.
When i took it apart there was 1 shim 0.010" between roller bearing and crank. It's a strange engine of diverent parts. Primairy cover is from 70, I always strobe the timing. Engine does not have cover for ignition plug in front,
On the timingside i have a cover also from 70 i think, it's with 3 ball lever for clutch.
So the engine does have a sort of history i don't exactly now.
With a solid thick shim prox 1.5 mm between bearing and pre 66 crank, everthing comes in line like primairy drive en so on

Strange Mitchell does have same situation like me,  with 734  post 66 crank.and won't fit?.....
One other diverance between my to cranks is the position of the dowel , to mount the stator.
It's few degrees of, looking at the splines of the crank. Position of splines on both cranks are the same so i Can see.
Can only timing ignition by disk i think..?..? So the timing strobe marks are  not usefull with the pre 66 crank i think?
Have pic of dowel on both cranks.

What is your opinion about it?  Am i wrong??

Gr gup.

[Bess]

Hi Alex,
           You didn't say why you want to use a pre 66 crank? From your explanation you are saying the post 66 crank hasn't been altered and fits your cases, the cases are pre 66 showing no signs of alteration. You want to use a pre 66 crank but its 1.5mm too short.

The only thing you have that's different from BSA'S original specification is the roller bearing. Have you tried a ball bearing on the pre 66 crank rather than a roller bearing, I did notice your original roller bearing outer race wasn't lipped (maybe nothing but its worth checking).

If you want to strobe the engine with the pre 66 crank, it is possible to accurately find TDC and scribe new timing marks onto the rotor.

Best wishes...

[Gup holland]

Hi Bess, i just stept in this discussion When i saw that Mitchell had same engine as mine. I wanted to find out how they did it to put a late crank in a early case.
Let me further explain my problem.

The late crank  734, has some problems. I dismanteld the engine  because of oil consumption . I overhold it 30 years ago, and took a peek on the TS end. I had no oil pressure problems. I discoverd some play at the big end , and diceded to act before it's to late.
The TS side is now already over +0.50 , the conrod ends are +0.20. The drive side end i Can slip off the roller bearing with my hands and is no tight fit anymore.
The crank is i think balanced, the flywheel is machined as also the center of the crank, see pictures.
The calculation figures for shimming isn't even visible anymore.  The weight between the two cranks is 1.1 kilogram.
If i wanted the late crank in, i need a new TS bush +0.60. I believe it stops at +0.50. The od of TS is now 36,78 mm / 1.448" .  Could choose for self made bush, after another regrind. But how far Can you go with this.?  And what to do on drive side bearing? For a beter fit. Use a loctite??
Like to use the late crank because he is balanced, but...........

Could get a pre 66 crank, wich has a TS of +0.10 , and big ends +0.20. And a good fit on the drive side for the bearing. Al needs a regrind. Then my old TS bush Can stay in and bored to +0.20". I think this is the cheaper way. The 1.5 mm ? When i read that a shim cup thickness is  0.034"/0,86 mm  and a few shims with it , i Can overcome the 1.5 mm/ 0,059".  Haven't got a shimcup yet, or make a soliid one?  Ring between the bearing.

The bearing wich always was in the engine is a two piece roller bearing, hoffman i believe.  Thats what you ment with single lipped bearing ? I looked at a ball bearing, but they have got the same dimensions If i am right. So it's a choice of what to use.

I'm learning  more about the engine lately because of the internet, we had only workshop manuals. They also added a oil sensor on the 62 case. Works perfect for over the years, see pic.

It also has a Lightning head on (2 Carls) with a early barrel ( now on +0.60 pistons in good order). The 2 bolts on the back are 3/8" altered on the bottom to 5/16" threads to acomandate the barrel. So its a engine of diverent parts in fact but it runs great. 
Originality is one other thing. It also sits in a 1970 Lightning frame.
I bought it in 1986 When was 17 without a drive licence, till now. But now with a licence

Have also a golden flash 1951 under construction for many years for hobby.  And a royal enfield interceptor mk2 2021.  It runs fantastic but the BSA is more fun.

So what you think?.

Greets alex (gup)

[Bess]

Hi Alex,
             You have a nice bike, I can see why you kept it for all those years.

   As said, I noticed the roller used on your bike never had a lip on the outer race, BSA specified a bearing with a lip on the post 66 engines. As your crank could move further into the outer bearing race I was thinking maybe that's how the wider crank fitted into the cases.
   
   If you use a deep groove ball race as originally specified you might find the crank doesn't have 1.5mm clearance?

Best wishes...

[Bess]

Hi Alex,
           I also noticed you had an issue with the crank and timing side bush with the post 66 crank, the oil supply to the rod bearings could have been reduced. I guess using the correct crank will be a better option.

Could you take the measurements of the pre 66 and post 66 for comparison for me?

Best wishes...

[Gup holland]

Hello Bess, the crank ran in de same bearing as your picture, i thought it was hofmann but is rhp. I know that original in my case a ball bearing is used. Looking at the specs of the ball bearing i see no diverrance with the roller bearing. I have not a ball bearing for comparison, Then i have to order one.

I was also disturbed that the oil hole in de TS bush was not in center of the oil Groove in the crank. It's always been so and had no oil flow problems, 30 years ago When i overhauled the engine i put in a high delivery oil pump. Cast iron i believe it was an MCA pump.
The center of the oil hole in the bush , doesn't come in the center of the groove but exatly on the side. So only the 1/2 of the oil comes directly in the groove.  That's looks me odd.
So, When i am going to use the pre 66 crank (best option i think) and it comes right next to the bearing it comes 1,5 mm to the primairy side, the oil hole and the groove better lines up.
Whats going to happen on the line up of the primary chain. Never had problems with it. But i never checked it If the chainwheel and clutch was inline?

Also took mesurement you ask, see pic.
As you see they are the same, the pre 66 / and late crank..

Took long ago Some mesurements , see pic. The diverance in the cranks is web thicknes. When the pre 66 is against the bearing the primary Will line up, or am i messing what, am i seeing this right.??
I always looked at the TS, as a fixed
point. This means there is prox 1.5 mm clearance between crank and TS bush??

What's your point of view?

Greets alex

[Gup holland]

I have a pic so you can see how much the big end comes through the bush, now to say , there was no spacer ring between drive pinion and worm drive for oil pump.
Maybe could this be a problem then?

I think??

[Bess]

Hi Alex,
           Leaving out the washer between the Crankshaft gear and the oil pump worm is strange, it is 1.9mm thick (the washer is soft and is crushed when used, probably to 1.5mm). Perhaps it has been left out of your engine to line the worm centrally to the oil pump drive. Can you check your engines the TS bush lip thickness again, you are needing a a lip thickness of approximately 0.155" and you stated yours is 0.100"?

The primary sprocket line up is done with shims, pt no. 40-0069.

Image dimensions from an original post 66 bush, the oil holes are drilled at an angle towards the engine.

Best wishes...

[Gup holland]

Thanks for your reply, things are coming together i think. They left  the washer out otherwise the ring came to far out and scored the pomp i believe?
The TS bush is still in the case so i could just prox mesurements. I found my very first TS bush replaced in the 90s. It has the mesurements that you gave me. There are 2 things different with the bush in the case:

1 the oil hole is further towards crank +/- 11mm from the outside. ( start of the hole) .

2 towards the crank the bush is 45 degree in and bush in case isn't.  See pic.

I have a thrustwasher ( never used) together with bush ( old) it comes prox 0.155, so your right.

You mean that When  i am going to use the pre 66 crank i need another TS bush ?
This pre 66  TS bush must have  a thicker flange (lip)?  Perhaps i dont know?

Greets alex

[Bess]

Hi Alex,
              The early bush pre 66, has a flange of 4.1mm thickness. The post 66 bush has a flange of 2.4mm.

So to get the post 66 large crank in your cases a post 66 bush was used moving the crank to the right. Therefore the thrust of the crank was taken by the bush flange, the oil hole to the shell bearings was partly covered and the con rods were 1.5mm to the right hand side. No too good!

So if you use the pre 66 crank you need to fit a pre 66 bush and a deep groove ball bearing. The primary sprocket will line up okay and don't forget the worm drive washer.

Best wishes...

[Gup holland]

This complete the story about the long crank. I know now what to do. I must get another TS bush pre 66.
The ring i al ready have.

That's should solve the prox 1.5 mm problem.

And a ball bearing If Needed.

Thanks for info , i started a topic of my bike on the dutch BSA forum one year ago. With the same questions.
You delivered me answers much quicker than the dutch club, pitty!
I Shall start here an topic of my bike soon here, you'll Can folow the progress.

Thanks you all, best wishes

Alex