BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: Mike Farmer on 27 Apr, 2021, 21:14

Title: Funny Funny
Post by: Mike Farmer on 27 Apr, 2021, 21:14
 :) :) :)

My recently rebuilt A65 bottom end is very smooth and turns easily in the normal direction of rotation, but its got a tight spot when I try to turn it backward. I dont want to start dismantling unnecessarily.

Any ideas Please. I've got an awful feeling about the oil pump fitting. I can't imagine its the pump because thats a brand new SRM pump.
Therefore gents any ideas here will maybe save me some time and swear words.

Mike 8) 8) 8) 8)
Title: Re: Funny Funny
Post by: geraldhattrick75 on 28 Apr, 2021, 10:23
Is the tight spot in sequence with the oil pump rotation, or is it more in keeping with engine rotation?

Timing side gear meshing?

What stage of engine build are you at? (fully rebuilt? Just bottom end?)

If fully rebuilt, have the spark plugs been removed?

Good luck,
Dave
Title: Re: Funny Funny
Post by: Mike Farmer on 28 Apr, 2021, 11:29
 :) :) :) :)

All good points.

Bottom end at this stage. I suspect the oil pump fitting and in truth I now think its going to boil down to the washer between the pump  drive spiral gear and the main drive gear, in that I may have inadvertantly put the wrong washer in. If that the case---read cockup.
Let you know.

Mike 8) 8) 8) 8)
Title: Re: Funny Funny
Post by: chaz on 28 Apr, 2021, 14:31
how does it feel without pump on? same or free,
Title: Re: Funny Funny
Post by: geraldhattrick75 on 28 Apr, 2021, 17:37
QuoteI now think its going to boil down to the washer between the pump  drive spiral gear and the main drive gear, in that I may have inadvertantly put the wrong washer in. If that the case---read cockup.


Welcome to my world....
Title: Re: Funny Funny
Post by: Mike Farmer on 28 Apr, 2021, 20:17
 :) :) :) :)

Hi Chaz. It certainly appearred to be OK before I fitted the pump but I can't honestly say that I turned it backward.

Mike 8) 8) 8)
Title: Re: Funny Funny
Post by: DAVE BRADY on 28 Apr, 2021, 21:02
Hi Mike,

Have you fitted the pistons and cylinders?

Dave.
Title: Re: Funny Funny
Post by: Mike Farmer on 29 Apr, 2021, 11:14
 :) :) :)

No to cylinders/pistons.

My course of action now is to remove the idler pinion and see if that makes a difference i.e. eliminate cam shaft.
If it persists then start looking at the oil pump assembling and see if I have something wrong.

Let you know.

Mike 8) 8) 8) 8)
Title: Re: Funny Funny
Post by: DAVE BRADY on 29 Apr, 2021, 11:23
Hi Mike,

A few basic questions.  Does the crank just have a tight spot or does it stop rotating backwards completely?  Obviously removing the pump drive and or idler will eliminate or implicate the pump or cam.  With no pistons and cylinders fitted it is possible when rotating the crank by hand to not keep the small ends central to the crank.  This can result in the in the big end nuts catching the crankcase and by chance this has only happened when turning it backwards.
I see you have described it as a tight spot so my suggestion may be moot but eliminates a possibility.

Dave.
Title: Re: Funny Funny
Post by: geraldhattrick75 on 29 Apr, 2021, 18:03
Another thought (as if you needed one...) changing the direction of rotation will cause the load on the oil pump drive to either try to move in or out. And, if the washer you fitted allowed a bit of slack,- might that movement cause the tight spot?......

Good luck,
Dave.
Title: Re: Funny Funny
Post by: Mike Farmer on 29 Apr, 2021, 22:03
 :) :) :)

That is seriously likely.

All will be resolved eventually, then I shall have great joy in publishing my result, folly or otherwise

Mike 8) 8) 8)
Title: Re: Funny Funny
Post by: Mike Farmer on 30 Apr, 2021, 15:27
 :) :) :) :)

Well I've got it sorted. What was it??I haven't got a clue except that it was at the oil pump. I suspect either the washer was a smidgen thin or I overtightened it. In truth I am coming down in favour of heavy handed.

So there tis, sorted. Thanks to all for your input. Now I can fit the primary drive etc and  pistons and cylinders and get the motor into the frame.

Mike 8) 8) 8) 8)
Title: Re: Funny Funny
Post by: geraldhattrick75 on 30 Apr, 2021, 20:11
Excellent news Mike.

Get the rest of the ironmongery built and placed in the correct location (exhaust stubs facing forward).

Don't rush anything. In fact double check absolutely everything.....

It's not that I don't want you to make any mistakes- I just don't want you showing me up by starting your engine before I do mine. (I've been dragging my heels for 20- 24 months)

Best of luck,
Dave

Title: Re: Funny Funny
Post by: Mike Farmer on 01 May, 2021, 08:32
 :) :) :) :) :) :)

I bought this in 2014 as a quick project.

Mike 8) 8) 8) 8)
Title: Re: Funny Funny
Post by: geraldhattrick75 on 01 May, 2021, 15:38
Nice one Mike. Makes me feel a little better....
Title: Re: Funny Funny
Post by: Mike Farmer on 01 May, 2021, 17:55
 :) :) :)

I've just finished the one that I bought in Dec 2012 Its now my son's but he is too busy with his job etc.

Mike 8) 8) 8) 8)
Title: Re: Funny Funny
Post by: geraldhattrick75 on 01 May, 2021, 19:05
Yeah I have a Velocette Venom which I talked my son into buying from a mate. He paid for it I did all the building (my choice).

Over beers a while back he said "you know the arrangement don't you?". I reckoned I did and he confirmed it "you ride it till you kick the bucket, then I get it in my garage."

We don't mince words, and we get on great.....

That took 3 years......
There's just something great about doing projects....
Title: Re: Funny Funny
Post by: MITCHELL on 02 May, 2021, 18:26
I bought the boxes of bits that is the a65 I'm now attempting to construct in the early eighties so I don't think either of you need to be to concerned,😁😁
Dave.