The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: UKlittleguns on 23.04. 2020 17:23

Title: Engine rebuild - Dynamo strap
Post by: UKlittleguns on 23.04. 2020 17:23
Hi Everybody,

I am sure I am not the first person to make this mistake but could find no comment about it on any other topic.  When I started my A7 rebuild everything was torn apart to the last item.  The dynamo strap was particularly annoying as it was flapping about and and really hindering the crankcase clean up.  The pivot stud was removed and the strap assembly put to one side for later attention.  Fast forward to the engine being nearly complete and time to install the dynamo.  Multiple rude words!  With the inner timing cover in place the upper dynamo pivot stud cannot be fitted.  The options were to undo a shed load of work or "think of something".  I chose the latter.

I drilled through the timing cover to allow the stud to be fitted and then closed the hole with a cap screw.  Accuracy is needed but at the end of the day it worked, cannot be seen and I think improves the breed.  You can remove the strap without major stripping.

I am not advocating this job at all.  Just remember to fit the dynamo strap before installing the inner timing cover!

Len   
Title: Re: Engine rebuild - Dynamo strap
Post by: KiwiGF on 23.04. 2020 22:10
Hi Everybody,

I am sure I am not the first person to make this mistake but could find no comment about it on any other topic.  When I started my A7 rebuild everything was torn apart to the last item.  The dynamo strap was particularly annoying as it was flapping about and and really hindering the crankcase clean up.  The pivot stud was removed and the strap assembly put to one side for later attention.  Fast forward to the engine being nearly complete and time to install the dynamo.  Multiple rude words!  With the inner timing cover in place the upper dynamo pivot stud cannot be fitted.  The options were to undo a shed load of work or "think of something".  I chose the latter.

I drilled through the timing cover to allow the stud to be fitted and then closed the hole with a cap screw.  Accuracy is needed but at the end of the day it worked, cannot be seen and I think improves the breed.  You can remove the strap without major stripping.

I am not advocating this job at all.  Just remember to fit the dynamo strap before installing the inner timing cover!

Len

A lot of people won’t have this problem as they were never able to get the strap off in the first place! (The bolts often rust into the case)
Title: Re: Engine rebuild - Dynamo strap
Post by: davedental on 04.05. 2020 19:00
Hi Everyone
I'm a newbie here and what a great forum it is. I've learned so much that has helped me start an A7SS restoration.
The problem I had today was also with a dyno strap bolt, but the forward one with the eyebolt. The screw head was well and truly mashed. I noticed that there was about 5mm of thread sticking out into the engine mount slot so I filed opposing flats on this and used an adjustable spanner to start turning the bolt out. Once started I could use pliers on the shaft next to the eyebolt and remove it. No rust! It was bent like a donkey's hind leg though., Straightened up and cut off the last 5mm and recut the slot. Sorted!
Bad news of the day was finding a section of sump plate bolt casting missing (timing side)and the thread of the stud in a bad way. Proper weld or JB weld? Hmmm..........
Title: Re: Engine rebuild - Dynamo strap
Post by: TimK on 05.05. 2020 06:38
Bad news of the day was finding a section of sump plate bolt casting missing (timing side)and the thread of the stud in a bad way. Proper weld or JB weld? Hmmm..........
Hi davedental
definitely proper weld if you'll be screwing the sump plate stud into the repair. JBWeld is ok cosmetically, but my attempts to tap into it haven't  been successful, A competent welder will be able to weld that area without distorting the case.
Cheers
TimK
Title: Re: Engine rebuild - Dynamo strap
Post by: davedental on 05.05. 2020 22:10
Hi Timk, Yeah, I'm sure your right. Might have to wait until this lockdown situation is still in place though.
Title: Re: Engine rebuild - Dynamo strap
Post by: Greybeard on 05.05. 2020 23:15
Hi DD,
Will you go to Introductions and give us quick post about your bikes and how you got here.
 *welcome*
Title: Re: Engine rebuild - Dynamo strap
Post by: davedental on 07.05. 2020 12:02
Welding being sorted this very day and helicoil kit on its way to sort another duff thread. Off to introductions now to say hello officially.