The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Steverat on 18.09. 2018 06:36
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...is 7/16" diameter where it passes through the crank cases but the holes in the corresponding frame lugs are 1/2". Can this be right? Makes it easier to get the stud in but cannot be good engineering practice surely?
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Mine is same, but I have some spigot/spacer sleeves in there through both sections, but can't remember if they were in there when I started...I also think the parts list doesn't show them/ any
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Yes there should be dowel tubes in there that keep the two parts of the frame lined up...
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G'day Brett.
I can't see them in any parts book. Do you have a part # for them?
Cheers
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I have looked but cant find them anywhere in a parts book, But every frame we have seen has them, common sense says it has them haha , just not a parts book!
Same Idea as where the two frame parts bolt together at the upper frame(Seat mount), there is also a dowel that goes through the complete section, 65-4488.
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Yes we've got that one, perhaps I'll procure another and saw it in half.
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Found the same thing with the CB900/1100. There's a long dowel in the oil pump that isn't in the parts list.
Wonder why people get confused and frustrated.
Where's that beer?
Cheers
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I ordered a new stud by part number from Draganfly, what came was even thinner, only 3/8” when even the hole on the crankcases is 7/16”. To use it I’d have to sleeve it twice. I wonder why they did that. Will call them and report.
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steverat I ordered crankshaft flywheel bolts by the part No these are 6 tough bolts to take the strains you could imagine they have to cope with, they said they had them, but sent me SET screws *problem* *bash* so they went back along with a lot more of my order --soft instead of hard washers etc------I could have gone to B&Q and got the same bits i ordered for a third of the price *rant* *pull hair out*
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Two years ago after a re build of my 1960 GF I was tightening down the barrel base nuts or tried to. They were so soft that the threads just stripped out of the nuts so returned them to the supplier with a note to say I expected better from them. ( DRAGANFLY ) and stopped using them altogether.
ELLIS
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So who would be the best supplier for correct BSA fasteners?
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@ Steverat..can you say the part no of the offending stud..sorry it's not obvious to me anyway? I could not find any pacers in my 59 A7SS rebuild dismantled stuff I got, but logic on trial build meant they MUST be there so I trial-fitted the front engine "Dynamo" plates then a measured and turned two spacers about 1/2 " x 3/8" (don't quote me) ...otherwise you bend the frame inwards when tightening, if we re on the same page?
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Pete- s-rats is a Plunger frame, your Swing Arm frame parts list shows the engine plates appear to have the spacers integral with the plates....Plungers models only have a top mount in those plates which are similar but way different
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Thanks for enquiring, DuTch is right, I'm talking about stud 67-1251 which goes through the engine at the front lower location and the lugs terminating the frame tubes in that area. The hole in the engine is 7/16" diameter and so I deduce the stud should be that size also. However Drags sent me a 3/8" stud. To complicate further, the holes in the frame lugs are 1/2" necessitating dowelling if fretting is to be avoided. I found a supplier of suitable thin wall tube on Ebay:
https://www.ebay.co.uk/itm/Capillary-tube-304-thin-walled-round-tubing-0-8-12mm-stainless-steel-1-4301-0-3/192641964429?ssPageName=STRK%3AMEBIDX%3AIT&var=492784365401&_trksid=p2057872.m2749.l2649
so I'm looking forward to getting that and will report.
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I have this problem with my plunger rebuild, made worse by the fact that over time the holes have all enlarged slightly. I’m going to start from scratch and make a new stud from a rod, cut to size and threaded. Does anyone have any recommendations for what material to use - would mild steel be OK?
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In my youth we just used a length of Whitworth threaded bar and enough washers to centralise the crankcase, then more washers and nuts to get a nice fit for the exhaust pipes.
In these more enlightened times I would suggest boring the well fretted crankcase holes just an inch or so deep and turning up a top hat bush which is a nice snug fit into the case and onto the mounting through bar. The bar will be a nice fit into the bushes which join the front and rear frame members. Then thread each end of the bar, but make sure not much of the thread enters the frame bushes. This means that everything fits nicely and the chance for further fretting is reduced. Choice of material? Some more enlightened member will be along soon. Studded bar worked, so mild steel should do unless you have access to the more exotic suggested metal.
Swarfy
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I'd say mild steel was a bit soft for that. I'd prefer EN32 but when stuck for small amounts of material for such things as decent studs, etc , I usually get a long allen (capscrew) bolt, cut it to lenght & thread it. Quite high tensile and machines fairly easily.
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.......In these more enlightened times I would suggest boring the well fretted crankcase holes just an inch or so deep and turning up a top hat bush which is a nice snug fit into the case and onto the mounting through bar. ...........
That's a sound idea, but precision alignment is imperative, there's no room for error (in my humble opinion.....) No doubt the holes are elongated due to loose nuts, so to avoid the risk of misalignment of the 'tophats' and depending how 'elongated, would be almost better to use as-is (iknow,I know- a bit rough but....), and ensure the nuts stay tight.... *doubt*
I agree that harder metal than soft cheese bar will be better, mine's 7/16" BSC