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Crankshaft connection bolt

Posted: Sat Nov 09, 2019 12:36 pm
by Anthony Woolhead
I don't know what's happened to my last post, I can't find it so here goes again. Thanks for all your replies about crankshaft nearside bolt. I solved the problem by making a strap spanner from a length of 1" x 1" oak ( yes you've guessed it, I am a retired carpenter/builder) with a length of webbing taken from the harness of an old strimmer, screwed and washered to one side. It worked perfectly.
After quite a struggle with the crankcase sides, which I removed with a homemade extractor, I have come to the final obstacle, the hexagon socket bolt inside the crankshaft. I have the allen key fitted with a long lever on the short end. To stop the crankshaft from turning I have passed a rod through the small end resting on the crankcase sides with (you've guessed it) two oak packings to protect it.
I have put enormous pressure on the lever and can feel the key flexing but it won't budge. Any suggestions please?


Re: Crankshaft connection bolt

Posted: Sat Nov 09, 2019 2:30 pm
by JohnnyBeckett
use a impact gun or rattle gun to undo the nut i do it all time it saves time messing about trying to undo nuts or bolts sometimes you can just hold the part you are undoing the gun does all the work i know a lot says do not use one i use them all day long if did not i would not get half my jobs done it make life a lot easier

Re: Crankshaft connection bolt

Posted: Sun Nov 10, 2019 12:12 am
by bh.sprint

The bolt is torqued to 60 ft/lb and may have been done higher so will need some force to undo it.

Also is the flexing just in the allen key or is the flywheel assembly also flexing either on the oak blocks( I know its oak but it may still compress slightly ) or is the unsupported shaft bending a bit ?
The tool supplied by Ariel supported the shaft as well as locking the flywheel assm. and made it very rigid, which helps to get the initial shock to the bolt to break its grip.
I have in the past to get a tight bolt undone held the allen key in a small vice and used two hands on the vice to break the bolts hold or even a bar in the vice to get more torque.

It may help to put the end cover back on to support the shaft but if it was hard to get off you may not want to do this-- Drags supply the side door extractors for £ 26-00 I think.

Brian H.

Re: Crankshaft connection bolt

Posted: Sun Nov 10, 2019 2:52 pm
by Anthony Woolhead
Many thanks for your support guys, I cracked it, I found a chrome plated steel tube from an old vacuum cleaner, about 2'-6" long x 1 1 /2" dia. Over the end of this I fitted a huge 5' long x 35mm socket, which I bought to undo the nearside flywheel bolt. The 1/2" drive fitted nicely over the Allen key. It took quite a few jolts with the full leverage but eventually went with a loud bang.

The central oil seal was badly damaged and all 3 main hearings felt rough. The bike has only done 23k but I think it has stood for over 50 years, maybe condensation has affected the bearings. Nothing else in the engine appears to have signs of wear.

Just got to get new parts and then put it all back together. Not looking forward to lining up the crankshaft in the centre bearing, hopefully it's not that difficult. I have already restored the bike and it's looking really good. Perhaps put some photos on soon.


Re: Crankshaft connection bolt

Posted: Sun Nov 10, 2019 7:52 pm
by bh.sprint

Pleased to hear the bolt is sorted.

Re lininig up the shafts. Some flywheel assemblies go together with no problems and line up straight away and others seem to need quite a lot of work to get them to the correct run out. If the shafts are out, tighten them up in stages and pull them into line at each stage , that worked on the Arrow.

Brian H.