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Enclosed Series D Crash Bars

rapcom

Well Known and Active Forum Website User
VOC Member
Gentlemen,
Whilst dismantling my Black Knight in search of a suspicious noise, the fact that you have to remove the FT293AS crash bars to remove the front head struck me as rather inconvenient. To remove them, you have to undo three of the crankcase studs, which is undesirable if you do not intend to split the crankcases.
It would be a useful modification to devise a way of removing the crash bars from the engine plates, presumably using some form of male/female spigot/socket arrangement, whilst retaining sufficient structural integrity for the crash bars to still fulfil their intended purpose of not only holding the side panels, but also protecting the bike (and your leg) in the event of an accident.
Has anyone done this modification, and if so, exactly how? Are there any drawbacks which I have not thought of?
Many thanks Rapcom
 

b'knighted

Well Known and Active Forum Website User
VOC Member
Whilst building my Knight some decades ago I found that the right crashbar had to be altered to clear the exhaust. The alteration, done by Roger Clark, was to weld in a piece of bar looped around the pipe. This, instead of being welded to the "propstand" plate has a threaded end with nuts either side of the plate. The left crashbar also has a solid end as Mac Read discovered when he tried to run the breather exhaust through it. The crashbars have been tested in action and retain adequate strength.

Cheers,
 

John Cone

Well Known and Active Forum Website User
VOC Member
Would it not be possible to replicate the existing plates on the the bottom of the crash bars and fit these to the crankcase. Where the existing stud holes in the crash bar plate are enlarge these out enough to allow the crankcase nuts to be encased or covered. lay one on top of the other and drill 3to4 new holes through both plates and then tap new threads in the plate fiited to the crankcase. You could even drill your elephants trunk hole as well. It would mean your that the bottom of the side panel would come out the 3/8 or 1/4 depending on the thickness of the plate, but i don't think it would notice. Your thoughts!
 

b'knighted

Well Known and Active Forum Website User
VOC Member
I can see what you are suggesting but you’d need to space the top as well, or distort the crashbar bar by pulling the top in by the new plate thickness. Then the side panels would sit out so you’d have to space the backs for the screws to pull in flat. When you then throw the bike up the road the stress on the bottom of the crashbar would be carried by very short setscrews. My suspicion is that a nut on a stud has more strength than the head of a small setscrew. How do the Vindian style crash bars with separate clamps top and bottom fare when tested by the road?
 

John Cone

Well Known and Active Forum Website User
VOC Member
Hi
Having made my suggestion without even going out to the garage to look, i can see that unless you have a front mounted sidestand the existing plate has a 3/4 or larger hole and a 1/4 hole already not being used each side. So do as i suggested make up 2 plates as per pattern and fit to the engine and use these exsisting bolt holes to fix the plate together.. Yes you may have to pack out the top a bit.
 

deejay499

Well Known and Active Forum Website User
VOC Member
On my Prince outfit, the crashbars have been removed from the plate and a threaded insert put into the end, this then goes back through the hole left and a nut put on the inside. It it almost invisible and still looks standard. Not sure how it would stand up in an accident but if welded and pinned should still be strong. When I remove the exhaust pipe, I just loosen the nut and pull the crashbar out a bit to give the required amount of clearance - easy!
 

rapcom

Well Known and Active Forum Website User
VOC Member
Many thanks for the responses so far. Having studied the bars from my own bike, and also a modified bar from someone else's bike, it is apparent that the tubes do not approach the plate perpendicularly, or even consistently at the same angle. Thus any insert, spigot or extension of the tube will not be at ninety degrees to the plate, and any retaining bolt or nut will not tighten down flat on the plate, reducing its effectiveness and strength.
Using a double set of engine plates introduces more problems with the alignment of the side panels and top mountings. John's two spare holes seem to be the sidecar mounting hole and the distributor cowl mounting hole. In my case, the sidecar mounting hole is actually in use for a sidecar fitting, making a double plate even more problematical.
B'Knighted's solution of welding a wiggle into the bar to clear the exhaust pipe does not address the problem of non-perpendicularity. The wiggle on the right bar can be adjusted in manufacture to work, but you still have to do the left as well.
The most elegant solution offered so far came to me via email off Forum from one of our most senior and knowledgeable members, and suggested cutting the tube from the plate, and welding a circular flange to the tube. If the central hole in the flange is made oversize or tapered, the angular discrepancy can be accommodated, tack-welded in situ for positioning, then finish-welded on the bench. Three bolt holes at 120 degrees through the flange and plate would complete the fitting. I have a photo of this installation available by email if requested.
Any other thoughts and suggestions?
 

rapcom

Well Known and Active Forum Website User
VOC Member
Roy, The crashbars are the mountings for the side panels-remember we are talking "Enclosed" Series D.....
 
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