1948 KH

[BrianReynolds]

Hello All, I am an expat Welshman in central Canada, I have worked on Brit iron over the last 50 years, but limited experience on Ariels. Recently I agreed to assist the estate of a collector to get a collection of bikes up and running, presumably for eventual sale. As part of this I am completing the assembly of a "48 KH, which is 90% restored to a high standard but I am having a problem with the inner primary case. When the case is bolted to the engine it appears the clutch input shaft is approximately 1/4" too short. When I try to install the chain wheel it rubs the primary casing when it still has 1/4" to slide on the bearing. I have checked the case is flat, all appears ok, so I am not sure if it is the correct case. When the clutch etc is installed without the case in place, the primary drive lines up perfectly and works as it should, so I am assuming there is an issue with this particular inner primary case. Were there different cases for different model years? I have looked on the AOMCC site at the parts books and manuals but this is not very clear. I also have 2 square 4's here, so I need to get familiar with them. Any assistance appreciated. Thanks, Brian.

[paul.jameson]

Hello Brian,
You have the wrong inner primary case - helpfully placed at the bottom of the photo. This is one from a single cylinder Ariel. The one for a KH has a step in the rear edge which sorts out your problem.

Paul

[JohnnyBeckett]

HI Can you have the wrong mainshaft in the gearbox or the wrong gearbox in the bike wear the main shaft is to short i know their is different lengths shafts that is what it sound like to me the mainshaft is to short

[JohnnyBeckett]

if you was using that inner case i think you will find Paul is right i did not take a close look at the case wen i first look at your post good luck with the rebuilds

[adrian.hannam]

Hi Brian, here's a link to a similar topic with photos of the cases.

http://forum.arielownersmcc.com/viewt ... 754#p67754

[BrianReynolds]

Thanks to all for the very helpful responses. I had been assured that "all the right parts were there" when I started this project, but obviously this is not the correct primary case. I was reasonably certain the shaft/sprockets etc were right as when assembled without the inner primary it all lined up and worked as it should. Ok, if you don't mind, a few more questions to you learned gentlemen: A) I now have to find the correct inner primary ( any suggestions? not too many lying around Manitoba, Canada) If I can find one, does it use the same outer primary case? or do I have to locate a matching inner and outer? B) There is a seal between the engine sprocket and crankcase, just appears to be a double sided flat seal which fits, but really doesn't look as though it should be there. I have tried looking at the parts books on this site but indistinct. Any assistance greatly appreciated, thanks again.

[simon.holyfield]

Brian,

Have you had a look at the parts books on the club website? that will answer your question A - compare the KH and singles part numbers.

[JohnnyBeckett]

HI on the chain case it will have numbers on it post the numbers up on the hear or look at the parts book to see if you have the right casings for the bike

[paul.jameson]

The primary chaincase outers are common to singles and twins so you will have the correct outer. Was there a single in the collection of bikes? If so, then maybe the person trying to put the single together is finding that the primary chaincase inner doesn't fit either, because it is the one which you should have. But if there wasn't a single in the collection you are down to the AOMCC, Ebay or Draganfly. Provided that the chaincase inner has the kink you can see in Adrian's photo and the hole for the footrest through it, you will find it is the correct part.
The oil seal is the same as for a Square Four. Dragnafly should be able to supply one.

[brenton.roy]

Hi Brian, have a really good look for it, because they aren't cheap..
If you can't find one, PM me. I bought one recently and could part with it.