Topic: 1973 CB500 airbox case question

[tthom580]

I'm new to the forums and new to motorcycles in general so I hope everyone will bear with me. If I'm posting in the wrong area or anything like that, let me know. I recently bought a cb500 k2 and have been working through issues with it since then. It came with some seemingly bottom of the barrel pods on it and the plenum of the airbox separate but no airbox case or case cover. I went to a local used parts warehouse and found what was labelled as I believe a case for a '75 cb550 but looks like the cb500 case does on the parts diagram and seemingly fits the plenum for my cb500 correctly. It's seeming like I'll need to buy the case cover/tool tray part online since I couldn't find it at the warehouse, so I'm hoping to find out whether this filter case that I bought is actually correct so that I don't waste money on a case cover/tool tray that won't fit this case. So the question is basically, are the air boxes interchangeable between a 75 cb550 and a 73 cb500? If so, does anyone have any good ideas on where to find the case cover/tool tray? If I got the wrong case, any ideas on where to get the correct one, and the cover to match it? Thanks in advance, I'll include pictures of the plenum and case and how they fit in hopes that will help. 

[bryanj]

You can use that on a 500 with a 500 filter and holding clip(clip same as 550) DO NOT fit the foam and steel 550 filter or you need a 550 air filter.
The cover is not absolutely necessary but handy to put a tool kit in

[tthom580]

Thanks so much for the response, I'll have to make sure I have the clip for the filter. As for the filter, is this what I'm looking for? https://www.ebay.com/itm/Honda-CB500-K0-K1-K2-1970s-Air-Filter-Cleaner-Element-Genuine-OEM-17210-323-030/264336350920?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=264336350920&targetid=942291022259&device=m&mktype=pla&googleloc=1028057&campaignid=10832464484&mkgroupid=106683819037&rlsatarget=pla-942291022259&abcId=9300397&merchantid=118833309&gclid=CjwKCAjw8MD7BRArEiwAGZsrBeMjRwI7ZBshn5Pp36c-D-XdsKlZ64-Op1FwAGWBNcj6vCNs5g7WJRoCwBkQAvD_BwE&pageci=d2ddd8e9-e6b1-4680-a03c-7590cd0b0ee6&epid=1223755738
 And I guess I'm not certain how to look for this foam piece you mentioned, would it come with the filter or would I need to buy it separately?

[bryanj]

You dont use the foam piece with the 500 filter, only the 550.
I have seen a wooden wedge used instead of the steel clip, anything that pushes the filter against the plenum to seal the rubber.

[tthom580]

Is this the metal piece you're talking about that I don't need? Or should this be part of the assembly? And is that air filter the one I want or is there a different one that would be more ideal? Again thanks for prompt responses, they're very much appreciated, just let me know at the point I need to quit pestering you and figure the rest out myself.

[Scott S]

 That is actually a completely different part. It's an aftermarket adapter to fit a large, single cone type filter on the plenum. It was originally sold by K&N. That replaces the air box part. Might be kind of desirable to some people.

[Scott S]

 Here are a couple of pics showing how that K&N filter fits.
 

[Scott S]

 And look at this diagram. The spring clip you are looking for is part #16. BryanJ is saying leave out #'s 27-30 and use the air filter (#15) that does NOT have the hole in the bottom for the pipe sticking up on part #27.

https://images.cmsnl.com/img/partslists/honda-cb550-k1-four-1975-usa-fuel-tankair-cleaner_bighu0038f4005_83c3.gif

 Order the correct clamps for the intake rubbers (#18). Don't be tempted to use hardware store hose clamps. I think I ordered a set from 4into1.com recently.

[bryanj]

Sorry, i missed out the "Yes that is the filter you need" The clip is NLA from Honda but a member on the UK site was making them and Dave Silver bought some from him, a wooden wedge or peg works just as well.
Tool trays do appear on ebay, usually without the mesh cover and spare fuse holder. If they are there snatch the sellers arm off!!

[tthom580]

Awesome, so I guess that aftermarket part would explain why I didn't have the original filter case with mine. I'm assuming I'm better off with the actual case rather than the aftermarket piece now though? Thanks so much guys, this has been really helpful, I'm gonna order the filter and hopefully I have all the pieces I need now, I'll try it on in the near future and let you all know how it works out. Thanks again everybody!

[Scott S]

 In my experience, that K&N adapter worked just fine. You'd have to do some research as to what current K&N filter would fit it.

[RAFster122s]

And look at this diagram. The spring clip you are looking for is part #16. BryanJ is saying leave out #'s 27-30 and use the air filter (#15) that does NOT have the hole in the bottom for the pipe sticking up on part #27.

https://images.cmsnl.com/img/partslists/honda-cb550-k1-four-1975-usa-fuel-tankair-cleaner_bighu0038f4005_83c3.gif

 Order the correct clamps for the intake rubbers (#18). Don't be tempted to use hardware store hose clamps. I think I ordered a set from 4into1.com recently.

Scott, is the reason hardware store clamps are ill advised is because they are too wide or that they cut into the rubber?
Thanks! David

[Scott S]

 Both!

[tthom580]

So one last question, is there a trick to getting all the parts for the airbox in there? I tried taking the carburetor off and connecting the plenum to the case and then putting the carb back in and that didn't work, tried connecting the plenum to the carb and then putting them in already connected which didn't work. Any ideas would help, it's been a bit of a pain the ass so far, so if there's an easy way I'd love to know about it.

[Kevnz]

I think you need the airbox and plenum sitting in situ with the carbs off, and then slide the carbs across and onto the manifold. Once the carbs are seated, you can fit the boots from the plenum and then secure the airbox. I found it easier if you push the 2 outer plenum boots into the plenum as that gives a bit more wiggle room. These things are such a pain you will probably get to do it multiple times and it gets easier each time. I did it so often tracing a fault on my 500 that I could have the carbs sitting on the workbench within 15 minutes! Bit of lube on the manifold rubbers helps. Worth it once it's all done.

[bryanj]

Also if the head to carb rubbers have gone hard its worth paying for new ones, makes it so much easier. Do Not use "jubilee" type clips on the rubbers they are too wide and cause air leaks

[newday777]

So one last question, is there a trick to getting all the parts for the airbox in there? I tried taking the carburetor off and connecting the plenum to the case and then putting the carb back in and that didn't work, tried connecting the plenum to the carb and then putting them in already connected which didn't work. Any ideas would help, it's been a bit of a pain the ass so far, so if there's an easy way I'd love to know about it.

Are you using spray silicon to lube the parts to assemble it all together? It helps.
Better yet.... Soften the rubber parts in a 3 to 1 mix of 91% isopropyl alcohol and wintergreen oil for 2-5 days.