Honda CB750 Sandcast

Reproduction 2-hole airbox

markb · 26 · 10968

markb

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I'm starting a thread here to continue a discussion about 2-hole airboxes from my restore thread.  Ash suggested getting some of us together to contact LPM about making a repro 2-hole airbox.  KP has already contacted them about this.  KP has indicated that there are three versions of the airbox, differing only in the top half.  Someone correct me if I'm wrong but I think these are the three:
2-hole without dents
2-hole with dents
3-hole with dents
I believe the 2-hole airbox without dents went up to about 302 and the 2-hole with dents went to 4006.
The 3-hole is the version that LPM currently produces and it sounds like they could supply that in a 2-hole version but it wouldn't be correct.
Obviously the demand would be greatest for the 2-hole with dents.  Who would be interested in getting a repro of either 2-holer?
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Steve Swan

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Wayne's 576 has the 2 hole w/o relief.  i will update the "Distinctions" list.

As far as requests for the 2 hole airbox types; I would like a 2 hole w/o relief.


markb

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Steve,
I just took the airbox off 1553.  I knew it was a 2-holer but I hit the jackpot on this one.  It has no reliefs!  Sorry, but this one is going on #97.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)



Wayne

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Don't forget if you don't currently have 2 hole hardware, you will need it. I'm thinking that stuff is going to be very hard to find. I'm currently fixing my original 2 hole air box for show purposes only. I think Santa is bringing me a 3 hole for Christmas that I can run the bike with.  ;)

Having said that I would get another if the price were right. We really don't need any more than the top piece do we? Might make it cheaper if it could be purchased that way.
[size=


Steve Swan

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I am posting again to help keep thread active in hope other members/owners of vins greater than 1553 will check their air boxes for relief.  Wondering if 2157 would have relief -or not.  Then, would need two of the earliest type boxes.


markb

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Good Deal !!!! 

You'll still need a 2 hole w/o relief for your 1553 !
I'd be happy with a repro for 1553 if we could get LPM to do it.
Don't forget if you don't currently have 2 hole hardware, you will need it. I'm thinking that stuff is going to be very hard to find. I'm currently fixing my original 2 hole air box for show purposes only. I think Santa is bringing me a 3 hole for Christmas that I can run the bike with.  ;)

Having said that I would get another if the price were right. We really don't need any more than the top piece do we? Might make it cheaper if it could be purchased that way.

Mine has all the hardware except for one of the wing bolts.  I think I have one of them somewhere.  I would think we could get the brackets manufactured.  I think you're right about needing the top half only.

Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


ashimotok0

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Just one comment. I managed to get a bottom half for my K0 to fit the original top half from LPM. He told me that he would not normally sell one separately but because he was quoting me on a large commercial job he agreed to supply one for 20GBP . But it did not mate up as it was slightly narrower than my original '69 K0 one. He then sold me the bottom half and separator piece so I had a full repro set. I have heard people having to 'shave off' air filters to fit the LPM repro too.

Cheers

Ash


markb

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That makes sense.  They probably made their molds from a good box.  Then when they mold a box and it cools off, it is slightly smaller than the original.  Are there other molders?  I know Yamiya sells them too.  I wonder where they get them and if that might be another option.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


vnz00

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Hi all,
#1853 has 2 hole airbox with relief. So we now have a 300 range where there was a cutover for the airbox information :)

 I repro'ed a 2 hole airbox using the lpm replica by filling the 3rd holes. Most people would not know the diff in how the relief differs between 3 hole & 2 hole so if lpm, maybe the no relief option would be better.

Regarding hardware, I cut down later brackets to suit. Note there are length differences in the long barbell type bolt running between the middle and top airbox halves. 2 hole airboxes use no rubber damping so barbell is longer. It gets shorter with thicker rubber used after K0 airboxes.

As the internal hardware isn't visible I am ok with later hardware. But then I have the good original airbox wrapped up and stored in a Swiss security deposit box ;)

A bit of cutting and filing will give a 2hole bracket within a couple of mm of the originals. The internal gold zinc plates could also be cut down or left full size for extra support against flexing. You will need to use the dowel/collars in the holes too, and unless shaved shorter, the rubber too (as dowel length is made for rubber to be used.

I think if u run without rubber, it is possible but the heights are out of whack.

Good luck- my repop gets painted in a couple of weeks. I'll post photos over Xmas.

Regards,
Steven.

vanzetto_svr@hotmail.com


hondasan

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I too "plugged" the spare hole in a LPM box to create a 2-hole type, but fortunately had all the original 2-holr box hardware to use with it.
The 2-hole brackets are actually TALLER than the 3-hole - the 3 hole were reduced in height to enable the rubber "cushion" to be sandwiched between the new bracket and box, with the box remaining at the same height as previous. You can modify the 3-hole brackets down to 2 as suggested, but if you do not fit the rubber, the box will be slightly higher on the bike (by the thickness of the missing rubbers).

Anyone had any luck dealing with Nishmatsu in Japan? - they were listing replica 2 hole brackets at one time, but I never managed to communicate with them. Then fortunately, DSS got soem NOS 2-hole brackets in which solved the problem for the next resto.

Cheers - Chris R.
Chris R.
302/338


Riccardo

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Chris,

also i've had problem to contact Nishimatsu.

But, surfing on Ebay, i've meet RICK DEGAN RMDDIST <rmddist@hotmail.com>.

He lives in Japan.

Rick is a good and disposable person, trought him i've purchased the front DC fender by the original producer of Yamiya, but at lower price and he was disposable to contact Nishimatsu por purchase the replica FRP/VTR Daytona fron fender, with arms in black.

He ordered and purchased the daytona repro fender for me, i payd him and he shipped all to me.

A great contact.

Try to touch Rick to contact Nishimatsu and le we know if the 2 hole filter repro is still available for us and prices.


P:S: do you've updated the VIN directory with dates of my K0?
Riccardo
Your Italian friend.
737/940 Restored
1081/1362 Preserved
1256/665 Restored - ex Owner: Chris R.
10253/10315 (K0) Next project
1969 - Kawasaki H1 Mach III low ign cover - Restored
1969 - Kawasaki H1 Mach III high ign cover - Restored
1971 - Kawasaki H1A - Restored
1973 - Kawasaki H1D - Preserved
1973 - Kawasaki Z1 Blackhead - Restored
1971 - Norton Commando SS - Preserved
1978 - Honda CBX - Unmolested Museum Quality
1988 - Honda CB 400SS - Unmolested
1997 - BMW R80 GS Basic - blue frame - Museum Quality
2007 - BMW HP2 Megamoto - blue frame - New


kp

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It would be great if we could get an airbox copied. I believe this is one part that should be easily manufactured. In relation to the 2 hole and the 3 hole, the 2 hole airbox has some notable differences to the 3 hole. The indent type has different indents to the 3 hole and the "inner" top half of the 2 hole is formed differently to the 3 hole. Please see the technical section of the website for a pictorial description of both. Manufacturing of the brackets would be a piece of cake to a metal shop. KP
Yabba Dabba KP


Wayne

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That makes sense.  They probably made their molds from a good box.  Then when they mold a box and it cools off, it is slightly smaller than the original.  Are there other molders?  I know Yamiya sells them too.  I wonder where they get them and if that might be another option.
Mark

Well I got a repro 3 hole with reliefs. I was hoping I could use the center piece as a template to finish the repair of my original 2 hole without reliefs. No such luck. The repro is smaller and almost falls inside my original. Does anyone know if any of the repo's out there fit to the original spec, or does anyone have an original center piece in near perfect shape they would be willing to sell?

If I remember correctly, with my early box the center piece would be glued in once I get my repairs made and a coat of paint on the inside. (I believe Mark's 1553 is an early 2 hole, glued)
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markb

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Sorry no luck on an original here. 
You're correct, I believe mine is glued.  Upon closer inspection one whole side is loose.  It would be nice if I could separate them for painting since I need to change the color.  Don't know what I'm going to do yet.  But if I get them apart I probably wouldn't glue them back together. 
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)