Honda CB750 Sandcast
The Restoration Shop => Fuel (gas - petrol) Tanks, Side Covers and Air Box => Topic started by: markb on December 01, 2010, 06:15:10 pm
-
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
-
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.
-
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
-
Good Deal !!!!
You'll still need a 2 hole w/o relief for your 1553 !
-
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.
-
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.
-
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
-
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
-
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
-
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
-
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,
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?
-
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
-
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)
-
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, My 2 hole air box was cracked and stuff. I took it to a local plastic welder and he rebuilt the centre spacer where the metal fittings slip in. He also fixed a number of cracks and you wouldn't believe the result.
The material Honda used to make these air boxes can be welded unlike some plastics. I've had side covers welded as well some Kawasaki covers and every time the outcome was successful. I doubt a good plastic welder would be challenged. KP
-
KP, I'm not sure if you meant your post for me or not but if so, I don't have a center section of any kind for my air box that's worth repair. The only one I have that is remotely together looks like it was thrown in a fire. It's twisted, burnt, brittle and cracked.
I would like to find a nice straight one. I can fix a crack or two no problem. I think I posted this somewhere already but here's the repair so far to my air box. Plastic welding wasn't an option as there were pieces missing and I would have needed a no relief air box for those pieces. Mainly, both corners were missing sections and someone had filled them with fiberglass and bondo. I re-fabricated the corner using ABS melted in acetone. I ground out good material and feathered it in both inside and out for strength. Once I get all the repairs made I'll brush ABS over the whole box to strengthen it and then give it the final wet sanding and shaping. Should look like new. Having a good center section will help me with the shaping of the corners and the lip that were missing at both ends.
This was before:
(http://cb750sandcastonly.com/coppermine/albums/userpics/10001/air_box_before~0.jpg)
And after repair but not final sanded or anything:
(http://cb750sandcastonly.com/coppermine/albums/userpics/10001/area_repaired~0.jpg)
-
Wayne,
I've seen a few 3-hole boxes on ebay that were pretty reasonable with the top in bad shape. I think the center section is the same. Maybe you could find a crappy box with an OK center section.
Mark
-
From what I can tell Mark the center is the same. I have been kind of watching for a decent one on Ebay. It's hard to tell from pic's how brittle the piece is. Hard to imagine some of those boxes getting so hot as to warp and burn the plastic back there. Had to have been from bikes backfiring on start up etc.
-
Whoa! Nope I don't think a plastic welder will fix that. But gosh; you've done a nice repair job with that. Tell us how you do ABS all over the job. I'm interested.
I think backfiring and fuel leaks was what melted many of them. KP
-
I'll go through the whole ABS repair procedure in a fresh thread once I get it completed KP. Don't want to toot my horn until I see the final product. I can tell you that it's very strong but also very time consuming. I guess you get out of something what you put into it.
-
I look forward to it. These discussion Boards provide us all with so much info on what the other guy is doing. The old saying "you don't know what you don't know" is so true. For a simple example, I knew nothing about Aero Kroil until Swannie put me on to it. It's been a God send in my restorations and Ash's info on turning the fibre glass covering inside out was so simple yet I never knew about that.
This Board is certainly picking up in recent months and for the better Yabba Dabba Doozie :D KP
-
I got looking at the LPM Air Box I received. I think I could easily make this into a no relief, 2 hole box. If I get a chance between all of the other balls I have in the air I might give it a shot. If it works out perhaps I could have them send me a couple of boxes without mounting holes, that way I could do it without filling in the mount area and drill the 2 holes per side in the correct spot.
Update: I just contacted LPM to see if they will send me one without mount holes drillled.
-
Of the early airboxes I have owned, mostly any warpage / melting has tended to be on the left side suggesting (to me) the problem stems from fuel in the box (blow back, fuel vapour condensing out in the box when not in use?) and being parked up on the side stand. Every used box I have had has been in poor shape, ESPECIALLY the centre plates which have often been beyond use. On one occasion I did repair a centre plate and bonded a sheet of .010" shim steel to it to add strength - that one has done another 94,000 miles so far since repair.
LPM did recently sell me a couple of centre plates, one of which fitted straight into a K0 box which had a destroyed centre plate - the fit was better than 95%, so okay for a "rider".
Fortunately, modifying a 3-hole box to 2-hole is made simpler by the fact that the "pads" on the box top to which the brackets mount appears to be the same size for both types, just different numbers of holes in them. Wonder why Honda made the bracket mounting pads so much larger than required for the 2-hole boxes?
Cheers - Chris R.
-
I wish I could be so lucky as to get one 95% Chris. An old original center section fits perfectly into my lower housing and I do mean perfectly. It touched around the whole circumference of the box. When I put the LPM piece in it is sloppy and if I put it tight to one end, the other doesn't even touch, resulting in a gap.
Repairing my original 2 hole is going to require a near perfect center section so I can fabricate the lip in one area of the upper half. Patience is a virtue. I'll find one. Has anyone ever purchased a Yamiya unit? I wonder if they are closer to spec?
My original lower with a broken center from an original air box.
(http://cb750sandcastonly.com/coppermine/albums/userpics/10001/air_box_center_orig2.jpg)
Nice fit all around:
(http://cb750sandcastonly.com/coppermine/albums/userpics/10001/air_box_center_orig1.jpg)
LPM is smaller overall:
(http://cb750sandcastonly.com/coppermine/albums/userpics/10001/air_box_LPM_center2.jpg)
Leaves gaps:
(http://cb750sandcastonly.com/coppermine/albums/userpics/10001/air_box_LPM_center1.jpg)
-
Karen got back to me from LPM. They are willing to send me an upper box without mounting holes drilled for about $31.00 CAD plus shipping. I'll go ahead and get one and we'll see what I can do with it.