Honda CB750 Sandcast

MADE UP OIL FILTER COVER NOT SANDCAST

kp · 13 · 5885

kp

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Fellas,
Just make sure you don't get taken in on this auction. This is not a real early sandcast filter cover.

LINK REMOVED - PIC'S BELOW

Many of you will know a fake from a genuine early filter cover but this Monstrosity is a standard ribbed oil filter cover turned down. The seller, who has featured on this site previously, has worded his auction to try and persuade buyers to think this is what came as a replacement for the sandcast. It may fit any CB750 engine, BUT, IT IS NOT SUITABLE FOR A 10 POINT RESTO and was never fitted to a sandcast as pictured.

Another fact is that this is not Honda's second generation cover. The ribbed reinforcing on the inside was the third iteration on this filter housing

At least other sellers acknowledge when their housings are turned down from a stock unit. This fellow; well you be the judge.

For those that may be tempted, be warned and know what your buying before you buy off this seller. KP  


Yabba Dabba KP



imabass

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Steve Swan

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There are now more and different sellers on ebay of these covers.

Beware !

These covers are most likely not orginal even though the different sellers' ad wording seems suggestive these are original parts. These sellers are referring to these covers as "1st," "2nd" and "3rd" generation FINLESS covers.

I am going to share what little I know about these covers and then back up what i know by reference to Honda literature. And, of course, my caveat is, I don't know it all !

1. "1st generation" - per my 69.7 Parts Manual, pictured is a finless cover. I have an original cover on my E254, it came installed on the the K4 engine fitted in 232 frame when i bought the bike. The finless cover has NO internal reinforcement ribbing. The pn, per the 69.7 parts manual - 15411-300-000. Polished and clear coated as per rest of engine covers.

2. "2nd generation" - i have seen finned covers with no internal reinforcing ribbing. i am not aware of (or cannot remember) any factory Honda literature referencing this finned cover with NO reinforcement ribbing. ?? Part number ?? Produced starting vin E4149 ??

3. "3rd generation" - Honda Service Bulletin CB750 #13, dated 1/26/70 discusses "a modified oil fliter case and center bolt have been developed to prevent oil filter case damage." The S.B. goes on to say, "the modified case has 8 ribs radiating from the center of the bolt boss inside the case......, being fixed with a 12mm width bolt instead of a 14mm bolt, to prevent over tightening." This 1/26/70 S.B. goes on to say the application is "for all CB750 units within the range Frame # 1783-9554." The case pn is 15411-300-010. The S.B. also notes this cover can be identified with the numeral "2" stamped on top portion between center.

The Honda Parts Bulletin, #CB750-13, dated April 24, 1970, notes this finned cover WITH reinforcement ribbing to fit all engine vins beginning at #1, pn 15411-300-010 -and- to replace pn 15411-300-000.

My February 1971 1st ed. of K1 parts manual lists the same pin as noted in above #3, with no distinction of application to any particular vins, frame or engine.

To my knowledge Honda NEVER produced a finless cover with reinforcements as advertised on ebay.

Please share anything else you know about any of these covers.

By casual observation, there are 3 covers -

1. finless unreinforced cover. (Standard part used on assy line, pn 15411-300-000)
2. finned unreinforced cover. (Need factory reference to part ?? What is the part number ??)
3. finned reinforced cover. (Replacement part per Honda literature, pn 15411-300-010)

As far as we know, there was only ONE type of finless cover produced.......? (no reinforcements)

As far as we know, there was TWO types of finned covers produced. (one type without reinforcements and one type with reinforcements.)

WHY does Honda Service Bulletin say the replacement finned with reinforced ribbing is for use "within the range Frame # 1783-9554." ? WHY THIS VIN RANGE ? Why not 1-xxxx

Why does Wyatt in his CB750 book say at E4148, oil filter bowl changed ? Where in Honda literature is this vin referenced in respect to the change in the oil filter cover ?

We need more clarification - PLEASE SHARE WHAT YOU KNOW !

PS - the following is what is noted elsewhere in website under "Production Models, Oil Filter."

Case, oil filter, vin 1 - 4148, pn 15411-300-000, Smooth exterior, no fins

Case, oil filter, vin 4149 - 7414, pn 15411-300-010, External cooling fins added

Case, oil filter, vin 1 - 7414, pn 15411-300-010, Internal strengthening ribs, added to finned oil bowl, number "2" on outside - Honda supercession, 26 Jan 1970

THE LAST 2 COVERS ARE 2 DIFFERENT PARTS.

?? WHY DO THE LAST 2 COVERS HAVE THE SAME PART NUMBER ??
One has internal reinforcement ribs, the other does not and they both have same pn.... ?


kp

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Here ya go Rivers. The elusive finned but rib-less cover. :o I have a couple of these and if you were going to turn them down to look like fin-less covers, this is what you'd use  ;D KP



Yabba Dabba KP


hondasan

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Of course, a TRUE finless cover as produced by Honda had a sandcast appearance internally (at least mine off E338 does), so even an internally ribbed one when turned down is not correct, which means that it doesn't actually matter which finned cover you modify - it will be a replica. And internal ribs or not, it looks the same when bolted onto the bike.

Each to their own I guess - -Chris R.
Chris R.
302/338


Steve Swan

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Thanks for your replies guys and great pics, KP.

Yes, as i have said in past - only original is original. Nothing else is original.

I have had a couple of those finned covers w/o reinforced ribbings i have turned off the fins in my lathe (smooth inside). One has to spend a considerable amount of time removing the fins -and- preventing -and- removing lathe turn marks from these modified covers to amke them look like cast originals. Not rocket science, but not as simple as "1-2-3"

If one were at a stringent show and the judges were down to the last 2 bikes to decide the best "original" and both bikes had smooth covers, the covers WOULD be ordered off and the winner would be the bike with the cover with the sandcast inside finish.

I still would like to know what the story is on the finned cover without reinforced ribbing........ What is the pn ? I would think the pn should be different than the finned cover w/ ribbing.

WHEN did Honda come out with this finned, un-reinforced cover (?4149?) Was this cover the cover Honda planned for when the very first crank cases were cast, considerening the crank case has the two external locating "dowels ?


chrisnoel

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I know in the world of restoring sandcasts it is accepted to put a turned filter on your engine as finding an original finless cover is darn near impossible.  It seems that most look at a cover with fins as somthing that just doesn't belong on a sandcast.  Just wanted to suggest that about half or probably more than half of all sandcast bikes came with post recall filters that had fins.  If you have your original filter cover with fins and no ribs inside you might want to think twice about hacking off the fins.  Mine is instaled on my motor and I proudly state "its original" when it is suggested that I cut off the fins. 


cb7504

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I am inclined to go with Chris Noel's thoughts on the type of oil filter housing. I have several of the finned none reinforced ribbed type on my bikes, still making it original even though not a first generation cover. Marty K.


1941wld

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Hi Guys,

Great info.

I bought a type I cover off eBay. Then I went to this web site and learned that my serial number did not come with a type I oil filter cover. Also, the cover I bought off eBay was a fake. It cost me a little money to learn this but now I'm there. Both of my bike have the type II cover. One recall fix per serial number (E3604), the other correct for serial number. Both bikes have the 12 mm hex head center bolt

Beware that these cover can be over tightened and break the center out, type I, II and III. Take a close look at your cover next time you remove it and look for stress cracks around the hole. You maybe surprised at what you find.

My question is:

Are we trying to bring the bike back to what it was when it rolled out the factory or after the recall parts were replaced? I guess if you have a museum piece you would want the factory bike without recalls, a rider you might want the improved/recalled parts on your bike.

Best Regards,
1941wld


markb

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Is there anyway to identify a fake without looking on the inside?
Mark
Mark B
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rickhahn

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G'Day from Brisbane
I have both a original round oil filter and a machined down finned type, The original came off engine 1023.
One thing which is different from the outside is the mearsurement of the chamfer. The original is 10/11MM
The machined down type is a lot smaller 8/9mm. When put side by side the are quite different. I dont know if
it is just the way the finned ones were machine down.Can anyone add to this.

Rick