Author Topic: crank cases  (Read 4753 times)

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Offline kew

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crank cases
« on: December 26, 2016, 08:05:54 AM »
Hello all,
I race a 750 and I have collected lots of used parts so I thought I'd sort them over the holiday.
I have some crank cases but I don't know if they are matched pairs.
I can't see any casting marks that look the same.
Is there something I should be looking for? :-[ :-[ :-[

Offline jack58

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Re: crank cases
« Reply #1 on: December 26, 2016, 01:39:03 PM »
should be a number on the back of both cases if you have any real low numbers or any sandcast cases or parts id like to get in line thanks jack

Offline kew

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Re: crank cases
« Reply #2 on: December 26, 2016, 03:18:48 PM »
Hello Jack, thank's for the reply.
I was told that there should be numbers on the flat part on the back of the cases but I can't find any.
I'll have another look tomorrow in the daylight.
All my cases are late numbers, I obviously need lots of spares as I race a sidecar.  ;D ;D ;D

Offline 754

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Re: crank cases
« Reply #3 on: December 26, 2016, 05:50:26 PM »
Are you thinking they may have got mixed up.
One thing that may help sort them is wider output bearing, on cases after 76 and again at 77.
 The other thing, the main bearing codes are marked under front motormount shelf on top case, these marks should correspond with the shells in the lower case.... I think you can determine what shell it is by the number markings.
 Any pics of the sidecar or details on the motors you run?
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Offline kew

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Re: crank cases
« Reply #4 on: December 27, 2016, 05:17:14 AM »
Yes I think some of the cases may be mixed.
I have some K and some F cases, the F cases with the wider casting for the output bearing are not mixed but I think the K ones maybe mixed.
They also don't have shells in them but I don't think they would tell me anything because the numbers on shells are a bit random to say the least.
I'm starting to pull my hair out and I haven't got much left anyway.
I raced an 836cc engine last season and finished 5th in the Camathius cup championship which is a European classic sidecar championship, I'm building a 1000cc engine for next season.

Offline tony sawyer

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Re: crank cases
« Reply #5 on: December 27, 2016, 06:54:12 AM »
hello mate if you get stuck i can probaly sort a set i
you might need to erode a stud
short of any battle scratches and scar that pass through both halfs
. they seem to shot up in price for no reason
how many sets you got mixed up

Offline kew

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Re: crank cases
« Reply #6 on: December 27, 2016, 09:04:03 AM »
Hello Tony, how are you mate?
I only have 2 sets that may be mixed and I do have some others so I'm OK but it's so bloody annoying because they are really good looking cases.
Have you got yourself a passenger yet for next season?

Offline bear

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Re: crank cases
« Reply #7 on: December 27, 2016, 07:02:11 PM »
Off topic I know but............

I note you blokes seem to be thinking of "going large" to take advantage of your new regs.

Can I suggest that you focus on your drive line.

The clutch aside,  I belive that you will need to upgrade both your cush drive and gear sets if you want to achieve an acceptable level of reliability.

Tony I know that you have souced aftermarket rubbers for your cush drive but I believe they are rated at around 75 duro, thats only marginly stronger than the std units unfortunately.

Cheers,
Brian
The older I get the faster I was.

Offline Medyo Bastos

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Re: crank cases
« Reply #8 on: December 28, 2016, 01:17:54 PM »
Off topic I know but............

I note you blokes seem to be thinking of "going large" to take advantage of your new regs.

Can I suggest that you focus on your drive line.

The clutch aside,  I belive that you will need to upgrade both your cush drive and gear sets if you want to achieve an acceptable level of reliability.

Tony I know that you have souced aftermarket rubbers for your cush drive but I believe they are rated at around 75 duro, thats only marginly stronger than the std units unfortunately.

Cheers,
Brian

would welding the sprocket carrier onto the hub be an option? is there a way of doing away with the inside bearing and spacer to make this happen?

Offline kmb69

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Re: crank cases
« Reply #9 on: December 28, 2016, 01:55:50 PM »
Off topic I know but............

I note you blokes seem to be thinking of "going large" to take advantage of your new regs.

Can I suggest that you focus on your drive line.

The clutch aside,  I belive that you will need to upgrade both your cush drive and gear sets if you want to achieve an acceptable level of reliability.

Tony I know that you have souced aftermarket rubbers for your cush drive but I believe they are rated at around 75 duro, thats only marginly stronger than the std units unfortunately.

Cheers,
Brian

would welding the sprocket carrier onto the hub be an option? is there a way of doing away with the inside bearing and spacer to make this happen?

Highly unadvisable. You need some kind of dampening to prevent "shocking" the gearteeth to fracture and eventually, if they last that long, to rip them off.  >:(

One might be able to design and make a new clutch outer with spring dampers, like every other manufacturer does, that would allow a "solid" primary sprocket.

Offline bear

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Re: crank cases
« Reply #10 on: December 28, 2016, 05:59:49 PM »

would welding the sprocket carrier onto the hub be an option? is there a way of doing away with the inside bearing and spacer to make this happen?

Highly unadvisable. You need some kind of dampening to prevent "shocking" the gearteeth to fracture and eventually, if they last that long, to rip them off.  >:(


The gear dogs are usally the weak link.

Example A

« Last Edit: December 28, 2016, 06:03:56 PM by bear »
The older I get the faster I was.

Offline madmtnmotors

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Re: crank cases
« Reply #11 on: December 28, 2016, 06:11:18 PM »

would welding the sprocket carrier onto the hub be an option? is there a way of doing away with the inside bearing and spacer to make this happen?

Highly unadvisable. You need some kind of dampening to prevent "shocking" the gearteeth to fracture and eventually, if they last that long, to rip them off.  >:(


The gear dogs are usally the weak link.

Example A



I knew that was coming. I was hoping you were going to include a picture of the "four dogs" though, I can never get enough of them...  ;)
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

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Offline bear

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Re: crank cases
« Reply #12 on: December 28, 2016, 06:15:42 PM »

One might be able to design and make a new clutch outer with spring dampers, like every other manufacturer does, that would allow a "solid" primary sprocket.


That sounds like a viable option that I hadn't considered Kieth.
The older I get the faster I was.

Offline bear

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Re: crank cases
« Reply #13 on: December 28, 2016, 06:21:20 PM »

would welding the sprocket carrier onto the hub be an option? is there a way of doing away with the inside bearing and spacer to make this happen?

Highly unadvisable. You need some kind of dampening to prevent "shocking" the gearteeth to fracture and eventually, if they last that long, to rip them off.  >:(


The gear dogs are usally the weak link.

Example A



I knew that was coming. I was hoping you were going to include a picture of the "four dogs" though, I can never get enough of them...  ;)


 ;D ;D ;D ;D



The older I get the faster I was.

Offline kmb69

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Re: crank cases
« Reply #14 on: December 28, 2016, 06:32:05 PM »

would welding the sprocket carrier onto the hub be an option? is there a way of doing away with the inside bearing and spacer to make this happen?

Highly unadvisable. You need some kind of dampening to prevent "shocking" the gearteeth to fracture and eventually, if they last that long, to rip them off.  >:(


The gear dogs are usally the weak link.

Example A



I knew that was coming. I was hoping you were going to include a picture of the "four dogs" though, I can never get enough of them...  ;)


 ;D ;D ;D ;D


Still hoping to get my hands on one of those.....for just a day or two.  ;)

Offline kmb69

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Re: crank cases
« Reply #15 on: December 28, 2016, 06:36:31 PM »

One might be able to design and make a new clutch outer with spring dampers, like every other manufacturer does, that would allow a "solid" primary sprocket.


That sounds like a viable option that I hadn't considered Kieth.

Got to think outside the box with these old girls!  ;)  8)

Brian, I lied to you last night. Did not have time for pictures today, but will do my best tomorrow.  ;)

Offline bear

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Re: crank cases
« Reply #16 on: December 28, 2016, 07:07:38 PM »

Still hoping to get my hands on one of those.....for just a day or two.  ;)


I apologize for my tardiness Kieth.
The motor has been on the bench gathering dust.
I will get my bum into gear when we get back from holidays.
As penance I will scrounge one of our cam sprockets and throw it in as well.

Cheers,
Brian
« Last Edit: December 28, 2016, 07:10:40 PM by bear »
The older I get the faster I was.

Offline madmtnmotors

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Re: crank cases
« Reply #17 on: December 29, 2016, 05:15:39 AM »

 ;D ;D ;D ;D


Nice! I hope to have a motor with enough power to make these mandatory... one of these days!  8)
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline RAFster122s

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Re: crank cases
« Reply #18 on: December 29, 2016, 07:42:15 PM »
I guess I don't follow entirely.  Are the gears modified by replacing the 3 dogs that are cylindrical pins with the 4 dogs with the wedge shaped dogs?  Does the gear have to be heat treated to make the new dogs strong enough to lessen any wear?

Curious about the story.  If there is a thread that discusses it and shares the mod, then direct me to it rather than repeat it...

Thanks! David
David- back in the desert SW!

Offline Don R

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Re: crank cases
« Reply #19 on: December 29, 2016, 08:51:37 PM »
 I wonder if you could bolt up a set and check the machining match at the outermost main bearings? There might be enough difference to spot a mismatched set, then swap them and check the result. Especially if there are only two cases mixed up.
No matter how many times you paint over a shadow, it's still there.
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 You don't need a weatherman to know which way the wind blows.

Offline bear

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Re: crank cases
« Reply #20 on: December 30, 2016, 12:39:22 AM »
Kew,

I apologize for draging this thread off topic.

David,
I will start a thread to address your question.

Cheers,
Brian
The older I get the faster I was.

Offline kew

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Re: crank cases
« Reply #21 on: December 30, 2016, 11:07:50 AM »
That's OK Bear, I'm interested in your gear thread anyway.
Don R, I think I have sorted it. I had main bearings as per the stamping on the top case and fitted a crank, with 1 of the bottom cases bolted up the crank would turn and with the other it would not.
Thanks for the suggestions gentlemen.

Offline Don R

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Re: crank cases
« Reply #22 on: December 30, 2016, 02:40:45 PM »
Good deal. I always cringe when I see guys on ebay selling half cases, rod caps and cam carriers with no caps. Your test proves they need to be matched.
« Last Edit: December 30, 2016, 02:42:28 PM by Don R »
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline Bill/BentON Racing

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Re: crank cases
« Reply #23 on: January 01, 2017, 05:23:54 AM »
Yep, me too, ....50lbs of boost might do sumpin, I need to call Dimey , see if he's interested,  lol, we all getting a little crazy, I like 2017 already. I'm betting we see 9's on some SOHC 750's this year! But I gotta build a big NA engine first. Happy New Year,  yes Brian, please get Keith dem gears,,,you da man!,Bill
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Offline Nose736

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Re: crank cases
« Reply #24 on: March 25, 2017, 11:39:29 AM »
You can miss match cases for cb as long as you plastigage for clearance, and keep the years close,EG  you can,t mismatch.sandcast with diecast They were line bored from the factory. Been doing it for years.