Author Topic: smpls '72 750 project  (Read 12150 times)

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Offline smpls70

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Re: smpls '72 750 project
« Reply #25 on: August 13, 2010, 06:54:07 PM »
If I was to take the valve cover off, and have a lil peek inside , check the valves and what not, what are the chances of the gasket getting wrecked ?? I checked into getting a new one, and the local dealer said 3 to 5 days ,, I want to get this motor in this bike in the next 2 to 3 days !!!!
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Offline smpls70

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Re: smpls '72 750 project
« Reply #26 on: August 15, 2010, 04:30:13 PM »
Little set back fri. nite, crashed my ( this is embarrassing :-[  ) bicycle , flipped right over the handle bars, hand plant, crunch :'(, ............... try dragging a 175 lb.(so they say ) motor across the garage floor with one hand. Took the points cover off, might need new ones ;D........
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Offline Doctor_D

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Re: smpls '72 750 project
« Reply #27 on: August 15, 2010, 05:46:21 PM »
If I was to take the valve cover off, and have a lil peek inside , check the valves and what not, what are the chances of the gasket getting wrecked ?? I checked into getting a new one, and the local dealer said 3 to 5 days ,, I want to get this motor in this bike in the next 2 to 3 days !!!!

Sorry 'bout the hand.  Better that than a TBI.

The valve cover gasket on these beasts is a rubber o-ring that can be reused repeatedly - unless it has been compressed flat or become to hard from age.
Take care,
David
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1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline smpls70

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Re: smpls '72 750 project
« Reply #28 on: August 15, 2010, 07:50:38 PM »
Got a tear on one of the corners of the gasket , it was pretty hard though, might as well get a new one, im rich and have deep pockets  ;D Shot some Marvel Mystery oil into the plug holes , ill let that soak in there . Thought it would be easy as can be getting those old plugs out since the motor is out, still couldnt get the plug socket to go in ??? Had to go down to 15mm socket , worked, I always thought 18mm , what gives ?
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Offline Zaipai

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Re: smpls '72 750 project
« Reply #29 on: August 17, 2010, 07:19:14 PM »
I don't know about those plugs, it might be normal for Champion plugs..

Here is the chart I use..

NGK plugs
BR6EA - 1 heat range hotter (cures slight rich condition....helps burn the extra fuel)
BR7EA - stock heat range
BR8EA - 1 heat range cooler (cures slight LEAN condition, especially in hot climates and carb popping)

I use the 8EA, seems to work very well..

.: Scott :.
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Offline MasterChief750

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Re: smpls '72 750 project
« Reply #30 on: August 18, 2010, 06:52:57 AM »
isnt the 8ea the stock heat range? my shop manual says to use it
1978 CB750 K - Project Red Headed Step Child
1976 CB750 K - Drag Bike
Some things i know, others i dont.
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Offline smpls70

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Re: smpls '72 750 project
« Reply #31 on: August 21, 2010, 02:32:46 PM »
Got a Honda brand valve cover gasket, what kind of sealant do I put on there , if any ??..........btw,my hand is broken. Doc. says no heavy lifting for a couple weeks  >:(  
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Offline smpls70

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Re: smpls '72 750 project
« Reply #32 on: August 22, 2010, 09:02:45 AM »
Sealant on valve cover gasket ? anyone , anyone ???
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Offline Doctor_D

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Re: smpls '72 750 project
« Reply #33 on: August 22, 2010, 11:52:24 AM »
No sealant on the rubber o-ring gaskets.  Torque to proper settings in an even pattern (start with center bolts and move outward in what might be described as a circular pattern) for best sealing.

And, take care of that hand.  If the orthopedist wants you in a brace or air-cast for six-weeks - do it. Then follow-through on the rehab. Seriously. ;)
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline smpls70

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Re: smpls '72 750 project
« Reply #34 on: August 22, 2010, 12:17:29 PM »
No sealant on the rubber o-ring gaskets.  Torque to proper settings in an even pattern (start with center bolts and move outward in what might be described as a circular pattern) for best sealing.

And, take care of that hand.  If the orthopedist wants you in a brace or air-cast for six-weeks - do it. Then follow-through on the rehab. Seriously. ;)
Hey thanks Doc.!! , for both . He just gave me a splint for the hand, said a cast wouldnt do me much good, im keepin' the splint on as much as I can, it's kind of nice not having to deal with a big old ugly cast  getting in the way,but its also easy to take the splint off to do  what needs to be done, within reason ............torque settings for the valve cover ?
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Offline Doctor_D

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Re: smpls '72 750 project
« Reply #35 on: August 22, 2010, 12:39:01 PM »
Torque specs should be in in your manual, but most small Honda fasteners are between 6-8 ft/lbs.  Use anti-seize on the threads to avoid the situation that usually accompanies Honda phillips (I've only been working on a CB750 for 8 months and must have drilled out 20 of them so far).  Better yet, replace them with stainless allens.  A member on the board sells kits. His info should be in here: http://forums.sohc4.net/index.php?topic=743.0
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline smpls70

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Re: smpls '72 750 project
« Reply #36 on: August 22, 2010, 01:25:21 PM »
Thanks again Doc  8)
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Offline smpls70

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Re: smpls '72 750 project
« Reply #37 on: August 28, 2010, 06:25:10 PM »
Did a little work on the Hippie Killer , tore the swing arm off, hopefully get the new one on Sunday,took almost all day to clean all the built up dirt grease and crud off the rear hub, but I thought it cleaned up pretty nice......
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Offline smpls70

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Re: smpls '72 750 project
« Reply #38 on: August 29, 2010, 02:57:50 PM »
AAAAAARRRGGGGGGGHHHHHHHHHHHHHH , swing arm is in, easy, tried getting the wheel on, no go!!The axel and all will not line up, its off buy a 1/2 inch or so. I swear I saw a post somewhere about this happening, but I cannot find it.Do I need to somehow put some kind of a brace in there to widen it ? Any ideas would surely be appreciated ,thanks.( damn this crippled hand ,it is not making it any easier  :'()
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Offline smpls70

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Re: smpls '72 750 project
« Reply #39 on: August 29, 2010, 03:17:50 PM »
Is the collar , next to the chain adjuster , in the correct place ??
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Offline smpls70

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Re: smpls '72 750 project
« Reply #40 on: September 01, 2010, 07:55:54 PM »
Is the collar , next to the chain adjuster , in the correct place ??
No, it is not in the right place,...thanks for the parts fiche !!! . Got that all in order  and put some new brake shoes on as well, and am pretty sure that I re-broke my hand  putting that wheel back on  >:( Ive gone this far , so I might as well try putting the motot in this weekend, saw a few posts on doing it solo, tip the motor on its side , and drop the frame down, wanna  gonna give it a shot this weekend, .........
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Offline smpls70

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Re: smpls '72 750 project
« Reply #41 on: September 01, 2010, 07:59:17 PM »
certainly is not a 700c
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Offline fasturd

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Re: smpls '72 750 project
« Reply #42 on: September 05, 2010, 06:37:12 AM »
Careful with that hand... I messed up my knee this summer and after Dr. fixed it I almost messed it up 3-4 more times just trying to get garage projects done!!!

I got my 70 Cb750 rat cafe going and not leaking but I rode the 400 to Sept 1st Thursday. Think you will make the Oct. one with the bike all together?

Bluecat motors in St. Paul has a 3rd Thursday get together and it is small but everyone actually speaks "bike" rather than just standing around trying to look cool. You should check that one out this month too.

Good luck on the build.

Bill
13 in the garage and counting...

Link to my link...   http://forums.sohc4.net/index.php?topic=58422.0

Offline smpls70

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Re: smpls '72 750 project
« Reply #43 on: September 08, 2010, 07:33:40 PM »
Back to to that good ole' valve adjustment,my achilles heel  :-[ One thing is it is sooooooooooooooo much nicer doing it with out the motor in the frame. Just want to verify if anyone is paying attention , if there is play in the rocker arms , then that is in fact the valve(s) that are to be adjusted ? Spun it to TDC 1-4 , adjusted the loose ones, then spun it 360 ended up on 1-4 again , and adjust the next set, see pic.................numbers with x next to them were adjusted ,.002 for IN. , .003 for EX. , did the try to slide the next size gauge in method, which I thought was a pretty cleaver idea. One other question, when tightening up the nut for the adjuster screw, how tight should they be, I dont have a torque wrench, but do I want to crank them down with alot of force , or just snug ?
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Offline smpls70

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Re: smpls '72 750 project
« Reply #44 on: September 12, 2010, 06:39:28 PM »
New exhaust gaskets. getting those exhaust flanges off, lots of work, penetrating oil, blood , sweat and tears !!!! done!!! FU MANCHU @ Triple Rock Social Club tonight  , taking a break, its Miller time  :)
« Last Edit: September 14, 2010, 08:02:19 PM by smpls70 »
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Offline smpls70

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Re: smpls '72 750 project
« Reply #45 on: September 15, 2010, 07:47:47 PM »
100, about time !!! 8) ....... Before I put the carbs on, can anyone tell me what the  needle clip position is on 657A , theres a chart somewhere that says the fourth position down, but I question that, so I thought it would be alot easier to change it now.   Hope to be riding this beast this weekend
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Offline smpls70

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Re: smpls '72 750 project...........up and runnin', kind of......
« Reply #46 on: September 21, 2010, 03:58:05 PM »
2 min. 2 midnight.......Started up pretty good. a few cranks.......was leaking oil out the filter case, so I switched it out from the first engine, topped off with oil, started right up,. drove it down the block :). Killed a few times and would not start back up, fist time it killed , forgot to turn the gas on, d'ouh! Felt like it wanted to die on deceleration??? like when coming up to a stop sign ,.looks like a few bugs need to be worked out,  try again tommorow.
« Last Edit: September 21, 2010, 05:52:52 PM by smpls70 »
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Offline Doctor_D

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Re: smpls '72 750 project
« Reply #47 on: September 22, 2010, 08:01:32 AM »
Grats on getting it to run.  Next step, carburetors.

These bikes almost always need a complete carb cleaning and rebuild at this stage of the game.  The small air and fuel ports that are part of the idle circuit are likely to be crusted up if not completely clogged.
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline smpls70

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Re: smpls '72 750 project
« Reply #48 on: September 22, 2010, 02:17:35 PM »
They have been rebuilt, twice,........im hoping that I just need to mess with the air mix/ idle screws , need to do timing as well,  and a carb sync, dont have a carb sync tool, im shoping around.....When the first motor was in the bike I suspect  that I was pretty much running most of the time on 3 cylinders ,now  I did not get very far on this new motor, was kind of getting late last night and did not have time to mess around with it , but om pretty sure all FOUR are  firing and let me tell ya, night and day differance between the two motors  ;D No smoke !!! First motor lots and lots of smoke. Better get crackin on this thing, today is the first day of fall, and winter will come around the corner real quick .
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Offline smpls70

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Re: smpls '72 750 project
« Reply #49 on: September 25, 2010, 07:12:22 PM »
Still stalling on me  ??? Doc. D. you might be right, might have to redo the carbs, again, 3rd times a charm. When you get the bike into 2/3 gear. it just stalls out and dies. I did the timing, think I got it pretty close, I have a pretty junky timing light , or maybe its operator error ??  the points plate ended up being advanced all the forward. The points are fairly new. Was also wondering if the way the clutch is adjusted could have something to do with this as well ? I wonder how old those clutch plates are inside the motor, might have to swap those out as well. ideas ??
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