Author Topic: 75' CB750 hardtail  (Read 47224 times)

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Offline Zaipai

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Re: 75' CB750 hardtail *UPDATE 5/26/11*
« Reply #75 on: May 27, 2011, 07:01:22 PM »
That is a great pic of your bike at the show.. Would make some great art for the living room!

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Offline gnarlycharlie4u

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Re: 75' CB750 hardtail *UPDATE 5/26/11*
« Reply #76 on: June 07, 2011, 11:13:24 PM »
Came here by way of something awful of all places. I have to say this thread is excellent and a bit inspiring.
Great job on the build so far!

Offline valt

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Re: 75' CB750 hardtail *UPDATE 5/26/11*
« Reply #77 on: June 20, 2011, 09:11:44 PM »
I have been riding a bunch lately and the only issue I have had seems to be the oil tank which I think I have solved. Other then that I have been to a couple of bike shows over the past couple of weekends.

http://s1129.photobucket.com/albums/m507/valtimeter/Rot%20Rally%20show/

http://s1129.photobucket.com/albums/m507/valtimeter/East%20Side%20Classics/

Also turns out That Motorcycle Show did a piece on the show I took my bike too. They have a trailer up, what's funny is me and my friend are fixing his ironhead in the background of some of the shots.

Working Man's Customs Show
« Last Edit: June 20, 2011, 09:31:02 PM by valt »

Offline gnarlycharlie4u

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Re: 75' CB750 hardtail *UPDATE 5/26/11*
« Reply #78 on: June 20, 2011, 10:31:18 PM »
I have been riding a bunch lately and the only issue I have had seems to be the oil tank which I think I have solved. Other then that I have been to a couple of bike shows over the past couple of weekends.

http://s1129.photobucket.com/albums/m507/valtimeter/Rot%20Rally%20show/

http://s1129.photobucket.com/albums/m507/valtimeter/East%20Side%20Classics/

Also turns out That Motorcycle Show did a piece on the show I took my bike too. They have a trailer up, what's funny is me and my friend are fixing his ironhead in the background of some of the shots.

Working Man's Customs Show

awesome. the idea of an actual "hey i don't do this for a living," grassroots bike show. is pretty refreshing.
still disappointed you didn't accept ur nom for botm.

Offline valt

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Re: 75' CB750 hardtail *UPDATE 5/26/11*
« Reply #79 on: June 21, 2011, 11:16:44 AM »
I have been riding a bunch lately and the only issue I have had seems to be the oil tank which I think I have solved. Other then that I have been to a couple of bike shows over the past couple of weekends.

http://s1129.photobucket.com/albums/m507/valtimeter/Rot%20Rally%20show/

http://s1129.photobucket.com/albums/m507/valtimeter/East%20Side%20Classics/

Also turns out That Motorcycle Show did a piece on the show I took my bike too. They have a trailer up, what's funny is me and my friend are fixing his ironhead in the background of some of the shots.

Working Man's Customs Show

awesome. the idea of an actual "hey i don't do this for a living," grassroots bike show. is pretty refreshing.
still disappointed you didn't accept ur nom for botm.

Ahh boo I didn't even see that, at least wait till I get the fender painted! Yah I made some friends at the show so it was pretty cool. My bike was like one of the 3 jap bikes in the show.

Offline valt

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Re: 75' CB750 hardtail *UPDATE Charging problems!*
« Reply #80 on: December 02, 2011, 01:24:36 PM »
Alright I have looked around and found the procedures for testing the charging system. But I'm not entirely sure that I am doing it correctly. I believe that possibly my stator is bad, but I'm not 100%.

I should note that all these tests are done on a cold motor with a brand new battery.

Part 1:
Testing CB750 Charging system

Part 2:
Testing CB750 Charging system

Part 3:
Testing CB750 Charging system

Offline valt

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Re: 75' CB750 hardtail *Charging Issues*
« Reply #81 on: December 29, 2011, 02:21:11 PM »
Well after testing and testing. I found out why my bike wasn't charging, and of course it was the stupidest thing ever!

Offline Retro Rocket

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Re: 75' CB750 hardtail *Charging Issues*
« Reply #82 on: December 29, 2011, 02:33:24 PM »
Well after testing and testing. I found out why my bike wasn't charging, and of course it was the stupidest thing ever!

At least you worked it out, thats the main thing... ;)
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Offline gnarlycharlie4u

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Re: 75' CB750 hardtail *Charging Issues*
« Reply #83 on: December 29, 2011, 02:59:15 PM »
Well after testing and testing. I found out why my bike wasn't charging, and of course it was the stupidest thing ever!

holy crap. how'd you manage that?

Offline valt

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Re: 75' CB750 hardtail *Charging Issues*
« Reply #84 on: December 29, 2011, 10:50:47 PM »
Well after testing and testing. I found out why my bike wasn't charging, and of course it was the stupidest thing ever!

holy crap. how'd you manage that?

Not sure, but we soldered the wires back together and hooked it back up and now its charging!

Offline gnarlycharlie4u

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Re: 75' CB750 hardtail *Charging Issues*
« Reply #85 on: December 30, 2011, 09:31:00 AM »
Well after testing and testing. I found out why my bike wasn't charging, and of course it was the stupidest thing ever!

holy crap. how'd you manage that?

Not sure, but we soldered the wires back together and hooked it back up and now its charging!

awesome! I'd make sure they're pulled away from the regulator and nicely insulated. Hot glue is always a good protector.

Offline valt

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Re: 75' CB750 hardtail
« Reply #86 on: January 12, 2012, 10:11:34 PM »
Well I moved the regulator rectifier underneath the battery tray and it has been fine. The other issue that I have fought and fought since I got it running was my oil tank not venting properly. It turns out that I'm retarded and the vent to the oil tank just plugs into the back of the motor.

So now the bike is all happy go lucky except for a valve guide seal which is leaking apparently. On cold start it blows smoke for a bit, but once its warm it stops smoking. My guess is this motor sat for a long time without any oil or running, so the valve guide seals dry rotted. I'm going to order some valve guide seals, pull the motor and hope that fixes it. I haven't seen anything else on the motor that would lead me to believe that its anything else.

Also I sent my fender to the guy in Indiana who painted my tanks and he has apparently decided it would be a awesome idea to steal my money and my fender. I sent the money and the fender to him about 6 months ago and have not heard from him since, despite lots of attempts to contact him. So if anyone in Indiana would like to pay him a visit I have his address.

Offline gnarlycharlie4u

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Re: 75' CB750 hardtail
« Reply #87 on: January 12, 2012, 10:24:18 PM »
Well I moved the regulator rectifier underneath the battery tray and it has been fine. The other issue that I have fought and fought since I got it running was my oil tank not venting properly. It turns out that I'm retarded and the vent to the oil tank just plugs into the back of the motor.

So now the bike is all happy go lucky except for a valve guide seal which is leaking apparently. On cold start it blows smoke for a bit, but once its warm it stops smoking. My guess is this motor sat for a long time without any oil or running, so the valve guide seals dry rotted. I'm going to order some valve guide seals, pull the motor and hope that fixes it. I haven't seen anything else on the motor that would lead me to believe that its anything else.

Also I sent my fender to the guy in Indiana who painted my tanks and he has apparently decided it would be a awesome idea to steal my money and my fender. I sent the money and the fender to him about 6 months ago and have not heard from him since, despite lots of attempts to contact him. So if anyone in Indiana would like to pay him a visit I have his address.

Sucks about your fender. I had a similar situation with a member on NGW in regards to a CX650e tank. Never heard from him again and he's not been online. I hope you get it worked out.

While you've got the head off to do the seals you might as well check and lap the valves if necessary. Also, check the cam tolerances and consider a new cam chain while you're in there.

Offline valt

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Re: 75' CB750 hardtail
« Reply #88 on: January 12, 2012, 10:57:58 PM »
I'm going to try and avoid actually having to take the stupid head off since that means replacing the head gasket and most likely the studs as well. The motor came out of a 20k mile bike, so there probably isn't any reason to replace the cam chain anyways. I'm going to talk to the honda mechanic tomorrow and hopefully do a leak down test and make sure its not something else.

Also weirdly Garage Company Customs has built a CB750 that looks suspiciously like mine.

http://www.garagecompanycustoms.com/gallery/?album=1&gallery=5

It's definitely making me consider some shorter tubes for the forks. I have a whole spare set that I would like to shave the fender mounts off of, so it may work out.

Offline gnarlycharlie4u

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Re: 75' CB750 hardtail
« Reply #89 on: January 13, 2012, 07:07:24 AM »
I'm going to try and avoid actually having to take the stupid head off since that means replacing the head gasket and most likely the studs as well. The motor came out of a 20k mile bike, so there probably isn't any reason to replace the cam chain anyways. I'm going to talk to the honda mechanic tomorrow and hopefully do a leak down test and make sure its not something else.

Also weirdly Garage Company Customs has built a CB750 that looks suspiciously like mine.

http://www.garagecompanycustoms.com/gallery/?album=1&gallery=5

It's definitely making me consider some shorter tubes for the forks. I have a whole spare set that I would like to shave the fender mounts off of, so it may work out.

haha I don't know about suspiciously like yours, but there are a few similar elements.

You can check the cam chain/ tunnel without taking the head off at least. But I've got $1 that says you drop a valve in the cylinder.
I'll be here waiting to tell you how to get it out when you do <3

Too bad you're not closer. I just bought a brand new leakdown tester and need an excuse (and a whole motor ::) ) to use it.

Offline valt

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Re: 75' CB750 hardtail
« Reply #90 on: January 14, 2012, 12:21:20 PM »
Well the valve guide seals are on their way and I purchased a spring compressor today as well. So as soon as the seals get here, I'm going to put them on and hope it stops smoking. I would really like to ride to houston with my friend, but our bikes are cursed and they never work together.

Offline bigtexan449

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Re: 75' CB750 hardtail
« Reply #91 on: January 16, 2012, 06:33:35 PM »
Well I moved the regulator rectifier underneath the battery tray and it has been fine. The other issue that I have fought and fought since I got it running was my oil tank not venting properly. It turns out that I'm retarded and the vent to the oil tank just plugs into the back of the motor.

So now the bike is all happy go lucky except for a valve guide seal which is leaking apparently. On cold start it blows smoke for a bit, but once its warm it stops smoking. My guess is this motor sat for a long time without any oil or running, so the valve guide seals dry rotted. I'm going to order some valve guide seals, pull the motor and hope that fixes it. I haven't seen anything else on the motor that would lead me to believe that its anything else.

Also I sent my fender to the guy in Indiana who painted my tanks and he has apparently decided it would be a awesome idea to steal my money and my fender. I sent the money and the fender to him about 6 months ago and have not heard from him since, despite lots of attempts to contact him. So if anyone in Indiana would like to pay him a visit I have his address.

Vault, where in Indiana is he? I live in NE IN. Maybe able to take trip and see him.

Offline 92sc300tt

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Re: 75' CB750 hardtail
« Reply #92 on: January 16, 2012, 06:54:40 PM »
I just want to say i love this bike!

Offline valt

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Re: 75' CB750 hardtail
« Reply #93 on: January 17, 2012, 12:44:17 AM »
Vault, where in Indiana is he? I live in NE IN. Maybe able to take trip and see him.

Hah, I will have words with him when I go back home to visit thats for sure!

Anyways I decided to go with my original fender idea which was to use the front fender on the rear. Here it is mocked up, I need to modify the fender mounts to make it work but it shouldn't be a big deal. I need to take the motor out this week anyways to fix the valve seals so I will do that while its out.



Offline theofam

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Re: 75' CB750 hardtail
« Reply #94 on: January 17, 2012, 08:22:57 AM »
Valt,

Nice looking scoot!  You're making me want to cruise CL for a 750 to chop up!

Offline JustinLonghorn

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Re: 75' CB750 hardtail
« Reply #95 on: January 17, 2012, 12:09:27 PM »
Hey man,

GL1000 front fenders are perfect for a Chop Rear fender. They are ribbed and have a ducktail.





http://www.ebay.com/itm/1975-77-Honda-Goldwing-GL1000-Front-Fender-GL-1000-/230557505554?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item35ae4c5812
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Offline lucky

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Re: 75' CB750 hardtail
« Reply #96 on: January 17, 2012, 12:22:53 PM »
Well crap, I pulled the plugs and found 2, 3, and 4 covered in oil. The plug on 4 was just wet with oil and looked like it had been barely firing. The strange thing is that #1 looks really rich but no oil that I could see.

Anyone have any idea what could be going on here? I'm going to tear it down again this weekend and see what I can find, but I'm not really sure what would cause this. It absolutely does not leak on the outside at all though, and to the best of my knowledge it did not blow oil before I took it apart.

You said you took it apart and replaced all the gaskets.
Did you measure and hone the cylinders and put new piston rings in?
If you did not it will keep smoking and burning oil forever.
The cylinders have to be honed id the engine is taken apart.
Did you look very carefully at the ring lands and measure them?
Did you measure the cylinders top and bottom and know the gap between the piston and cylinder?

About the frame.
Not every welder knows how to weld a motorcycle frame.
You have to hire someone that is a welder that knows about motorcycles.
Measure the front of the rear axle slot to the same place on the front of the frame. It should be the same.
Or measure from the front of the rear axle slot to the bottom cross bar that the center stand is attached to. Should be the same.
Some welders have only welded bar-b-que grills. Some welders have only welded steel buildings and know nothing about motorcycles. Be careful when hiring a welder and ask them if they have experience with motorcycle frames.
BTW...I am a certified welding inspector. And I have spent much of my life welding motorcycle frames.
« Last Edit: January 17, 2012, 12:30:06 PM by lucky »

Offline lucky

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Re: 75' CB750 hardtail *Charging Issues*
« Reply #97 on: January 17, 2012, 12:33:22 PM »
Well after testing and testing. I found out why my bike wasn't charging, and of course it was the stupidest thing ever!

The Honda workshop manual explains how to check the alternator out put and the charging system components.Step by step.

Offline lucky

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Re: 75' CB750 hardtail
« Reply #98 on: January 17, 2012, 12:35:50 PM »
Not to criticize, but it doesn't seem exactly square... The right side seems a little pulled back.  Is it just the brace?

I agree Rachet. It looks way off! It can be fixed though. It is not too late.
Click ONCE  on photo to enlarge image.
« Last Edit: January 17, 2012, 12:42:55 PM by lucky »

Offline lucky

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Re: 75' CB750 hardtail
« Reply #99 on: January 17, 2012, 12:50:03 PM »
I would want to be there when he's aligning it all together, though.  But beyond that, any welding show/welder with a good reputation can handle welding these frames.  Not a BIG deal with the thick walled tubing, etc.

EDIT:: I'll try and start a build thread for my almost-finished 550 hardtail frame.  I bent/made the ass-end myself, its coming along nicely.
The tubing on a Honda CB750 is only 1/16 thickness. Or .062 thousandths.
Most chopper frames that are rigids are .120 thousandths wall thickness.
Also after market rigid chopper frames are 1-3/8 inch diameter and the Honda frame is only 1 inch diameter.