Author Topic: 74' cb750 - my rat bike  (Read 68847 times)

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Offline Bouncer

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Re: 74' cb750 - my rat bike
« Reply #50 on: January 25, 2009, 07:47:14 AM »
Simply awesome looking. What brand shorty shocks are those?

mdi...the ones from cyclex

I have those same MDI/Forsa shorties. Can those be taken apart completely? I was thinking about powdering mine but really haven't taken any action on them. As I am working on 5 other things on the bike at the same time.
New to the game.

1981 CB650C (Finished) Rat Bike

1978 CB750F Project "Bear Down"

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #51 on: January 25, 2009, 09:04:34 AM »
I have those same MDI/Forsa shorties. Can those be taken apart completely? I was thinking about powdering mine but really haven't taken any action on them. As I am working on 5 other things on the bike at the same time.

i dont think they can be 'completely' disassembled...if you compress the spring, you can remove the top eyelit as its just screwed onto the shock shaft with a locknut.  after you remove the top and spring though i dont think you can actually disassemble the body of the shock which makes powdercoating a no-go.

i didnt really pay much attention to the body though as i just disassembled them to remove the chrome shrouds.

Offline Speed King

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Re: 74' cb750 - my rat bike
« Reply #52 on: January 25, 2009, 09:45:39 AM »
That thing is badass.

Offline luder

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Re: 74' cb750 - my rat bike
« Reply #53 on: January 25, 2009, 02:12:10 PM »
I like it............luder

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #54 on: January 25, 2009, 08:26:18 PM »
That thing is badass.

I like it............luder

Thanks guys, im sure itll be a blast to ride come summer...i need to get my carbs sorted yet.  i rebuilt them a few months ago but one of the bowl gaskets seems to have dissentigrated and its leaking gas all around the top of the float bowl!  Then, new side covers and a seat and she should be ready to go!

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #55 on: January 28, 2009, 01:29:07 PM »
ordered some new parts today...

-100/90/19 front tire
-130/90/18 rear tire
-Jt 38t rear sprocket
-Jt 18t front sprocket
-oring chain
-front/rear wheel bearings
-tapered neck bearings
-4 carb rebuild kits.  just rebuilt them but i mainly cleaned and reused the original parts.  after having leaking problems, im going to replace everything this time around.

if anyone has suggestions on the seat, id love to hear!! 

Offline Really?

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Re: 74' cb750 - my rat bike
« Reply #56 on: January 28, 2009, 01:47:35 PM »
I like the way ekim98 modded the stock seat.  Something similar might look right on there.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline andy750

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Re: 74' cb750 - my rat bike
« Reply #57 on: January 30, 2009, 05:18:58 AM »
I like how your bike is turning out and the low profile boxer look of it -very nice and very original -some nice touches! Ill be interested to hear how it rides when its finished as it looks like the rear tire will bottom out on the fender? I agree with Giga that a low profile seat would really look good on this bike...

Did you really get a 38t rear sprocket? Normally its 48t....a 17t in the front would have given you a little more punch at stoplights...just a thought.

cheers
Andy

Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #58 on: January 30, 2009, 05:50:50 AM »
Quote
I like the way ekim98 modded the stock seat.  Something similar might look right on there.

thanks for that pic.  ill probably do something similar but with a smaller profile..

Quote
the low profile boxer look of it -very nice and very original -some nice touches!


thanks for the compliments.  i loveee bobbers and im pretty happy with how its turning out.  if i wouldnt have built it like i am, it woulda been hardtailed with 12" apes and a springer seat...but i figured this would be a bit more comfortable  8)

Quote
it looks like the rear tire will bottom out on the fender?

there is a bit more clearance under that fender than it looks like..probably about 2-3 inches before the tire bottoms out!  i sat on the bike and gave her a workout (jumpin up and down-rear shocks on softest setting) and the suspension actually feels pretty good.  of course, a road test is the only true test.

Quote
Did you really get a 38t rear sprocket? Normally its 48t....a 17t in the front would have given you a little more punch at stoplights...just a thought.


yup, you read correctly...38t rear and 18t front.  im not really too worried about "punch from a stoplight" as thats what my bmw is for.  i wanted to set this bike up for highway riding and as long as its not too much of a dog, ill keep the long gearing.  if i went too far, ill swap sprockets.

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #59 on: January 30, 2009, 11:20:24 AM »
need some help guys...how the HELL do you get these bearing collars off in the rear wheel?  im guessing i need a specialty honda tool?  what a pain in the ass..alls i wanna do is replace the gosh darn bearings.  is that too much to ask?  >:(



also, replaced the stock honda filter housing with this..



new wheel bearings and neck bearings



im guessing this is the 'chain oiler' bolt?  it was in the end of the crankshaft and had to be removed to get the front sprocket off.  does anyone plug this up with a solid bolt?  im running a self-lubed o-ring chain and alls this thing does is cause a mess...


Offline Bouncer

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Re: 74' cb750 - my rat bike
« Reply #60 on: January 30, 2009, 07:34:57 PM »
Nice, where did you get the screw on filter adapter from? I have been looking for one with no luck.
New to the game.

1981 CB650C (Finished) Rat Bike

1978 CB750F Project "Bear Down"

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #61 on: January 31, 2009, 05:37:19 AM »
picked the filter adapter up from ebay for $50.  seems to be made pretty darn well...the diameter is pushing it as far as the adapter couldnt be ANY larger and still screw on without hitting the case.

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #62 on: January 31, 2009, 11:43:41 AM »
new tires: 
-130/90/18 rear
-100/90/19 front







rebuilt the carbs a second time...this time i replaced every replaceable part along with all new gaskets.  spent a bit of extra time setting float heights and bench synching them..  hopefully she'll quit leaking now!






Offline Soos

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Re: 74' cb750 - my rat bike
« Reply #63 on: January 31, 2009, 11:50:28 AM »
I keep hearing of you 750 riders complaining about leaking carbs.


I ran a set on my 650 for a season, and they leaked ocassionally.
Especially after leaning on the sidestand for 4 hours or more..

But only with those stock brass float valves.
Bought a set of 6 of them from Z1 with rubber tips on them.
they were advertised as being for the cb650. They fit and worked wonderfully.


I think I paid 10 or 12 for the set of 6?


Just a thought when fighting leaks...




l8r
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Just think to yourself what would Alowishus Devander Abercrombie do?
"Brix will be shat by your neighbors." - schwebel
(61mm)652cc 1979 cb650

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #64 on: January 31, 2009, 12:04:02 PM »
Quote
But only with those stock brass float valves.
Bought a set of 6 of them from Z1 with rubber tips on them.
they were advertised as being for the cb650. They fit and worked wonderfully.

thanks for the tip!

my carbs already have the foam floats..they arent in the best shape though so maybe ill replace them anyways!

the carbs have been leaking around the bowls.  when i bought my float bowl gaskets, i was warned that some batches of the gaskets dont handle gas well and swell which causes leaking.  sure enough, when i pulled the bowls this morning the gaskets had swollen so much that they pushed out and cause a leak.

the rebuild kits i bought have different gaskets (they have a fabric core/reinforcement) and im hoping they seal better!

splittie

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Re: 74' cb750 - my rat bike
« Reply #65 on: January 31, 2009, 03:22:01 PM »
Did you finally get your rear bearings replaced?

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #66 on: February 01, 2009, 10:18:40 AM »
Did you finally get your rear bearings replaced?

no...im a little pissed about the whole situation.  not a single motorcycle mechanic in the area has the correct tool to remove the bearing collars.  i keep getting "dammnnnn thats an old bike..you cant even buy that tool anymore".  i found one guy who has the tool but its over an hour drive which doesnt seem worth it just to remove a bearing collar. 

im going to try to make the tool myself today.  ill just weld two little tabs onto a long rod or something and see how it works.  it doesnt help that the idiots that had the bike before me center punched all the collars so they wont spin easily.

Offline PxTx

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Re: 74' cb750 - my rat bike
« Reply #67 on: February 01, 2009, 11:17:27 AM »
I don't know of many CB750 which have needed the wheel bearings replaced, let alone needing replaced a second time!  Good Luck man.  Maybe you can try adding some heat to the aluminum to help loosen the tolerances up.

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #68 on: February 01, 2009, 01:31:51 PM »
I don't know of many CB750 which have needed the wheel bearings replaced, let alone needing replaced a second time!  Good Luck man.  Maybe you can try adding some heat to the aluminum to help loosen the tolerances up.

who knows what was done to the bike before i bought it...thats why id prefer to replace the bearings myself and know exactly whats going on.  i planned to take the bike on a thousand mile trip in march so i wanted all new bearings/tires/etc., but i duno if ill have it finished now.

pardon my language, but the #$%*ing idiot that replaced the bearings last time ruined the hub.  i finally got the collar out after making my own tool, but it completely destroyed the colar and the threads in the hub are so buggerd up from the (4) 1/8" center punches that the previous owner made that i dont think the hub is salvagable... >:(

time to start looking for another rear wheel.  ive got a neighbor who said he has a spoked cb500 rear wheel...would that fit my bike?  also, any 'k' model rear wheel will fit with the drum brake? i dont even wanna pull the front wheel apart now.
« Last Edit: February 01, 2009, 01:58:39 PM by dp2275 »

Offline Soos

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Re: 74' cb750 - my rat bike
« Reply #69 on: February 02, 2009, 06:05:22 AM »
Where you located at?

I got a spoked cb650 rear with a drum.
I have removed the tire so shipping is possibility, but it's not the lightest rim in the world either.
Needs a good cleaning, but in usable shape.
PM me if interested.



l8r
-=≡ Soos ≡=-
Just think to yourself what would Alowishus Devander Abercrombie do?
"Brix will be shat by your neighbors." - schwebel
(61mm)652cc 1979 cb650

Offline PxTx

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Re: 74' cb750 - my rat bike
« Reply #70 on: February 02, 2009, 06:31:05 AM »
I've got rear rims laying around if you want to swing by the Willow Grove area, I would help you out.

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #71 on: February 02, 2009, 11:20:34 AM »
pm'd both of you guys..

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #72 on: February 05, 2009, 07:31:03 AM »
front sprocket, rear sprocket, o-ring chain, and kickstand rubber all showed up...
now i need a warm day to get back to work.  its 13* here currently  :(




dickey

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Re: 74' cb750 - my rat bike
« Reply #73 on: February 05, 2009, 05:43:59 PM »
Boo. I read through 5 pages and now I want more  ;D

Offline dp2275

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Re: 74' cb750 - my rat bike
« Reply #74 on: February 09, 2009, 05:45:18 PM »
successfully disassembled the front wheel without issue.  ive got a rear wheel and new plated spokes/nipples on the way. rims and hubs will be going out for powdercoat when i return home from school in two weeks.