Author Topic: First Post-- Newb questions on 77 CB750  (Read 2549 times)

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Offline rhuff

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First Post-- Newb questions on 77 CB750
« on: July 26, 2016, 09:37:21 PM »
Hi all from Minneapolis.  I am an owner of a couple of Harley's.  I've had other bikes, types in the past, but nothing older than the 90s.  I'm not overly mechanically inclined, but can figure things out with direction and the wonderful help of youtube.

That being said:  I found a 77 cb750 that has been worked over a bit into a cafe style bike.  I like it.  It's a decent price i feel at $1500. 

My concerns:  bike scrapes it's exhaust when turning hard-  it's been lowered.  I don't like the rear shocks and planned on replacing even before I looked at the bike.  This brings me to my next question-  if I do end up with shocks with more travel, how hard is it to raise up the front travel?

The front brakes suck.  Rear seem fine.  What am I looking at to improve front braking if a new pad doesn't rectify the problem?

Bike has no turn signals-- I'm sure this would be easy to do?  THe rear brake also stays lit up all the time and does not get brighter when applying brakes.  What would need to be done to change this? 

Anything else I should be looking for or at with this bike?  It's clean for the price and runs beautifully. 

Thanks.  Sorry for what might seem like dumb questions. 

Offline madmtnmotors

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Re: First Post-- Newb questions on 77 CB750
« Reply #1 on: July 27, 2016, 06:54:46 AM »
Welcome aboard!

As far as raising the front, it depends on what method was used to lower the front.
Front brake feel can often be improved by replacing the 40 year old rubber brake hose with braided stainless hose.
Turn signals are easy, even if new wires have to be run.
You will need to locate the switch(es) for the rear brake light and inspect/adjust/or replace.
Check the date code on the tires and inspect the sprockets for wear, especially the front sprocket (it wears the quickest).

You'll have to post picts. The biggest gripe I have with the whole "cafe'" genre is the total and utter lack of documentation regarding the modifications made. IMHO this raises the previous owner's status to the level of "Damn P.O."...

At least it runs well.
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 rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #2 on: July 27, 2016, 07:20:40 AM »
Thanks for the response.

[/img]

Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #3 on: July 27, 2016, 07:29:19 AM »
Here is the bike I truly like and want.... Too much money for me to spend on a 3rd bike.  If I could get it for $3000..... I'd take it in a second.

Any thoughts, opinions on price and what's been done?


Offline Phinn

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Re: First Post-- Newb questions on 77 CB750
« Reply #4 on: July 27, 2016, 07:49:21 AM »
if I do end up with shocks with more travel, how hard is it to raise up the front travel?

If the head angle wasn't altered by cutting the frame, it should be relatively easy.  The front is sometimes lowered by shorter tubes and springs, sometimes by mounting the tubes higher in the triple tree.  Returning to stock tubes, springs and mounting in the triple tree are relatively easy.

Quote
The front brakes suck.  Rear seem fine.  What am I looking at to improve front braking if a new pad doesn't rectify the problem?

The front brake system is simple. I'd pull the caliper and clean it out thoroughly and replace both the piston and seal (and pads).  Also, remove the caliper arm that the front brake mounts on to, and remove the pivot pin that allows the arm to swivel. That pin gets rusted frozen easily, so it has to be removed and re-greased. A nice new brake line, banjo bolt and washers are always a good idea if the brake fluid has gone crystalline.  And the master cylinder has a piston and spring (and supporting parts) inside that can be replaced with a kit.  The fluid return hole inside the master cylinder is very small, and frequently blocked by old fluid, so it must be cleaned thoroughly until it's cleared. 

You can upgrade the master cylinder to a more modern one, but some people have reported using a master cylinder that's too large and powerful for the stock front brake pad, which yields so much compression power that the brake goes from zero to 100% (i.e., locked up) with no range in between, no feel, which is also very bad.  So, unless you plan to also upgrade to a whole new brake caliper, or dual disks, which people have done, I'd stick with a master cylinder that is comparable to the one that it came with. 

Quote
Bike has no turn signals-- I'm sure this would be easy to do? 

Sure.  There are lots of options online. 

Quote
THe rear brake also stays lit up all the time and does not get brighter when applying brakes.  What would need to be done to change this? 

The rear brake light has two filaments -- one that stays lit all the time (a running light) and a second one that brightens the light when the brake light switch is closed.  That switch is inside the brake lever housing.  There's another brake light switch on the right hand side, attached by a 4-inch spring to the foot-operated brake lever. 

The front turn signals are configured as dual-filament (running and signal lights) the same way as the tail/brake light.  However, the rear turn signals are signals only, and thus have only one filament. 

Quote
Anything else I should be looking for or at with this bike?  It's clean for the price and runs beautifully. 

Hard to say. If it runs beautifully, then do the scheduled maintenance until you identify something in particular that needs attention.
« Last Edit: July 27, 2016, 07:51:19 AM by Phinn »
1978 CB750K -- "Mouse," a former basket case, resurrected

Offline Phinn

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Re: First Post-- Newb questions on 77 CB750
« Reply #5 on: July 27, 2016, 08:22:24 AM »
The drag pipes are causing the scraping while turning. Ditch them and replace with a proper exhaust. Your bike will handle better and run better.

+1

Also, you may need to put a zip-tie on your clutch cable, to hold it to the frame at the cross member, above the header pipes. It keeps it from roasting.
1978 CB750K -- "Mouse," a former basket case, resurrected

Offline madmtnmotors

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Re: First Post-- Newb questions on 77 CB750
« Reply #6 on: July 27, 2016, 09:07:52 AM »
The front does not appear to have been lowered. Maybe raise the front wheel and measure the overall length of the fork.

Some higher resolution picts of the rear suspension might help answer further questions.

The bike appears to be fairly well sorted at first glance. Like cal says, something other than drag pipes will help.
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 rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #7 on: July 27, 2016, 10:57:38 AM »
The drag pipes are causing the scraping while turning. Ditch them and replace with a proper exhaust. Your bike will handle better and run better.

The rear shock angle looks altered. That can be contributing to a lowered stance. Can you post a more detailed/clearer picture of the upper shock mount, and the swing arm?

what are my options besides a stock replacement or 400$ plus on cycle xchange?  Don't want to drop a lot of coin.


Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #8 on: July 27, 2016, 12:39:31 PM »
Here is the bike I truly like and want.... Too much money for me to spend on a 3rd bike.  If I could get it for $3000..... I'd take it in a second.

Any thoughts, opinions on price and what's been done?

Anyone have thoughts, opinions on this one? 

Sorry, pics didn't copy from my above post.  The red 76
« Last Edit: July 27, 2016, 12:49:35 PM by rhuff »

Offline Gene

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Re: First Post-- Newb questions on 77 CB750
« Reply #9 on: July 27, 2016, 05:27:12 PM »
re: the tail light, check your foot brake switch.  there's a chance the switch has rusted and is stuck open, with the brake light always on.  It's a cheap easy fix if that's the culprit.
*1973 CB750K3 (Bow)

Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #10 on: July 27, 2016, 09:07:32 PM »
I agree it's not worth the 4200 he's asking.  I think maybe if I could get it for 3000 I'd be happy?  Dunno....won't pay more than that.  It's been for sale for awhile.  Obviously.

Offline enwri

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Re: First Post-- Newb questions on 77 CB750
« Reply #11 on: July 28, 2016, 05:58:14 AM »
That looks to have those lowering brackets on the back, on the standard mounts. It moves the shock mount back. Should be able to remove them put the shock back where it should be.
77 CB 750 k.. 29 years and counting.
91 TDM 850 (No.34) so comfy and soft
8? XJ 550 meh...
76 XL 350 Super Sport stump puller..
80 XR 200 idiot proof
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Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #12 on: July 28, 2016, 07:00:19 PM »
That looks to have those lowering brackets on the back, on the standard mounts. It moves the shock mount back. Should be able to remove them put the shock back where it should be.

I'm not sure if I can quite see what you're saying in the pictures, can you explain a bit more so if I go back to look at it I can hopefully tell? 

Here is a few more pics

Offline seanbarney41

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Re: First Post-- Newb questions on 77 CB750
« Reply #13 on: July 28, 2016, 07:12:53 PM »
That looks to have those lowering brackets on the back, on the standard mounts. It moves the shock mount back. Should be able to remove them put the shock back where it should be.

I'm not sure if I can quite see what you're saying in the pictures, can you explain a bit more so if I go back to look at it I can hopefully tell? 

Here is a few more pics
the lowering block can easily be seen in these pics.  Remove your lower shock bolt, remove the little bracket thingy that the shock was bolted to from the the swingarm, bolt the shock to where the bracket thingy was attached on the swingarm, there now its not lowered anymore.  Be sure and put the bike on the center stand or you will have problems.

If it works good, it looks good...

Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #14 on: July 28, 2016, 07:30:42 PM »
That looks to have those lowering brackets on the back, on the standard mounts. It moves the shock mount back. Should be able to remove them put the shock back where it should be.

I'm not sure if I can quite see what you're saying in the pictures, can you explain a bit more so if I go back to look at it I can hopefully tell? 

Here is a few more pics
the lowering block can easily be seen in these pics.  Remove your lower shock bolt, remove the little bracket thingy that the shock was bolted to from the the swingarm, bolt the shock to where the bracket thingy was attached on the swingarm, there now its not lowered anymore.  Be sure and put the bike on the center stand or you will have problems.

Gotcha.  Thank you.

Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #15 on: July 28, 2016, 07:31:40 PM »
Anyone know if these appear to be stock shocks?

Offline Phinn

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Re: First Post-- Newb questions on 77 CB750
« Reply #16 on: July 28, 2016, 08:02:23 PM »
Anyone know if these appear to be stock shocks?

Measure them, from the center of the top bolt to the center of the bottom bolt.  That would help.
1978 CB750K -- "Mouse," a former basket case, resurrected

Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #17 on: July 28, 2016, 09:03:57 PM »
Anyone know if these appear to be stock shocks?

Measure them, from the center of the top bolt to the center of the bottom bolt.  That would help.

From what I'm seeing, stock would be about 13?

Offline seanbarney41

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Re: First Post-- Newb questions on 77 CB750
« Reply #18 on: July 29, 2016, 01:56:25 AM »
I can't tell from the pics


totally unrelated but you are gonna want to re-aim your head light before riding at night
If it works good, it looks good...

Offline rhuff

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Re: First Post-- Newb questions on 77 CB750
« Reply #19 on: July 29, 2016, 06:36:55 AM »
I can't tell from the pics


totally unrelated but you are gonna want to re-aim your head light before riding at night

Yeah, I noticed that sad, limp little headlight.