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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Tue Jul 19, 2016 9:06 pm Reply with quote Back to top

Hello from the Connecticut seacost!

Just joined this forum today and I gotta say I could have used its help about 25 years ago when I got my first old CB750.

I have had more than a few CB750s since that 1980 Custom (which is long gone) many of which were SOHC but there were indeed a few of the DOHC bikes.
Most were cheap to free and used as parts bikes back when I was young and had mostly negative cash flow.

Now I am old and have mostly negative cash flow and its been 10 years since my last bike - 73 CB750k3.

But I did pick up a fairly solid 79 Limited Edition: noisy cam chain and valves, very noisy clutch but runs.

I am in the process of going through the bike now:
valve clearance is good
front cam chain was about as loose as it can get and not come off but it seems to have tightened up ok.
Static timing done and it almost idles well.

As soon as I can swing a new set of vacuum gauges and plug wires/boots (old ones are SHOT) I think it'll be good.

I still have to check the clutch out - seems even noisier than I remember DOHC clutches being, but that could just be all the time that has passed.
I will be replacing all the cables and such that are questionable as funds allow, but not quite sure how long that is going to take just yet.

Still have to come up with the cash to insure and register the thing too, but I am to just be able to say I have an old CB750 again right now.

Getting it on the road will come.

And should be a lot easier with some of what I have already seen here: more information here than I knew back in the day (especially since I was figuring it out all by myself back then.)

After it is on the road I will start thinking about getting it "pretty."
Maybe.

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1982 CM450E - Spare bike 
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Duke
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PostPosted: Tue Jul 19, 2016 10:06 pm Reply with quote Back to top

Welcome

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Duke

1981 CB900 Custom

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pd750
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Joined: Aug 01, 2007
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Location: Waldron , Arkansas

PostPosted: Tue Jul 19, 2016 11:25 pm Reply with quote Back to top

Welcome to the site dugans ... Smile

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1982 CB750C (Sold) Haven\'t found another , yet . 
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genesound
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Joined: Jul 24, 2007
Posts: 44788
Location: Studio City, CA

PostPosted: Wed Jul 20, 2016 12:05 am Reply with quote Back to top

Welcome here wave

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NMT - New Member Thread, a Must Read, click here!!! - Information For New and Veteran Members.
Contains SITE RULES, how to enter required bike information in your signature, thread and picture posting...
Also some important DOHC wrenching tips, and some other information, shop manuals.
Kindly read this linked thread with the rules before posting
pictures or asking lots of questions that are already answered in it.

ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
81 CB900C, 83 CB1000C. 
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holysmokes
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Joined: Jul 25, 2007
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PostPosted: Fri Jul 22, 2016 8:05 am Reply with quote Back to top

hello

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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Mon Jul 25, 2016 6:47 am Reply with quote Back to top

Thanks for the welcome.

Update:
vacuum gauge set is on order along with a new adjustment tool and wires/caps.

Re-ran all of the cables and they no longer seem like they need to be replaced... imagine that.
Handlebars turn much better too. Wink

The fuel petcock may have a problem but I am not ready to get a new one just yet.

Hopefully have this thing on the road in short order.

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1979 CB750L - Rebuild 99% complete, daily rider
1982 CM450E - Spare bike 
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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Fri Jul 29, 2016 10:49 am Reply with quote Back to top

Update: 7/29/2106

Carb synchronizer came wednesday and while the rest of the family was watching politics on tv I got to work on the bike.

They synced up ok but still ran rough so I figured I would leave it be since it was late-ish and pick it up again thursday.

On thursday I realized I had forgotten to put one of the vacuum port plugs back in.... DOH!
Idles pretty well after that...
Still need to get some more washers- only 2 of the port plugs have 'em.

Did some cleaning and some rehab of the tank paint: it had a crappy gloss black with flat white center stripe paint job. Sanded down and rattling canning some flat black.

Mechanically pretty sound now, other than a front brake light switch that is busted (ordered) and one leaky fork seal (will live with for a bit.)

Got the registration done and the plate is on the bike- just waiting for a lack of rain to ride now.

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1982 CM450E - Spare bike 
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pd750
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Joined: Aug 01, 2007
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Location: Waldron , Arkansas

PostPosted: Fri Jul 29, 2016 11:00 am Reply with quote Back to top

dugans wrote:
Update: 7/29/2106

and one leaky fork seal (will live with for a bit.)


You might try a Seal Mate :

https://www.youtube.com/watch?v=8wlzfoVroSY

I made on out the side of a gallon milk jug . They do work .

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Please put the year and model of your bike in the signature section on your profile / member account page and set \"Always attach signature \" to YES . Just below the Reply box , check the box in front of \"Attach signature (signatures can be changed in profile)\" .

1982 CB750C (Sold) Haven\'t found another , yet . 
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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Fri Jul 29, 2016 5:19 pm Reply with quote Back to top

Ok, now some visual proof of the bike:
First got it home:
Image

In the garage after doing a lot of the initial checks:
Image
Image

And finally, after getting it legally on the road:
Image

Definitely ride-able and also definitely NOT done:
Once it warms up idle is all over the place- well really only two places: 3000 rpm and right around stalling. Shocked

Could just be the insulators, could be that whoever the previous owner had rebuild the carbs did a... yeah, less than great job.

Like it says in the sig- Work In Progress.
It will get ridden while the work goes on.... well, maybe not AS it is being worked on, but, yeah, you get the idea I am sure.[/img]

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1979 CB750L - Rebuild 99% complete, daily rider
1982 CM450E - Spare bike

Last edited by dugans on Fri Jul 29, 2016 5:33 pm; edited 1 time in total 
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seanathon
Feel the Power
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Joined: Aug 08, 2014
Posts: 549
Location: Bangor, Maine

PostPosted: Fri Jul 29, 2016 5:22 pm Reply with quote Back to top

Good looking bike - love the K/L/F tank style. Are your plans on restoring it, modifying it, or just making it rideable?

All good ideas Cool

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Seanathon
1981 CB750c
1963 BSA B40
1974 Triumph Trident T150v (future project)

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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Fri Jul 29, 2016 5:37 pm Reply with quote Back to top

I had to fight with photobucket to get sizes right- easier to set size and THEN upload.

Basically my plan is to RIDE.
After that, getting it nicer is a plus but I have never been a fan of spending more time cleaning than riding.

I would like to have it as original as possible but since I am cheap some of the harder to find items may never appear- like proper side covers for a limited edition bike.

I'll fab up something decent enough, eventually.

By the way- it looks ok but the pics of it look much better than the bike does in person. Very Happy

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1982 CM450E - Spare bike 
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pd750
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Location: Waldron , Arkansas

PostPosted: Fri Jul 29, 2016 6:00 pm Reply with quote Back to top

Pretty much same as my philosophy . Ain't much good if you aren't using it for what it was designed for . Wink

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1982 CB750C (Sold) Haven\'t found another , yet . 
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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Sat Aug 13, 2016 3:29 pm Reply with quote Back to top

I was wondering why I had such lousy mileage (about 22mpg) so I began looking closely at my carbs. They synced up but I KNEW they weren't right.
Pulled off the exposed air cut valve cover- yup, gasket is toast.
Got stuff to make bypasses for all 4.
Pulled off the float bowl on #1- nothing dreadful.
Pulled off the float bowl on #2:
Image

Kinda explains that weird rattle...
#3 is ok, still have to open up #4.

New carb holders are expected monday (killed the bike budget for the month right there) and I am hoping that the quick and dirty carb check will help enough that I can use the bike for my commute and save money for a full carb rebuild.

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1982 CM450E - Spare bike 
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pd750
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PostPosted: Sat Aug 13, 2016 3:59 pm Reply with quote Back to top

Just remember to install the right jets in the right places . Wink

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Please put the year and model of your bike in the signature section on your profile / member account page and set \"Always attach signature \" to YES . Just below the Reply box , check the box in front of \"Attach signature (signatures can be changed in profile)\" .

1982 CB750C (Sold) Haven\'t found another , yet . 
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dugans
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PostPosted: Sat Aug 13, 2016 7:05 pm Reply with quote Back to top

I went for consistency- all 4 have the same size in the same place. Wink

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1982 CM450E - Spare bike 
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pd750
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PostPosted: Sat Aug 13, 2016 8:07 pm Reply with quote Back to top

Hopefully the PO got them right .

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1982 CB750C (Sold) Haven\'t found another , yet . 
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genesound
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Joined: Jul 24, 2007
Posts: 44788
Location: Studio City, CA

PostPosted: Sat Aug 13, 2016 9:13 pm Reply with quote Back to top

This:

Image

_________________
NMT - New Member Thread, a Must Read, click here!!! - Information For New and Veteran Members.
Contains SITE RULES, how to enter required bike information in your signature, thread and picture posting...
Also some important DOHC wrenching tips, and some other information, shop manuals.
Kindly read this linked thread with the rules before posting
pictures or asking lots of questions that are already answered in it.

ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
81 CB900C, 83 CB1000C. 
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dugans
On a roll
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Tue Aug 16, 2016 5:36 pm Reply with quote Back to top

I may be taking a closer look this weekend but I am hoping not:
When I took it to work last time (50 miles each way)- ran ok-ish up to about 60 and then squat. And got about 22 mpg.
A quick ride this evening felt far better and it even idles right now!
If I get decently above 30 mpg and no real issues.... Riding time.
Making the carbs RIGHT can wait until I save some coin....and can't ride due to weather. Wink

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1979 CB750L - Rebuild 99% complete, daily rider
1982 CM450E - Spare bike 
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pd750
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Joined: Aug 01, 2007
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Location: Waldron , Arkansas

PostPosted: Tue Aug 16, 2016 8:10 pm Reply with quote Back to top

Jets in the wrong holes ?

That thing should be getting about twice the mileage and have you praying your brakes still work good .

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Please put the year and model of your bike in the signature section on your profile / member account page and set \"Always attach signature \" to YES . Just below the Reply box , check the box in front of \"Attach signature (signatures can be changed in profile)\" .

1982 CB750C (Sold) Haven\'t found another , yet . 
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dugans
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Wed Aug 17, 2016 9:17 am Reply with quote Back to top

Felt pretty good on the way here this morning.
5th gear at 6000rpm and still had plenty of power.
I'll know for sure when I get gas but I have the feeling mpg will be ok now.
It wasn't jets in the wrong holes but jets having fallen OUT of the holes entirely.
I know that at least one po was not too good with this thing so almost anything is possible, and I know the carbs need to be done up right... Just not gonna do it right NOW if I don't have to.

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1979 CB750L - Rebuild 99% complete, daily rider
1982 CM450E - Spare bike 
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dugans
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Joined: Jul 19, 2016
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Location: Bridgeport, Connecticut

PostPosted: Thu Aug 18, 2016 6:00 pm Reply with quote Back to top

Here is the Cheap in Connecticut update for the day:
Carbs are good enough.

Chain started jumping just a bit so I tightened it up a hair while at work and made it worse.
A bit worrying on the way home, so I loosened it up about half a hair and made it home.
Checked things closely (yeah, I know it is smart to check everything thoroughly BEFORE trying to do a 50 mile commute. Twice.) and it looks like one of the previous owners changed the rear sprocket and chain- both look fine- but was scared of changing the front sprocket.
That thing is pretty beat up.
The folks I bought it from included a new 530 chain and 16/38 sprockets, but that means converting from a 630 to 530 and I since the 630 sprockets appear to be 16/38 I am not sure I want to do that.
No gearing expert but I think that will get my highway revs screaming like a banshee.

Time to research gearing and decide which way to go.
I do know of gearingcommander, but if anyone has comments suggestions or just wants to make fun of me, feel free. Wink

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genesound
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Joined: Jul 24, 2007
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PostPosted: Thu Aug 18, 2016 8:18 pm Reply with quote Back to top

You didn't say what's on it now...

Stock sprockets for your bike were 15/38 = 2.533

Those new 530 sprockets are 16/38 = 2.375, so the motor will run a wee bit slower than stock for the same ground speed.

530 is a much better chain for these bikes though. The later years after 79 used them instead of 630s. Stock they used 18/46 = 2.556 which was close to the old ratio, but had more teeth in contact with the chain, for less sprocket wear and chain stretch, but still had less rotating mass.

_________________
NMT - New Member Thread, a Must Read, click here!!! - Information For New and Veteran Members.
Contains SITE RULES, how to enter required bike information in your signature, thread and picture posting...
Also some important DOHC wrenching tips, and some other information, shop manuals.
Kindly read this linked thread with the rules before posting
pictures or asking lots of questions that are already answered in it.

ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
81 CB900C, 83 CB1000C. 
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dugans
On a roll
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Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Thu Aug 18, 2016 9:26 pm Reply with quote Back to top

Yeah, I forgot to mention that the 630 was on it when I bought it.
I hadn't checked into what chain came on the bike when it was new until tonight but it does look like somebody changed it.
Been too long since I messed with bikes, and even longer since I had a DOHC 750....

I truth I don't think I ever had to pay all that much attention to chains and sprockets:
never had a worn out sprocket and just replaced whatever chain was on the bike when I got it.

I think I am going to give the 16/38 a shot.
The next thing I'll have to figure out is if the chain needs to be shortened ..... well, maybe have to see if the sprockets actually FIT the bike first.
With what I have seen so far, nothing would surprise me too much, really.

Thanks for the reply- I actually DID do the research my own self but you make me feel a bit more confident that changing to the 530 is a good plan.

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1982 CM450E - Spare bike 
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genesound
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Joined: Jul 24, 2007
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PostPosted: Thu Aug 18, 2016 10:26 pm Reply with quote Back to top

When I said what's on it now, I meant tooth count...

_________________
NMT - New Member Thread, a Must Read, click here!!! - Information For New and Veteran Members.
Contains SITE RULES, how to enter required bike information in your signature, thread and picture posting...
Also some important DOHC wrenching tips, and some other information, shop manuals.
Kindly read this linked thread with the rules before posting
pictures or asking lots of questions that are already answered in it.

ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
81 CB900C, 83 CB1000C. 
View user's profile Send private message Send e-mail Visit poster's website
dugans
On a roll
On a roll



Joined: Jul 19, 2016
Posts: 161
Location: Bridgeport, Connecticut

PostPosted: Fri Aug 19, 2016 4:40 am Reply with quote Back to top

Current sprockets look to be 16/38 too.
Beefier chain and somewhat larger diameter, especially in th back.
Hard to count teeth(or do much work) in my garage as I have a small wood shop in there as well.

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