Author Topic: 72 cb750 first 60 mile ride!  (Read 2121 times)

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Offline sohcphreek

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72 cb750 first 60 mile ride!
« on: November 26, 2012, 07:49:52 PM »
hey first 60 miles on this 72, Killer ride but took along time to start! Work in progress. Oh yea Lots of IPA!
sohcphreek
« Last Edit: November 26, 2012, 08:27:48 PM by sohcphreek »

Offline Stev-o

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Re: 72 cb750 first 60 mile ride!
« Reply #1 on: November 26, 2012, 08:19:51 PM »
What is your starting procedure?   My K4 likes full choke and no throttle til it fires up.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline sohcphreek

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Re: 72 cb750 first 60 mile ride!
« Reply #2 on: November 26, 2012, 08:26:04 PM »
I have tried everything , cold this thing take 20 min. to start, with a charger. Warm once it starts 1 time it will fire the second you hit the button. Im so frustrated.!
Today I ordered a "genuine Honda" point plate loaded with the parts and hope that this helps??
thanks for any help!!
Chris

Offline Stev-o

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Re: 72 cb750 first 60 mile ride!
« Reply #3 on: November 26, 2012, 08:37:43 PM »
You have a good battery?    For cold start:
Turn on key, gas and choke
Do not give any throttle and hit start for 5 sec.
If no start, wait 10 sec and try again.

How does it run once warm? 
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline sohcphreek

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Re: 72 cb750 first 60 mile ride!
« Reply #4 on: November 26, 2012, 08:50:50 PM »
runs like a sewing machine ! It just woont star the next day
thanks chris

Offline sohcphreek

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Re: 72 cb750 first 60 mile ride!
« Reply #5 on: November 26, 2012, 09:04:20 PM »
the battery is good
chris

Offline Stev-o

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Re: 72 cb750 first 60 mile ride!
« Reply #6 on: November 26, 2012, 09:09:23 PM »
runs like a sewing machine ! It just woont star the next day
thanks chris

I'm guessing that's a good thing!  Something is obviously wrong, consider giving it the full 3000 mile tune up if you don't know the history (plugs, caps, points, adjust valves, timing and sync carbs).
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline sohcphreek

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Re: 72 cb750 first 60 mile ride!
« Reply #7 on: November 26, 2012, 10:09:37 PM »
ok thanks

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 72 cb750 first 60 mile ride!
« Reply #8 on: November 26, 2012, 11:44:42 PM »
paint looks sweet!

double check that you have fuel in the carb bowls before the first attempt
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline 70CB750

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Re: 72 cb750 first 60 mile ride!
« Reply #9 on: November 27, 2012, 12:26:24 AM »
Here is a dumb question - to start her, do you hold the throttle  1/3 - 1/2 open?

It took me a while to figure that one out when she was new to me:)

What heat spark plugs and what your plugs look like?

Fuel line routing?  It should go down or level from the tank, not up (like over carb bracket or such)

The chokes are all adjusted and working?


Love the color, what a beauty!

Offline greenjeans

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Re: 72 cb750 first 60 mile ride!
« Reply #10 on: November 27, 2012, 06:47:39 AM »
Definitely do the 3000 mile tune.    Then, do it again just to familiarize yourself with the procedure and double-check things.   Doesn't take long.

The new points plate should help.    Also, judging by how spotless that beauty is, I assuming that the carbs are spotless too ?   If there is one thing

I've learned about these beasts over the last 10 years - it's the carbs must be spotless.    Pay close attention to the float levels - search for the clear tube

method to verify the level of fuel.        These things should start 1st push of the starter - hot or cold.    Choke on if it is really cold.   Mine generally

does not need choke unless it has been sitting for quite a while or it is really cold.

Are you getting a good fat spark from your plugs ?      If those are the original coils and plug wires, the caps and the ends of the plug wires can get

very corroded.    You migh try snipping 1/4 - 1/2 inch of the ends of the plug wires and installing some new plug caps & plugs.   Cheap.

You'll probably find the ends of your plug wires are green with corrosion.

Good luck.     


by the way - that bike looks great.   Haven't seen a paintjob like that one before.   Definitley a head-turner.
Yep, I'm the kid that figured out how to put things back together...eventually.

Offline iron_worker

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Re: 72 cb750 first 60 mile ride!
« Reply #11 on: November 27, 2012, 06:59:43 AM »
You sure those pilots aren't clogged?

IW

Offline Z-MO

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Re: 72 cb750 first 60 mile ride!
« Reply #12 on: November 27, 2012, 10:36:00 AM »
More IPAs might help   ;)
'75 CB750 Chop
'72 CB750 Cafe

Offline sohcphreek

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Re: 72 cb750 first 60 mile ride!
« Reply #13 on: November 27, 2012, 04:09:20 PM »
well pulled air boxes and the choke is completely closing, checked the plug wires for corrosion and all are clean, new starter installed and it cranks powerfully, i pulled the drain plugs on carbs and they all have fuel. I guess I will replace the point plate and at the same time check valve clearences.
After 20 mins. trying to start this beauty (no result ) I'm done til new parts arrive. Its crazy that once it starts , it starts fine the rest of the day. But tomorrow the same thing happens.

Offline madScientist

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Re: 72 cb750 first 60 mile ride!
« Reply #14 on: November 27, 2012, 04:14:34 PM »
How do the plugs look? Black and sooty? White? Brown?

Have you tried starting it right off the bat with the throttle wide open and no choke?
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Online seanbarney41

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Re: 72 cb750 first 60 mile ride!
« Reply #15 on: November 27, 2012, 04:35:47 PM »
Tried kick starting?...often you will get a hotter spark from kicking, starter eats up precious ignition voltage, especially if all is not perfectly kosher in your switchesw and wiring
If it works good, it looks good...

Offline lucky

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Re: 72 cb750 first 60 mile ride!
« Reply #16 on: December 02, 2012, 05:13:39 PM »
Great paint job and graphics!!!

Offline Killer Canary

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Re: 72 cb750 first 60 mile ride!
« Reply #17 on: December 02, 2012, 06:00:20 PM »
Just for a larf, drop a tsp of fuel down each plug hole and then try a cold start. Also, do your choke plates have the spring loaded flaps on them?
If it's worth doing at all it's worth over-doing.
Honda MT250, CB400F, CB450K, CB550, GL500, CBR929
Kawi GPz900, H1