Author Topic: CB750 Spark Advancers = what are the differences  (Read 17879 times)

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Offline PeWe

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Re: CB750 Spark Advancers = what are the differences
« Reply #50 on: May 27, 2017, 11:51:23 PM »
You need to turn plate (1-4) and 2-3 points more clockwise to line up with F, but grooves does not allow more movements?
this has been common for me in the initial setup.

Reduce gap. Easier with dwell meter, adjust when engine is idling around 2000rpm. 8 cyl setup 23 degrees on both. This will make both to be equally set.

If advancer unit has a huge play when center nut is not tightened, the correct posistion can be found with a piston stop and find the real TDC that "T" should line up with.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline MauiK3

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Re: CB750 Spark Advancers = what are the differences
« Reply #51 on: August 10, 2017, 07:59:15 PM »
Like 754, my advancer is marked AD125. Does anyone know what that is? Seems different than all photos I've seen.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline scottly

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Re: CB750 Spark Advancers = what are the differences
« Reply #52 on: August 10, 2017, 08:41:43 PM »
Honda used two different suppliers for the advancers. One was TEC, and the other was Denso. The symbol near the 2-3 timing marks on your unit is Denso. My K1 has a similar part. 
Don't fix it if it ain't broke!
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Offline HondaMan

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Re: CB750 Spark Advancers = what are the differences
« Reply #53 on: August 11, 2017, 01:56:40 PM »
Like 754, my advancer is marked AD125. Does anyone know what that is? Seems different than all photos I've seen.
The ones marked with the 'AD125' were seen (in my old notes) during the later K3 bikes, in the summer of 1973. They have a slightly slower advance curve (at least, when the springs were new!) and led me to discover how much these bikes prefer a later curve when used in city riding a lot. These seemed to vanish by the K4.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline PeWe

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Re: CB750 Spark Advancers = what are the differences
« Reply #54 on: August 12, 2017, 01:26:29 PM »
I have an AD125-01 on the shelf. Written to come from a CB750 Super sport 1975. I have not used it yet, probably to my CB750 K2 project.

It has a slower curve as using shortened springs?
« Last Edit: August 12, 2017, 01:29:04 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Online CycleRanger

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Re: CB750 Spark Advancers = what are the differences
« Reply #55 on: August 12, 2017, 08:14:13 PM »
Honda used two different suppliers for the advancers. One was TEC, and the other was Denso. The symbol near the 2-3 timing marks on your unit is Denso. My K1 has a similar part.

Actually, that symbol is for Hitachi.
Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline scottly

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Re: CB750 Spark Advancers = what are the differences
« Reply #56 on: August 12, 2017, 10:07:26 PM »
Honda used two different suppliers for the advancers. One was TEC, and the other was Denso. The symbol near the 2-3 timing marks on your unit is Denso. My K1 has a similar part.

Actually, that symbol is for Hitachi.
Thank you for the correction CR. :-[ :-[ :-[
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline HondaMan

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Re: CB750 Spark Advancers = what are the differences
« Reply #57 on: August 12, 2017, 10:22:12 PM »
I have an AD125-01 on the shelf. Written to come from a CB750 Super sport 1975. I have not used it yet, probably to my CB750 K2 project.

It has a slower curve as using shortened springs?


Yes, very similar to cutting off 1/2 turn of both springs. That was how I first discovered that these engines like it. ;)
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline PeWe

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Re: CB750 Spark Advancers = what are the differences
« Reply #58 on: August 13, 2017, 07:03:53 AM »
I have an AD125-01 on the shelf. Written to come from a CB750 Super sport 1975. I have not used it yet, probably to my CB750 K2 project.

It has a slower curve as using shortened springs?


Yes, very similar to cutting off 1/2 turn of both springs. That was how I first discovered that these engines like it. ;)
OK, that will be fine. Springs must be OK when the seller wrote it came from a 8000 miles bike. The cam holders from same bike were tight and fine.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline scottly

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Re: CB750 Spark Advancers = what are the differences
« Reply #59 on: August 17, 2017, 07:24:14 PM »
Honda used two different suppliers for the advancers. One was TEC, and the other was Denso. The symbol near the 2-3 timing marks on your unit is Denso. My K1 has a similar part.

Actually, that symbol is for Hitachi.
CR, would you happen to know the symbol for Diachi? Thanks.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Online CycleRanger

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Re: CB750 Spark Advancers = what are the differences
« Reply #60 on: August 17, 2017, 07:38:32 PM »
CR, would you happen to know the symbol for Diachi? Thanks.
That one's easy.
Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline scottly

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Re: CB750 Spark Advancers = what are the differences
« Reply #61 on: August 18, 2017, 08:14:54 AM »
That's the symbol I saw on one of Matt's replacement condensers. :( Thanks.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline HondaMan

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Re: CB750 Spark Advancers = what are the differences
« Reply #62 on: August 19, 2017, 08:23:02 PM »
That's the symbol I saw on one of Matt's replacement condensers. :( Thanks.

Yeah...we see it on dispensaries around here, too, looks just like that.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline YoungBlood

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Re: CB750 Spark Advancers = what are the differences
« Reply #63 on: June 10, 2021, 09:15:41 PM »
PeWe, any chance you remember or still have that advancer from the 75' Honda Cb750F? I am curious what the od was on its pin.
When you're going through hell, give it some more gas.

Offline PeWe

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Re: CB750 Spark Advancers = what are the differences
« Reply #64 on: December 31, 2021, 12:41:38 AM »
PeWe, any chance you remember or still have that advancer from the 75' Honda Cb750F? I am curious what the od was on its pin.
I see this now ;)
That advancer has moved into my blue K6 with Dyna-S ignition.
-I do not know which pin you ask about.

I cut the springs as both my other TEC 300 advancers.
Stable idle, ign spot on F. Full adv at 2600-2700rpm.
I set ignition to match F at around  1000-1200 rpm.

 Advancer has a several degrees  lash noticed when nut is not tightened. Case mark will match with TDC (T) when advancer is in its counterclockwise position.

That engine has an alternative case mark 3mm to the right I use when timing the cam and advancer in its clockwise position. It will easy move to that when rotating crank with the big nut. No plugs in.
When done back to counterclockwise and set ign F to match stock case mark.

Bike had 104whp in October with good torque curve from low so ignition is fine. Shell V-Power street fuel.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967