Author Topic: JMR billet engine build  (Read 22999 times)

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Offline slikwilli420

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Re: JMR billet engine build
« Reply #100 on: June 13, 2017, 12:22:37 PM »
On the f2 tank the bung is larger. The 1/2" fit good and i use a aluminium washer at the bottom for sealing.  I have a f1 tank that i can check for what tread it is.


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F0/F1 tanks are different from F2 tanks in thread size. Still not sure how a non metric cap threads onto a metric bung, unless you just got lucky.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
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AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline frodef2

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Re: JMR billet engine build
« Reply #101 on: June 13, 2017, 01:58:43 PM »
i know for sure that there are plumber supplies that fit the F1 tank. The F1 tank i have, had a toilet water shutoff ball valve as a tap..  I have to get a picture of that setup :)

Other news. i took the bike for a short spin. with the datalogger.  i thought i gave it a good spin. But it turns out i was pussyfooting it.

Dataloggers don't lie. I stopped just short of half throttle. I think can also see from the logs that the accelerator pump engages at about 22% throttle.
I need to get to a longer straight and a less crowded location



green is AFR, blue is RPM, and the pink is Throttle in %


« Last Edit: June 13, 2017, 02:00:32 PM by FrodeF2 »
76' Supersport

Offline frodef2

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Re: JMR billet engine build
« Reply #102 on: June 13, 2017, 02:27:19 PM »

F0/F1 tanks are different from F2 tanks in thread size. Still not sure how a non metric cap threads onto a metric bung, unless you just got lucky.

i did some more research on the threads. Turns out that we in norway in our infinite wisdom. Use imperial measurements for pipe diameter, and Metric for the threads.
That means that the 1/2" marked on the bag of the cap i purchased indicates that its meant for half inch pipes, and the tread is R15. which indicates that the thread is a 15mm pipe thread. The "R" also supposedly indicates that the thread is conical

Frode J
76' Supersport

Offline PeWe

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Re: JMR billet engine build
« Reply #103 on: June 14, 2017, 08:44:09 AM »
Pipes, valves, water mixers for kitchen, toilets, washing facilities have both inch and R threads in Sweden too...
I guess that's why plumbers have a huge setup of tools and connecting stuff. They must get the job too since it can be confusing to get it right direct as needed.
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 frodef2

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Re: JMR billet engine build
« Reply #104 on: June 15, 2017, 12:18:41 PM »
During a small trip today, i noticed that the engine was running rougher. I flipped through the readouts on the motogadget, and noticed that the battery voltage read 11.4V. Looks like the regulator failed after 460km.

I barely made it back home, with the battery reading 11V flat.
I have checked the connectors from the generator and they were fine.





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76' Supersport

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Re: JMR billet engine build
« Reply #105 on: June 16, 2017, 10:20:48 AM »
Frode,

What kind of hp and torque does this bike make?
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline frodef2

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Re: JMR billet engine build
« Reply #106 on: June 16, 2017, 10:22:44 AM »
I haven't had the time to hit the dyno yet. I will post the figures when i have.


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76' Supersport

Offline SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #107 on: June 16, 2017, 11:14:54 AM »
I haven't had the time to hit the dyno yet. I will post the figures when i have.


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Please do. I am sure I am not the only one who's curious what one of these big blocks can do.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline calj737

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Re: JMR billet engine build
« Reply #108 on: June 17, 2017, 08:17:11 AM »
During a small trip today, i noticed that the engine was running rougher. I flipped through the readouts on the motogadget, and noticed that the battery voltage read 11.4V. Looks like the regulator failed after 460km.

I barely made it back home, with the battery reading 11V flat.
I have checked the connectors from the generator and they were fine.
Where is the Regulator Black wired tapped into? With an M-Unit, it's best to use LOCK or AUX as the sensing source for the battery status.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline PeWe

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JMR billet engine build
« Reply #109 on: June 18, 2017, 12:27:29 AM »
I haven't had the time to hit the dyno yet. I will post the figures when i have.


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I guess you'll get around +100rwhp, + 90Nm
I had mine on the dyno 2 days ago. 93rwhp, 87Nm.
My 4-4 restrict more than visible on the graphs. WOT up to around 180-200 kph work fine, but stop there. Release of throttle a little wake up the engine. More main jet no good.
A good exhaust must enter >100rwhp.

Mike's billet block is really  recommended for those that need big bore. Streetable and no leaks as can happen when bore the original block to 76mm to take the big sleeves.
Graph here
http://forums.sohc4.net/index.php?topic=49438.msg1925222#msg1925222
« Last Edit: June 18, 2017, 12:53:25 AM 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

Offline frodef2

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Re: JMR billet engine build
« Reply #110 on: June 18, 2017, 08:00:23 AM »
I found the cause of the "missing voltage". lets just say that the responsible has been punished.

Now i just need dry weather to continue the tuning.


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76' Supersport

Offline grcamna2

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Re: JMR billet engine build
« Reply #111 on: June 27, 2017, 05:06:11 PM »
Very nice custom Hot Rod CB750 Frode.I was curious if the rear suspension 'swing arm' is from a Suzuki GS1100E ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

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Re: JMR billet engine build
« Reply #112 on: June 27, 2017, 05:07:47 PM »
I haven't had the time to hit the dyno yet. I will post the figures when i have.


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I guess you'll get around +100rwhp, + 90Nm
I had mine on the dyno 2 days ago. 93rwhp, 87Nm.
My 4-4 restrict more than visible on the graphs. WOT up to around 180-200 kph work fine, but stop there. Release of throttle a little wake up the engine. More main jet no good.
A good exhaust must enter >100rwhp.

Mike's billet block is really  recommended for those that need big bore. Streetable and no leaks as can happen when bore the original block to 76mm to take the big sleeves.
Graph here
http://forums.sohc4.net/index.php?topic=49438.msg1925222#msg1925222

Nice!  What kind of torque does it make, PeWe?
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline frodef2

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Re: JMR billet engine build
« Reply #113 on: June 28, 2017, 10:13:04 AM »
Update regarding the charging issue.

As i wrote a few posts back, the bike stopped charging. I found the cause and it was that the rotor came loose from the crank.  I figured i must have forgotten to torque the bolt, and just re torqued it. Today, the first sunny day in weeks. I tried to start the bike again. The bike just spun the starter. The rotor had loosened again. This time i was 100% sure i torqued it to spec. So i started looking for other causes.



Turns out the bolt was too long. The bolt bottomed out about the same time as it seated at the thick washer that came with the generator upgrade. This means that the threads took up most of the clamping force, and not the cone of the crank.

DoH!




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76' Supersport

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: JMR billet engine build
« Reply #114 on: June 28, 2017, 10:39:39 AM »
Always good to find a non-problem.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline PeWe

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JMR billet engine build
« Reply #115 on: June 28, 2017, 11:29:27 AM »
I used medium thread lock on my bolt just for sure.
Dyno yet Frode?
I did before my vacation June 16. Result on Mikes billet block thread.
« Last Edit: June 28, 2017, 11:32:10 AM 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

Offline SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #116 on: June 28, 2017, 01:47:45 PM »
That photo highlights how perfectly machined the cooling fins are on the 1000cc JMR block compared to the variations in the fins on the head from casting and wear/tear.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline PeWe

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Re: JMR billet engine build
« Reply #117 on: July 03, 2017, 02:16:37 AM »
Is the OEM starter motor OK for the 1005cc?
I installed 900 DOHC motor with sprocket when I thought OEM should be too weak.
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 SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #118 on: July 03, 2017, 09:27:58 AM »
Is the OEM starter motor OK for the 1005cc?
I installed 900 DOHC motor with sprocket when I thought OEM should be too weak.

PeWe, The 900 DOHC drops in without mods, right.  I know there are a couple more robust starters recommended to just beef up the 750 starter.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline PeWe

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Re: JMR billet engine build
« Reply #119 on: July 03, 2017, 01:21:21 PM »
CB900 DOHC -81 starter motor drops in nicely. It must be the 0.8 kW version. The gear needed too for stronger gear ratio. The CB750 starter cover will fit too.
http://forums.sohc4.net/index.php/topic,146746.msg1836993.html#msg1836993
Only the 12V wire that need to be replaced, screw connection on motor.

I used a battery cable 16mm2, 600mm long complete with shoes. It works fine despite  a little bit thin, I looked for thicker 25mm2 but found a cheap one that could be used direct.
http://www.biltema.no/no/Bil---MC/Elektrisk/Batteriverktoy-og-tilbehor/Batterikabel-2000034731/

I used this direct with 1005cc since I thought CB750 std will be weak after reading the thread about starter motors and big bore/high CR engines.
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 SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #120 on: July 03, 2017, 04:58:49 PM »
CB900 DOHC -81 starter motor drops in nicely. It must be the 0.8 kW version. The gear needed too for stronger gear ratio. The CB750 starter cover will fit too.
http://forums.sohc4.net/index.php/topic,146746.msg1836993.html#msg1836993
Only the 12V wire that need to be replaced, screw connection on motor.

I used a battery cable 16mm2, 600mm long complete with shoes. It works fine despite  a little bit thin, I looked for thicker 25mm2 but found a cheap one that could be used direct.
http://www.biltema.no/no/Bil---MC/Elektrisk/Batteriverktoy-og-tilbehor/Batterikabel-2000034731/

I used this direct with 1005cc since I thought CB750 std will be weak after reading the thread about starter motors and big bore/high CR engines.

This should almost be "stickied."  Great upgrade for higher compression motors -- even a Wiseco 836. 
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
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  • Posts: 14,928
  • Bought her new 4/75
Re: JMR billet engine build
« Reply #121 on: July 05, 2017, 04:57:50 PM »
I have a stock starter motor on my 1000 @ 10.5:1 with a AGM battery and it spins just fine.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline frodef2

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Re: JMR billet engine build
« Reply #122 on: July 05, 2017, 09:26:32 PM »
Yep, same here. AGM battery and stock starter. No problem.


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76' Supersport

Offline frodef2

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  • Posts: 182
JMR billet engine build
« Reply #123 on: July 19, 2017, 01:14:54 PM »
Finally able to ride the bike again. #$%*ty weather and a nasty flu have kept me from riding for almost a month.



The rotor is now securely fastened to the crank, but other small problems have surfaced. Two NGK d8ea sparkplugs have died on me.  For cylinder 2 and 3. They gave up at almost at the same time.





Still have issues with exhaustleaks messing with the lambda readings. And the clutch is still slipping on full throttle.

I have the APE extra fiber clutch installed, with the springs from the kit.

I have changed the oil since last time. The oil i used during break-in  was motul 3100 20-50 and now i am using redline 20-50.

Frode j




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« Last Edit: July 19, 2017, 01:16:42 PM by FrodeF2 »
76' Supersport

Offline PeWe

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  • Posts: 15,654
  • Bike almost back to the 70's 2015
Re: JMR billet engine build
« Reply #124 on: July 22, 2017, 02:13:07 AM »
Spark plugs have insulators full of soot? Thats the way plugs have died for me.
I use Denso X24ES-U. No problem with NGK D8EA either.

- Checked the fuel level in float bowls? Clear tube the only way to see the reality if plugs are pitch black.
- Ignition correct for 2-3?

Slipping clutch...
- Are the metal plates glass beaded? That is a trick to get Honda discs to grip better. I do not know about APE clutch, though.
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