Author Topic: JMR billet engine build  (Read 22708 times)

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Offline frodef2

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JMR billet engine build
« on: February 22, 2017, 12:40:39 PM »
So, back in 2014/15 i started to gather parts to build a high power cb750 engine.
In February of 2015 i had gathered all parts and started the assembly.

I had the case machined to accept the JMR billet block, and then powdercoated
I received the cases back from the powdercoater cleaned and nice. I re cleaned everything myself, as the coater told me he had to blast the cases for powder prep. I finished the assembly of the engine and even installed it in the frame.

The thing is, i had a bad feeling about the cleanliness of the powdercoater even after i had recleaned the cases. So i ordered a snake cam on ebay to inspect the oil gallerys.

First i inspected the main crank oil gallery, and i found sandblasting sand at the generator cover side of the oil gallery. 

I am was so bummed out by my crappy inspection and assumption that the cases were clean. That i left the engine in its assembled but "graveled" state until now.

The pewee video in the hi-po forum made me want to get it right.

So here are the pictures from the dismantling



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« Last Edit: February 22, 2017, 12:55:58 PM by FrodeF2 »
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Offline Darren Jakal

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Re: JMR billet engine build
« Reply #1 on: February 22, 2017, 12:45:49 PM »
Let's see.

Offline frodef2

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Re: JMR billet engine build
« Reply #2 on: February 22, 2017, 01:02:39 PM »
This is the state the bike has been in the last two years






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Offline SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #3 on: February 22, 2017, 01:57:26 PM »
Better to find out now than LATER.
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)

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2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
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Offline JoeCooley

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Re: JMR billet engine build
« Reply #4 on: February 22, 2017, 03:12:10 PM »
Those are nice blocks. What size pistons are you running? They look huge! 😲
Joe in San Diego - Quick Cyles
78 CB750K 836cc Highway Racer - http://forums.sohc4.net/index.php/topic,162264.0.html

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Offline camera7

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Re: JMR billet engine build
« Reply #5 on: February 23, 2017, 05:15:23 AM »
Where's e would you find these new and improved cam tensioner?


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Offline camera7

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Re: JMR billet engine build
« Reply #6 on: February 23, 2017, 05:16:10 AM »
What is a JMR billet


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Offline frodef2

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Re: JMR billet engine build
« Reply #7 on: February 23, 2017, 05:47:20 AM »
It is a cb750 sohc engine with these cylinders:

http://forums.sohc4.net/index.php?topic=49438


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Offline 70CB750

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Re: JMR billet engine build
« Reply #8 on: February 23, 2017, 06:29:16 AM »
Following

Offline frodef2

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Re: JMR billet engine build
« Reply #9 on: February 27, 2017, 11:53:38 AM »
Today i removed the rest of the parts from the bottom half pf the case, and cleaned the gallerys on the top half.

A decent ammount of sand was removed from the plug area of both the generator plug and the filter area plug.





Next out is the gearbox oil gallery, and the main oil gallery in the bottom case half.




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Offline SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #10 on: February 27, 2017, 01:12:43 PM »
This has to be a pain in the butt, but much better than ruining this awesome big block by not clearing the sand.
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 innovativems

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Re: JMR billet engine build
« Reply #11 on: February 27, 2017, 01:20:03 PM »
Fast progress!


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Offline MRieck

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Re: JMR billet engine build
« Reply #12 on: February 27, 2017, 07:33:56 PM »
Those are nice blocks. What size pistons are you running? They look huge! 😲
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Offline frodef2

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Re: JMR billet engine build
« Reply #13 on: March 01, 2017, 11:52:12 AM »
Just came back from the garage after cleaning and inspecting the bottom half.

Absolutely no "gravel" in sight.

I also managed to get the the bottom half of the engine together, up to the point where i noticed my torque wrenches where missing.

The bottom is only snugged together right now to get the sealant squeezed.

Frode j


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Offline frodef2

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Re: JMR billet engine build
« Reply #14 on: March 02, 2017, 11:48:25 AM »
Back from the garage again. Torqued the main bearing nuts to 20 ft-lb in 3 steps. And the 6mm bolts to 10Nm in 3 steps.

I also fitted a 90degree bend to the oil pressure switch location. I will be using a pressure transducer to be able to see the actual oil pressure on my motogadget speedo.




The next step will be mounting the pistons and the cylinder. 
I am not looking forward to getting the flimsy oil rings in without pinching one.



Frode j




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76' Supersport

Offline frodef2

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Re: JMR billet engine build
« Reply #15 on: March 05, 2017, 10:46:38 AM »


Started timing the camshaft. Got the exhaust opening to one degree of the camcard, but the closing is 7 degrees late. I remember getting updated cam specs by email the last time, but i am unable to locate them.




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Offline Don R

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Re: JMR billet engine build
« Reply #16 on: March 05, 2017, 10:55:16 AM »
 Been there myself I have a big bore stroker that needs to come back apart. . That bike is awesome, I can't wait to see it all together.
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Offline frodef2

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JMR billet engine build
« Reply #17 on: March 06, 2017, 01:00:59 PM »



Finished with the cam adjustments. I must say, i am not sure why i need to measure both the opening and the closing of the valve on both intake and exhaust to verify the correct cam adjustment.

I mean, on a single cam engine. If you get one valve opening correct, wouldn't the rest be correct also? Anway, i followed the degreeing guide on the webcam website. And in the end my lobecenter measurement came in 0,5 degree over the cam card. Using the calculations on the webcam site.  Only took 3 hours. Not bad for an IT guy.




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Offline Davez134

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Re: JMR billet engine build
« Reply #18 on: March 07, 2017, 07:45:35 AM »
Looking great! My understanding for degreeing both the intake and exhaust is not so much to verify the opening and closing on the card, but to get the lobe centerlines of both intake and exhaust as close as possible. On my webcam for example neither the opening/closing or centerline matched the card exactly, but I got the centerline on both intake and exhaust to 103.5 degrees. I hope that makes sense.

Offline frodef2

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Re: JMR billet engine build
« Reply #19 on: March 07, 2017, 12:35:36 PM »



Engine in frame, and mock fitted the carbs.




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Offline somesuch

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Re: JMR billet engine build
« Reply #20 on: March 07, 2017, 09:46:24 PM »
need more updates!!! :)

Offline frodef2

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Re: JMR billet engine build
« Reply #21 on: March 11, 2017, 10:10:13 AM »







3 picture updates from today.

Made a fixture plate for the new regulator, dyna 2000 box and the motogadget m unit.




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Offline SOHC4 Cafe Racer Fan

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Re: JMR billet engine build
« Reply #22 on: March 11, 2017, 10:32:40 AM »

Engine in frame, and mock fitted the carbs.
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Are those Mikuni RS34s or larger?
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 #23 on: March 11, 2017, 10:56:21 AM »

Engine in frame, and mock fitted the carbs.
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Are those Mikuni RS34s or larger?

Yes, they are rs34's. Bought them together with the head and cylinders from mr. Rieck.


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76' Supersport

Offline Old Scrambler

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Re: JMR billet engine build
« Reply #24 on: March 11, 2017, 11:26:35 AM »
Its looking REAL good :) :) :) Nice motor work :) :)

Depending on your weight...........you may want to have stronger springs on the shocks ;)
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