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Author Topic: 750 drag bikes in progress  (Read 3971 times)

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Offline cbr954

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750 drag bikes in progress
« on: January 03, 2015, 05:09:16 PM »
So figured I would start a build on the two bikes I am building.  One for me and one for my dad.  Will be built for the local 1/8 mile here in Sturgis.  I have two motor builds under way with lots of parts inbound!   Both will be in the 1030cc area for displacement. Dads motor will have many RC parts that I have collected to replicate a motor he had back in the 70's. but also with Carrillo rods.  More to come as parts keep rolling in.
« Last Edit: January 03, 2015, 05:23:48 PM by cbr954 »
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline hotdog

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Re: 750 drag bikes in progress
« Reply #1 on: January 03, 2015, 11:42:22 PM »
subscribed - should be interesting
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Offline springer

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Re: 750 drag bikes in progress
« Reply #2 on: January 04, 2015, 05:24:38 AM »
subscribed
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1975 cb55f
1977 cb550k
2007 suzuki gsx1300r Just a Speed Toy
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Offline SBR-CB400F

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Re: 750 drag bikes in progress
« Reply #3 on: January 04, 2015, 08:32:41 AM »
In the other lane waiting patiently in the water.
Keep us updated, Please  ;)
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1975 cb400f, 14.435 @ 89.01MPH at Willowbank Street Series 28 March 2015
1976 cb400f Nostalgia Drag Bike.
1.871 @ the 60'
8.632 @ 78.44 mph over the 1/8.
13.822 @ 91.91 mph over the 1/4
1977 cb750f2 Resto Project
1973 cb750k4 Chopper project
1971 cb750k1 Restoration Project
1975 cb750f1 Drag bike
1.549 @ 60'
4.425 @ 330'
6.895 @ 98.05MPH  1/8 mile
10.993 @ 116.76MPH  1/4 mile

Offline Greg H

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Re: 750 drag bikes in progress
« Reply #4 on: January 04, 2015, 01:56:33 PM »
Looking good mate . Should be very interesting .
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Offline cbr954

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Re: 750 drag bikes in progress
« Reply #5 on: February 04, 2015, 06:18:56 PM »
While waiting for blocks and crank to get back from machining I decided to build a stand to mount the top cases to my mill/lathe so I can bore them out for the big sleeves. Took a bit of time to set up but it worked well.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline cbr954

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Re: 750 drag bikes in progress
« Reply #6 on: February 18, 2015, 03:32:58 PM »
The second crank finally showed up today so cleaned and checked bearing clearances and assembled with Carrillo rods.  Still waiting on other pieces before getting the bottom ends buttoned up.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline SOHC4 Cafe Racer Fan

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Re: 750 drag bikes in progress
« Reply #7 on: February 18, 2015, 04:11:21 PM »
Carrillo rods!!  Way cool!
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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 jaguar

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Re: 750 drag bikes in progress
« Reply #8 on: February 22, 2015, 07:23:56 AM »
Neat project.
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Offline cbr954

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Re: 750 drag bikes in progress
« Reply #9 on: April 20, 2015, 06:18:53 PM »
Haven't been updating much so will try to catch up.  Bottom end going together, cycle X undercut gears, cycle x heavy duty primary chain and cam chain.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline cbr954

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Re: 750 drag bikes in progress
« Reply #10 on: April 20, 2015, 06:20:21 PM »
Cycle X bored cylinder for the 72mm MTC pistons. 

Comparison of stock 750 piston to the 72mm
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline cbr954

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Re: 750 drag bikes in progress
« Reply #11 on: April 20, 2015, 06:26:52 PM »
Opened the chambers up to the new pistons.  I installed oversize intakes, had to do some sinking of the valves in the seats to get valve to valve clearance.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline cbr954

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Re: 750 drag bikes in progress
« Reply #12 on: April 20, 2015, 06:28:46 PM »
After a bunch of claying for piston to head clearance and piston to valve clearance she is finally together.  That is a RC327 cam ;)
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline cbr954

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Re: 750 drag bikes in progress
« Reply #13 on: April 20, 2015, 06:31:26 PM »
Back in the frame and had it running last weekend.  Have some issues to work out on the old CR33 carbs.  Had to run the CR31 carbs off of my other bike so  could hear it run.   Thats an RC exhaust.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline Stev-o

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Re: 750 drag bikes in progress
« Reply #14 on: April 20, 2015, 07:04:42 PM »
Subscribed. Are you able to post a video? We would love to hear it.
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'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline cbr954

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Re: 750 drag bikes in progress
« Reply #15 on: April 20, 2015, 07:28:41 PM »
Cant seem to get it to load on here.  Sound is not the best cant seem to get good true sound.  Here is a link that should work.https://www.facebook.com/dnold1/videos/vb.100000565338178/1036792453016256/?type=2&theater  Dont mind the hesitation I am still in a fight with the carbs >:(
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline Tews19

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Re: 750 drag bikes in progress
« Reply #16 on: April 20, 2015, 08:07:27 PM »
Some fast work you do!
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Offline johno

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Re: 750 drag bikes in progress
« Reply #17 on: April 21, 2015, 04:42:42 AM »
Bike sounds nice CBR,    easy tell which cam you have, cant beat a nice lumpy cam for a blood rush.
just curious, what size inlet and exhaust valves did you put in ?
cheers johno
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Offline cbr954

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Re: 750 drag bikes in progress
« Reply #18 on: April 21, 2015, 06:13:40 AM »
johno,  33.5mm intake and stock exhaust.  Its nothing fancy.  Couldn't afford a good head right away.  Did my own porting and valve work.  Checked my work as I went with my home made flow bench.  No numbers just comparison readings with a manometer.  I got comparable readings to a RC head I have.   Hopefully if things go right I can afford a good head from Mike sometime, but for now this will get me up and running and get me to the track.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline BPellerine

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Re: 750 drag bikes in progress
« Reply #19 on: April 21, 2015, 02:26:38 PM »
nice to see that bike running again ,cool dragbike!bill
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Offline cbr954

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Re: 750 drag bikes in progress
« Reply #20 on: May 03, 2015, 06:08:56 PM »
Got the wheelie bars mounted.  Couple of misc things to finish up and hopefully ready for some test and tune this next weekend when the local track opens up for the year.
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03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline SOHC4 Cafe Racer Fan

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Re: 750 drag bikes in progress
« Reply #21 on: May 03, 2015, 06:39:40 PM »
I love the Old School Cool of that seat. 

Have fun draggin!
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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
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