Author Topic: 750K2 Hot Rod Revival - Early Christmas  (Read 43167 times)

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Offline MCRider

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Re: 750K2 Hot Rod Revival - 5/20 it Lives :)
« Reply #175 on: September 26, 2019, 12:31:46 PM »
Are either of you Joe or Ron from Indianapolis area?? I'm in indianapolis and have been dialing CR29's for a year +. Would love to chat in person if able sometime.
Kevin Stuhrenberg
812-593-4100

So I'm trying to decide about fuel flow to the CR29s.   The tank currently has a New OEM style dual output petcock with the standard 5.5mm (ish) fuel line.  The Fuel inlet on the CR29s appears to be an 8mm (ish) inlet. 

I'm trying to decide if I'm good just plugging one of the outputs of the petcock and running a single line to the carbs, or if I should get a Y-Adapter to merge the two smaller diameter lines into a single 8mm line?

Thoughts?

Joe
Hi Joe: I had Phaedrus I plumbed with the 2 spigot tap to the CR29s. Used a T and had fuel line everywhere but it worked. Phaedrus II has a single nipple tap, and I used an in line reducer to get the hoses to work. Its a straight shot from the tap to the nipple on the carb ( a little underslung curve. The line goes up into the carb).

So you could close off one, and do the straight shot routine. But you wont have a functioning reserve, I don't think, unless you use both nips on  the tap.
I'm in NW Indy. New Augusta area. Ron  And I have VM29s, not CRs. Oops
« Last Edit: September 26, 2019, 12:37:49 PM by MCRider »
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
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Offline Kstuhren

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Re: 750K2 Hot Rod Revival - Back from Dyno
« Reply #176 on: September 27, 2019, 06:07:30 AM »
Ok. Do either of you have any extra needles or jets you don't need anymore for the CR's? Sudco is my only source at the moment. Working through tuning a 930cc with high lift custom ground cam.

Offline MRieck

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Re: 750K2 Hot Rod Revival - Back from Dyno
« Reply #177 on: September 27, 2019, 06:55:01 AM »
Ok. Do either of you have any extra needles or jets you don't need anymore for the CR's? Sudco is my only source at the moment. Working through tuning a 930cc with high lift custom ground cam.
What needles and jets are you looking for?? I have a lot of CR parts.
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Offline CBJoe

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Re: 750K2 Hot Rod Revival - Back from Dyno
« Reply #178 on: September 27, 2019, 06:56:53 AM »
Ok. Do either of you have any extra needles or jets you don't need anymore for the CR's? Sudco is my only source at the moment. Working through tuning a 930cc with high lift custom ground cam.

Hi Kevin, I live on the East side of Indy in Irvington.  About the best I could do is confirm the jetting I had with CR29s on my 836.  They came to me pretty much set up so I don’t have much tuning experience with them.  I actually sold them to Steve Hoy out at Hoy Cycles in Danville and he’s running them on one of his bikes.

I moved to the Mikuni RS 34s

I’m out of town till Monday but send me a PM if you want to chat.

What kind of issues are you having?


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Offline Kstuhren

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Re: 750K2 Hot Rod Revival - Back from Dyno
« Reply #179 on: September 27, 2019, 07:46:47 AM »
Ok. Do either of you have any extra needles or jets you don't need anymore for the CR's? Sudco is my only source at the moment. Working through tuning a 930cc with high lift custom ground cam.
What needles and jets are you looking for?? I have a lot of CR parts.

Great! Are you local to the Indianapolis area by chance?
I'd like to try some YY7's or 6's or play with the Cutaway's a bit. I've been taking a lot of notes as I test ride but would need to clean them up before I shared them.
The only things I have really confirmed is that the carbs are touchy, one adjustment does affect other circuits, the hesitation I'm experiencing at low load, high throttle opening is not related to ignition type/ timing or coil choice.  Lots of data pointing toward leaning out things but keeping things cool obviously goes with that too. I'll find the right combo eventually I suppose.

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Back from Dyno
« Reply #180 on: September 27, 2019, 08:42:24 AM »
Great! Are you local to the Indianapolis area by chance?
I'd like to try some YY7's or 6's or play with the Cutaway's a bit. I've been taking a lot of notes as I test ride but would need to clean them up before I shared them.
The only things I have really confirmed is that the carbs are touchy, one adjustment does affect other circuits, the hesitation I'm experiencing at low load, high throttle opening is not related to ignition type/ timing or coil choice.  Lots of data pointing toward leaning out things but keeping things cool obviously goes with that too. I'll find the right combo eventually I suppose.

Oh boy I wish Mike was in Indy  ;D....hes up in the North Eastern US.   I'd suggest just PM'ing him what you are looking for to see if he's got some to sell you.

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CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
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Offline MRieck

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Re: 750K2 Hot Rod Revival - Back from Dyno
« Reply #181 on: September 28, 2019, 05:34:08 AM »
 I'm on Cape Cod right now....will check and see what needles I have Sunday afternoon. Joe....maybe I'll go on a world tour when I retire 6/2021. ;D
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Offline CBJoe

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750K2 Hot Rod Revival - Back from Dyno
« Reply #182 on: March 01, 2020, 03:46:42 PM »
Getting ready for the season...I've screwed around with the bike so much since i picked it up from Sparty that I regretfully haven't even ridden it that much.  Hoping to change that this year  ;D

I've just about gotten everything buttoned up and finished good enough for now.  Pretty much completed all the wiring loose ends and installed Joker Machine rear brake stay and arm.  Electrics are working as expected. 

After the Dyno results from last year, I upped the Mikuni Mains from 120 to 125.  I have 122.5s in case that jump is too big.  I took it for a 20 min ride today and it seems to be running great minus a high Idle I need to Work on.   

To Dos:
- Verify carb jetting
- Get idle lower (right now it wants to idle the best arond 1800 RPM.  I'd like to get that down a bit.
- Relocate Horn
- Install Drilled Disk I got from Kenny at CycleX
- Ride the hell out of it to shake out all the quirks

Wants:
- Steering Damper
- Excel Rims

« Last Edit: March 01, 2020, 03:49:28 PM by CBJoe »
'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
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Offline andy750

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #183 on: March 03, 2020, 04:50:43 PM »
Nice work Joe! I am a big fan of Joker Machine parts and really like how the brake stay looks on your bike. I have the adjuster at the back but even that makes a difference.

For high idle I chased this last year and for me it was spark plugs...my 836cc K4 would idle find at rest but after a run it would be 1800 -2000 rm. Changed carb boots/clamps/carbs but in the end it was the plugs  8) Good luck!

Looking forward to your next Dyna run!

Andy
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

Offline lash

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #184 on: March 03, 2020, 05:45:43 PM »


For high idle I chased this last year and for me it was spark plugs...my 836cc K4 would idle find at rest but after a run it would be 1800 -2000 rm. Changed carb boots/clamps/carbs but in the end it was the plugs  8) Good luck!

Looking forward to your next Dyna run!

Andy
[/quote]

What plugs? I am having the same problem with my 836..
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Offline CBJoe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #185 on: March 05, 2020, 12:17:41 PM »
Hi Andy, I can try some new plugs, but this behavior came specifically when I moved to rs34 carbs. So it’s more likely my jetting setup. 

I’m gonna play around with it this weekend hopefully.  It may be something simple




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'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
'65 CB77
'66 CM91 (C90'ish)

Offline andy750

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #186 on: March 05, 2020, 04:39:02 PM »


For high idle I chased this last year and for me it was spark plugs...my 836cc K4 would idle find at rest but after a run it would be 1800 -2000 rm. Changed carb boots/clamps/carbs but in the end it was the plugs  8) Good luck!

Looking forward to your next Dyna run!

Andy

What plugs? I am having the same problem with my 836..
[/quote]

Denso plugs. Changed them out for new NGKs and all was well with the idle. Now I have run Densos for years so not sure what changed maybe just a bad plug and it was a coincidence. BUt changing plugs helped my idle whatever the reason  8)
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

Offline lash

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #187 on: March 05, 2020, 04:56:37 PM »
I have been using NGK D8EA’s only so I guess my problem is something else. I buy them from my Honda dealer so I hope they are not the fake ones!
« Last Edit: March 05, 2020, 04:58:13 PM by lash »
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Offline CBJoe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #188 on: March 05, 2020, 06:40:56 PM »
I have been using NGK D8EA’s only so I guess my problem is something else. I buy them from my Honda dealer so I hope they are not the fake ones!
I’ll have to double check, but I believe these are the same plugs I’m running.


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Offline PeWe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #189 on: March 06, 2020, 10:56:47 AM »
Throttle cables need to be adjusted?
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 CBJoe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #190 on: March 06, 2020, 08:19:39 PM »
Throttle cables need to be adjusted?

Hoy PeWe...temperatures rising in the next two day so i'll play a bit. I have throttle cable free play adjusted pretty well.   I think some of my situation may just be a need to let the bike warm up rich on choke for a bit before coming to warmed up idle temp.  I may look to make a remote idle adjust to assist this.  I totally understand i'm not running the most efficient setup...but it sure sounds good ;) 
'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
'65 CB77
'66 CM91 (C90'ish)

Offline PeWe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #191 on: March 06, 2020, 11:30:10 PM »
Several guys here have adjusted idle to work on a cold engine. It will idle too high when warm.
Idle to be adjusted correct on warm engine. When cold you need to keep the throttle open, or adjust the easy access idle screw to later adjust back when warm.

It depends on the carbs, my Mikuni carbs have increased idle on choke.
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 CBJoe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #192 on: March 07, 2020, 07:51:19 AM »
Several guys here have adjusted idle to work on a cold engine. It will idle too high when warm.
Idle to be adjusted correct on warm engine. When cold you need to keep the throttle open, or adjust the easy access idle screw to later adjust back when warm.

It depends on the carbs, my Mikuni carbs have increased idle on choke.

Thats probably the way to go....I just ordered some pieces to make a remote idle adjuster. 
'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
'65 CB77
'66 CM91 (C90'ish)

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Ready for Spring
« Reply #193 on: March 07, 2020, 11:56:04 AM »
I'm so let down at the moment I don't even know what to say    >:( :'(

While starting the bike up today, I had my old friend the starter clutch come back.  So I went ahead and pulled the cover off and replaced the starter gear with one I got from Bill Benton and also replaced the Rollers and Springs.

Torqued the bolt back down...put the covers on and started the bike up.  It sounds great still....and then it started blowing smoke.

I have no F$()@king clue why.....its never burned a bit of oil.  WTF did it start now?  What could I have done wile replacing starter clutch to cause this?

I had to walk away...I pulled the 1 and 4 plugs and they looked fine.  Engine was too hot to pull the 3&4.

'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
'65 CB77
'66 CM91 (C90'ish)

Offline RAFster122s

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Re: 750K2 Hot Rod Revival - Blowing Smoke :(
« Reply #194 on: March 07, 2020, 01:27:32 PM »
Joe, what happens on a 750 if there is too much oil in the top end?  Can it lead to some of that oil getting sucked into the motor. Your guides are not loose so it would not be past the valve guides. It sounded like it was running on all four so it isn't or shouldn't be unburnt fuel unless your float hung open and you loaded up on fuel in a cylinder. It will smoke from too much fuel.
Not enough fuel to hydrolock a piston or bend a valve one would think. 
David- back in the desert SW!

Offline CBJoe

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750K2 Hot Rod Revival - Blowing Smoke [emoji20]
« Reply #195 on: March 07, 2020, 01:37:41 PM »
It didn't smell like fuel or unburnt fuel.  Was white/blue smoke and smelled like oil smoke.

Heres the plugs....didn't run very long while smoking but Cylinder 2 looks darker.  I'm gonna make a plan of attack and come back later to troubleshoot.   Cylinder 1 on top....




Silver lining....if the head/cylinder comes off its getting further upgrade....but I didn't want to do it this way.
« Last Edit: March 07, 2020, 01:39:58 PM by CBJoe »
'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
'65 CB77
'66 CM91 (C90'ish)

Offline RAFster122s

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Re: 750K2 Hot Rod Revival - Blowing Smoke :(
« Reply #196 on: March 07, 2020, 06:53:38 PM »
Don't jump to conclusions unless your money has been burning it's way outside your wallet already and is refusing to return... Then go buy your lovely bride a gift she will like before you go throwing cash at the problem.  Got a Boroscope? There are several good Android and Apple and PC compatible boroscopes out there that are not a ton of money and they are useful for investigating pipes, motors, plumbing, firearms, and other tight areas... Buy one with good optics and high resolution and newer ones have better LED lights able to light up a dark area without washing out details.
David- back in the desert SW!

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Re: 750K2 Hot Rod Revival - Blowing Smoke :(
« Reply #197 on: March 07, 2020, 06:58:05 PM »
Getting tan deposits on top of #1 and #4 bar.   #2 and #3 both show sooty deposits there but insulators look good. I don't think you can judge #2 that quickly. It is very clean running  so you must have it very well tuned.
David- back in the desert SW!

Offline PeWe

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Re: 750K2 Hot Rod Revival - Blowing Smoke :(
« Reply #198 on: March 07, 2020, 10:27:09 PM »
It was a thread not long ago about high level of oil inside valve cover.
The owner had oil smoke and had thoughts about oil return holes not flowing oil quick enough so oil level raised over guides and engine was smoking. I think it was a CB750 K0.

He noticed MLS head gasket to have small holes, this in combination with thicker HD studs gave less area for the oil to flow back.

I have also seen MLS gasket where oil return holes are smaller than the holes in the cylinder. I'll check that in future builds.
If it has, grind holes to same diameter as cylinder holes.

I do not know the final findings and conclusions on that smoking bike.
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 RAFster122s

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Re: 750K2 Hot Rod Revival - Blowing Smoke :(
« Reply #199 on: March 08, 2020, 12:18:25 AM »
Drop our resident master head porting and tuning expert Mike R and HondaMan a PM or email to see if they might have a moment to consider chiming in on the sudden appearance of smoke and this change.
Probably an electrical problem... ;). Humor...
David- back in the desert SW!