Author Topic: 750K2 Hot Rod Revival - Oil Culprit Found  (Read 15367 times)

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Offline CBJoe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #275 on: February 21, 2021, 02:09:37 pm »
We'll see Jerry...I'm hoping I dont have to do too much work on the bottom end short of removing everything to have the cases bored for the new cylinder.

This already has an APE worked crank and falicon rods.

Lots of planning needed....I just figured its time to take it apart so I can assess and at least get the core engine bits dealt with.

I'm gonna have to go slow on this as its new territory for me.
'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 - Oil Culprit Found
« Reply #276 on: February 21, 2021, 03:12:31 pm »
Sorry to hear that Joe but at least you found the root cause. Can you educate me on the benefits of CALFAB swingarm from motogpwerks?

Good luck!
Andy
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico (CB750K4), 2003 - European Tour (CB750K4), 2004 - SOHC Easy Rider Trip (CB750K4), 2008 - Adirondack Tour 2-up (CB750K4) , 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. VStrom DL1000 2003
4. XLR650L 2006

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

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #277 on: February 21, 2021, 03:23:39 pm »
Hey Andy...its just a nicely made boxed swingarm made specifically for the CB750.  So wheel hub and pivot shaft spacing are all stock.  But its a little longer.  I think 1"???  need to check.

I believe that CALFAB was a company that folded a long ago and chris at motogpwerks picked up....but don't quote me on that. 

here's an older thread where it was discussed. 

http://forums.sohc4.net/index.php?topic=139903.0
'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 - Oil Culprit Found
« Reply #278 on: February 21, 2021, 03:42:49 pm »
Ah I see thank you for the info. I agree it looks a very well made swingarm and if Chris is doing it you know it will be quality.
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico (CB750K4), 2003 - European Tour (CB750K4), 2004 - SOHC Easy Rider Trip (CB750K4), 2008 - Adirondack Tour 2-up (CB750K4) , 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. VStrom DL1000 2003
4. XLR650L 2006

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

Offline CBJoe

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750K2 Hot Rod Revival - Oil Culprit Found
« Reply #279 on: February 21, 2021, 03:52:29 pm »
kind of hard to see...but the exhaust valve guide seal is lifted off the guide for cylinder 3.....




I believe that this all came about after the dyno session where I had then run a bit past where I needed RPM wise.  I know the catastrophic effects of over rev'ing an engine.  Is this a sign of floating a valve?

This changes nothing in my plans...just interesting to see
'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)

Online PeWe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #280 on: February 22, 2021, 04:21:30 am »
I was going to answer "check if valve seal has left the guide".

Clean the head and replace all seals just for sure.
I have never seen a loose valve seal when using the seals included in the gasket kits.
- Is this happen more with KPMI red Viton seals?

I saw one seal last year that has lifted, it sat loose on guide. Kibblewhite 5mm stem kit.

Some of the bronze guides had a little bit play. Not enough to take it apart but definitely not good enough to assemble again. A little bit more than 25.000 km.
Too rich and too lean jetting might have helped to shorten the guide life.

I used another refurbished ported head (K2 style) with stock guides, F2 34mm inlet valves and 28mm KPMI ex.
Chamber volumes 23.7- 23.8cc (old head 24.4cc)

I cranked up the compression with that head giving 101whp, before max 93whp.
Billet block, JE 71.25 mm ordered from Dynoman, around  CR11:1 since chambers were bigger.

I changed cam too, from RC295 profile to Megacycle 125-75.

I have another head ongoing, new stock guides I believe is better on a street bike. KPMI 33.5/28.5 mm valves.
Same chamber volume as my 101whp head. But thinner base gasket this time will increase compression a little bit more.

Lets see if it will give more on the wheel. 105whp and keep the good torque my 101 head gave is my goal.
Or even better, surpass Mike's +106 whp, the value to beat!! ;D

My cheap compression tester showed 197.5 vs 202.5 PSI on last head.
(Old head had around185-190PSI thicker head gasket)

If compression is higher with next head, more power might be around the corner.
Hopefully no pinging.
Cure then is to replace head gasket from 0.75mm to my old 1mm MLS.

The chambers will get a good squish area to avoid it, hopefully it will become true.
I might get the head this week. I'll update my K6 build thread.

Good thing with MLS, use again, again..... Some spray were Viton is worn. I'll use Loctite 3020 after recommendation from my nearby shop.

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #281 on: February 22, 2021, 02:39:37 pm »
Hey Pewe....I'm very much going to need to do some self educating on building this motor.  I've helped Ron (MCrider) with his 915 build in Phaedrus...but when it comes to calculating compression ratios and such I'll need to plan appropriately when gathering parts and such.

Luckily I've already got the RS34s, Megacycle 125-75, and a built bottom end.  Hopefully wont have to redo that stuff much if at all.

Been reading your build in the Billet Block thread. Getting me excited to have one of my own ;)

Cheers, Joe

'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 MRieck

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #282 on: February 22, 2021, 07:53:31 pm »
 Those are OEM brown, Viton guide seals. I suspect more of a bronze guide problem....they do not last very long especially with high lift/duration cams. That one looks like it got caught in the keeper groove and pulled off the guide.
Owner of the "Million Dollar CB"

Online PeWe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #283 on: February 23, 2021, 01:29:07 am »
OK Joe, you'll also aim to beat Mike's Dyno result? ;D
+106whp
(105whp is really good too)

http://forums.sohc4.net/index.php/topic,83748.msg2092142.html#msg2092142

Mike know the recipe.
As often written back in the days: "If you cant beat them, buy them".

100whp is minimum with Mikes Billet block and avoid hall of shame ;D ;D

I hope my next dyno will be OK.
Typical if it will be less than 100 after writing this. ;)

There are some guys with JMR  Billet block equipped street bikes.

Fun with an internal race, entering the good dyno chart zone.
Use rear tire pressure for street.
Not cheating using 3.5BAR instead of maybe 2.5BAR. ;D ;D
« Last Edit: February 23, 2021, 02:56:29 am by PeWe »

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #284 on: February 23, 2021, 04:00:35 pm »
PeWe...I think I'll be happy with over 100whp  ;D  I will be for sure trusting mikes recipe for a good setup. 

These 836 pistons and cylinder look tip top (minus some carbon buildup).  I'll probably just set them aside for a future project or sell.  Everything looked so nice I almost felt bad taking it apart. 

Gonna be worse taking the bottom end apart to bore the top case for the bigger cylinder.  I wish there was a way to just keep it together and mate the block/pistons and head.  I dont think I really need to rework anything in the bottom end unless I find something funky or need to upgrade something to deal with the increased displacement/power.

Heres the specs on the bottom end....probably less than 1000 miles on it

Bottom End Parts and Labor:
Falicon Knife Edge connecting rods with ARP premium bolts
New OEM Honda cam bearings
New OEM Rod bearings
APE H-D Bottom end bolt kit
New OEM Honda primary chain tensioner
APE lightened and balanced crankshaft (balanced for sustained operation to 14,000RPM)
Barnett H-D clutch springs
New OEM Honda clutch fibers and disks
FAST by GAST undercut transmission
'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)

Online PeWe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #285 on: February 24, 2021, 02:51:14 am »
You might have a reason for open the bottom end.
- Primary chains. I did not see them on your list

I use the stronger that Classic Cycle City can provide, at least before.

MessnerMoto has written a thread about stronger primary chains.

He found equal (or same) sold as timing chains for cars. (Audi, Lamborghini...)
Only problem is the lenght, 72 links.
68 links needed so chain has to be cut and riveted again. Do this without a new master link feels scary.

Another alternative is timing chain I gave my almost stock K2, timing chain for old BMW. It is not as strong as the other but stronger than stock.
Available in correct lenght, 68 links.
All this is written in that thread. I added some photos of stock, CCC and BMW chains I bought.
(My K2 build thread has a link to the chain thread)

- The primary hub cush rubbers can be old and hard.

Both my bikes got new. I sent the hub to Germany where they replaced the rubbers and reriveted the hub. Also replacement of the 2 needle bearings at the same time.

There is a cush rubber kit you can order from France discussed on the forum.

CycleX sell a kit too.
Both these use screws to get it together. Strong Loctite can be a good idea to keep them tightened.

Offline MRieck

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #286 on: February 24, 2021, 05:04:43 am »
 I think he has the HD primary chains from Germany in there Per. Easy enough to check by pulling the oil pan.
Owner of the "Million Dollar CB"

Online PeWe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #287 on: February 24, 2021, 05:27:51 am »
Those chains are very durable!
I pulled my pan to measure my chains slack. I was ready to pull engine to replace them when I had cylinder off.
Very little extra slack. 65.4 mm, measured pan gasket surface to stock tensioner flat surface. Did it several times to ensure the good news.

It was a little bit under 65 when installed. First start must have added a little.
Maybe 0.5mm more slack despite tough run in and throttling during carb tests.

They look like these if Joe has not seen them. Camera selfie.
Shiny with rectangular side plates, not 8- shaped as stock.

Good idea to open pan to clean strainer and not find any debris.

« Last Edit: February 24, 2021, 05:33:48 am by PeWe »

Online PeWe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #288 on: February 24, 2021, 05:40:49 am »
Another thing when Billet block is up.
Mine looked really good when I lifted them after 25.000 km. Bores look mostly as when I installed it. A scary moment that ended up in confidence. ;)

Really good idea to find correct jetting on dyno asap and avoid to torture valves, seats and bores with way too rich or lean.

My old head with 5mm stemmed exhaust valves were carbonized.

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #289 on: February 24, 2021, 09:13:45 am »
Hey Per....thanks for the pics.  I will for sure be doing a general inspection of the bottom end.  Unless someone sees a way around it I'll have to split the cases anyway to bore for the block.

I also messaged Mirko as I have one of his cam chain tensioners...but I remember that someone had fitment issues on it with the billet block.  Not sure what the end result of that was.  I have a KA Performance tensioner in there now.  Probably will just reuse it and the cam chain since theres so few miles on it. 

Joe
'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 MRieck

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #290 on: February 24, 2021, 01:32:32 pm »
Hey Per....thanks for the pics.  I will for sure be doing a general inspection of the bottom end.  Unless someone sees a way around it I'll have to split the cases anyway to bore for the block.

I also messaged Mirko as I have one of his cam chain tensioners...but I remember that someone had fitment issues on it with the billet block.  Not sure what the end result of that was.  I have a KA Performance tensioner in there now.  Probably will just reuse it and the cam chain since theres so few miles on it. 

Joe
That was me Joe. Mirko kindly sent me what should be the solution to the problem.
Owner of the "Million Dollar CB"

Offline CBJoe

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Re: 750K2 Hot Rod Revival - Oil Culprit Found
« Reply #291 on: February 24, 2021, 01:38:52 pm »
Hey Per....thanks for the pics.  I will for sure be doing a general inspection of the bottom end.  Unless someone sees a way around it I'll have to split the cases anyway to bore for the block.

I also messaged Mirko as I have one of his cam chain tensioners...but I remember that someone had fitment issues on it with the billet block.  Not sure what the end result of that was.  I have a KA Performance tensioner in there now.  Probably will just reuse it and the cam chain since theres so few miles on it. 

Joe
That was me Joe. Mirko kindly sent me what should be the solution to the problem.

Good to hear Mike...I already have sent him a message, so hopefully he'll help me out the same. Check your PMs....i've got the head ready to come your way. 




'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)