Topic: 1974 CB550. Racetech Monoshock. JMR Head. Built Engine. "BLAC"

[BLAC]

Bryan, If you are removing those valves, ease them super carefully through the seals, or consider not reusing them. Had to take my Z1 apart and replace those because they got damaged on a disassembly and reassembly. 

This is part of why I'm putting the motor on hold, I dont have enough experience in engine work to feel comfortable messing with this stuff outside of simple assembly.  The seals are brand new red Viton seals so I'm not sure if they are as fragile as stockers, but I'm not sure...

Im getting closer and closer to that point of "just take the motor and a pile of cash and give it back to me running" 

[SOHC4 Cafe Racer Fan]

Especially when it's not a stock refresh and you have invested some significant coin in go fast parts.

[BLAC]

Im getting closer and closer to that point of "just take the motor and a pile of cash and give it back to me running" 

There's no shame in having a pro do a pro's work. Especially given what you've spent thus far on the motor. Custom motors demand extensive knowledge and experience to make them go fast, reliably, and repeatedly.

Totally, I'm not ashamed to get help, I am just having a hard time finding it and would rather not ship my motor around the country If I could help it. 

[joeyvans]

Totally, I'm not ashamed to get help, I am just having a hard time finding it and would rather not ship my motor around the country If I could help it.

Cal is probably jumping in his Merc as we speak. Road trip!



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[BLAC]

Totally, I'm not ashamed to get help, I am just having a hard time finding it and would rather not ship my motor around the country If I could help it.

Cal is probably jumping in his Merc as we speak. Road trip!

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Hahaha i hope so!  I just spoke with APE and they do piston milling, but they wont take the motor and do the measurements or anything beyond the milling itself, so I would have to get everything sorted and then just take them the pistons and the specs.  Email out to MRieck to see if he wants to get reacquainted with my engine..

 

[Camrector]

Bud I know exactly how you feel. I was in the same place a few months ago with my 592 motor. Well I packed it all up and sent it to Mark (Hondaman) Paris. Today it all came back. 592cc, 12-1cr, JMR stage 4, megacycle 126-20, lightened balanced APE crank, and Fast by Gast race cut gears.
To much money invested into this to leave anything to chance. She is dialed in and ready. Thanks Hondaman!

[BLAC]

Bud I know exactly how you feel. I was in the same place a few months ago with my 592 motor. Well I packed it all up and sent it to Mark (Hondaman) Paris. Today it all came back. 592cc, 12-1cr, JMR stage 4, megacycle 126-20, lightened balanced APE crank, and Fast by Gast race cut gears.
To much money invested into this to leave anything to chance. She is dialed in and ready. Thanks Hondaman!

That's awesome, looks great too!

The bottom end was pretty straight forward, plastiguage, torque rods and mains to spec and call it a day... the machining with the pistons is too much for me to do on my own. 

I just hate the feeling of not knowing what I don't know.  Flying blind up in here! 

[754]

Beg or borrow a head to mark the piston,  then it will be easy.

[BLAC]

Beg or borrow a head to mark the piston,  then it will be easy.

Ah great idea, that will help a ton if I can find one!

now off to draft my craigslist ad "looking for head in LA".  wish me luck! 

[BLAC]

Bryan - I've got a "bin" head if that would help. Text me an address and I'll ship it off.

your kindness knows no bounds

[BLAC]

Wait until you see the invoice for S&H then say that! 

It's going to be flying private, won't it.. z

[754]

When you get the head, guides must be straight, loose ok.
Sharpen up a valve stem with head removed to a point on a lathe, or use a rod.
 Install head,maybe old gasket snug it up. Then put pistons at tdc, use tool to make a punch mark.

 This to locate cutter for fly cutting. Need valve diameter plus clearance, valve angle.
Now you are almost ready.. Just need to know how deep, and have a machinist ready, APE in this case.

[NobleHops]

Bryan, you got this. You can do this, you have a lot of smart people to help. Dig in!

[BLAC]

Sounds good frank!  That's how mike explained it as well and we are going to jump on a quick call tomorrow before I dive in and break something.

Thanks for all the help, gotta love the motorcycle family 🙌🏼

[SOHC4 Cafe Racer Fan]

My brother, you have big brass ones!  Kick-ass!

[JoeCooley]

I have a head laying around if you want it. Pretty sure its a 550, maybe 500. Either way, its yours if you want it. Just drive down and pick it up. Maybe we can do a trade?

[RAFster122s]

Is the reason he will not use his head that he will be using each intake & exhaust with his modified punch to mark for clearance?  Can doing this can damage a valve guide?  It would be work, probably too much to disassemble his rebuilt head, not to mention likely damage  to a valve guide seal in assembly and disassembly?

If you decked your rebuilt head it would be important to know this amount wouldn't it?  It would affect the depth of your cut, right? This holds true for the junk head would require you to know the height of mating surface to the deepest spot or a reference point in the head's dome for comparison between the two heads?   Or is it a measurement of the thickness(height) between the mating surface of the head to cylinders and mating surface of head to camshaft cover?
I am trying to wrap my head around the measurements between the two heads where variation between the two will impact the measurements needed for the depth of cut between your JMR breathed upon head and the " junk"  head.

I was going to suggest you be careful how you word a CL ad when seeking a head.  
But, Cal and Joe have offered you a junk head they have lying about to use for those measurements, saving you from needing to place a seeking/wanted ad for a head.

[BLAC]

I made progress on my rear sets today.  I'm really happy with how they turned out.

If no one sees something fundamentally flawed in this set up let me know, I'm thinking about welding it up tomorrow 

[RAFster122s]

BLAC,  looks really good to me.  Given much thought how you will integrate a rear brake switch into the rear sets?  Going to use a "waterproof" microswitch with a lever arm off a cam on your brake lever or something to utilize the stock (pull) plunger switch? Just spitballing...  No clue how it is normally tackled.
Cal has built several with rearsets so, imagine he can share his solutions if you do not have a solution in mind.

Cal, thanks for the explanation on the cover...
 
Looking good ,  I hope the 10% taking 90% of the time will not be the case.

[DaveBarbier]

Hey Blac, might be interested in this video and others from this guy Jafromobile. He's not working on a bike motor, but the theories are the same. This video is about valve clearance and at the end, marking pistons for fly cutting. He keeps the valves in. There is another video where he remeasures after fly cutting and finds that he has to go a bit further. I think it's the next in the series. Anyway, check him out if you're interested. I learned a lot from watching his videos.

[slikwilli420]

Forget the rear brake switch. There should no instance where you are applying only the rear brake. On a bike like this you should be using front brake almost exclusively. Unless you really know how to use it a rear will only get you in trouble.

[540nova]

Forget the rear brake switch. There should no instance where you are applying only the rear brake. On a bike like this you should be using front brake almost exclusively. Unless you really know how to use it a rear will only get you in trouble.

Sitting at a stop sign or red light, on a steep hill.

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[bwaller]

Just so you're aware, that placement is a tad "aggressive". Meaning cramped, and uncomfortable in no time! It's about the exact spot I use for my racebike and I'd grind through an engine case before hitting a peg. Take this with a grain of salt if you choose, but for the most comfort, 2-3" directly under the swingarm pivot puts your feet under your mass so adding weight to the pegs in turns is most comfortable. Feel free to tell me where to go, I've heard it before.  Two pics, one for the track, one for the street. Another thought about needing a rear brake switch is for passing a safety for licensing, methinks you'll need. Move the switch brackets/spring inside the frame as in lower pic.





 

[BLAC]

Thanks everyone for the thoughts and video!

I agree the position is on the aggressive side, but I'm young and dumb and ride sport bikes more than anything else so I'm used to the abuse... at least for now.

(i also fixed the image sizing on one of the photos, not sure why it posted in a massive size)

[bwaller]

Yeah true, you young dumb guys are flexible.  Have at it, it'll be just fine.

Cal, exactly what happened, except it was breakfast out. My gang knows I'm an early riser!