Topic: Paddy - '78 CB750 - Version 3.0 Coming Soon!

[SOHC Digger]

I had the same issue and I would never use anything but soda on engine parts again.  It might take more time and energy, but having glass beads cause your engine to fail is a chance nobody should take. 

[Terry in Australia]

Not wanting to add to your misery mate, but the only way you can be totally sure that you've removed all the blasting media, metal filings etc is to completely strip your engine down to the bare cases and flush out all the oilways, then thoroughly wash every part in a parts washer, strip and flush your oil pump, oiltank and lines. Half-arse it, and risk damaging it again. Cheers, Terry.  

[cheapride]

This really sucks man.  I am learning from you and really hope my engine runs fine.  I too have not done a motor before and am so very nervous to start it up for the first time.  Would an inspection under the valve tappet covers after the first start up find this out or would the assembly lube still be covering everything?

 
The benefit of pulling the tappet caps and watching for oil is that within a few moments there wil be oil everywhere and you can say whew.

The problem is that if you don't see oil within a few moments, you don't really know anything. Maybe a few more moments and you'll get oil. Maybe you'll never get oil and you have to dismount and disssemble. Ony to find out that had you waited another moment you'd have oil. Or had you waited another moment you'd had a boat anchor.

Its a frustrating trick.

Could you turn of the kill switch and hit the starter button and get pressure though the head without the engine running or does the engine have to be running to build up the pressure?

[MRieck]

This really sucks man.  I am learning from you and really hope my engine runs fine.  I too have not done a motor before and am so very nervous to start it up for the first time.  Would an inspection under the valve tappet covers after the first start up find this out or would the assembly lube still be covering everything?

 
The benefit of pulling the tappet caps and watching for oil is that within a few moments there wil be oil everywhere and you can say whew.

The problem is that if you don't see oil within a few moments, you don't really know anything. Maybe a few more moments and you'll get oil. Maybe you'll never get oil and you have to dismount and disssemble. Ony to find out that had you waited another moment you'd have oil. Or had you waited another moment you'd had a boat anchor.

Its a frustrating trick.

Could you turn of the kill switch and hit the starter button and get pressure though the head without the engine running or does the engine have to be running to build up the pressure?

That will work (just pull the plugs and disconnect the ignition points/pick up leads). If he had one of the frame kits he could remove the cam cover and physically verify oil is flowing.

[theofam]

Sounds like I should pop open the motor.  Was hoping not to, but I understand your opinions based on the pics I've provided.  I did have quite a few shavings in there.  I won't know how many more are lurking if I don't split the case.

I was hoping for a quick media blasting turn around from my guy that would allow me to get the head and cylinder to my machinist today before my kids' spring break.  Didn't happen.  So, I'll get those parts to the machinist in a week and a half.  From that point, I'm at least 7-10 days for the machinist to do his thing. 

That'll give me the first part of April to open the case, at which point I'll have it media blasted again.  I've sustained a couple paint chips during assembly/disassembly.  Even marred the paint by the oil galley when I hit the cylinder upward with a rubber mallet.  So, I've come too far for it to not be dang-near perfect.  I'll just redo all the engine paint.  What's an extra few days at this point?

I'll be out of pocket hanging with my kids until early April.  Until then, thanks to each of you who has provided encouragement, guidance and advice (even when I didn't like what I read)!

[Terry in Australia]

When you get your cases, head and cylinder block back from the blasters, submerge them in a tub full of warm soapy water and use paint brushes, bore brushes and pipe cleaners etc to remove every single grain of grit from the oilways and all the internal threads.

Flush them again with your garden hose, and they'll be good to go. When you empty the tub you'll probably be shocked by the quantity of blasting media present, my last set of cases I had blasted (on my blue K2) left around a cup full of grit behind. Scary.

Make sure you thoroughly wash every internal engine part in solvent degreaser and strip and flush your oil pump to remove any blasting media that might be hiding there, and flush your oil lines and oil tank, I've no doubt that it will have blasting media present. Best of luck! Cheers, Terry.  

[Old75_ratafe]

I'm with Terry if this were a car engine a mandatory hot tanking would be called for after blasting and machining like this for this exact reason.  After watching this play out I am defiantly going the soda blasting route if I strip my cases.

[I Zombie]

I'm with Terry if this were a car engine a mandatory hot tanking would be called for after blasting and machining like this for this exact reason.  After watching this play out I am defiantly going the soda blasting route if I strip my cases.

Does your machinist have a hot tank or larger parts washer? I had a local tranny shop do mine. They have whats basically an industial dish washer, for lack of a better example. They did my cases, block & head, (for a case of beer) after I had chem stripped all the paint & gunk off them. Should be a good way to remove the excess blasting material.

[MCRider]

I'm with Terry if this were a car engine a mandatory hot tanking would be called for after blasting and machining like this for this exact reason.  After watching this play out I am defiantly going the soda blasting route if I strip my cases.

Does your machinist have a hot tank or larger parts washer? I had a local tranny shop do mine. They have whats basically an industial dish washer, for lack of a better example. They did my cases, block & head, (for a case of beer) after I had chem stripped all the paint & gunk off them. Should be a good way to remove the excess blasting material.

Having had 3 cases plastic bead blasted, I'd say you can't get away without becoming personally invovled. You have to use a brush on every screw hole. There wil be media packed in the corners that automatic washers just won't get out. It's like thanksgiving. 10 hours prep, 45 minutes to eat it and 10 hours to clean up. Still, hard media is the only way to truly strip it. Having a soda blaster, home unit, it wouldn't touch it.

My blaster guy has a industrial soda blaster, but he wouldn't use it on the cases. They use so much pressure they wouldn't be able to hold the case still while blasting. So it was plastic beads.  I was disappointed he wouldn't use his soda on my cases, maybe someone else will.

[mrrch]

Even without having my cases blasted I went thru and sprayed brake cleaner and air into every hole & passage.

[Old75_ratafe]

I'm with Terry if this were a car engine a mandatory hot tanking would be called for after blasting and machining like this for this exact reason.  After watching this play out I am defiantly going the soda blasting route if I strip my cases.

Does your machinist have a hot tank or larger parts washer? I had a local tranny shop do mine. They have whats basically an industial dish washer, for lack of a better example. They did my cases, block & head, (for a case of beer) after I had chem stripped all the paint & gunk off them. Should be a good way to remove the excess blasting material.

Having had 3 cases plastic bead blasted, I'd say you can't get away without becoming personally invovled. You have to use a brush on every screw hole. There wil be media packed in the corners that automatic washers just won't get out. It's like thanksgiving. 10 hours prep, 45 minutes to eat it and 10 hours to clean up. Still, hard media is the only way to truly strip it. Having a soda blaster, home unit, it wouldn't touch it.

My blaster guy has a industrial soda blaster, but he wouldn't use it on the cases. They use so much pressure they wouldn't be able to hold the case still while blasting. So it was plastic beads.  I was disappointed he wouldn't use his soda on my cases, maybe someone else will.

Weird I've seen guys use home made units in their drive way to do this.  In fact I was under the impression soda blasting was better on aluminum as it would not warp or eat into the aluminum???  I forget who but I know a member here did his carbs with one.  It makes a mess in the driveway but only takes a garden hose to get ride of (or the next rain).

[Terry in Australia]

I don't think you need to worry about warping your cases mate, and Pops Yoshimura blasted his race engines with really coarse abrasive grit to increase the surface area of the metal, which aided cooling, so if anything, using a really coarse grit can actually be beneficial.

Soda is probably fine as long as you thoroughly wash it out of everything, and better on carbs, I buggered a set of K4 carbs by beadblasting them years ago, they looked great, but I managed to block all the idle circuits and the bike ran like crap.

I like the idea of hydra-blasting, Cliff (maduncle) had his 450 cases done recently and I like the fact that they come out almost shiny. If I had mine hydra blasted, I'd be tempted not to paint them. Cheers, Terry.

[MCRider]

I'm with Terry if this were a car engine a mandatory hot tanking would be called for after blasting and machining like this for this exact reason.  After watching this play out I am defiantly going the soda blasting route if I strip my cases.

Does your machinist have a hot tank or larger parts washer? I had a local tranny shop do mine. They have whats basically an industial dish washer, for lack of a better example. They did my cases, block & head, (for a case of beer) after I had chem stripped all the paint & gunk off them. Should be a good way to remove the excess blasting material.

Having had 3 cases plastic bead blasted, I'd say you can't get away without becoming personally invovled. You have to use a brush on every screw hole. There wil be media packed in the corners that automatic washers just won't get out. It's like thanksgiving. 10 hours prep, 45 minutes to eat it and 10 hours to clean up. Still, hard media is the only way to truly strip it. Having a soda blaster, home unit, it wouldn't touch it.

My blaster guy has a industrial soda blaster, but he wouldn't use it on the cases. They use so much pressure they wouldn't be able to hold the case still while blasting. So it was plastic beads.  I was disappointed he wouldn't use his soda on my cases, maybe someone else will.

Weird I've seen guys use home made units in their drive way to do this.  In fact I was under the impression soda blasting was better on aluminum as it would not warp or eat into the aluminum???  I forget who but I know a member here did his carbs with one.  It makes a mess in the driveway but only takes a garden hose to get ride of (or the next rain).

The carbs guy could have been me. I have a Harbor Freight unit and I blasted my carbs and told about it here. Haven't started the bike yet. But i cleaned the carbs inside and out, all the brasses etc, rinsed them in the sink. They appear to be fully serviceable and quite clean.

AS to cases, I've blasted many. It will take the lacquer off of sidecovers, slowly. But it won't take the paint off of crankcases. AS far as being better, people have been sand and bead blasting crankcases without harm for eternity. They just need to be thouroughly cleaned.

[Old75_ratafe]

lol actually good chance it was you MC.

[GK]

I don't think you need to worry about warping your cases mate, and Pops Yoshimura blasted his race engines with really coarse abrasive grit to increase the surface area of the metal, which aided cooling, so if anything, using a really coarse grit can actually be beneficial.

Soda is probably fine as long as you thoroughly wash it out of everything, and better on carbs, I buggered a set of K4 carbs by beadblasting them years ago, they looked great, but I managed to block all the idle circuits and the bike ran like crap.

I like the idea of hydra-blasting, Cliff (maduncle) had his 450 cases done recently and I like the fact that they come out almost shiny. If I had mine hydra blasted, I'd be tempted not to paint them. Cheers, Terry.

Rick.b has a cb400 build in here somewhere Terry and used  Woodys hydroblasting in melbourne (same guy i'm using at the moment) he has had oil leak issues and has ridden it for two years and the cases are still like brand new no staining and still shining like a top, when hydroblasted the cases become impervious to oil or other substances, this guy guarentees his cleanup afterwards being a bike enthusiast, but I will still be going over my cases with a fine tooth comb

[Terry in Australia]

I don't think you need to worry about warping your cases mate, and Pops Yoshimura blasted his race engines with really coarse abrasive grit to increase the surface area of the metal, which aided cooling, so if anything, using a really coarse grit can actually be beneficial.

Soda is probably fine as long as you thoroughly wash it out of everything, and better on carbs, I buggered a set of K4 carbs by beadblasting them years ago, they looked great, but I managed to block all the idle circuits and the bike ran like crap.

I like the idea of hydra-blasting, Cliff (maduncle) had his 450 cases done recently and I like the fact that they come out almost shiny. If I had mine hydra blasted, I'd be tempted not to paint them. Cheers, Terry.

Rick.b has a cb400 build in here somewhere Terry and used  Woodys hydroblasting in melbourne (same guy i'm using at the moment) he has had oil leak issues and has ridden it for two years and the cases are still like brand new no staining and still shining like a top, when hydroblasted the cases become impervious to oil or other substances, this guy guarentees his cleanup afterwards being a bike enthusiast, but I will still be going over my cases with a fine tooth comb

Thanks mate, it looks like a plan! Cheers, Terry.

[theofam]

Yesterday I started open-heart surgery on Paddy.  As I pulled the starter, I wondered if I used the correct hole to route the starter's power cable through.  Is it the big rectangle, or the circular hole?





Once I pulled the case halves apart, everything looked pretty tidy.  No metal flakes laying around.







I did, however, find some plastic blasting media lurking in a couple places, but nothing close to the amount I found piled in the oil galley's cap (photo above several posts).





My brand new main bearings aren't anymore.  It's as if they've some of the media melted to them.  I'll order more.



And I think I learned Hondabond and rubber don't play well based on the appearance of this o-ring on the oil channel between the top and bottom cases:



So, I think I'll also order primary and cam chains just in case they got tweaked/stretched when I tried (although gently) kicking the motor over after it sat post-ride.  You may recall it ran all the way home, but when I tried to kick it over the next day it was seized due to rocker arms that got a little toasty on the cam.

[theofam]

Today has been generally bad news on Paddy.  I reminded myself, however, that I shouldn't be in a funk.  If my problems today are my biggest issues, life doesn't suck.

I started out by taking the cases to my media blaster.  I spoke with him yesterday, explained I have a pretty good feel for all the oil channels now, and asked if I could tape up the motor this time.  He said, "Sure!"

This morning they set me up on a 55-gallon drum with tape, putty (for oil passages), and a rag with Xylol to clean any oil residue prior to taping.



You may notice my head and cylinder at the bottom of the pic at the far left.  They were ready for me to take home.

I taped up the bosses for the main bearings:



Stuffed some putty where the o-rings go on the 2 & 3 cylinder studs then taped them up:



And finished by puttying and taping the other various oil orifices.

Then, it was time to take the head and cylinder home for cleaning.  I saw the guy helping me shaking the head, and it was snowing plastic media.  He looked concerned.  Although I expected some media, I couldn't figure out why all that would be coming out given they'd taped it up.

I asked him if we could take the tape off there and blow it out with an air gun.  He obliged by taking me over to an employee using an air gun to blow the trunk out of a recently blasted Cutlass.  Here's what the "taped" head yielded when uncovered.



Media EVERYWHERE!  The air gun did a decent job, but I was pissed when I untaped the bottom of the head and found these:



Two deep razor-blade gashes to my gasket surface.     I showed it to Air Gun Guy, and he didn't have much comment.  More on that later.  Air Gun Guy told me his dad chem dips all his stuff when rebuilding motors, since the media often plugs oil channels.  He recommended I go two doors down to Blue Oval Performance, a full machine shop that could clean it up.

On my way out, I showed the main guy the razor blade slits, and you could see the color leave his face.  He explained he farmed the tape job out to the "new guy" (a.k.a. Air Gun Guy) and should have watched him closer.  I guess that's why Air Gun Guy didn't have much to say earlier - he knew he'd f'd up.

Frustrated, I walked a couple doors down to Blue Oval Performance - a cool machine shop specializing in Ford Shelbys, Mustangs and Cobras.  Never even knew it was there.  The owner Rob was very helpful.  He immediately noticed my #4 exhaust valve is BENT!    The white stuff around the edge of the valve is daylight seeping through.



He also said the shop that decked my head during rebuild #1 dragged metal across the head during the process, as evidenced by the semi-circle marks that appear three times across the head:



In the above pic you can also see media stuck in the bent valve.  Why?  Because the media fits in the opening.

I decided Rob was my guy.  I wasn't going to drive the 40 minutes north to the shop that did my cylinder and head work.  I was ticked about the poor deck job, and Rob seemed to know his stuff.  He said middle of next week I'll know if I need to order any more valves and he'll have some initial feedback for me.  I told him I'd drop off my pistons for him to ensure they still fit OK in the cylinder sleeves.  I also want him to see if my #4 piston is OK given the bent valve.

I'm in a holding pattern until next week. That'll give me time to find and order parts; take the oil pump apart to see if it's hiding any metal shavings or plastic media; clean out the oil lines; and take a closer look at the motor's crank, primary and counter shafts, transmission, clutch and kickstarter.

Here's to hoping you're reading this after a nice spin on your bike today - sure wish I was able to!

[MCRider]

Man what a day!

How'd the valve get bent?

[MCRider]

Guess it never even occurred to me to blast the cases on the inside. The three I had done were bolted together so the only thing that got inside was the overspray. That was bad enough for clean up.. Didn't want anything to hit the bearing lands.

[theofam]

MCRider, they don't blast the inside of the cases, but that media gets everywhere, which is why I used putty and tape on the oil channels. 

I'm not sure how the valve got bent.  I just looked at the piston and there is nothing to suggest it hit the piston.  I guess it's possible I bent it when the motor was seized.  Since the cam was frozen, and I applied pressure to the kickstarter to see if it would turn over the following day, maybe the exhaust valve was open and the piston pushed against it.  Only thing I can figure since it ran until I parked it.

[MCRider]

MCRider, they don't blast the inside of the cases, but that media gets everywhere, which is why I used putty and tape on the oil channels. 

I'm not sure how the valve got bent.  I just looked at the piston and there is nothing to suggest it hit the piston.  I guess it's possible I bent it when the motor was seized.  Since the cam was frozen, and I applied pressure to the kickstarter to see if it would turn over the following day, maybe the exhaust valve was open and the piston pushed against it.  Only thing I can figure since it ran until I parked it.

Makes me worry about mine. 

But the cam chain wasn't broken? The crank couldn't turn, pistons go up, unless the cam was turning too.

Oh well let us know, as you are.

[brandEn]

That main oil gallery O ring looks like it was pinched. Is that even possible?

[theofam]

MCRider, I agree.  My suggestion for how it was bent doesn't seem plausible.  Not sure how it happened.

brandEn, you're right, it does look pinched.  I don't have the case halves in front of me to see how that could have occurred.  Suffice it to say if it's possible to screw it up, I probably did it.

I'm learning at the rate of serious cash depletion.

[Old75_ratafe]

Like I said there is a reason hotrod shops hot tank engines.  Guess we all learned a lesson (unfortunately the hard way) from you.  Good luck on the rebuild.  I would make the first shop pay for the resurfacing personally.