More oil conundrums

[Colorado]

I'm trying to restore a '78 IT400. The old bikes called for 20:1 in the gas and 10W-30W 'SE' type in the gearbox. The newer 50:1 oils confused me, but I finally opted for 32:1 castor in the gas and it worked fine.

For the gearbox I chose 80W gear saver after asking questions locally. It seems okay too, but my recently adjusted clutch is already running out of adjustment so I'm wondering if the different viscosity effected it --- of if the clutch is just going (no slipping yet; engagement is just all the way at the end of the travel).

My main question goes back to the fuel mix though. I'm about to pull the top end and overbore. My Clymers (which calls for 20:1 in the tank) says I should run 16:1 during break in. I'll be breaking in after the cylinder bore, and am not sure what to run then since the newer oils don't run at 20:1 to start with :| :think: This really shouldn't be so complicated!


To complicate further, I saw Klotz oil for sale at Pro Flow and ordered a case of original Techniplate. It should arrive soon. But NOW I'm wondering what blasted ratio to run it at! Is it an older formula that I should return to 20:1 with?
:bang: :bang: :bang:

 

[dirt bike dave]

IMO, 32:1 with any good quality oil and you will be fine.

 

[Colorado]

IMO, 32:1 with any good quality oil and you will be fine.

Thanks Dave, but my question was more complex than that. If 32:1 is always good, why did they used to call for 20:1? If you're right, and 32:1 is always good, are you saying it's also always good for break in? Then why does my Clymers call for 16:1 instead of 20:1 during that period?

Also, do you, or have you, ridden older bikes and applied that philosophy with umblemished results? Don't mean to disparage your opinion, but that is all you offered.

Thanks,
Colorado

 

[mtk]

Your manual was written in the '70s. Oil is a whole lot better today than it was back then. 32:1 is fine.

 

[Colorado]

Your manual was written in the '70s. Oil is a whole lot better today than it was back then. 32:1 is fine.

All the time, guys? Should I maybe do 20:1 for break in to be safe?

Please hold my hand on this one. You're saying run the same oil for break in as after everything's seated?

And what about Klotz original techniplate? How 'original' is it? Is it a 70's vintage formula that ought to move me back to a higher ratio because it's more of a 70's oil, albeit a good one?

Please spell it out. "32:1 with good oil" is already what I decided for general use. I'm asking something more specific now. I'm not worrying about going through a few plugs --- just want to give my old air cooled top end a shot at longevity.

Thanks again!

 

[Jaybird]

Older bike recommendations were to use lots of oil, as in a 20:1 ratio. This was a bit of CYA for the bike mfg's. This meant that the general public was going to use plenty of oil to protect the bearings, etc.. I think the same rational was used for break-in recommendations."the more oil, the better off".
Problem is, if you aren't prepared for jetting the bike, a high oil to fuel ration can cause a lean, hot burn.
You can pick just about any brand of conventional moto pre-mix you want and 32:1 will be adequate protection. You will need to jet for that ration, or any ratio for that matter. Your bike has jets in it now that are suited for a certain ratio/air temp/atmoshpere/etc...but chasing to find that will drive you mad.
Simply decide that 32:1 is a good ratio and build from that with new jetting.

Klotz is a quality oil. You won't go wrong.
Running a different ratio such as 16-20:1 is not going to hurt anything, BUT you will need to jet for it. You will also need to completely rejet and tune if you switch back to 32:1. Much ado about nothing.
I suggest starting, and staying, with 32:1. It will break in just fine, and 20:1 wouldn't be of any great advantage.

 

[dirt bike dave]

Even back in the 70's we safely ran 32:1 on air-cooled bikes with inferior oils to what we have today.

Back then I figured the reason the bike makers put the 20:1 stickers on the new bike tanks and in the owners manual was for two reasons:

1) Like Jaybird says, it was a CYA for them
2) To help their dealers sell more oil!

 

[Colorado]

And now ... the top end

Thanks for the complete response Jaybird, and the added opinion Dave. I feel more confident now.

I pulled the top end last night. The piston is galled on both sides --- ahead of the pin on the right and behind on the left. I also had noticable lateral rocking at the wrist pin, and the carbon staining and fine grooves just below the top ring were worn clean and smooth in a wavy line around the piston. I'll replace the wrist pin and wrist bearing along with the oversize. Is there a way to measure and assure that there's no wear in the connecting rod short of splitting the cases, tearing down the crank, and taking it somewhere? The Clymers doesn't say anything about that. My last IT400 broke the connecting rod at the pin and sent the rod through the piston and cylinder sleeve skirt and both case halves. Total loss!

The top ring had some movement in and out, and could be compressed together, but the bottom one was frozen solid in it's groove. I had to bend it up getting it out, and it wasn't easy. I have some carbon build up inside the piston crown. Is this consistent with everything above, or might it indicate another problem?


Thanks again for your help.

 

[Ol'89r]

I also had noticable lateral rocking at the wrist pin,

Is there a way to measure and assure that there's no wear in the connecting rod short of splitting the cases,

The top ring had some movement in and out, and could be compressed together, but the bottom one was frozen solid in it's groove. I had to bend it up getting it out, and it wasn't easy. I have some carbon build up inside the piston crown. Is this consistent with everything above, or might it indicate another problem?
QUOTE]

Colorado.

Gotta agree with dirt bike dave, mtk and Jaybird. The oils we have today are much better than what we had in the 70's. May I suggest using a synthetic. I have had very good luck with YamaLube R at 32:1. Have used this oil in both modern 2 strokes and vintage bikes with great results. One of the problems with the old castor based oils is the tendency to gum up the inside of your engine. This can cause your sticky ring problem and also has more carbon build up. The modern oils burn more complete. I can remember when everyone ran Blenzol. That stuff made your eyes water. :yikes:

If your engine is properly set up with all of the right clearances, 32:1 is sufficient as a break in ratio.

Your wrist pin and rod bearing should have clearance when you rock them. But, you should not have any up and down movement. To check for this, put the rod at top dead center and grab the top of the rod with both hands. Rest the heels of your hands on the base gasket surface and try to move the rod straight up and down. If you feel any movement or hear any clicking in the big end bearing, you should replace it. If it feels tight, you should be ok. Same with the small end bearing.

Just my $ .02

 

[Colorado]

Colorado.

Gotta agree with dirt bike dave, mtk and Jaybird. The oils we have today are much better than what we had in the 70's. May I suggest using a synthetic. I have had very good luck with YamaLube R at 32:1. Have used this oil in both modern 2 strokes and vintage bikes with great results. One of the problems with the old castor based oils is the tendency to gum up the inside of your engine. This can cause your sticky ring problem and also has more carbon build up. The modern oils burn more complete. I can remember when everyone ran Blenzol. That stuff made your eyes water. :yikes:

Guess we'll see if I've really figured out the quote feature.

I've got ten quarts of Klotz coming, so will probably run that for a while. When I was 16 the smell of it could have been bottled as a cologne and I'd have bought it. I'd have smelled like the backside of Ake, or of Brad Lackey. I'll expirement a little when it's gone. I did try some Bel-Ray synthetic in my vintage bikes at 50:1 (as recomended on the bottle) and could hear the tired IT trying to seize as it reved down. It scared me and I poured 5 gallons of pre-mix out as weed killer in my alley (please don't tell the EPA). My KDX is running good using the Castor 927 at 32:1, without noticable smoke or any fouling (the aroma isn't as good as Klotz was though, or my 47 yr. old senses are jaded).

If your engine is properly set up with all of the right clearances, 32:1 is sufficient as a break in ratio.

Thanks. I dropped the cylinder off today for boring and a Wiesco piston at a shop that does a lot of vintage work. $65 for machine work sounded like the high end of the range, but they can get all of the parts, gaskets, etc., I want without me running them down myself. They're a motorcycle junkyard too, and are going to see if they have a good intake boot for me. I plan to polish the ports myself before reassembly.

Your wrist pin and rod bearing should have clearance when you rock them. But, you should not have any up and down movement.

My Clymers says that lateral rocking indicates a worn pin or needle bearing. I already ordered new ones this morning, even though I couldn't see any fatigue or cracking in the bearing cage. I figured replacement now would sure beat wishing I had later, and thought the wavy pattern of wear below the compression ring, as well as the piston galling forward on one side and behind on the other might indicate undesired lateral slop. It seemed logical, and as long as I'm doing the bore and piston thought more new parts might be safer in the long run anyway.

To check for this, put the rod at top dead center and grab the top of the rod with both hands. Rest the heels of your hands on the base gasket surface and try to move the rod straight up and down. If you feel any movement or hear any clicking in the big end bearing, you should replace it. If it feels tight, you should be ok. Same with the small end bearing.

Just my $ .02

Thanks for that last! I'll do the main bearing check tonight. RE: the small end, the bearing's out, and I have a new bearing coming. What I'm really wondering though is if the connecting rod itself can wear in the holes to the point that even with new bearings the risk of failure is there, and if there's a way to check for that wear. I've been collecting all of the parts for this old IT to make it look just like (well, or really close) one would have on the showroom floor in '78, and I want it to run like a new '78 too, without blowing up on me like my '77 did.

 

[Jaybird]

IMO, one of the most important procedures to follow during a rebuild is the coating of all parts with a proper break-in fluid.
Many state to use straight pre-mix for this task. However, break in fluid is placed on because of the initial start-up, seating of the rings, and the intial shut-down periods. Fluid film that conventional oil provides protects all of your internal surfaces during run, but for the conditions I just mentioned, we must depend on boundery lubrication (protection provided when a fluid film has been punctured by microscopic metal asperities). Fluids and films that are labeled specifically for break-in, will have the boundery lubrication products in it that conventional oils do not. Some also have additives that are not good for a wet-clutch type ride, as they have loads of moly in them, so you should use caution when choosing a break-in fluid. Some use other chemo-absorbed type chemicals that do not effect clutch plates.

Shoot me an address and I'll comp you a bottle of break-in fluid.

 

[Jaybird]

Colorado,
I remember getting an e-mail or PM from you, but can't seem to find it now.
Can you re-send?

Jay

 

[nickyd]

jaybird - interesting point...I've always used two stroke oil or motor oil (for a thumper) when doing the rebuild...I remember a while back when the CRF 250F was released people were pissed because the rings weren't seating and I saw many a debate from the "engine builders" who recommended assembly DRY....I was just completely blown away with this idea....I happened to mention it to my dad who said that he used to take a straw full of borax or ajax powder and they (he and his racing buddys) would blow it into the spark plug hole to help seat the rings.....I almost passed out...I am still not sure what to think....

 

[Jaybird]

OK...I may get corrected by Eric, Rich, Bill, Terry, or any of the guys who have forgotten more than I have ever known about engine dynamics, but I want to give you my take on the break-in thing...


When we rebuild a motor, the cylinder will have intentional hatch lines on it. These small lines, or swirls around the piston jug will help oil to be distributed along the path of the piston by the oil ring.

The more perfect the circle of the cylinder is, the better the breakin will be, due to the fact that the piston surface and the rings match up.
The more out-of-round the cylinder is, the harder it is for the rings to seal things up well. This can result in a loss of compression, and in a 4 cycle motor, abnormal consumption of oil.

If the cylinder is slighltly out of round (egg shaped) then there will be high spots and low spots. The high spots are in contact with a small bit of the ring surface. These high spots will actually wear down, as will the rubbing surface of the ring. The rubbing and taking away of metal in these areas will finally subside when there is more surface area of the cylinder in complete contact with the rings surface.
This is reffered to as the rings "seating".

On mass production bikes, it is very easy for the machine work to be slightly sub-standard. I suspect that being the case on the Honda's that were having seating problems.
An aftermarket machining will more often be of much better quality. The circle of the piston bore will be more true and round. Which will allow for a better break in seating of the rings, without a noticible loss of compression, and very little wear between cylinder wall and ring face.


The rate of the wearing of the high spots is contingent on what sort of product is supporting lubrication in that area.
Oil lubes protect metal from wear by forming a thin layer of oil between the mating surfaces. This wedge of oil keep the metals away from one another and will not allow the small hills and valleys of the metal surface to break through the wedge and get to the metal on the other side. This is reffered to as "full fluid film" or "hydrodynamic" lubrication.

Problem with oil is, it takes a certain volocity and pressure at the microscopic level to keep the oil forming a layer between the metals.
When there is not enough force to keep the oil wedge in place, there are additives in oils that take over, so to speak, when the fluid film fails.
The additive package of the oil provides materials that take over the job of lubrication that the oil can't perform. This is reffered to as "barrier" or "boundery" lubrication.

Comman components of additive packages in oils are Zinc-d and molybdenum, although there are a host of others. These items will coat the metals surfaces with electrically charged polar molecules that form a protective barrier on the surfaces of the metals. They will allow some of the metal to be sheared away when there is contact, but the simple act of the intial shearing lets the chemicals that now reside on the metals oxide layer change the way the shearing takes place. Instead of high heat that gets created with unprotected wear, the intial wear changes the construction of the oxide layer and lets the wear sort of smooth itself in, in laymans terms. I could go on and on about what happens molecularly at this stage, and some of it is yet to be fully understood by the lubrication engineering community. But the simple facts are that the breakin is completely reliant on the barrier package of oils, and the trueness of the machine work itself.

If the metal is being protected by nothing, then the wear of the mis-matched parts will create great heat at the micro level. This changes the metals make-up and allows for even more wear, since the remaining surfaces are brittle and rough from the last pass of wear.
This can continue until the surfaces are eating at each other until failure.
If there is a barrier additive in place when the wear occurs, then the shearing of the metal in high spots still takes place, but the chemical reaction that the additive provides keeps the metal from micro-heating and keeps the metalurgy consistant, until more surface area is in contact, OR volocity and pressure build, allowing the oil to finally form that wedge between the surfaces and do the job it was intended to do.
Start-up and shut-down are the most critical times during a break in...or anytime for that matter. When we start the engine, there is no oil being pumped, or being moved. And it may only be a stroke or two that is not being protected before start. But that momentary unprotected time takes off loads of metal in mis-matched (or brand new) jugs. This is the time that the barrier additives of the motor oil is so very important.

Break-in fluids and materials are simply barrier additives in concentrated form. The very best know product for barrier protection at break-in is molybdenum, or "moly". Moly can cause problems when high concentrations of it are introduced to the clutch plates of a bikes wet clutch, so it is not advised to use moly break-in products.
But you should use a break-in fluid of some sort. Whether it be a specific sort of fluid, or simply a good motor oil. Something needs to be used. Not only are you seating the metals of the jug ands rings, but there are bearings and races that are also in need of a wear in, albeit nothing compared to what the cylinder and rings see.
But in the case of the cam lobes, lifters, and the journals, even the slightest bit of unprotected wear can result in less than optimum engine performance.

Granted, once the engine is up and running, there is oil being introduced to the parts. But that intial start and the shut-down can be terrible for eating away metals if your oil doesn't provide a good barrier package.
When we slother on a rebuild fluid, we have treated the metals surfaces so they can handle times like start-up that there is no oil and additives being sloshed around. Most break-in treats will also still be present on the metals surfaces for some time. Even if you drain the oil right away, the treatment on the metals still remains for some time.

I could go on and on, including the synthetic and dry-run issues, but I'll save that for another rant.

And, nick...
I find the story about the straw full of Borax very interesting. I can see where it would be looked at as an old school way to get the wearin going fast...which in my mind is a bad thing. BUT, there are issues that may be taking place with that method that the old school guys never even considered. They simpy knew it worked and used the method.
I am going to investigate this procedure a bit more, as I've never heard of it. There could actually be something happening chemically with borax that may have been a good thing.
Don't do the borax thing though. :) Plenty of products that are far better suited for the task.

WAIT...I think I just posted what I did in the last post here...ony with more boloney and hot air! LOL... oh well...

 

[nickyd]

great post - I have used and will use oil, OR a specific rebuild fluid - for my money and my training, its all I can comprehend...I simply cannot see DRY building a motor....or using borax...very interesting stuff no doubt....to further complicate the issue you made a point about the certain properties of oil before it reaches optimum temperature - did you see that press release by a representative from castrol that said that motor oils are X% (i can't remember exactly) less effective before they reach their ideal temperature of X - he went on to say that "HE" recommended you start the bike up, let it idle for a very short time and GO....he said its better to get the oil up to temperature quick that let the bike warm up....now he's concerned with lubrication - not necessarily the properties of your engine metals.....I just found it nice to finally have an opinion to explain why my wife has her car in drive and going 40mph before the starter even finishes winding....ha

 

[Jaybird]

As I mentioned above, there are some phenomenons of lubrication that still have the engineers baffled. In the past two decades, consumer motor oil has went thorugh some very radical changes, due mostly to finding out things that were previously unknown and tweeking the fluid accordingly.

With the advent of synthetic oils, fine tuning fluid for specific applications has become even more doable in just the past few years. The molecular structure of synthetics is very structured and consistent. This allows for spot-on manipulation of the chemicals, as with dino oils the molecular structure can be somewhat irregular and inconsistant.

The methods we use for break-in are based soundly on past knowledge and theory. And just as oils have changed, so have methods. Some of the old oil formulas that were at one time state-of-the-art, are now unacceptable.
Same with methods.

Scientists couldn't figure out alot of the lubrication stuff previously because they didn't have equipment available to measure the actions happening at the micro level.
That issue was worked through and the resulting equipment allowed for further study.
And like I said before, the advent of synthetics gave the engineer a new frontier to use.
Most recently, inproved testing and monitoring equipment has been developed and there are phenomenon that were before unexplained, now coming into clear light.
Nanotechnology is taking many disciplines of study into new relms, lubrication applications as well.
Won't be long and everything we are doing today will be passe'. :)

 

[nickyd]

Jaybird, with what you just said, I have decided that whenever I need a new top end I am just going to drop a new piston into my gastank. I figure that science has come far enough to allow me to use these new "smart pistons" - you know the ones you just drop in your gas tank and they know where to go...hahaha

 

[Jaybird]

I do invision a cartridge type motor assembly with gas supported bearings and slides, but that's just me. :)

 

[darringer]

I have some carbon build up inside the piston crown.

I noticed this little tidbit of information after re-reading an earlier post. This condition is consistent with the bike running very lean, or at least overheating. The premix has actually burned onto the inside of the piston crown from the excessive heat.

 

[Colorado]

Colorado,
I remember getting an e-mail or PM from you, but can't seem to find it now.
Can you re-send?

Jay

Jay,

I just happened to look back at this thread. Thanks for the original offer, and the later attempt to hook back up with me. I assembled with a healthy coating of Klotz on everything though, as I had it (plenty too) and wasn't in the mood to wait.

Steve (aka Colorado)