KDXRIDER.NET

Some may have seen this, others not. I did a search on kdxrider and didn't find it, so . . .

http://www.mototuneusa.com/break_in_secrets.htm

Opinions? I will be breaking in a new Wiseco this week. Yes, I did a search for piston breakin but after reading, and a bunch, I was a little confused. I think in general the gist seemed to be to cycle the piston through varying and increasing heat loads. I looked at Wiseco's website and no real answers there - maybe I'll contact them directly.

Anyway, what do you think about the article?

I've posted that on here before, but the link probably said 'link' or something like that. I've performed rapid break-in sucessfully many times with great sucess. However, I've performed 'old school' break-ins many, many, many times. This was always with sucess as well, but there are gains to be had from the rapid method as explained in the article. I would stick to the regular old method unless you're very confident you can follow these instructions to the letter. A dyno works best, and there is not much 'danger' when using one for break-in as you are in a controlled environment. Most of the one's I've done have been on a kart motor on a kart track. A track is a good place for this method. The engine decelleration part is ABSOLUTEY key. A big open field or something like that is good for a bike. Have you ever heard an engine get flogged on a dyno? Try to mimic this when doing the break-in. You can pretty much feel when the rings seat. WARM-UP big time especially with that wiseco. I'd let it get borderline too hot(15min warm-up idling)....Shut off, check for leaks, swap in fresh plug, go to town.

Jet rich, and don't use synthetic oil. Plain old weedeater oil at 20-32:1 will be good. This goes for any break-in.

In college when we were building Honda CBR600 F4 motors for mini-formula cars we always broke them in that way, never had a problem. I broke in my top-end like that too. But don't take that as gospel, I have only done this on ~6 engines. Lots of interesting reading on mototune's site.

I've had successful (rings seated well) break-ins using both methods.

I've had UNsuccessful (rings not seated well) break-ins with the heat-cycle 'slow' method.

I've had NO unsuccessful (rings not seated well) break-ins with the 'fast' method.


All anecdotal and therefore useless information.

Old hat and age-old information, but a common name for Wiseco is Seizeco.

That has nothing to do with a piston 'failure' but an incorrect use/fitment of a forged piston.

You might be fine with .002" clearance on a cast piston, but likely would NOT be fine using that clearance on a forged (Wiseco) piston.

If you happen to have an 'A' cylinder (the smallest bore) in good shape, I'd suggest being careful with a Wiseco. Measure your setup. Do not trust what some machinist told you unless you saw it yourself.

I do the fast way too. Never had a problem and the never had blow-by.

When I was a Part 135 commercial pilot, they had me cycle the engine through the RPM/manifold pressure range (most had constant-speed props). Key was flying at a low nose angle to keep the speed, and cooling up. Mixture richer than normal. When decending to land, let it cool down slowly.

Breaking in an engine that would be flown over Arizona mountains was a serious consideration.

Rick

^ That's basically the same thing. It all boils down to the point of you only have a small window to get great ring seal, and you must be under a load to do it....As much load as possible really...

I've had successful (rings seated well) break-ins using both methods.

I've had UNsuccessful (rings not seated well) break-ins with the heat-cycle 'slow' method.

I've had NO unsuccessful (rings not seated well) break-ins with the 'fast' method.

2nd these results.

Good feedback and food for thought. I'm beginning to wonder where's the greatest risk: keeping the stock 220 piston in or risk seizing the new piston!!

I'm still debating whether or not to do the fast or slow break-in. I'm going to put some more time into it. What's interesting is the breadth of the debate: the right way in breaking in your new piston ranges from slow & steady to fast & hard.


A few more questions for CC, slightly off-course but not off-subject and within the realm of this thread (since you brought it up ); you have obviously spent a significant time in thinking through and writing about piston size and clearance. So . . .

1) I see from a previous post you suggested that since a Pro-X piston clearance should be minumum .002" that a minimum for the Wiseco should be .003-.005 (.003 "iffy"), stating "basic forged piston facts". Why the need for the larger clearance and why is .003 "iffy"?

2) Why would additional caution be needed if I have an "A"-sized cylinder and I use the Wiseco if the differences between between the letters is very small? What's a 220 owner to do if he has an "A" cylinder yet should by most accounts replace the piston with a Wiseco (PLEASE correct me if I'm wrong here, that's my interpretation of what I've been reading)? HELP!!!

Am I reading too much into this!? Perhaps I've done one too many searches

BTW, a sincere thanks to all for the feedback; if it sounds like I'm whining above I'm . . . well, maybe I'm whining a little bit - I'm just a tad overwhelmed with what I thought was relatively straightforward. I mean, I've done 8 maybe 10 top ends in my lifetime - albeit years ago - So while I'm no pro I ought to be able to get through this!!

I've done it both ways and I like the run it hard method better. First of all, it makes sense. Second, it means you can get to riding. Third, I just have to wonder what racers do when they change rings at the track and who, for instance, breaks in RC's bike. Fourth, it seems like my bikes run a little better with the run-it-hard method. I've never not had good results.

Yamajeb wrote:Good feedback and food for thought. I'm beginning to wonder where's the greatest risk: keeping the stock 220 piston in or risk seizing the new piston!!

I'm still debating whether or not to do the fast or slow break-in. I'm going to put some more time into it. What's interesting is the breadth of the debate: the right way in breaking in your new piston ranges from slow & steady to fast & hard.


A few more questions for CC, slightly off-course but not off-subject and within the realm of this thread (since you brought it up ); you have obviously spent a significant time in thinking through and writing about piston size and clearance. So . . .

1) I see from a previous post you suggested that since a Pro-X piston clearance should be minumum .002" that a minimum for the Wiseco should be .003-.005 (.003 "iffy"), stating "basic forged piston facts". Why the need for the larger clearance and why is .003 "iffy"?

2) Why would additional caution be needed if I have an "A"-sized cylinder and I use the Wiseco if the differences between between the letters is very small? What's a 220 owner to do if he has an "A" cylinder yet should by most accounts replace the piston with a Wiseco (PLEASE correct me if I'm wrong here, that's my interpretation of what I've been reading)? HELP!!!

Am I reading too much into this!? Perhaps I've done one too many searches

BTW, a sincere thanks to all for the feedback; if it sounds like I'm whining above I'm . . . well, maybe I'm whining a little bit - I'm just a tad overwhelmed with what I thought was relatively straightforward. I mean, I've done 8 maybe 10 top ends in my lifetime - albeit years ago - So while I'm no pro I ought to be able to get through this!!

I said that? I didn't go check..but I think that rendition is a bit off. I used .002" not as a known and accepted proper cast piston clearance, but a pretty much known and accepted improper forged piston clearance. That's not the same as saying .002" is the recommended Pro-X piston clearance. It's pretty tight for cast, too.

Consider the source metal for the two types of pistons. A cast piston comes from chopping up/melting a bunch of metal and pouring it into a mold. Using cloth as a similar product, it turns out like felt. The bits and pieces won't have a grain to them. Like a whole piece of cloth (woven..having a grain..a direction to the threads) a forged piston has the same 'grain' characteristic. Consider that metal will expand more in one 'grain' direction' than the other because the metal is 'aligned'. So it is that a forged piston needs greater piston/cylinder clearances to survive.

So...why use a piston that has to have a 'sloppy' fit anyway? Because, generally speaking, a forged metal piece of anything is stronger than a cast piece of metal anything. Why? Same reasoning. Because of the 'grain' aspect. Wiseco pistons are generally lighter than their cast counterparts, too. Why? Same reasoning.


The cylinder/piston sizing differences are small. A bit less than 1/2 of one thousandth of an inch. They do add up, though. Sizing goes through 'G'. There's .003"!

The 'A' caution was just that. NOT a 'You cannot put a Wiseco in an 'A' cylinder, but you had better be careful doing so.

Guess what? You'd better be careful putting ANY piston in ANY cylinder. That's just the way it (should) goes.

Do you indeed have an 'A' cylinder? That's doubtful. What should you do? Measure your setup to make sure you're OK and you will be fine.

Hey Canyn, do Wiseco's come with a recommended clearance in the piston specs?

I don't know if they do or not.

I've looked on the Wiseco website for that information in the past. Didn't see it.

I've seen a Wiseco in a box...and that's all that was IN the box. No literature/spec sheet/install guide. That's an anecdotal input, not of much use when it comes to 'The Way Things Are.'

I see this on their site:

Wiseco “M Series” pistons are designed to run at a specific piston to cylinder clearance, andare manufactured under controlled conditions for a specific bore size. Finish hone the cylinderto achieve the recommended piston to cylinder clearance, which can be found on the label on the piston box. NOTE: Additional bore clearance may be necessary for modified engines. (May include head or cylinder work, aftermarket pipe, or ignition modifications)

Emphasis mine.

I've read specs for exhaust bridges, exhaust valves, but not a general one-each number of piston-cylinder clearance. That's 'cuz there is no such thing. That spec will vary with bore size, application, etc etc and furthermore, etc.

.002" (my guesstimate) would probably be fine if you aren't too zealous a break-inner. Less than that (imo and all that happy disclaimer junk) is pretty darn thin.

One thing to be thankful for...you don't have to deal with something like this on a rebuild!!



Re:

I'm getting feedback indicating that Wiseco pistons can be problematic...

Somewhere along the line some things are being misunderstood or mis-taken.

I've never said, and neither do I think you will ever find anyone saying that Wiseco's are junk, bad or otherwise crap. Where the problems come up is when they are not installed properly. The term/word Seizeco is not indicative of Wiseco's poor products but of the sense of the people using them!!

There's a difference.

Thanks, CC - you've eased my concern a bit . I do intend on exercising as much care as I can muster and I agree totally about confirming clearances regardless.

As far as the letter designation on my cylinder - is there a way to find out without removing the head? 'Manual states the stamp is on the "top left side of the cylinder" but I don't see it on the outside. If not, no biggie - she's coming off real soon.

Again, many thanks.

I'll schedule my one brain cell to take a picture of the alpha designation so you can see where it's situated.

Yeah. Good luck with THAT!

It is on the top left. That's left as in if you're sitting on the bike (uh...facing the bars? The handlebars?)

It's the top left front I recall. It's not under the head.

I thought I'd posted a pic of that before...........

Came across this whilst nosing around the web:


From EG's website:

When you initially start the engine after a rebuild, manipulate the choke to keep the engine rpm relatively low. Once the engine is warm enough to take it off choke, drive the vehicle around on flat hard ground. Keep it under 2/3 throttle for the first 30 minutes. Two common myths for proper engine break-in are; 1) Set the engine at a fast idle, stationary on a stand. 2) Add extra pre-mix oil to the fuel. When the engine is on a stand it doesn't have any air passing through the radiator and it is in danger of running too hot. When you add extra oil to the fuel you are effectively leaning the carb jetting. This can make the engine run hotter and seize.

My intention is not to instill fear, panic and apprehension. Forewarned is forearmed, knowledge is power and all that.

Two (more) anecdotal inputs to give you an idea from whence I cometh.

I paid a lot of bucks to have a cylinder replated. It came back out of round. I didn't diagnose that before I bolted it on. A feeler guage doesn't work too well for bore measurements. I trusted the outfit doing the replate to do it right. They didn't.

A couple of V-8s ago I paid a machine shop to mock-up my engine to check piston to head clearances. They did (they said). With the short block assembled I set a head on top of the block and turned over the motor. The piston bumped off the head deck over 1/4"!!

Two examples of being told something, being promised something, expecting something...that were mistakes. Or outright lies. The former merely brought about a lot of wasted time trying to figure out what was wrong with the bike. The time would never have been wasted had the plater done a decent job.

The latter would have been catastophic had I trusted the machine shop to have done what they said they were going to do..had done...charged me for!!!

You're responsible for what you bolt up. If you cut corners or assume much of anything the total that comes due from the oversight may be a hefty sum.

Well put, CC - thanks a mil

Hey, CC, found the stamp - right where you said it would . . . "B" !!

I'm gonna try this method if the Pro-X I pull out this winter has any blow-by due to the rings not seating....

Indawoods wrote:I'm gonna try this method if the Pro-X I pull out this winter has any blow-by due to the rings not seating....

Which method?

Hard....

Well then...I'm glad I checked this AFTER I got my camera, ventured out into the dark, of night (did I say freezing cold dark of night?) and took some pics!

For anyone looking and not finding, here they are anyway. If you can't tell, the alpha designation is on the top, left, front of the cylinder:






Re: Right where I said it was...

What? You figured I was lying to you? So..you're SURPRISED??!!