Previous top end? Look at your heads please

So, I have had my 250f for a few years now and have never had nor do I currently have any issues with it. Just a lack of proper maintenance in checking valves on my part. Other than that I maintain properly everything else. I have feeler gauges ordered so I can properly check valves. Here is the question I am posing though. On the head there are etchings on it in 2 places which only has me curious on what was done to it by previous owners. I believe I am 3rd in line. I bout it from a young kid who stated it was too powerful, he owned it a few months and I bought it from his dad. I don't know prior history. On to the etchings... On the brake pedal side of head there is the etchings 5z84 right at the carb intake and at the base of head is the etchings 4zc-88. I have no idea if these mean anything. Can you fellow owners look at your head and inform me if these are on other bikes or if possibly mine has been worked on? Thanks you guys.

I just looked at a bunch on ebay with the zoom view on pictures...i dont see that lettering on any of em (my bikes not here, where I am at).

 

How bout some pics? Even though I don't think those are SUPPOSED to be on the head from what I am seein in a lot of pics of heads for sale.

Here are a couple of pics. They look engraved but I don't know what purpose they might mean.

image.jpg

image.jpg

Lol, might have to turn head to the left as you look at these pics. I don't understand why but this damn I-pad rotates all pictures when I post them. Might have to go back to camera and download on computer again. Hopefully someone can give me some sort of insight.

Ya that doesn't look original, lol. Not sure what they mean, and can't really help on that aspect of it.

Only way to find out is when I pop the top off. Will do that after I get feeler gauges in. Not going to dive too far into head other than checking clearances though. Will inform if anything really stands out. Just thought I would throw it out there. Runs a bit more powerful than other 250's and that has been mentioned by a couple of people that have ridden it. Thought it was just me...

Mine has something like that. The only problem is my bike is also second hand and I'm not sure if these are original either.

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Working on my valves today and also noticed the same thing in both places you have shown, I'm in South Africa so I can only assume these come from the factory like this.

Working on my valves today and also noticed the same thing in both places you have shown, I'm in South Africa so I can only assume these come from the factory like this.

 

 

Ok, well I ask you to go look at a multitude of heads with good pics for sale on ebay. I am not seeing etching like that on any of them. Not to mention the etchings do not look like somethin theyd do in the factory. I could be wrong I suppose.

Ok, well I ask you to go look at a multitude of heads with good pics for sale on ebay. I am not seeing etching like that on any of them. Not to mention the etchings do not look like somethin theyd do in the factory. I could be wrong I suppose.

 

I agree they look like a 5 year old wrote them on there.

I bought this bike 3 weeks ago and have no idea of it's history so this head could have been bought off Ebay from the US for all I know. :excuseme:

 

Intakewriting_zps5983bdda.jpg

I think I might stop at a dealer this week and look at the brand new virgin models. Who knows, our bikes might have been raced and worked on by whomever and that is their personal way of knowing what they did to these heads. That's pretty much all I can think of.

I would agree that its possible it is etched by someone who did head work. May mean something to them. I just dont see it on EVERY head. If it was a factory thing, it seems like it would be on all of them. Would be cool if some of the real know it guys who have seen a lot of these heads over the years would chime in...cuz now im curious, lol.

Edited by J_WR2fitty

I know when my brother had his shop he would mark his work

my 09 has no marks on it and i am the original owner

I think its a pretty safe bet that they have been worked on somehow to a degree. I want to ride this weekend, then after that I think I will start tearing into it a little more.

my 2012 has similar marks on it, and I bought it new from the dealership...

I have two prior heads that I kept from the 2007 YZ250F that I have bought/owned since new, including the bike. The heads - the one on the left I think - was the original head, and the one on the right was bought brand new from CyclePartsWarehouse:

IMGA0623.jpg?t=1382492553

 

And here is a close-up of the etched numbers of each head:

IMGA0626.jpg?t=1382493058

 

IMGA0627.jpg?t=1382493260

 

The one on the bike now, has etchings as well and it was bought brand new also. So whether or not they are refurbished and sold as new, I have seen these etchings on every head I have bought new since owning the bike.......

 

Clarification on whether these etchings are existent on all new heads would definitely send mixed messages to a buyer as to whether or not a head was refurbished and hopped up or possibly a person buying a bike brand new off the floor would question it as well I suppose.

 

I just know that I have seen them on the latter two heads I have. The one on the right in the first picture and the one on the bike now; both of which were purchased new.

Edited by nokickstandsallowed

I guess really the only person who would know is any builder who has dealt with these heads. I have opened a can of worms here I do believe. If any builder happens to see this, it would be great to hear their input..

I guess really the only person who would know is any builder who has dealt with these heads. I have opened a can of worms here I do believe. If any builder happens to see this, it would be great to hear their input..

Yes, exactly!

 

The reason being, is because manufactures' marks are stamped, tag plated or in the cast mold in the final stages of manufacturing and etching or engraving is something that is usually done when raw sorting at a facility before repackaging purposes when buying from a endorsed supplier that has rights to exclusively sell OEM parts from the direct manufacturer supplier.

 

5XCO2 is on the bottom of the intake side (on each of the three heads I have) just below where the carburetor hooks up, and it is in "raised form" indicating a cast mold transfer. That is surely something the manufacturer did, and not something a secondary supplier/seller would do, unless it was exclusively their own design by trade and they own all the rights to stamp, cast mold or tag plate anything they wish to sell.

Edited by nokickstandsallowed

It could be a system that Yamaha use to keep a track of particular batches manufactured or the worker that assembled that particular engine or head?

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