Cylinder pics....bad news?

81 replies to this topic
  • 02WR426Cali

Posted March 16, 2011 - 05:57 PM


Hey guys check out my cylinder it's looking a kind of bad. I did some preventitive maitanance a while back and put in a new piston/ rings. Cylinder looked great back then. It was almost 2 years ago when I did it, but I put less than 20 hours on the bike in that time and was riding other toys I have. There is still good cross hatching but there is a few ridges up top and one at the bottom. You can barely feel them running your finger over it, but you can feel it's not flat. There is also lines going up and down from the piston skirt, but no grooves.

Is this cylinder trashed? Will a good hone fix this?

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  • Gerry B

Posted March 16, 2011 - 07:13 PM


Theres nothing wrong with that cylinder. Give it a quick hone and throw it back together.

  • YZ450F4

Posted March 16, 2011 - 07:25 PM


+1 on that Gerry B

  • grayracer513

Posted March 16, 2011 - 08:14 PM


The ring ridge doesn't look promising. I recommend you have the bore measured. Remember that the allowable wear is only .002".

  • powers450f

Posted March 16, 2011 - 08:34 PM


HONE IT and ride it dude. GR 513 is just won of those paranoid worst case scenario dudes.

  • 02WR426Cali

Posted March 16, 2011 - 09:21 PM


Yeah I was hoping to just hone it and put it back together but I get paranoid sometimes too. But hone it is!

Side note: what causes the ring ridge? It almost seems that it got real hot and the piston was up top and the ridges came while it cooled down. Sort of like a cold siezure.

Edited by 02WR426Cali, March 17, 2011 - 06:20 AM.

  • grayracer513

Posted March 17, 2011 - 08:18 AM


What causes the ring ridge is that the rings come to a complete halt at TDC and reverse direction. Combustion pressure is not peaked at this point, but it's pretty high, and the exposure to the heat and pressure forces away a great deal of the minimal lubrication the rings get. Then you factor in the phenomena in which friction is the highest between two moving parts when the relative speed is the lowest, and you have an area of increased wear right where the rings reverse.

And while I appreciate powers' enlightened assessment of my disposition, I would nevertheless have a competent technician measure that cylinder, especially if 3-4 quick passes with a ball hone do not completely remove all shadows of those ridges. The .002" wear limit allows only .001" to be worn from opposite sides at any one point. If you've never seen Nikasil peel off of a cylinder wall, well, you haven't lived. Me? Paranoid? It's not my money :thumbsup:

  • 02WR426Cali

Posted March 17, 2011 - 05:51 PM


Wow that's a little complicated how that all works, but thank you for the info.

  • 02WR426Cali

Posted March 25, 2011 - 05:53 PM


Ok guys I just got my cylinder back from ASRacing. They honed it using a flex hone so they claim yet there is no new cross hatching. I've read on hear many times over and over in hundreds of posts that honing puts on new crosshatching and that is the reason for doing a hone.
There is crosshatching at the very top and at the bottom where the rings don't ride. But that was there all along. It is shiny in the middle where the rings ride with less crosshatching than before I sent it to them.

So why does my cylinder look like this?

Posted Image

Posted Image

  • Padgett

Posted March 25, 2011 - 07:14 PM


When a cylinder is plated they use a diamond hone to finish the bore. Your cylinder should run a while, but If it was mine I would be sending it off for re-plate. The top photo shows the ring ridge. I got two cylinders in my shop that has the plating worn off right at the top of the cylinder. Once the plating wears down it starts flacking or burning off very fast. I would spend the $200 and have it re-plated myself. The after market plating is very strong and unless you trash a piston, chunk a ring or suck some sand in, the new plating should last many years.

Here is a little information about re-plating.

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  • grayracer513

Posted March 25, 2011 - 08:16 PM


From that picture, I am of the opinion that the cylinder was never touched beyond the possible use of a Scotch Brite pad. The picture you posted is not of a cylinder that has been honed.

  • 02WR426Cali

Posted March 25, 2011 - 08:25 PM


That's exactly what I thought Gray. I can't believe a shop that has a good rep would claim they do something and then not do it.

  • Aka.Goose

Posted March 25, 2011 - 08:48 PM


Yeah man, no way was that honed...If it was, it wasn't done right...Hell, it appears to have less cross-hatching than your earlier pics from above...But maybe that's just from the pics being different...If your vertical lines from before are gone, then obviously they did something...

Here's a pic of a fresh hone for comparison:
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  • 02WR426Cali

Posted March 25, 2011 - 10:26 PM


Here is the response I got from the shop. The pic he mentioned is the one above with the fresh hone.

"I am sorry that you aren't happy. It is our promise to make sure you are 100% satisfied.

I would be happy to lap the valves in. The Yamaha seats are much softer than say Hondas, and generally don't require heavy lapping when changing to stainless valves. It has been my experience that the Stainless valves seat in well in Yamaha heads designed for Titanium valves. Heavy lapping takes life off the valves and is usually done when the Dyekem test dictates. We try and get the seats perfect so lapping isn't required. Some solvent may pass through before the valves are cycled and run. I can lap it so that no liquid will get through before it has run. With the Yamaha's, it usually isn't necessary. With Honda's, lapping is more required as the seats are much harder.

On the cylinder, we thought it looked strange as well. It did look like it was worn past spec. The Nikasil has been worn away by the rings. The flex hone we use is made for Nikasil and works well. It is not designed to tear up the Nikasil as diamond hones can. I would be happy to run it again or switch to another hone that is harder and see if the ring bar at the top can be smoothed and more crosshatch be left. The last cylinder pic is a CRF cylinder. They always clean up like that. They use a really hard Nikasil and it very rarely shows any wear. The Yamaha's use a two piston ring design and tend to show wear faster on a cylinder than the single ringed CRF's

Let me know what I can do to make you confident in your parts. Redo them, refund your money, whatever you would like."

  • Aka.Goose

Posted March 25, 2011 - 11:00 PM


Wow...There's so much in there that I personally don't agree with, that I don't even want to break it down...IMO, I'd take the refund and try someone else...But I'm not a professional, so I guess take my opinion with a grain of salt...

Wait and see what GR has to say, his advice hasn't let me down yet...

BTW, I strongly disagree that your cylinder "looks strange" or "worn past spec" and the notion that Honda's Nikasil is in some way "harder" than Yamaha's, or that Honda's cylinders somehow last longer because of a single ring design...

  • 02WR426Cali

Posted March 25, 2011 - 11:31 PM


Yeah I know what you mean. I don't agree with all of that gibberish either.

  • primerib108

Posted March 26, 2011 - 03:43 AM


Diamond honing harsher than ball honing?

  • moto2000

Posted March 26, 2011 - 06:42 AM


At this point, I would send the cylinder off to be replated at US. Chrome, Millennium, Powerseal ect..... most have a exchange program, so you would have a fresh cylinder in your hands in a week.

  • grayracer513

Posted March 26, 2011 - 08:00 AM


Most of what he said about the valves is OK. Not well written, but not far off, either. Usually, I never lap valves, and they seal pretty well right off. You said they seeped, but not how much. A very small amount of wetting around the seat is acceptable in a fresh cut. Dripping liquid is not.

He never honed that cylinder, and if it "looks worn beyond spec", why didn't he measure it? That whole thing is BS.

Diamond honing harsher than ball honing?


  • 02WR426Cali

Posted March 26, 2011 - 01:48 PM


Yeah the valves were just seaping through not dripping. The seaping wasn't just around the seat though it made the whole combustion chamber wet and spread out. It would probably take a long time for all the liquid to come through if ever. So I guess they should be ok then?

And yeah I agree on the cylinder why didn't he measure and not just do an eyeball test.

I am planning on re-using the piston/ rings anyway as they only have 20 hours on them or so. I didn't hone the cylinder las time and never had any problems as far as compression and oil consumpsion it sealed up well and kept the water from getting to the bottom end also. I only wanted to hone it this time to clean it up and hopefully get rid of the ring ridge that showed up. There is still cross hatching throughout the cylinder as you can see in the original pics and there was never any cyl/ piston issues so i'm guessing I can put it back together and it will be ok.....

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