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Diode663

Need some ideas on 04 450

6 posts in this topic

I just tore down my bike and removed the head so I can send it out to have the intakes replaced and the seats cut. I wasn't going to take the cylinder off at first but then decided to check it out to make sure everything was good to go. Turns out everything is not good to go and I am glad I checked. The nikasil on the back (intake) side of the cylinder has flaked off and it caused the piston to get scuffed and generally gnared up. The skirt is also cracked in the webbing on the same side. Now that would be no big deal, things like this happen.

Heres where the big deal comes in though, this isn't the first time this has happened. Shortly after purchasing my bike the same thing happened in the same spot and it took out the oem bore and piston. I noted that the nikasil looks extremely thin compared to other coated cylinders I have seen. But I figured it was just one of those things that happen and chocked it up to a bad cylinder. To fix the problem I purchased an oem cylinder and got a wiseco 13.5:1 high compression piston, slapped it in and called it a day. I have had maybe 30 hours on the bike between then and now. My first thought was maybe its piston slap because I haven't had good success with wiesco and against my better judgment I went with them because I am a parts unlimited dealer and got it cheap. The piston seems pretty tight in the bore and I would believe that the opposite side of the bore would become equally screwed. I had my friend come over who has an extremely keen eye for this sort of stuff noted that the bore appears to have high and low spots, and that combined with extremely thin coating caused the flaking which led to the death of the piston. The only thing is I don't have a dial to verify the bores continuity.

So basically I am thinking about getting an aftermarket cylinder from cylinder works (I get them cheap because I am a dealer). I felt my ideal action would be to send the cylinder out to la sleeve to have an awesome liner put in, but they don't have the liner in stock and their turn around is quite slow, and I am in a time pinch at the moment. Also I was thinking to send the cylinder out to lukes racing. I have used them before when I had a YZ134 and I had a ring break and get jammed between the cylinder and the piston and the coating didn't have so much as a scratch on it. They do great work but aren't accepting orders until the summer time for some reason, so that is out.

I will break down what I'm asking of you guys.

1. What other things could lead to this type of failure?

2. What are your thoughts on the oem cylinders

3. Is this a common problem? If so is there a solution?

4. Has anyone had any experience with cylinder works?

5. What piston do you guys recommend? I'm quite certain I will be going with oem

6. How much do you love Entenmann's chocolate donuts?

I appreciate your forthcoming input guys.

Pics to follow.

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2. What are your thoughts on the oem cylinders

  • I know of no problem with them. Because Nikasil (or other similar nickel matrix silicon carbide coatings under other trade names) is so extremely hard, it cannot be machined easily. Because it is applied as a plating process, there is no way to assure it is applied to a perfectly even density over the entire bore surface. The solution then is to apply it in a very thin layer, generally about 0.002" thick or less, so that it requires only touchup honing and cross hatch surfacing. I doubt seriously you were able to see variations in the thickness of the plating visually.

3. Is this a common problem? If so is there a solution?

  • No. But in some foreign countries besides New Jersey, the lower grade gasolines sometimes had a high sulphur content, which would attack the plating. That's never been a problem here that I'm aware of. You may have a lubrication problem.

5. What piston do you guys recommend? I'm quite certain I will be going with oem

  • OEM or CP

6. How much do you love Entenmann's chocolate donuts?

  • They taste like plastic

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2. What are your thoughts on the oem cylinders

  • I know of no problem with them. Because Nikasil (or other similar nickel matrix silicon carbide coatings under other trade names) is so extremely hard, it cannot be machined easily. Because it is applied as a plating process, there is no way to assure it is applied to a perfectly even density over the entire bore surface. The solution then is to apply it in a very thin layer, generally about 0.002" thick or less, so that it requires only touchup honing and cross hatch surfacing. I doubt seriously you were able to see variations in the thickness of the plating visually.

3. Is this a common problem? If so is there a solution?

  • No. But in some foreign countries besides New Jersey, the lower grade gasolines sometimes had a high sulphur content, which would attack the plating. That's never been a problem here that I'm aware of. You may have a lubrication problem.

5. What piston do you guys recommend? I'm quite certain I will be going with oem

  • OEM or CP

6. How much do you love Entenmann's chocolate donuts?

  • They taste like plastic

When talking about the high and low spots I was thinking it had more to do with sleeve that the plating was applied to rather then the variations of the coating itself. I was using rotella and changed it often since I got the bike. But I never really liked the way it felt coming out of the bike. It always kinda reminded me of brake fluid. I will be switching oils as well, I'm thinking a maxima or bel-ray thumper. I haven't made up my mind as of yet.

And I guess you're right they do taste like plastic, but I love them for some reason.

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When talking about the high and low spots I was thinking it had more to do with sleeve that the plating was applied to rather then the variations of the coating itself. I was using rotella and changed it often since I got the bike. But I never really liked the way it felt coming out of the bike. It always kinda reminded me of brake fluid. I will be switching oils as well, I'm thinking a maxima or bel-ray thumper. I haven't made up my mind as of yet.

And I guess you're right they do taste like plastic, but I love them for some reason.

They do indeed taste like plastic, but I normally have a few with my coffee in the morning...

Since its on the intake side, maybe its a dirty airfilter or something.

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I was using rotella and changed it often since I got the bike. But I never really liked the way it felt coming out of the bike. It always kinda reminded me of brake fluid. I will be switching oils as well, I'm thinking a maxima or bel-ray thumper.

Rotella has an unfortunate tendency to loose it's viscosity when used in a transmission. If you have been running it for longer than about two hours, it has probably slid back to a 30wt or lower viscosity. I should mention that this will not be visibly obvious when the oil is cold, but it happens, nonetheless.

I know that most of the Maxima line pretty durable, but I don't have any documentation on Bel-Ray. Mobil 1 Racing 4T and V-Twin oils are excellent. My choice is Amsoil MCF or MCV (10w-40 and 20w-50).

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