[Wesley S]

You can only guess at the cause now. But a clogged injector on #2 sounds like a good candidate.

Clogged injector + me staying in it for too long. 🤦 Oops...

What can I say, I like to go fast 😎

I'm thinking I should probably just get a used piston for $25 bucks off the evil-bay (so it matches the rest of em) Clean the injectors out & slap her back together... What's the worst that can happen 🤷

And as much as I hate to do it.. I guess maybe I can avoid holding her pinned W.O.T. in 6th gear for a little bit & see if that doesn't help alleviate the 👉👌 situation.... I dunno 😒

Or at least until I can afford a set of low compression, forged Pistons & rods... and a maybe a turbo... & Some turbo cams & upgraded valve train & a Haltec ECU... And... And...

J/k 😜

....or am I 🤔

 

[Mr.Cannon]

Ouch, I hadn't seen those posts so seems to be an issue to look out for. Below is a quick snip I found about melting pistons and between bad fuel deliver and/or air delivery I wonder if you were running lean due to valve clearances. You're at high miles and the link you attached was above 37k so I wonder if you tear down if you'll find burn or hanging valves coupled with a fuel pump that isn't 100% functional.

 

[Wesley S]

Ouch, I hadn't seen those posts so seems to be an issue to look out for. Below is a quick snip I found about melting pistons and between bad fuel deliver and/or air delivery I wonder if you were running lean due to valve clearances. You're at high miles and the link you attached was above 37k so I wonder if you tear down if you'll find burn or hanging valves coupled with a fuel pump that isn't 100% functional.

View attachment 228297

Valves all look good to me...

Before 👆 and after 👇 cleaning

Seems like it's just that one piston that's F#@KED... And some scoring on the cylinder wall of course 🤦

Everything else seems perfect... The cams, cam chain and tensioners all seem fine with hardly any wear.

 

[NewRedRider]

These are pretty hardy engines. I think the worst is you buy yourself some time to get the rest of the parts to complete the rebuild the way you want. The best results are an engine that uses a little extra oil and might be a little low on one cylinder. But you saw the video of the bike running on 3 cylinders pouring what looked like gas out of the exhaust. 😳 Nice job on the heads! 👍 You should port and polish them while they're on the bench. 😁

 

[Mr.Cannon]

Wow, the head cleaned up really nicely and the cylinders look very good as well and I wouldn't be surprised if there was a defect in the metallurgy of that piston. Definitely keep us updated on your plans and if you decide to rebuild or swap a used engine. It's too bad the 07+ engines can't be swapped. Good luck with everything.

 

[Wesley S]

The best results are an engine that uses a little extra oil and might be a little low on one cylinder.

I suppose I'll have to hone her out a bit... I for sure won't feel good about reassembly if I can still feel scoring on the cylinder wall...

Melted piston chunks in the pan...

For some reason they used some 12 point bolts (I think) 🤷 on the rod caps... But I don't have a socket that works, grrr :/

The service repair manual mentions checking the oil passages in the cam holders... Take note, mine were almost completely clogged from "oil coking" I believe it's called.

Very minimal wear on cam chain guides

But also... I don't think the cam chain tensioner is stock, so perhaps it was all serviced per schedule... Still didn't save me

Nice job on the heads! 👍 You should port and polish them while they're on the bench. 😁

Thanks 🙏 I was thinking about it... Haha...
Tell me these rough, cast aluminum intake runners don't leave room for improvement? 😁

 

[NewRedRider]

The oil passages in the cam holder is the most troubling thing you've shown. I wish you had some history on this engine.

 

[dannoxyz]

...
For some reason they used some 12 point bolts (I think) 🤷 on the rod caps... But I don't have a socket that works, grrr :/

That's because someone's been in there and stripped bolt-head by using SAE sized socket. Metric 12-point socket fits perfectly without any issues. Here's what bolt-head should look like.

Looks like there's about 1.5mm of good splines at bottom. You might be able to grip it by grinding down tip of socket about 2mm to remove inner bevel. Then you'll have nice sharp tips to grip bolt-head.

 

[Wesley S]

That's because someone's been in there and stripped bolt-head by using SAE sized socket. Metric 12-point socket fits perfectly without any issues. Here's what bolt-head should look like.

Looks like there's about 1.5mm of good splines at bottom. You might be able to grip it by grinding down tip of socket about 2mm to remove inner bevel. Then you'll have nice sharp tips to grip bolt-head.

I think the fuzzy, zoomed picture makes it look worse than it is...

and I'm pretty sure I'm the only one who tried putting an SAE socket on it, lol... It was only that one, and I didn't turn very hard and now I know I need a 12 point metric socket 🙃

But that is a good tip about grinding off the rounded edge of a socket 👌

 

[NewRedRider]

I split this thread into 2 posts.

 

[Wesley S]

I split this thread into 2 posts.

Seems logical enough... Thanks... 👌

Cute little guy... Almost key chain ornament size 😝 the steel rod is tiny, but surprisingly heavy for a 15k rpm engine...

Also... Upon closer inspection 🧐 that notch on the rod cap bolt head is part of the design 🤷

The scored cylinder after running O'Reilly's rental tool through it for a while... I can barely feel those and most of them are well below the piston skirt when it's at BDC...

Of course I'm not an engine builder & I don't have the correct micrometer & I'm just winging all of this... I plan to check my work with ring gap & a compression test...

Worse case... I saw upper engine cases on the Evil-Bay go for $150ish

 

[NewRedRider]

A little JB weld will fix her right up. Nope.

 

[Wesley S]

A little JB weld will fix her right up. Nope.

That sounds like a "Derek-ism" 😜.

JB weld has only been proven to successfully repair cylinder heads & blocks...

Unfortunately it failed when used to repair a holy piston... Who would've guessed 🤪

But that being said... TIG welding seems to work fine in a pinch 🤷 lol

 

[Wesley S]

Slight change of plans... Not to be too critical of my first hone job attempt... But in hindsight, that seems dumb & I have serious doubts 🤪

Moving along, I was on Amazon and did you know they have slightly oversized Honda CBR 600rr pistons readily available for $90? You can get them +.5mm = 67.5mm... or +1mm = 68mm

and the interwebs say I should be able to get a hole bored .5 over for < $60 🤷

So at this point, I'm pretty sure that would be the only correct way to fix this, using this engine case, and not having to worry about that cylinder all the time...

Now I just need to find a local shop who will actually do it before I go ordering the piston...

 

[dannoxyz]

Who's the manufacturer of those pistons?

Closely inspect piston you removed. Does there appear to be any kind of coating on skirt?

 

[NewRedRider]

I was going to ask, didn't Honda put a coating on the cylinder walls?

 

[Wesley S]

AHL-US is the company it's showing...

AHL : PISTON AND PISTON RINGS

WELCOME TO AHL WE KEEP YOU RUNNING WITH OEM QUALITY PARTS

www.amazon.com

They look identical to stock & have the same - "IN EE" markings on top...

I'm not next to it now, but I don't remember any special coatings or anything mentioned about coatings in the service manual... 🤷

 

[dannoxyz]

AHL is popular company for lots of stuff. I used their pistons & rings in my CBR250RR since OEM is long gone.

On CBR600RR, I seem to recall liners are MMC and cast in place with block. With pistons having durable skirt coating. Similar to Porsche & BMW alloy engines from '80s. I'll have to look this up...

Wossner are my pistons of choice, make them to any alloy & specs of your choice.

 

[dannoxyz]

From here: What Are The Parts Of A Honda CBR600RR Engine?

10. Here is the upper crankcase, showing the matching upper halves of the crankshaft bearings.

Each cylinder's bore is hard-plated directly on aluminum. This eliminates the insulating effect of the iron liners that were previously used. Old-timers like those iron liners because they can be rebored. This engine can't be rebored. On the other hand, this engine takes care of itself so well that at 25,000 miles, it hasn't needed any help.

I've heard the coating is Nikasil (NiCom in U.S.) similar to what's been used on Porsche 911 engines for decades. In which case, new layer of Nikasil should fill in gouges and reduce clearances back to stock levels.

Power Sports

Our power sports plating services include NiCom (nickel composite coating) for engine cylinders. Contact our Wisconsin location to learn more

www.uschrome.com

Looking into this some more...

 

[dannoxyz]

Some info from V4, I suspect CBR600RR is similar.

I've rebuilt many Porsche engines Alusil blocks or Nikasil-coated cylinders. Dirt-bikes too. Plateau-honing stage is key.

Honing Aluminum Blocks

Manufacturers who produce “linerless” hypereutectic aluminum blocks today include Audi, BMW, Honda, Mercedes, Porsche, Volkswagen, Volvo, and Yamaha. Most late-model engines have aluminum blocks to save weight, including most of the familiar domestic V8s such as Chevy LS, Ford 4.6L modular and...

www.enginebuildermag.com