Discussion Pre-Split Cam Chain

Not ideal and a bit iffy given the RPM these things do. ZXR's have weak chains and tensioners to begin with.

I would buy another.

I've also had issues with aftermarket cam chain pins (from A1 imports), they supplied several pins in different diameters, unfortunately for me I grabbed the one that was wider than the hole in the plates and cracked the plate, so I had to order a replacement chain.

 

I used an EMGO chain breaker kit, which I still have. Bought from MCAS.

The trick with chain tools is to avoid extending the pins on the tool too far out of the centre guide, as they will flex and break.

You want the large outer section of the tool up flush against the chain plates, then you wind in the pin with the inner section.

Getting it all lined up is an art. I use a small section of appropriately sized ziptie through the cam chain to line up all the plates, insert the new chain pin into the tool (with the tool pin would all the way in), line everything up and start winding it in. The tool and pin will push the ziptie out the other end, so use the hollow end piece to allow it to go through.

 

So what you do is get #12 flush against the chain (with #5 the upper pin guide), with the new chain pin inside, then the spring and a drive pin larger than the new chain pin. The riveter pin is used at the end to squish the edges of the pin to enlarge them, though it never really works well because they're designed for drive chains with rivet master links that have copper ends that squish easily.

You might end up backing off #12 a bit so you can see if the pin is being driven in straight initially. So long as the drive pin isn't overly stressed. Getting the alignment right helps massively, it's hard to start initially but once it 'goes' it will go the rest of the way easily. Make sure you use the lower pin guide (hollow) initially, then swap it out for for the small anvil.

When in doubt, back it off, check, and try again. If you force it, something will break.

 

I've always tried to peen the new pin but it never really works because the pins are hardened steel, force it too hard and you damage the riveting pin or the chain pin. On a drive chain, the rivet link ends are soft and hollow, the round end of the rivet pin fits perfectly and you squish them to a specified diameter. Go too far and they crack, meaning you have to replace the master link.

You want to use a drive pin larger than the chain pin so that you have a larger surface area, otherwise you have to keep the pin perfectly aligned, as when you turn the thread to drive the pin, it starts rotating and can spin off the chain pin. The larger drive pin makes it easier. Also it stops you driving the chain pin in too far.

I prefer endless cam chains these days, but that said I've never had an open ended one separate and destroy an engine. Most modern bikes and the ZXR's have the cam chain on the RHS of the engine, there is a mod you can do with the ZXR where you grind away some material around the crankcase allowing you to slip an endless chain over the end of the crank.

https://2fiftycc.com/index.php?threads/zxr-cam-chain-mod.9043/

On a bike like an FZR with the cam chain in the middle it's not possible

 

Peening the pin is only possible for DIY if it has soft ends as seen on drive chains. I have only seen that on roller cam chains and drive chains. I usually attempt it anyway but get no squish on the pin, as they are hardened steel.

Most bikes use a multi-plate morse chain with hardened steel pins. No rollers. Obviously the factory links/pins are peened over but done with special tooling in a factory, allowing the links to move freely.

I would say the required tools to achieve a factory peen on a morse chain would make it impossible to do in-situ with an opened ended chain being assembled in an engine.

I'd wager the joining link pins on open ended morse cam chains are an interference fit, and rely on that to prevent them coming apart, whereas the factory-done links are not a complete interference fit, and they peen the ends over to prevent plates falling off but allowing the link to move.

 

You could always try centrepunching them once assemebled, but it's difficult to hold a chain still on a solid surface and also have a hammer and punch handy. You need about 6 arms for all that.

 

Some example pics from when I did a cam chain on a Zeal I had. The ziptie trick is a game changer

 

My ZXR250 when the supplied pin was too large for the plates - it went pop