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Rebuilding our 23 MC250f and hit a bit of an issue. The stock and vertex piston use super strong c clips and I bent one getting it out which of course I didn’t care because they’re not getting reused. But getting the new ones in is absolutely ridiculous. So much so in fact the service manual calls for a specific tool. Here’s the kicker, 450 tool $35/40 bucks, 350 tool is the same. 250 tool is $165! I appreciate the fact I’ll never have to worry about a circlip coming out but a tool that expensive to install them is crazy. Anyone had any experience or luck finding a different way? Dealt with various c clips over the years but these are insane. I stabbed myself in the finger enough times to make myself order the tool at this point.
I just did my kids 23 350 last week. I was dreading putting the clip in, turns out it was the easiest one I’ve ever installed. No tool or pick needed, just insert the top tab and work it around with finger pressure and finish last little bit with tiny screwdriver.
I did however destroy the scraper ring trying to get it in with a pick, and that ring is $130 msrp. I’ve done a good 75 pistons over the years, never needed a ring compressor, it’s impossible without on this bike.
Not sure how you just worked those in with a finger but thanks for the tip on the compressor tool.
As Zzips said, you can get them in the old fashioned way... but it's not easy given the space you have to work with. If you put the piston on without the cylinder, you have a little more room to work... but then it's almost as difficult to get the cylinder on. If you put the piston in the cylinder first, using a ring compressor, and then put the piston/cylinder assembly on (per the manual)... you have very little space to work with. Per Zzips, you have to put the tang in first, then slowly work it in going clockwise and using your finger and something like a small screw driver. They have a lot of tension, so it is difficult to get the first 1/3rd of it started... after that, it will generally snap in pretty easily. If I am not mistaken, the tools are specific to the I.D. of the pin bore. If you are using an aftermarket piston/pin, such as a CP, the wrist pin may have a slightly different I.D. and the tool may not work as well.
Same as others, fingers and small screwdriver, maybe needle nose pliers to assist a little.
The piston and rings are easy to get in without a compressor, assuming you do this first off of the engine and take your time squeezing the rings in.
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The compression ring was as easy as any others, but the oil ring is different from any I’ve ever seen. The inner expander ring is gapless and puts a ton of tension on the scraper. Using small tools, I chipped it and gave up and used a compressor.
Yeah the ktm’s have that special oil ring design which many believe is one reason their engines are so good. I just take my time and make sure the expander is properly in the scraper and use my fingers and squeeze it into the cylinder from the top down how the service manual shows.
I said screw it and just JB-weld the pin in place 😆.
I did a couple of 250 top-ends without the circlip tool and after that experience, now I have the special tool.
Got the tool today. Might be expensive but it worked perfectly. Circlip installed in 5 seconds.
The took makes it so much better I got lucky and got the tool for my bike from a dealer that was going out of business and selling it all off. I hated doing it before that.
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