Which pin lock do you prefer?
I have lost my share of both on installation but neither have been a issue running.
I will say I lean towards standard.
i like the spiralock but never had an issue w either.
Quote from: m in sc on January 15, 2026, 09:25:56 PMi like the spiralock but never had an issue w either.
I find them to be a bitch sometimes to remove when needed.
Spiral loks are for heavily loaded engines and prevents wrist pin pound out of pin rings.
No need on these 'lil engines unless severely over rev'd.
Make damn sure wrist pins are compatible with lock rings.
High rpm spiral for sure.
The rest standard. Standards main failure is usually due to a nick in the wire from instal. Have to be careful getting them in.
Nicks yes, but main problem is not seated in the groove.
Hears a good one for ya'll...
Production engine was having troubles kicking the wrist pin out and messing up the engine.
A few hundred a month!
Everything "checked good" in inspection of new and failed engines.
Same cylinder every time, the pin was damaging bores. The pin ring was pounded out as was the groove.
Finding out about this I said the only thing that would do this is mis-alignment, as in offset conrod, mis-machined piston or crooked crank.
Offset was zero, always same failed cylinder, so common denominator was the crank was off-axis.
They scoffed at this since the original basic inspection had shown within tolerance.
A few weeks later and after a few more 100's of failed engines, they did a full dimensional of the crank. Results: "#5 journal was offset by .08mm to the rear".
I said that is not the problem, the journal must be off-axis to the mains!
Needless to say, 100's of new failures after the .08mm was corrected.
Turns out the dummy "engineer" had zero idea what the dimensional report indicated.
#5 journal was 2 degrees off-axis.
Oy vey :whistle:
In karting land a lot of ham fisted mechanics throwing pistons in after every hour of run time meant a surprising amount of circlip failures. 20k rpm wasn't helping either.
Which engines have you played with?
I have some play time with Yam 100,sirio and a little $3000 50cc italian jewel Comer50!