Possible wrist pin super lightweight

[Andres]

So I was clean my garage and I found a pin that holds the valve lifter of a chinese dirt bike (125cc) so I compare with a normal wrist pin for a motorized bicycle and look exactly the same but a bit thinner my question is can use this or not is light weight meaning less vibration. My opinion is it will work if it will take the heat of the dirt bike is hotter than the motorized bicycle .Do you think it can sustain RPM????

 

[Frankenstein]

I think it would be a bad idea, I feel like the Chinese will have done everything to the bare minimum , so they felt that the wrist pin was good enough (and so far has been) so thinner would probably be cheaper and they didn't go cheaper obviously .

I also know a valve lift doesn't come nearly under as much stress as a wrist pin (think about it, wrist pin quite litteraly transfers enough energy to get you accelerating up a hill at decent speeds, meanwhile a valve lift just lifts valves with maybe a 10 pound spring load behind it.)

Give it a shot if you have an extra motor laying around.

 

[Andres]

Only got 1 engine

 

[zippinaround]

I think the pin itself isn't too important but the bearing is worth swapping out I'd think , if it's lighter and the same length could be worth trying .

 

[Frankenstein]

The pin effectively connects the piston to the crank shaft. It's just as important because the crank needs to compress the gas and air in the cylinder, pin connects the piston bone to the crank bone.

 

[Andres]

I think the pin itself isn't too important but the bearing is worth swapping out I'd think , if it's lighter and the same length could be worth trying .

The bearing even pass

 

[zippinaround]

The pin effectively connects the piston to the crank shaft. It's just as important because the crank needs to compress the gas and air in the cylinder, pin connects the piston bone to the crank bone.

The pin connects the piston to the Conrod which is connected at the bottom end to the crankshaft , yes it is obviously important but The stock one is fine whereas the stock bearing is not , most of the engines I've come across have z-l Conrods where the bottom bearing is not even caged the rollers are just stuffed in there , seems more dangerous to me .

 

[Thomas jester]

Does anyone know where I can find a titanium wrist pin for a 66cc motorized bike

 

[6blueoval9]

Does anyone know where I can find a titanium wrist pin for a 66cc motorized bike

I was after one myself till I read a crap load of failure reports..maybe it was just the use with the bushings being offered but no real resolution came about..The place that was supplying the pins and bushing are off the radar anyways.

I would suggest Just drilling out the stock pin 1.3mm to lighten it and get a better quality bearing.

 

[machanic]

I was after one myself till I read a crap load of failure reports..maybe it was just the use with the bushings being offered but no real resolution came about..The place that was supplying the pins and bushing are off the radar anyways.

I would suggest Just drilling out the stock pin 1.3mm to lighten it and get a better quality bearing.

Titanium can't be made hard enough to be a bearing surface even with nitriding, but the stock rod can be lightened, most high performance two stroke pins have a tapered bore, thick in the middle to thin on the ends, the ends can be thinner because they only carry half the load each.