Wicked 090

[Deets066]

How far off is it?

 

[Deets066]

I could Probly get a custom pin bearing that’s smaller so I have to bore it less.

 

[mgr1]

Bearing 15x18mm vs 13x17mm small end?

 

[Deets066]

Bearing 15x18mm vs 13x17mm small end?

Yup

 

[mgr1]

That is a problem. No bearings in 15x17mm.

You need a custom conrod or custom piston.

Do You know the big end pin diameter and the conrod length from this 084?

 

[Deets066]

That is a problem. No bearings in 15x17mm.

You need a custom conrod or custom piston.

Do You know the big end pin diameter and the conrod length from this 084?

There’s only so many custom 70mm pistons.


I wonder if crank works could help me out

 

[Red97]

Make 2 reducer caps and run the 13mm pin in the 15mm piston hole.

Whittle Couple of bronze caps. should do the trick.

Bore the I'd to just fit the 13mm pin, turn the od to just fit the piston.

Same length as the pin boss for full support.

Fully closed/ or a hole in the end, depending on circlip style.

May have to shorten the 13mm pin a bit, but I would go that route before messing with the rod end.

 

[mgr1]

1mm reducer tickness with that rpm's and torque?

 

[Red97]

1mm reducer tickness with that rpm's and torque?

You want 1mil bdft?

Or to make a few dozen 3 cuts?

Some of the bronze will be harder than the aluminum...

I don't see it any different the bushing the small end of an auto rod, those are not much more than 1mm wall if that.

 

[mgr1]

Thats why i asked it.
Thanks for you knowledge Red97.

 

[Definitive Dave]

13mm pin is too short for an 090 piston

 

[Red97]

13mm pin is too short for an 090 piston

How short are we talking?

 

[Definitive Dave]

 

[Red97]

View attachment 233158

Perfect.

 

[Definitive Dave]

that might work, measure three times, lathe once

 

[Red97]

that might work, measure three times, lathe once

Find enough material to lathe 7 times..

As long as the 13mm pin is captured on the cir clip ends. That should be the only "problem" area. The 13mm pin sneaking out to tango with the circlip/ transfer port.

But a blind bore bushing would solve that.

 

[Deets066]

I do believe I could make that happen, I’ll see just how much bearing the 13mm pin will have on the piston and decide with my inadequate engineering skills if it will be enough to hold 157cc together running on nitro. Lol

 

[Lightning Performance]

Use the bronze sintered bushings available.
Joes right about using bushings that look like cam buttons with holes punched in them... been there did that a long time ago to big bore a Yamaha dirt bike. Make them big so they fit the piston tight. Our first slide in set ruined the piston from slop.

Thought you were doing this from the start.

I used aluminum cam buttons to test fit mine. Had a local tool maker spin up the bushings in bronze. It worked great but it needs little play or beats up the wrist pin clip bore in the piston. We had to use driveshaft cup needle bearings and reamed the rod to fit. Fuggin runner to. It was like an MX 385 or something like that when finished. Wheelie machine. Stuck nitro in it to. My cuz damn near hit a pole with it on a hot shot so we gave up on nitro runs in the street.

Nice call on flattening the case top. 518 the plate.
It should go with a pipe

 

[Deets066]

A couple of these should do it.

 

[Red97]

I think it will work fine.

During teardown I would inspect the pin/bearing extra close...

It is a bit under the 25% piston to pin size ratio.. likely see a bit of deflection. But should have plenty of service life... Should