Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

My thoughts exactly. I’ve ordered a piece of Teflon Ptfe from eBay.

I had low compression on the front cylinder of the Knucklehead.The piston o-ring apparently was pinched during assembly. When replacing the ring I noticed the scoring in the cylinder wall. Enough you can feel it with your nail. So I took the old ring and cut it in smaller pieces and fit it into the piston pin opening on each side. I’m pretty finicky about things.

When I get the Teflon I will cut the discs and put them in the R31.

An update on the R32, couldn't be ignorant towards the engine and the itch to make it work again didn't stop. So I ordered the new camshaft which basically has more pronounced middle lobes.
Despite that still struggling to make this run on both cylinders.

I am aware of another case of the struggle but is there anyone else who bought this engine and having issues getting a stable and reliable run out of it ?

That's really bad the new cam worn off. Brass is not the right material for gears. I would have asked for a refund to be honest.
One thing I noticed on mine was the vavle covers in the  crankcase were not moving up and down easily . I have to sand them off to have a free movement. I think that might have caused the wear on yours and mine.

New cam shaft seems to holding okay. How do you set the valve setting? Through the screw on the lifter at the bottom?

Hey guys,

I’ve lost another 10 hours of my life trying to get my R31 to run correctly. 😩

Ive never have had a miniature engine that I couldn’t get running correctly, with some work and time, but my god - I’m about to give up. Don’t wanna know how many hours I’ve put into mine, and simply can’t get my R31 running on both cylinders.  The tank side cylinder runs strong, but the opposite cylinder refuses to run.  Strong spark at the right time, correct valve clearance, compression, I just can’t figure it out.

Gonna tear the engine down completely and see what I can find out.  So far, the new cam hasn’t worn.. but will be watching it closely.

I absolutely love my R29 Knucklehead.  It’s got easily over 40 hours on it, and it’s a “one flip wonder”

I had such high hopes and excitement for Jin’s R31 Shovel. I chose it over Jin’s  Panhead.

Just bummed 😔

I personally think the whole cam design is flawed specially for a vtwin engine
Not sure how much this particular ignition timing is affecting the overall performance as well.
 I messaged Jin to see how he can help .

Funny you mentioned hall sensor. Now i have very intermittent ignition.  It quits after 4-5 ignition cycle. I noticed the engines gets quite hot even when it ran on one cylinder. And I turned on Mt desk fan to cool it down. The heart transfers quickly to the components under the base too.

I was thinking shovelhead would have any potential issues of knuckle head ironed out but it seems just a rushed product.

We need to make list of us and he has to send new cam shaft free of charge. Buy at least he's learning

Another 4 hours piddling w’ my R31 went by yesterday, with still no luck getting it to run on both cylinders.  I’m seriously at the point of buying another R31, and hoping this one runs and a stainless cam will be available.

Never have been stumped with an IC engine like the R31.. I’m 41 and have been taking apart engines since I was 6 years old.  People in the neighborhood would give me their old lawn engines when they’d buy a new mower.  Best “toys” I had as a kid