Dyno testing 'performance mods'

[Chainlube]

3rd tank of fuel on the TDR moto cylinder with the zero blowdown porting...

Green line is the stock untouched CDH cylinder (open transfer)

Blue line is the stock untouched TRD moto cylinder

Brown is with the exhaust port raised 3mm and widened 4mm.

I suspect the transfers are just too high, not so much the exhaust roof being too low. I could shim the base, deck the top and port it further... If I keep raising the exhaust port It'll have nothing down low. I think I'll just melt this cylinder down and turn it into something useful.

Thing is, this TDR cylinder was AUD$18. The CDH cylinder was AUD$28. In this case, the $10 saving is not worth the 2.5HP drop in power and top speed.

That's 3 for 3. TDR snake exhaust, cylinder and piston, all not worth the gamble.

A little porting helped it, but it's pitiful.

 

[WillitBoost]

If it's been verified as junk, then probably not worth testing again here...

My CDH ported piston, plain piston and CDH cylinder arrives tomorrow so I can get stuck into some reed testing. I just saw Smolik's dyno graphs of the P85 with piston port vs reed. It made 0.5HP less with the reeds, with the stock pipe.

I'll need to wear this new piston/cylinder combo in again before I can do any substantial testing. I really want to test my new pipe!

 

[WillitBoost]

A little porting helped it, but it's pitiful.

It was definitely going in the right direction. I'm considering dropping in 4 base gaskets and cutting out another 3mm from the exhaust roof... It's trash anyway so I don't really care if it wrecks it...

 

[WillitBoost]

Alright, you talked me into it. Hold my beer

 

[DieselTech]

Alright, you talked me into it. Hold my beer

Got it!!!

 

[GW's Motorized]

I've held and seen it with my own hand. My degree wheel agreed with my findings.

They suck. Even after doing work to try and improve them they don't have much more power then any typical quality "80" engine. Maybe a bit more torque

This is the thread where I started off optimistic about making it good. I gave up on it and decided to keep the bottom end for a possible 54-56mm saw build. The first 2 posts have all the pictures and details, if you happen to be curious. https://motoredbikes.com/threads/the-110-adventures.61113/

IMO the only thing that engine is worth is the bottom end for a saw build.

 

[ImpulseRocket]

If it's been verified as junk, then probably not worth testing again here...

My CDH ported piston, plain piston and CDH cylinder arrives tomorrow so I can get stuck into some reed testing. I just saw Smolik's dyno graphs of the P85 with piston port vs reed. It made 0.5HP less with the reeds, with the stock pipe.

I wouldn't entirely call it junk, but it's a waste of money unless you want to use the base for a saw build, the cylinder for a door stop, and the head for a paper weight.

I also saw his dyno results. I am honestly not that surprised it picked up a tiny bit of power over the reed and windowed piston setup. Honestly, even half a HP isn't worth mentioning. I doubt that it needs the reed and window even with a pipe.

 

[Chainlube]

It was definitely going in the right direction. I'm considering dropping in 4 base gaskets and cutting out another 3mm from the exhaust roof... It's trash anyway so I don't really care if it wrecks it...

Cut an alloy adaptor ring for the base and cut off the top, I mean machine off.

 

[WillitBoost]

Sounds like an awful lot of work haha... I wonder if a shorter stroke would help here, it would increase all 3 durations...

 

[Chainlube]

JB weld the transfer.