2.5L Rocket Stroker Engine Kit with 6 Speed Transmission (R&D)

[Claviger]

I'm a day late but here's the graph. This is my bike, if I were to only up the stroke to 4 inches with NO other changes. There are things to optimize and maximize the gain of stroke, cam timing, intake diameters/length, exhaust dimensions etc. These are CRANK measurements, mulitpliy them by .875 for fairly accurate WHEEL measurements.

Mufasa 2.3 --- Mufasa 2.5
213lb-ft --- 227lb-ft
273hp --- 276 hp

As you can see, there are clearly other restrictions and flow bottlenecks, indicated by the 6200 RPM+ roll off in power, which is why they end up essentially at the same HP. The stroker is making 133lb-ft by 2200 RPM, so right at cruising legal speed range in most places, and will be enjoying a nice EGR effect from the big cams. I suspect this would be like a 45-50mpg setup for touring.

 

[Claviger]

I just got off the phone with a company who is on board with manufacturing new Cylinder liners.

Coincidentallly I have a complete motor in the mail on the way to my house.

The price on new Liners is shockingly low, no Nikasil coating required with the material they use.

I need to get the new (to me) motor torn down on arrival and ship them the top case half with liners in place so they can do the development work. He doesn't think going from 4 inch to 4.125 inch bores will be a problem

Will post more when I have solid info.

PS: The price for the 3 liners INSTALLED is under 1k USD...

 

[Claviger]

More follow up. I have confirmation that 4.125 pistons are easily sourced, in whatever compression ratio. I've also confirmed molly side skirt coating, and top gas ports are available as well as hard anodizing.

These would be CP pistons, billet 2618s.. JE and Weisco are essentially the same company now and want a 6 piston minimum order, they will also do all the same options.

So basically, the very top tech pistons currently available can be had in the bored out size. At 105mm by 94.3, the displacement comes put to 2450cc. Now throw a stroker crank and rods in.... 2640cc.

That 15% bigger, that's a whole different animal ladies.

2 6 4 0 ...

 

[barbagris]

2 6 4 0 ...

You could just buy a 350cc royal Enfield and bolt them together!. @idk went too far with the 500 - and ended up selling the R3.

 

[Claviger]

One more resource. Cometic will custom cut a reusable copper gasket to match whatever size is required. I'll be sending them my extra, new, headgasket to make a template from so they'll have it on file.

 

[Joesmoe]

Don't mean to hijack the thread: wonder if they could make a more reliable valve cover gasket. I'd be happy to donate an example.

 

[barbagris]

Don't mean to hijack the thread: wonder if they could make a more reliable valve cover gasket. I'd be happy to donate an example.

That's actually something that could be done via 3D printing and probably in something a bit stiffer. Calling Mr @Claviger

 

[R-III-R Turbo]

While we're waiting on the 2.5L components' lead time...

6th Gear Update

Research is done and the new 6 speed tranny parts are designed.
We have found a way to fit 6th gear in - without compromising any existing gears.
6th will be the thickest cogs in the box.

I wasn't aiming for a certain rpm at say 80mph - we'd have to take what we get,,, as we are retrofitting an additional gear, and there are constraints like what diameter cogs we can fit in, and constant mesh gears with fixed centres so not a lot of options for teeth numbers.

Won't bore you with the technical challenges overcame but here's the way it has worked out;

• • Calculated to run 2200rpm at 80mph
• • Theoretical top speeds are (wait for it!) 225mph @ 6300rpm,,, or 320mph for 9000rpm engines

Other ratios calculated either a diameter that won't fit, or a ratio that makes it unfeasible to have a 6th speed (i.e. revs only drop a modest amount at ~80mph vs existing 5th's 3000rpm).

So we have settled on this 2200rpm @ 80mph and 225mph top end for stock rev limit ratio gearing, to proceed into operational testing.

Currently we are 3D printing the new stage 1 hybrid prototype gearbox for operational testing by hand and tweaking.
By hybrid I mean it's the OEM metal gearbox with the new 6th gear parts fitted in plastic.

Next update should be a video demonstrating the prototype box in operation, proving the concept, toggling through gears!

Stand by

 

[warp9.9]

While we're waiting on the 2.5L components' lead time...

6th Gear Update

Research is done and the new 6 speed tranny parts are designed.
We have found a way to fit 6th gear in - without compromising any existing gears.
6th will be the thickest cogs in the box.

I wasn't aiming for a certain rpm at say 80mph - we'd have to take what we get,,, as we are retrofitting an additional gear, and there are constraints like what diameter cogs we can fit in, and constant mesh gears with fixed centres so not a lot of options for teeth numbers.

Won't bore you with the technical challenges overcame but here's the way it has worked out;

• • Calculated to run 2200rpm at 80mph
• • Theoretical top speeds are (wait for it!) 225mph @ 6300rpm,,, or 320mph for 9000rpm engines

Other ratios calculated either a diameter that won't fit, or a ratio that makes it unfeasible to have a 6th speed (i.e. revs only drop a modest amount at ~80mph vs existing 5th's 3000rpm).

So we have settled on this 2200rpm @ 80mph and 225mph top end for stock rev limit ratio gearing, to proceed into operational testing.

Currently we are 3D printing the new stage 1 hybrid prototype gearbox for operational testing by hand and tweaking.
By hybrid I mean it's the OEM metal gearbox with the new 6th gear parts fitted in plastic.

Next update should be a video demonstrating the prototype box in operation, proving the concept, toggling through gears!

Stand by

Will the next one have the sixth gear dog in the shifting drum or just the shafts in the box? Oh and did you keep the same modal pitch of the gear teeth as all the others or did you have to alter it?
Very interesting. So 1516 rpms at 55 if someone shifts her into sixth then. So what are the mapping plans for fueling and timing and other various ecu technical filtercarb ?

 

[Paul Bryant]

Very cool Arto, you are doing it, not just talking about it.
I, for one am very interested.