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

[barbagris]

(2) Premium 6th gear kit - Complete Transmission Upgrade - includes undercut dogs, deepened & widened circlips, billet replacements for the weaker gears, improved dog meshing from a selector drum upgrade, and also comes with all the OEM/Triumph consumables like gaskets, oil, circlips etc needed to do the upgrade.

But still misses the R3 Guru to actually do the work!. I suppose I could catch the ferry from Spain to Cork

 

[Idaho Red Rocket 3]

Calculations done a while back indicated ~27% reduction in engine RPM while maintaining the same road speed, going into 6th from 5th.
As in ~2200rpm down from ~3000rpm, at ~80mph.

The only practical means available so far is the 3D printed plastic gears in the video, where the input speed is ~73% of the output speed, so this initial practical test is consistent with the calculations.

I forgot the laser tachometer so RPMs are just from counting revs (blue tape!) per second by stepping through the footage frame by frame in a video editor program. That and the transmission was being spun with a handheld battery drill, so the input speed could vary slightly.
Hence the "approximate" RPMs and %'s!





The plan is - if it works and is reliable, that is - to make the kit available in 2 levels of "trim";

(1) Standard 6th gear kit - base kit of what's needed to have the 6th gear

(2) Premium 6th gear kit - Complete Transmission Upgrade - includes undercut dogs, deepened & widened circlips, billet replacements for the weaker gears, improved dog meshing from a selector drum upgrade, and also comes with all the OEM/Triumph consumables like gaskets, oil, circlips etc needed to do the upgrade.

I live in a state that has 80 MPH speed limit. When riding at that speed my RPM is definitely much higher than it needs to be. I would like to have an overdrive 6th gear.

Question ?? Why did you choose 2200 RPM at 80 MPH as the target RPM/Speed numbers ? Is there a benefit at this RPM as opposed to using something in the 2300 to 2600 RPM range for 80 MPH ? Would the peak torque RPM be a good choice for the target RPM at 80 MPH ?

 

[R-III-R Turbo]

I live in a state that has 80 MPH speed limit. When riding at that speed my RPM is definitely much higher than it needs to be. I would like to have an overdrive 6th gear.

Question ?? Why did you choose 2200 RPM at 80 MPH as the target RPM/Speed numbers ? Is there a benefit at this RPM as opposed to using something in the 2300 to 2600 RPM range for 80 MPH ? Would the peak torque RPM be a good choice for the target RPM at 80 MPH ?

Unfortunately the Rocket transmission is not a 6 speed with 1 set of gears just left out,,,, it's a 5 speed that happens to have 2-3 bits out of a 6 speed already in it (6 gear + N positions on the detent wheel, 6 + N positions on the GPS, and a blank space on the selector drum above 5th).

So there are a lot of constraints that really limit the options.
E.g. when it comes to effective RPM drop & top speed, the input and output shaft centres are fixed, so the sum of the paired cog pitch diameters must be equal to twice this shaft centres distance, also the gear module has to be the same so teeth will mesh.

The 3 feasible options I came to conclusion of;

(a) this option calculated to give 2200rpm at 80mph, i am sure it will work although there are a number of challenges

(b) this option calculated to give 2700rpm at 80mph, i am also sure it will work, and less challenges than option (a), doesn't drop the rpm as much as I'd like/not enough to make the job worthwhile

(c) this option is sort of a happy medium between (a) and (b), calculated to give 2400rpm at 80mph, which is satisfactory, however... it is venturing too far into the unknown.


Hence I picked option (a). I might develop option (c) in parallel to see if it'll even work, but the focus will be ion (a).

 

[Idaho Red Rocket 3]

Good answer. Thanks for the detailed info.

What is the current RPM at 80 MPH ? Actual 80 MPH corrected that is. As we all know the speedo reads a lot higher than actual unless you have it corrected.

 

[Jvheli]

Good answer. Thanks for the detailed info.

What is the current RPM at 80 MPH ? Actual 80 MPH corrected that is. As we all know the speedo reads a lot higher than actual unless you have it corrected.

3000 rpm at 80 according to my bikes tach. My speedo was calibrated on the dyno.

 

[Paul Bryant]

I agree completely with A) Arto.
The five speed gear box is a good set of ratio's, having sixth as an "overdrive" to drop cruising RPM would be a much wanted welcome.

Re the reality, simply trust your calculations, (so long as you have done the math correctly, which I don't doubt that you have) it's all simple mathematics.

 

[Paul Bryant]

The math is the easy part (yea', I know, hours of it!)
The challenging part will be the organizing of the production of the components, along with the expense and time there of.
(I know you know this)

This modification will truly bring the Rocket into it's own as an open road Power Cruiser.

 

[Joesmoe]

Let me know when you accept orders.

I'd like to be in line.

 

[IMFASTTOO]

The math is the easy part (yea', I know, hours of it!)
The challenging part will be the organizing of the production of the components, along with the expense and time there of.
(I know you know this)

This modification will truly bring the Rocket into it's own as an open road Power Cruiser.

YES as long as you keep it above 2000 rpm and dont lug it in 6th

 

[Kruser]

YES as long as you keep it above 2000 rpm and dont lug it in 6th

I can see it now.. Idleing up to a ****** rocket doing 80mph. He whacks the throttle. I smile and whack mine to 1/2 and dust him.