FINAL 164CC setup with testing results!

[QuantiQualification]

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[Little_Thumper_Boy]

Fun stuff. Thanks for sharing, always enjoy watching the results of these projects!
It appears head/valves generally become limiting factor on 'top speed' with these little thumper BBKs - the Honda's 125's just won't rev that much more w/o it, beyond a mere cam upgrade. IME gains are low-mid range (w/o headwork that is).
Is this your Trail CT in the video? Can you tell us the elevation?

 

[SneakyDingo]

Yay, new video! I was hoping you'd release one, I kept checking back on your channel to see if you'd gone missing or were just busy.

Did you go full Rollie Free, underwear and all?

 

[m in sc]

suggestion: run 6 stock springs. i went thru this on the grom as well way back. as far as the limiting factor, it still has a stock ecm and i am 100% convinced its th etiming curve int he ecm. My wifes stock supercub will hit 60, but has a different ecm. .02

 

[QuantiQualification]

Fun stuff. Thanks for sharing, always enjoy watching the results of these projects!
It appears head/valves generally become limiting factor on 'top speed' with these little thumper BBKs - the Honda's 125's just won't rev that much more w/o it, beyond a mere cam upgrade. IME gains are low-mid range (w/o headwork that is).
Is this your Trail CT in the video? Can you tell us the elevation?

Yes, this is my Trail CT in the video . Gains are mostly mid and low, like you suggest but definitely get a good bump at the top end. Timing and head work to get more out of it, you are correct!

 

[QuantiQualification]

Yay, new video! I was hoping you'd release one, I kept checking back on your channel to see if you'd gone missing or were just busy.

Did you go full Rollie Free, underwear and all?

Like I was flying! Nah, I just scooted back a little bit to drop my helmet down and she started a wobbling. Next time, next time . . . 70 mph here we come.

 

[QuantiQualification]

suggestion: run 6 stock springs. i went thru this on the grom as well way back. as far as the limiting factor, it still has a stock ecm and i am 100% convinced its th etiming curve int he ecm. My wifes stock supercub will hit 60, but has a different ecm. .02

Timing definitely is one of the limits! You can feel the wind go out of the sails as you pass 7500 rpm. 6 stock for the clutch is what I was running. I can back off to two of the stiffer springs and see where that leaves me. The unique clutch in the trail just doesn't seem to have enough throw to deal with the 6 stiff ones that I have on now and still give smooth easy shifts.

 

[SneakyDingo]

Like I was flying! Nah, I just scooted back a little bit to drop my helmet down and she started a wobbling. Next time, next time . . . 70 mph here we come.

Can't wait

 

[Mac-7]

I dont think the 5-8 mph performance gain was worth $1500

 

[QuantiQualification]

I dont think the 5-8 mph performance gain was worth $1500

Mine could only do 52 mph indicated ~50 mph actual so 10-11 mph. If there was any hint of a breeze, 45 mph. Anyway, I had three specific goals and it took $1500 to get there for me. 1) 55 mph constant (headwinds, hills, etc.) 2) Minimum range of 150 miles on a full tank 3) 150cc minimum engine capacity 4) As reliable as stock. For me, stock was unusable based on the speed and engine capacity, hence the effort, but it is not for everybody.

 

[m in sc]

I dont think the 5-8 mph performance gain was worth $1500

then don't do it. it also adds midrange and drivability is greatly improved, and its a fun project
but to each their own.

 

[dmonkey]

Sounds like it made the capable of what you wanted from it. I appreciate that you've shared this process, the parts, specs, and costs, the attempts and failures, as well as the success with us. The bike itself, irrelevant of the engine, gets sketchy above 60 mph (or so I've observed on downhills). Because of that I don't have much interest in more top speed under optimal conditions, but what you've accomplished of being able to hold 55 mph through hills and headwinds, that's the performance that matters to me in making the CT more usable. I put 1,200 "highway" miles on mine last weekend and sure could have benefited from that extra power.

 

[m in sc]

i firmly believe the rubber swingarm bushings are the cause, Im going to change mine out to bronze ones for multiple reasons but stability at higher speeds is def one of them.

 

[Mac-7]

Mine could only do 52 mph indicated ~50 mph actual so 10-11 mph. If there was any hint of a breeze, 45 mph. Anyway, I had three specific goals and it took $1500 to get there for me. 1) 55 mph constant (headwinds, hills, etc.) 2) Minimum range of 150 miles on a full tank 3) 150cc minimum engine capacity 4) As reliable as stock. For me, stock was unusable based on the speed and engine capacity, hence the effort, but it is not for everybody.

I’m glad that you got that much improvement

how much to you weigh?

 

[QuantiQualification]

Around 145 before gear and accessories.

 

[m in sc]

im at 205-210 and with a 143cc and pretty much otherwise all the same mods (except still running stock gearing & no oil cooler), im only a few mph behind on top speed . i can hit 60-62 sitting upright on a flat, have tapped close to 70 on a downhill, and can maintain 55-56 up hills pretty easily.

IF i went 164 i also would have changed the gearing a bit, as theres more torque and then can pull a less agressive final ratio. was quite common on the groms back in 14-15-16 with 164s being fit to do this as well. (i know i did). same stuff, was common to be able to hit 70-73 actual top speed with same mods, but different w/ecm of the grom


just as a data point.

 

[Milkman]

Really enjoyed your videos and we are practically neighbors here in KY. Once I get some break in miles out of the way I’d love to take my ‘23 up to just be able to hold 55 regularly, don’t need flat out speed. With the new engine it’s a whole new what part fits and works challenge.

 

[freenode]

...as far as the limiting factor, it still has a stock ecm and i am 100% convinced its th etiming curve int he ecm. My wifes stock supercub will hit 60, but has a different ecm. .02

Agree. The Super Cub 50 series (AA01) ECU activates a fuel economy driving mode that forces a 60km/h limit when wide open throttle in top gear (4th gear). Kitaco has a module called the Power Inspire that deactivates or releases the limit and increases top speed (for the Super Cub 50). Most likely there is a similar limit on the Trail 125.

 

[m in sc]

that's very interesting...

 

[DaleT]

Agree. The Super Cub 50 series (AA01) ECU activates a fuel economy driving mode that forces a 60km/h limit when wide open throttle in top gear (4th gear). Kitaco has a module called the Power Inspire that deactivates or releases the limit and increases top speed (for the Super Cub 50). Most likely there is a similar limit on the Trail 125.