Free and Inexpensive Scooter Performance Mods

[TBR125]

Generic Disclaimer:         

Conditions apply. If you experience the following symptoms, speed obsession, random vehicular disassembly, or wrecking please see your psychiatrist for assistance and rehab.


Hi,

I own an Agility 125 scooter for transportation. I have always worked toward increasing performance as much as possible considering my limited budget. The following posts will outline the mods I have completed that can be done by almost anyone for free or very little cost (I am assuming time is free which for many it is not).

Current scooter.

[TBR125]

Soon after I acquired the scooter I began having occasional start problems and started running non ethanol fuel. On warm days the bike would die after a few seconds and then would not restart until it had sat for an hour. After research and diagnostics I found the problem was the expanding wax auto enricher. The bike ran rich from the factory and the auto enricher always gave the equivalent of full choke.

Solution: Manual Choke

$28 at the time of purchase.

https://hammerheadperformance.com/manual-choke-for-150cc?matchtype=&network=g&device=c&adposition=&keyword=&gclid=EAIaIQobChMIpb_a55rQ6AIVC5SzCh1mjgsHEAYYAyABEgKt4_D_BwE

[TBR125]

I was having valve float problems going down hills and needed to check rpm with a Tachometer.
I mounted it under the mirror screwed on a scrap doorbell striker bar.

Tachometer:

11$ at time of purchase.

https://www.amazon.com/Maintenance-Tachometer-Replaceable-Motorcycle-Paramotors/dp/B07PMJH7QV/ref=sr_1_5?dchild=1&keywords=tachometer&link_code=qs&qid=1586052983&sourceid=Mozilla-search&sr=8-5

[TBR125]

I wore flat spots in the 14g roller weights from riding on the highway with the variator fully extended for long periods. I replaced them with 12g Dr. Pulley sliders.
The valve float was from unwittingly hitting 11500rpm at 78mph:) Tachometer proved useful.

Sliders:

25$ at time of purchase.

https://www.amazon.com/Dr-Pulley-Sliding-Roller-Weights/dp/B00VUXF8W6/ref=sr_1_3?dchild=1&keywords=dr+pulley&link_code=qs&qid=1586053462&sourceid=Mozilla-search&sr=8-3

[TBR125]

The Dr. Pulley slider completely changed the power band and massively increased mid range pull. I realized with the tach that the bike had sufficient power but was running out of variator range to stay at max power at 7500rpm. The drive belt was running within 1/2 an inch from the outer edge of the pulley sheaves. The hindrance to utilizing the full pulley face and effectively increasing the pulley diameter was the sheaves contacting each other at the shaft on the drive boss.

The solution was to remove material from the pulley sheave cone until the belt could reach the full diameter. The belt was 20mm and the pulley groove when compressed was 23mm. Leaving 1mm for safety I removed 1mm of material from each pulley face. I then shortened the drive boss by 2mm.

Cost: Free+4 hours sanding

[TBR125]

With the variator tuned the bike cruises at 7500rpm at 74.6mph. With the extra variator range power was the limit. My stock exhaust was crunched and highly restrictive. I purchased a hi flow exhaust unit because it was cheaper than I could build a baffled pipe for.

Performance Exhaust:

$24 at time of purchase.

https://www.ebay.com/c/22009506411

[TBR125]

Here is the exhaust.

[TBR125]

With unlimited exhaust capabilities I am increasing air intake by installing a large UNI foam filter to the carb. The carb in the pic is not the one from the bike.

UNI Air filter:

18$ at time of purchase.

https://www.amazon.com/dp/B001KO6KS6/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B001KO6KS6&pd_rd_w=HdoPO&pf_rd_p=48d372c1-f7e1-4b8b-9d02-4bd86f5158c5&pd_rd_wg=DBnys&pf_rd_r=41ZNGA6CSMJPNC7G5TSB&pd_rd_r=1c1311ad-c03d-42b4-9168-1f21f7355272&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyNFVIRDhaMjRaN0dOJmVuY3J5cHRlZElkPUEwNTMxNTk5MlBGQzNMMURFS0RYViZlbmNyeXB0ZWRBZElkPUEwMTc0OTA3R09OMExSN0VUQkxQJndpZGdldE5hbWU9c3BfZGV0YWlsJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

[TBR125]

I'm currently re-jetting and tuning the carb. I will update the post with future mods.

Hope some of this was helpful. Let me know if additional info is needed.

[scooterfan]

Thanks for sharing. I was thinking about a similar variator mod as well. The only downfall I can think of is that driving belts probably need to be replaced more often - because when the belt becomes worn (narrower) the inner part of the belt might start touching the variator Shafts ?

[CROSSBOLT]

Really impressive! Good pictures! The variator mod makes sense. De dee is the first to do something like this on a Downtown 300i and could never understand how he did what.

You rapidly becoming the go to guru!

[TBR125]

Thanks. I understand the mechanical aspects but will need some advise in the future on electrical harnesses.

[CROSSBOLT]

Aha! That can be some of the biggest mysteries! Wiring diagrams NOT in the service manuals are very scarce. The ones that are in the service manuals tend to be incomplete monochrome line drawings. This will be fun for all! No, REALLY! Har, har!

[TBR125]

Thanks for sharing. I was thinking about a similar variator mod as well. The only downfall I can think of is that driving belts probably need to be replaced more often - because when the belt becomes worn (narrower) the inner part of the belt might start touching the variator Shafts ?

That was definitely a concern. I accounted for it by controlling the drive boss length which negates the effect of a worn belt.

[jeeves]

Good job! [emoji106][emoji106][emoji106]
Will follow this thread.
Courious to see how the jetting is gonna go!

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