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#1 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,601
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ZS172-FMM-3A 249 to "300cc" kit
I found this kit on AliExpress for $125. It is calling it a 300cc kit. The bore is increased from 72 to 74mm. I think it is probably 280cc, but I'LL TAKE IT!
This kit will probably fit the 6 speed engine (ZS172-FMM-5), but I am going to try it on the 5 speed engine. I need to find an advance key for the timing as well. I haven't been able to find a NC250 style resonator exhaust for this engine. The one made for the NC (water cooled engine) probably won't fit right. This seems like a perfect Winter project: |
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#2 |
Join Date: Nov 2022
Location: Dallas TX
Posts: 610
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Thumper, I use this calculator for CC:
https://www.performancetrends.com/Ca...splacement.php With the original OEM advertised "Bore x Stroke 72x61.4" figures and the above calculator I get: Engine Displacement of 249.99 CC If I use 74mm as the Bore figure I get: Engine Displacement of 264.07 CC Keeping the Stroke the same on the engine the Bore would have to be 79mm to get an Engine Displacement of 300.96 CC |
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#3 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,601
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That makes sense. 72 to 74 mm is not much! Then again, the bore/stroke is already oversquare. Maybe a subtle increase in piston diameter coupled with head porting and a timing advance will bump HP to 24 or 25. I wish we could find a resonator style open flow exhaust system that fits this engine. I will keep looking.
Last edited by Thumper; 11-05-2022 at 12:26 PM. |
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#4 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,601
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This kit got delayed in shipment. Then the order was "cancelled" but I didn't get reimbursed for the payment I made. Now there is an update that it has a new delivery date
![]() Still waiting! |
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#5 |
Moderator
Join Date: Oct 2016
Location: Houma, La.
Posts: 11,685
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You can get a little more compression by only using a single layer of the head gasket. Wiseco may have a 74mm high compression piston that might work. It takes a good bit of research but might be worth the effort. I'm looking for a 72mm for the KPX.
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2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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#6 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,601
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The ~10:1 OEM setup is working with regular unleaded. I am sure the 74mm piston (or whatever is in the kit) also has the same compression ratio, so will also work with regular unleaded.
I know, I know, we get 70mpg, so why not fill it with premium! But the head porting and advance key will complement the modest displacement increase. Of course, I don't know when I will find the time to do ANY of this ![]() |
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#7 | |
Moderator
Join Date: Oct 2016
Location: Houma, La.
Posts: 11,685
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Quote:
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__________________
2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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#9 |
Moderator
Join Date: Oct 2016
Location: Houma, La.
Posts: 11,685
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All these china bikes make good projects for learning at a minimal cost. Stick around too long and you will be doing the same.
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__________________
2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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#10 |
Join Date: May 2023
Location: Central Florida
Posts: 9
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![]() ![]() I have the 22 templar x 6 speed myself modded out and I'm loving it! can hit 90mph fully pinned and head/torse tucked down. I'd still like to know if anyone has found any options for the 79mm bore/300cc kit upgrade to the 3a motor? thanks guys!
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2023TEMPLAR X 6Sp <3 Central FL ![]() ![]()
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#11 |
Join Date: May 2023
Posts: 1
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Exhaust and cdi box questions
sshoress, can you show links on your exhaust and ignition system??
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#12 | |
Join Date: Aug 2020
Location: Australia
Posts: 1,378
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Quote:
If you experience any thing like this, or the seller start to make replacement sent claims, especially without tracking or will not refund... Open a ticket with Aliexpres ASAP. I've had sellers draw out orders long enough for customer support to expire. Just open a ticket with Aliexpress and raise concern/doubt. I learned the hard way. |
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#13 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,601
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I did receive the kit. But the amount of work involved in gaining 15cc displacement is hard to justify. It is certainly not a "300" cc kit. But the quality seems high. It is an OTOM kit, 74mm.
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-NOS 2020 KTM 250SX (2-stroke motocross) |
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