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#1 |
Join Date: Feb 2012
Posts: 23
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250cc 4 valve Grom Clone
Hi im in the south Kansas City area
This is a Condor 150cc swapped to the Zongshen "CB250r" 250cc 4 valve engine. Complete build price after i insall the wideband AFR gauge and the new cluster is about $2800 but i sold the 150 motor brand new for 400$. The idea was to create something more reliable and less expensive than the Daytona/zongshen 212cc 4 valve. This motor cost me $560 and i know the ZS212cc 4v is around $1100. https://www.youtube.com/shorts/DFqqaxOrgqE I will be happy if it can hit 90mph with the 17/31 sprocket setup. Last edited by warrenpeas; 12-17-2023 at 11:36 PM. |
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#2 |
Join Date: Jan 2024
Posts: 28
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Nice project. 90 on a mini! WOOT, WOOT!! I just picked up one of these recently and I'm almost done building it into a stunt bike. I'm sticking with the 150, but I replaced the carb with a tunable PZ27 and the exhaust with a KPT200 pipe and a slip-on muffler.
I just joined up so I'll probably document my build. I'm coming out at a total around $2500 total. Can you tell me more about that exhaust you have? |
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#3 |
Join Date: Feb 2012
Posts: 23
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exhaust
the pipe is from aliexpress listed as kpt200 exhaust. the slip on is from amazon. https://www.aliexpress.us/item/32568...Cquery_from%3A
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#4 |
Join Date: May 2018
Posts: 1,611
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What’s up with the engine ?the name on the side of it looks like zonsen ,is it a clone of a clone or are my eyes failing me faster than I think ?
I have no interest in these bikes but it would be a lot of fun wringing it out . |
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#5 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,561
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4 valves ?!
Nice swap! but Whoa,whoa, whoa. That is a 2 valve engine, isn't it?
4 valve zongshens are WATER cooled, aren't they?
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it Last edited by Thumper; 01-21-2024 at 03:32 PM. |
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#6 | |
Join Date: Feb 2012
Posts: 23
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Quote:
turn on closed caption and change the setting to english to understand what the hell they are saying. here is the video of the 4v head here he disassembles the top end. here is the video of the dyno test vs the zs172fmm-6 vs a 172 2 valve i think and explain the power band difference . here he compares the zs172fmm-6 to an older 2 valve version? zs172fmm-? i just found these videos earlier today before work and havnt had time to watch them all and read everything they said but it is informative. |
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#7 |
Join Date: Feb 2012
Posts: 23
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when i was looking for ths motor i was tlaking to a seller in China i had bought zs190 horizontal engines from. i told him i wanted the most powerful Vertical AIR COOLED 4 stroke engine he could sell me and this was it he told me. although i wonder if there might be a more powerful 300cc option after looking into it more. Oh and i was trying to keep the price under 1000$ delivered. I paid $560 for this delivered to my door. in comparison the zongshen 212cc 4 stroke horizontal motor is $1080 delivered.
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#8 | |
Join Date: Jan 2024
Posts: 28
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Quote:
OK, I just pulled the trigger on the 4-valve 250. There is also a 4 valve 300, but it appears to have a funny exhaust angle, so I thought 23hp would be enough. The 300 is the Zongshen NB300-F Someone should try this out. |
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#9 | |
Join Date: Jan 2024
Posts: 28
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Quote:
Total fail... 5 months later I'm getting a partial refund. I am ordering the ZS172FMM3a for 19 HP instead of 23.. |
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#10 | |
Join Date: Feb 2012
Posts: 23
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Quote:
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#11 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,561
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Amazing! Very cool. I like it !!!
I FOUND it. Yes, the ones I found appear to be 5 speed. I see the gear position diagram has 1-N-2-3-4-5 in the decal on the stator cover: I saw "Zongshen" on one red valve cover photo. I wonder if Zonsen is another pirated logo, or just a different Zongshen logo. Could be made by Zongshen. Heat could be an issue depending on where you are driving and how hot it is out. You would want wings focusing air through that head if you are riding off road (slower speeds, more work!).
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it Last edited by Thumper; 01-21-2024 at 10:52 AM. |
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#12 | |
Join Date: Feb 2012
Posts: 23
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#13 |
Join Date: Aug 2013
Posts: 253
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I doubt a 300 will fit, but it might. Some YouTuber put a CBR300R engine on a Grom. So you never know.
Personally, I think the Sweet spot is between 175cc and 200cc. You still get good fuel economy, especially if it's a higher compression engine, tuned well, but also a lot more torque and top speed than the 150. I'm wondering if it was a plug and play, or did you need to weld any mounts? From the space I see inside that bike, I probably would want a size smaller engine. Most engines run between 180 and 212F, this due to them being water cooled and 212F is the boiling Temperature of water. |
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#14 | |
Join Date: Feb 2012
Posts: 23
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Quote:
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#15 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,561
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You have a rare engine there, and fitting it into the Grom clone must have taken some deft engineering. Very cool.
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it |
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