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#17 |
Join Date: Feb 2012
Posts: 23
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i buy mine from alibaba. have bought 4 in the past 18 months. look for the seller CQJB they are completely professional and located on chongqing very close to the zongshen factory. they do live streams on alibaba. they will get you what you paid for on time. we have bought over a dozen engines from them and never a problem. you can ship via air for 10-14 day delivery to usa or via sea for 30-60 day deliver and save a few bucks. @Anna Hu is on facebook and is the CQJB seller we use. also alibaba has buyer protections where they dont get paid until you inspect the product and accept delivery.
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#18 | |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,562
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Quote:
Can you post a few close up photos of the mounting of this 4 valve 250 in the Grom clone? I still can't believe it. I mean photos showing the head in that frame! Thanks!
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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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#19 |
Join Date: Feb 2012
Posts: 23
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pictures
its only a tight fit for the throttle cable on the pwk32 carb. only about 1/2 inch space between the throttle cable and the tank.
you see that blue hose connecting the carb to the manifold? im going to try a piece of 1.5 inch diameter pipe instead of this silicone blue hose to connect it to the manifold i think because i can feel that hose slightly collapsing and expanding when the engine is running. the frame is in the way so that 3 inch section of hose is needed to move the carb back close to the rear tire to clear the frame . im talking about the side setion if the frame being in the way because that manifold angles to the right and i cant find a better manifold one because it needs to be oval not circle to match intake port on the motor. |
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#20 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,562
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That is one seriously musclebound Grom clone.
It looks gnarly, probably rides that way too ![]() Nice
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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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#21 |
Join Date: Feb 2012
Posts: 23
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im having difficulty getting it tuned. first i tried a 28mm PE carb i think is too small and my wideband gauge was telling me the main jet needed to be 100 or 105 which i cant understand at all so today i put on the 32mm pwk and im getting closer with a 130 main jet
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#22 |
Join Date: Dec 2023
Location: Earth
Posts: 11
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How the progress?
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#23 |
Join Date: Jan 2024
Posts: 28
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I'm going to do this to my RPS Condor, but I think I'm going to use a 2 valve engine for 19HP. Updates?
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#24 | |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,562
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Quote:
And you managed to get oil cooler/lines in there too. Wow.
__________________
-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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#25 | |
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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#26 | |
Join Date: Jan 2024
Posts: 28
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Quote:
I think when you go down on carb size, you also have to go down on jet size because the smaller throat and higher flow results in a much more powerful venturi. I'm planning on using my pz27 on it. I would love the wide band. It is telling you you're rich when it said to bring the jet size smaller. This makes sense when you think about it because the airflow is increasing while the throat isn't so you get a bigger change in pressure. Now I need an oil cooler. I ordered a 30 tooth 520 JT rear sprocket for a grom that I hope will work. I don't think there is room for a 16 or 17 up front. I'm also going to get creative to get that intake right. |
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#27 |
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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#28 | |
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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