CB300RL Engine

[XLsior]

Found this on Alibaba.


Zongshen/Zonshen ZS175FMN

300cc, 4 valve,6 speed, counterbalanced, Estart.


https://www.alibaba.com/product-detail/300cc-Engine-Zongshen-CB300RL-Electric-Start_1600989367791.html?spm

[culcune]

Found this on Alibaba.


Zongshen/Zonshen ZS175FMN

300cc, 4 valve,6 speed, counterbalanced, Estart.


https://www.alibaba.com/product-detail/300cc-Engine-Zongshen-CB300RL-Electric-Start_1600989367791.html?spm

I believe a few members got one of those a couple years back. One member had a long-ish thread in which they stuck one in a Hawk. That being said, the 300's that a few members bought, might not have been that 175FMN engine.

The brand Dongfang is offering a 300cc 173FMN engine in a dual-sport and it is even street legal in California (a big deal since California has much stricter state emission standards than the federal US government). However, I cannot seem to find specs on how many gears its transmission has (5 or 6).

(example)
https://www.360powersports.com/dongfang-300cc-df300rtt-dirt-bike-with-single-cylinder-4-stroke-air-cooled-big-21-inch-wheel-street-legal/

[XLsior]

The other 4 valves I've seen forum users posting were not counterbalanced 6 speeds...

[Dusman]

I put the 2 valve version of that engine in my Hawk (PR300, counterbalanced, 6 speed). It runs like a champ and outperforms most Honda CRF300Ls I’ve seen. I’ve got over 5,000 miles on it now with zero issues: https://chinariders.net/showthread.php?t=33557

There was a fellah on the Templar FB group that was trying to sell that 4 valve head to people with my engine, but he wanted upwards of $500 for the whole head package if I remember correctly. I thought that was highway robbery.

[Thumper]

Techncally, it is probably about a 285cc engine. With a 75mm bore, it would have to be a 68mm stroke to have 300cc displacement. If it is the more common 65mm stroke, it calculates to 287cc. But the four valve head has to breathe much more easily! It probably has more torque earlier.

I got an Otom big bore cylinder kit claiming 300cc for my 172FMM (249cc). It turned out to be a 265cc kit. With a ported head and cam, it would probably be worth all of the trouble of installing the cylinder/piston kit, even with a 2 valve head!

Either way, the liquid cooled NC300 would stay cooler on the trails. You can add a fan to the radiator to make sure the heat doesn't get out of control!

[Mumen Rider]

I believe a few members got one of those a couple years back. One member had a long-ish thread in which they stuck one in a Hawk. That being said, the 300's that a few members bought, might not have been that 175FMN engine.

The brand Dongfang is offering a 300cc 173FMN engine in a dual-sport and it is even street legal in California (a big deal since California has much stricter state emission standards than the federal US government). However, I cannot seem to find specs on how many gears its transmission has (5 or 6).

(example)
https://www.360powersports.com/dongfang-300cc-df300rtt-dirt-bike-with-single-cylinder-4-stroke-air-cooled-big-21-inch-wheel-street-legal/


That's a five speed and a PR250(zs172) going off of it's physical appearance and the fact it's got the 14kw rating and not the 15kw rating that a PR300(zs175) would have.


I put the 2 valve version of that engine in my Hawk (PR300, counterbalanced, 6 speed). It runs like a champ and outperforms most Honda CRF300Ls I’ve seen. I’ve got over 5,000 miles on it now with zero issues: https://chinariders.net/showthread.php?t=33557

There was a fellah on the Templar FB group that was trying to sell that 4 valve head to people with my engine, but he wanted upwards of $500 for the whole head package if I remember correctly. I thought that was highway robbery.



I know who you are talking about, it was $450 shipped but I think he has since lowered the price for the package to $350.







Either way, the liquid cooled NC300 would stay cooler on the trails. You can add a fan to the radiator to make sure the heat doesn't get out of control!


The NC series of engines have completely different mounting points than the ZS172 series of engines. It would not be worth the amount of modification for a 2-4hp gain over a water cooled NB300 that would bolt right into anything that came with a counter-balanced ZS172/175. You can skip the water cooling and just buy a NB300-F which is an air cooled NB300. Or if you have a ZS172/175 that's two valve just swap in a TYX300 that will bolt right in(including head mount), make more power than a 4 valve ZS175 and have an oil filter.

[Thumper]

I had not seen the NB300. I see it on Alibaba now. Looks great! But I've been burnt before (fortunately, only ~ $120 shipping), and won't buy from there or AliExpress if it is more than $10-$15 for things like mirrors, lights... And this was with AliExpress intervening and insisting I get a refund. But only after I had to pay for return shipping. I did get the refund for the item, but not the shipping. That was NOT how the original sale was posted. In fact, I had promise from AliExpress that shipping WAS the responsibility of the seller, untill the email disappeared (before I copied and pasted it for proof). I never got my shipping refunded. We hear about items not clearing customs, or items not as advertised pretty often on this website. I don't know why but these things happen.

[XLsior]

I just find it interesting how the tech is hybridizing and progressing...


I anticipate the 350cc class is just around corner (actual 300cc)



the CG150-200 cc is mostly gone now.



it's nice to know more options are available in the off chance a new engine is desired.


Yes I've been stung by Aliexpress a few times but most disputes have resolved in my favor.
Though I've only ever purchased things that I could cover a loss on...


Never tried an Alibaba and 1 crate motor + shipping isn't exactly cheap. However If I had connections to an importer or could strike up a bulk order with a few other people it could be a less risky consignment.

[Thumper]

AJ1 has the NB300 engine

https://aj1moto.com/collections/engines/products/zongshen-nb300-zs174mn-5-engine

This is probably a Chinese owned importer, but I haven't heard about any issues with AJ1. They've also got a complete line of dirt bikes.

[XLsior]

NB300-F air cooled


https://www.alibaba.com/product-detail/CQHZJ-High-Quality-New-Engine-4_1601031764374.html

[Mumen Rider]

NB300-F air cooled


https://www.alibaba.com/product-detail/CQHZJ-High-Quality-New-Engine-4_1601031764374.html


Do not order from CQHZJ, they can't package the engines correctly and you end up with a ruined engine by the time it gets to you.

[XLsior]

Good to know Mumen Rider.


I have no intentions of ordering any crates from Alibaba.


I"m happy wrenching on basket case engines I find on marketplace/Gumtree/Craigslist.


Though I might get a semi auto 125cc Lifan for my other CT110 rolling chasis from Ebay....someday.


focusing on the 450MT funding right now. Seems like a better investment longterm.

[Thumper]

I would order from AJ1. They have great looking dirt bikes. The engines are priced competitively.

[BuuThatClone on YT]

Im currently running a ZS175FMN 5 speed noncountetbalanced 300cc 4v in one of my KP Mini 150s. I just picked up a 167FMM CG250 that I'm gonna throw the "350cc" BBK on before i throw that engine on that bike. The CG350 is actually a 268cc kit with a bore & stroke of 72.5mmx65mm. The ZS175FMN is actually a 271cc 4v engine with a bore & stroke of 72mmx61.4mm, they sell the big bore kit for the ZS172FMM & ZS172FMN, but i knew i was just gonna big bore it so i just bought the engine. As for my KP Mini 300 4v, you can find that build on my YouTube channel linked below, or if you look up ZS175FMN you'll see my videos pop up as well. I plan on starting a build thread on here, but I mainly post in the Zongshen zs172fmm-3a group and the clone groups as well as the respective groups for my builds.

https://youtube.com/@buuthatclone?si=D1wxeUqOe1km5b02

On that note click the link &

[XLsior]

are you sure the 350 BBK will fit in a 167fmm case if the piston is 72.5mm but the case opening is 73mm


Good luck with that, I hope it fits.


I'd be interested in knowing the upper frame clearance difference and head width between the CG250 stock and the 4 valve?

[BuuThatClone on YT]

are you sure the 350 BBK will fit in a 167fmm case if the piston is 72.5mm but the case opening is 73mm


Good luck with that, I hope it fits.


I'd be interested in knowing the upper frame clearance difference and head width between the CG250 stock and the 4 valve?

From my research, the 167FML is the 223cc engine with the 15mm wrist pin. The 167FMM is the 229cc engine with the 16mm wrist pin. I checked the stock replacement cylinder specs with the "350cc" cylinder specs and everything seems to line up, I just need to place the order on the BBK, cams *I'm buying different options*, and lifters, along with porting the head when I take it off. When you get a moment, check out how the builds are coming along.

[XLsior]

The wrist pin isn't the problem.



the problem is the case opening and the cylinder skirt outside diameter, as well as head stud location



though the 167FML sounds like a timing chain OHC. While the 167FMM is 99% a CG250 OHV pushrod engine.


However engine stamping can be hit and miss with chonda clones. And I would advise removing the head and checking components and dimensions prior to purchasing any aftermarket BBK, piston or cylinder head.

[BuuThatClone on YT]

The wrist pin isn't the problem.



the problem is the case opening and the cylinder skirt outside diameter, as well as head stud location



though the 167FML sounds like a timing chain OHC. While the 167FMM is 99% a CG250 OHV pushrod engine.


However engine stamping can be hit and miss with chonda clones. And I would advise removing the head and checking components and dimensions prior to purchasing any aftermarket BBK, piston or cylinder head.

Thats what I meant by the specs line up, inner case & outer skirt diameters match. Bolt spacing matches. Wrist pin matches. Overall height including piston skirt match. Everything seems to line up. If it doesn't fit, I don't really care as I'm literally doing all this for research for the community. But based on the numbers, everything looks like I'll be good.
Keep your eyes out for that one, but for now, I'm playing with my KP Mini 300 4v ZS175FMN