Hawk 250 300cc engine swap?

Kari · 05-18-2023, 09:01 AM

So a couple months ago my stock hawk 250 engine threw a rod bearing in the middle of driving and my stator went bad not too long after. I seen a zongshen cbs300 279cc engine that looks like it has the same mounting points as the one on the hawk. Any suggestions or ideas?

XLsior · 05-19-2023, 06:32 PM

cbs300 is liquid cooled no?

also has a counterbalance front case protrusion that might foul on frame/ mount brackets.

That being said it could be doable if you found radiators that could be adapted to the hawk...

but as simple bolt in swap...definitely not.

Egandp · 11-25-2023, 05:12 AM

Could get their PR250 engine.

Dusman · 11-27-2023, 10:55 AM

Hello,

I have just installed the Zongshen PR250 6 speed counterbalanced engine in my Hawk. It shares the same bottom end/crankcase as the PR300. It will fit the Hawk, but certain modifications need to be made to make it fit inside the Hawk's engine bay and to run the engine with the carbureted Hawk's wiring harness.

A. Certain engine mounts have to be cut out and re-welded back in. There's two ways to do this:

1. You either have to cut out the lower front mounts, install the motor into all of the other mounts (except the upper mounts, more on that later...). Then, weld the lower front mounts back onto the frame with the lower front mounts *attached* via the bolts to the PR250 engine while you weld it in place. Then, you'll have to remove the engine again, finish welding the lower front mounts in from the top of where the mounts come into contact with the frame tubes, re-paint that area, then re-install your PR250/300 engine. Also, for the upper front mounts, the ones that require 3 bolts, you'll have to re-make your own mounts with 1/8" thick flat steel (3" width) purchased from the hardware store. Before I took the engine out to finish rewelding the lower front mounts, I also removed the extra downtube that sticks out in between the two "dual spar" tubes that come off the front of the frame. That allows more wiggle room and prevents the frame from contacting the engine case without sacrificing frame integrity. This is the method I chose.

2. The second way is that you can cut out the rear middle mount tange on the right side that comes off the rear cross member of the frame to get the engine in the bay. Second, you have to elongate the holes on the lower front mounts. Now, your engine will fit in the engine bay, but if you re-weld the rear middle mount's tange back to the frame, I'm not sure you'll be able to easily get the engine out again. With the method I used above (1), you can get the engine in and out as needed, though it takes some work as it's tight in there!

B. Now, to get the PR250/300 to run on the carbureted Hawk's wiring harness, you'll have to remove the stator, stator wires, and flywheel from your Hawk's stock CG 250 motor and install them into your PR250/300. While it could theoretically be done by completely changing your electrical system over to a GPX FSE 250e or Templar X 250 wiring harness, good luck finding one of those since as of the writing of this post, they have been for me, totally unobtanium.

It's a lot of work, but it's worth it for me to have the 6th gear, the counterbalancer, and the ability to ride comfortably at 60-65 mph without having to lose that low tractor-factor with first gear for off-roading.

Thumper · 11-27-2023, 12:34 PM

Gee. I've gotta say that with these motorcycles costing well under $2000 brand spanking new, that is one heck of a lot of work to do to get a working Chinese motorcycle. You can even get a good 20hp 249.9cc bike with inverted front forks, 18/21" wheels for under $1800 delivered. Well, we love to tinker. I have a new head in the garage waiting for me to work on porting. Maybe in January

Dusman · 11-27-2023, 12:40 PM

You're not wrong Thumper! For me, I'd certainly rather have just bought a Templar X and went with that, but sadly I don't have @ $2K laying around. Also, the PR250 was a gift, and I like to tinker, so it works out great for this ole' boy! LOL
However, people ask if the upgrades are worth it and I state something like this: "For you, probably not. For me, yes, because I enjoy working on these things and seeing what mods I can do as much I enjoy riding them."

Deckard_Cain · 11-29-2023, 09:47 AM

Quote:

Originally Posted by Dusman

You're not wrong Thumper! For me, I'd certainly rather have just bought a Templar X and went with that, but sadly I don't have @ $2K laying around. Also, the PR250 was a gift, and I like to tinker, so it works out great for this ole' boy! LOL
However, people ask if the upgrades are worth it and I state something like this: "For you, probably not. For me, yes, because I enjoy working on these things and seeing what mods I can do as much I enjoy riding them."

That you, Dustin?

Jason here.. lol.

Tag, you're it!

Also, that PR250 install is awesome.

Dusman · 11-29-2023, 10:32 AM

Yes sir! In the flesh!

05-18-2023, 09:01 AM	#1
Kari Join Date: May 2023 Posts: 2	Hawk 250 300cc engine swap? So a couple months ago my stock hawk 250 engine threw a rod bearing in the middle of driving and my stator went bad not too long after. I seen a zongshen cbs300 279cc engine that looks like it has the same mounting points as the one on the hawk. Any suggestions or ideas?
	0

11-27-2023, 10:55 AM	#4
Dusman Join Date: Jan 2018 Location: NC Posts: 215	The Zongshen PR250/300 Hello, I have just installed the Zongshen PR250 6 speed counterbalanced engine in my Hawk. It shares the same bottom end/crankcase as the PR300. It will fit the Hawk, but certain modifications need to be made to make it fit inside the Hawk's engine bay and to run the engine with the carbureted Hawk's wiring harness. A. Certain engine mounts have to be cut out and re-welded back in. There's two ways to do this: 1. You either have to cut out the lower front mounts, install the motor into all of the other mounts (except the upper mounts, more on that later...). Then, weld the lower front mounts back onto the frame with the lower front mounts attached via the bolts to the PR250 engine while you weld it in place. Then, you'll have to remove the engine again, finish welding the lower front mounts in from the top of where the mounts come into contact with the frame tubes, re-paint that area, then re-install your PR250/300 engine. Also, for the upper front mounts, the ones that require 3 bolts, you'll have to re-make your own mounts with 1/8" thick flat steel (3" width) purchased from the hardware store. Before I took the engine out to finish rewelding the lower front mounts, I also removed the extra downtube that sticks out in between the two "dual spar" tubes that come off the front of the frame. That allows more wiggle room and prevents the frame from contacting the engine case without sacrificing frame integrity. This is the method I chose. 2. The second way is that you can cut out the rear middle mount tange on the right side that comes off the rear cross member of the frame to get the engine in the bay. Second, you have to elongate the holes on the lower front mounts. Now, your engine will fit in the engine bay, but if you re-weld the rear middle mount's tange back to the frame, I'm not sure you'll be able to easily get the engine out again. With the method I used above (1), you can get the engine in and out as needed, though it takes some work as it's tight in there! B. Now, to get the PR250/300 to run on the carbureted Hawk's wiring harness, you'll have to remove the stator, stator wires, and flywheel from your Hawk's stock CG 250 motor and install them into your PR250/300. While it could theoretically be done by completely changing your electrical system over to a GPX FSE 250e or Templar X 250 wiring harness, good luck finding one of those since as of the writing of this post, they have been for me, totally unobtanium. It's a lot of work, but it's worth it for me to have the 6th gear, the counterbalancer, and the ability to ride comfortably at 60-65 mph without having to lose that low tractor-factor with first gear for off-roading. Last edited by Dusman; 11-27-2023 at 12:28 PM.
	2

11-27-2023, 12:34 PM	#5
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,331	Gee. I've gotta say that with these motorcycles costing well under $2000 brand spanking new, that is one heck of a lot of work to do to get a working Chinese motorcycle. You can even get a good 20hp 249.9cc bike with inverted front forks, 18/21" wheels for under $1800 delivered. Well, we love to tinker. I have a new head in the garage waiting for me to work on porting. Maybe in January __________________ -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
	1

05-19-2023, 06:32 PM	#2
XLsior Join Date: Aug 2020 Location: Australia Posts: 1,297	cbs300 is liquid cooled no? also has a counterbalance front case protrusion that might foul on frame/ mount brackets. That being said it could be doable if you found radiators that could be adapted to the hawk... but as simple bolt in swap...definitely not.
	0

11-25-2023, 05:12 AM	#3
Egandp Join Date: Nov 2023 Location: Pittsburgh, Pa Posts: 3	Could get their PR250 engine.
	0

11-27-2023, 12:40 PM	#6
Dusman Join Date: Jan 2018 Location: NC Posts: 215	You're not wrong Thumper! For me, I'd certainly rather have just bought a Templar X and went with that, but sadly I don't have @ $2K laying around. Also, the PR250 was a gift, and I like to tinker, so it works out great for this ole' boy! LOL However, people ask if the upgrades are worth it and I state something like this: "For you, probably not. For me, yes, because I enjoy working on these things and seeing what mods I can do as much I enjoy riding them."
	1

11-29-2023, 10:32 AM	#8
Dusman Join Date: Jan 2018 Location: NC Posts: 215	Yes sir! In the flesh!
	1