Hawk engine swap to Zongshen PR250/300

Dusman · 12-13-2023, 10:00 AM

To fit in the PR250/300 engine into the engine bay, you have to do the following:

1. You have to round out the end of the down tube that extends beyond the twin spar part of the frame or the front of the engine will not be able to fit due to the counterbalancer. I cut a "V" in there with a cutoff wheel with an angle grinder and then rounded it out with a Dremel tool using a cobalt grinding bit. You can see the area that needs to be removed in the photos below with the circled areas.

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Dusman · 12-13-2023, 10:38 AM

2. Carefully cut out the lower front engine mounts, re-install the engine into the engine bay, then tack weld the lower front engine mounts into place (top photo). This will allow you to finish re-welding them back onto the frame after you remove the engine (bottom photo). You can also see in the top photo how notching out the end of the downtube in step # 1 allows just enough clearance for the counterbalancer.
See photos below.

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Dusman · 12-13-2023, 10:57 AM

3. Fabricate the top front engine mounts. This will be necessary due to the fact that the OEM top front engine mounts are not long enough to reach the recess into the engine where the engine mount bolts mount to these mounts. I re-installed the engine via the rear and top mounts only, used cardboard to get a general idea of the size I needed, cut it to fit and then poked holes into the cardboard exactly where the mounting bolts go through. Then I took a piece of 3/8" stock steel I purchased from the hardware store, cut it to fit with a cutoff wheel on my angle grinder, checked fit, then ground it down the rest of the way with a bench grinder to where it fit perfectly. I then drilled holes through the steel using carbide bits and an electric drill. This step will also give you a chance to check that your lower frame engine mounts still fit after repositioning them and re-welding them back in. Make sure to put the engine mounting bolts through those lower frame mounts to ensure a good fit. See photos below of fabricated front upper engine mounts below.

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Dusman · 12-13-2023, 11:53 AM

4. Reinstall engine for (hopefully!) the last time. Check engine fitment at all mounts via re-installation (front lower, front upper mounts, top mount, top rear, and bottom rear mounts). See photos below.

12-13-2023, 10:00 AM	#1
Dusman Join Date: Jan 2018 Location: NC Posts: 211	Repositioning lower engine mounts for PR250/3000 To fit in the PR250/300 engine into the engine bay, you have to do the following: 1. You have to round out the end of the down tube that extends beyond the twin spar part of the frame or the front of the engine will not be able to fit due to the counterbalancer. I cut a "V" in there with a cutoff wheel with an angle grinder and then rounded it out with a Dremel tool using a cobalt grinding bit. You can see the area that needs to be removed in the photos below with the circled areas. Last edited by Dusman; 12-13-2023 at 12:00 PM.
	2

12-13-2023, 10:38 AM	#2
Dusman Join Date: Jan 2018 Location: NC Posts: 211	2. Carefully cut out the lower front engine mounts, re-install the engine into the engine bay, then tack weld the lower front engine mounts into place (top photo). This will allow you to finish re-welding them back onto the frame after you remove the engine (bottom photo). You can also see in the top photo how notching out the end of the downtube in step # 1 allows just enough clearance for the counterbalancer. See photos below.
	2

12-13-2023, 10:57 AM	#3
Dusman Join Date: Jan 2018 Location: NC Posts: 211	3. Fabricate the top front engine mounts. This will be necessary due to the fact that the OEM top front engine mounts are not long enough to reach the recess into the engine where the engine mount bolts mount to these mounts. I re-installed the engine via the rear and top mounts only, used cardboard to get a general idea of the size I needed, cut it to fit and then poked holes into the cardboard exactly where the mounting bolts go through. Then I took a piece of 3/8" stock steel I purchased from the hardware store, cut it to fit with a cutoff wheel on my angle grinder, checked fit, then ground it down the rest of the way with a bench grinder to where it fit perfectly. I then drilled holes through the steel using carbide bits and an electric drill. This step will also give you a chance to check that your lower frame engine mounts still fit after repositioning them and re-welding them back in. Make sure to put the engine mounting bolts through those lower frame mounts to ensure a good fit. See photos below of fabricated front upper engine mounts below.
	2

12-13-2023, 11:53 AM	#4
Dusman Join Date: Jan 2018 Location: NC Posts: 211	4. Reinstall engine for (hopefully!) the last time. Check engine fitment at all mounts via re-installation (front lower, front upper mounts, top mount, top rear, and bottom rear mounts). See photos below.
	2