Removing a flywheel Bashan Enforcer 250

[Nieto13]

Hey All!
Hope everyone is doing well and still able to ride this time of year. Need some help please. I have a Bashan Enforcer 250 and need to remove the flywheel to change the starter clutch. I bought a 28mm puller which didn't fit and have tried many ways to remove it without success. Man this thing is stuck on there, Any suggestions and help would be greatly appreciated as I can't figure it out.
Thanks a million.

[grumpyunk]

If this has the CG250, I used a three-legged puller and a big hammer. Made the 'legs' of the puller as long as I could, and reached behind the flywheel. Tightened the center bolt to put some tension on the assembly. Got out the big hammer and gave the puller bolt a good whack. I messed up in that the pointy end of the puller bolt was off-center on the bolt head, so I bent the bolt. I think I may have given it a couple good whacks, increasing force as I went along, and making sure the puller bolt was tight. It let loose, and that was it. I got a replacement bolt at Ace Hardware.
I had a magneto puller that I thought would fit, so was unprepared and resorted to the three-legged puller as it was my only other choice. A replacement flywheel is not as expensive as I thought it would be in case I messed it up.
If you have the CB type(OHC) the procedure should be similar if not exactly the same.
I used some Blue loctite on the threads upon re-assembly, FWIW.
tom

[Nieto13]

Thank you for the help! Honestly, I don't know what engine it is. I believe it's the same as the Hawk 250 non counterbalanced engine (239cc), I brought it to a friends house and used his compressor and air gun to remove it. I jammed the gear with a screwdriver to prevent it from moving and put a long 14mm bolt in the shaft. Then attached the air gun to the bolt head and after a minute it popped off. It took a tremendous amount of force. The reason I needed to remove it was to replace the starter clutch. Some magnets were broken and the starter would just spin and not engage. So after replacing the starter clutch and the starter itself, it still doesn't work. Maybe the starter relay which I tested and hear it click on/off but perhaps there is a short? I just don't know.

Word to the wise: I watched a youtube video and jammed a small screw (without the head) into the shaft and put the 14mm bolt on and cranked down. It didn't work and when I tried to drilled it out I messed up the threads in the shaft and now need a new shaft. I must have fbeen out of my mind

[grumpyunk]

The CG250 has rocker arms under the top cover while the CB250(I think) has overhead camshafts. The former has two pushrods on the flywheel side.
The starter clutch is a 'sprag clutch' that had a whole lot of 'fingers' that are arranged at an angle so they will jam in one direction, and slide in the other. It is rotated by a couple intermediate gears and the starter motor gear. It can sit still when the engine starts.
If you jumper past the starter relay directly to the terminal on the starter motor using a regular jumper cable, the starter motor should energize and rotate the crankshaft. The relay is just a big switch for the larger battery cables and carries a big jolt of juice when the starter is connected.
If the starter doesn't rotate when jumped, either the battery is not producing enough current(low charge? worn out?) or the starter motor may be damaged or worn. If you have used the starter for a long time, you could have worn brushes, or they could have fallen out of the brush carrier due to loose screws or ???. You can take it apart, but be careful to mark it such that you can keep the parts aligned to put them back in the same position or the motor may run backwards... Use a punch and 'dot' the bits or marker if you do. You may(will) have to figure out how to keep the brushes back from the armature upon re-assembly.
tom

[Nieto13]

Thanks for all the information!

The engine must be some variation of the CG250. It is definitely not an overhead cam engine. I replaced the sprag clutch and the starter still just spun around and did not engage the engine. The starter and reduction gears look fine. I don't believe there is a bendix on the starter. I disconnected the starter relay and jumped it and it works just fine (it's brand new). If you have any additional info please let me know.

Would you happen to know where to buy a motor shaft for a BSR/Hawk2 250. I have to replace this due to the stripped threads while removing the flywheel. I pulled the motor off the frame and am either going to do it myself or bring it to someone.
Happy Thanksgiving
Andrew

[grumpyunk]

I had miine apart(SG250) with the CG250 engine. There are two stepdown sets of gears between the starter motor armature gear and the sprag clutch assembly ring gear.
When I went to put it back together, my first reaction was to put the gears on backward inside the side case cover, and then again inside the gear cover where the armature gear protrudes.
Took off the cover, and flipped the first reduction set. It now engaged the sprag gear. You could test its mesh and it should be engaged with the sprag, able to turn readily in one direction. It is difficult to reach the teeth... but you may be able to use a screwdriver to give them a push.
Put the side cover back on, and popped the second reduction set in. Cover didn't want to fit. Poked around a while, thimking, and finally realized I had this one backwards also. Actually reverse the above, as it was the fact I couldn't get the cover to go into place readily that clued me I was upside down. Finally put the gears in properly, and you could feel the mesh all the way to the sprag. You should be able to rotate the gears with the removable cover off, in the backwards direction and they should stay meshed. You should be able to see the gear mesh with the armature gear.
{ I assume the starter motor spins, but the crankshaft does not.} If I have it wrong, lemme know.
You should be able to attempt to rotate the accessible(visible) gear and find it difficult in one direction. If it is easy to rotate in both directions, either the sprag is not working, or the gears are not meshing. There should be a washer on the shafts of both reduction gear sets. You can look for 'witness' marks on the gear sets to see on which side they belong.

tom

[Nieto13]

Thanks for all the info!
I just finished re-threading the drive shaft. I am ordering a new sprag (starter clutch) and flywheel. When I reassemble everything I will assemble as per your advice. I don’t know if I ordered all the parts I need. It’s the large gear behind the flywheel, the sprag clutch, and the flywheel. The key way is in good shape. I can’t help thinking there is another magnet or something missing? It seems too simple.
Andrew

[grumpyunk]

One thing with a sprag clutch.... You can test it after install. When you go to place it on the flywheel, you need to rotate the gear & sprag to fit it over the finished surface of the flywheel. It should go on with little force if you rotate while sliding it over the ring.
You should then find it grabbing tightly in one direction, and sliding freely in the other.
The pieces are sort of figure-8 shaped, but not so defined, with a fat 'waist' sort of, if they are what I think they are. All slots in the sprag should be filled. I think it needs to be lubricated so the fingers can move freely. If it slips, then it may need to be cleaned. There should be a slight tension of the fingers onto the surface, which may be reduced if the sprag is dirty or jammed with thick grease/stuff.
They are pretty reliable, so replacement should be a last resort unless something has happened.
Why are you replacing the parts?
tom

[Nieto13]

Thanks for the helpful and very useful info! I will try it once the parts arrive.

It all goes back to the starter spinning and not engaging the engine. I changed the starter, volt and ohms tested the relay, inspected all gears. The next logical thing to check was the sprag (starter clutch). Once I pulled off the flywheel i found the sprag magnets broken. I also noticed broken "teeth" of sorts in the flywheel itself (it's magnetic). I have no clue where they came from or what broke. I have pics of it all including the related starter system parts but could not reduce the file size enough to accommodate the website. Anyway that's why I have to replace the parts.
Andrew

[grumpyunk]

The description would point me towards a failed sprag that came apart to some degree.
If you look at the inner diameter of the sprag, you should see a whole lot of shiny rectangles. Those are the contact spots that will rub on the flywheel sprag surface.
When the starter motor spins the two gears, and then the sprag, those rectangles more or less stand up due to being pushed the 'wrong way'. When they stand, they get jammed against the flywheel and the other end against the outer of the sprag. Given they cannot compress being solid metal, getting jammed pushes them tightly against the flywheel, and they grab.
If the sprag does not grab in one direction, and spin freely in the other, it is not working properly.
tom

[Nieto13]

Thanks again! I have a good understanding of what you are describing. The tiny rectangles were damaged and many were missing. If you have a minute, I am attaching a link to the parts I will buy. Please let me know if I'm on the right track or missing anything.

The first link is the flywheel and sprag.
The second link is just a photo of the large gear that sits behind the sprag (starter clutch)

It appears to reinstall it all the larger gear goes on first, then the sprag (starter clutch) attaches to the backside of the flywheel by three allen screws, and then they slide over the keyway on the shaft. It doesn't look like there is any bearings or other sprockets (magnetic or otherwise?) that go on the shaft. Thanks for all your help!
https://partsroketa.com/product/magn...or-bashan-250/
http://www.chinapartsdepot.com/shopp...exd.asp?id=506

[grumpyunk]

I do not think there are two sprag clutches. The flywheel it attached to the crankshaft and is held in place by the taper of the shaft, and the bolt. It has no sprag.
The biggest starter gear has a sprag built into it that fits over the smooth race on the end of the flywheel(magneto) closest to the crankcase.(innermost).
I don't see any need for a second sprag on the starter gear. To my knowledge, the starter gear grabs onto the magneto and uses that to rotate the crankshaft.

Looking at the magneto, the center is a sprag clutch. The sprag on the starter gear on my CG250 fits OVER the magneto, and grabs onto the machined surface on the inner side of the magneto.
Look here for the parts lists: https://brozz250.com/Tech-Info/Engine-Diagrams

Remember this is a CG250, not a CB(ohc). I do not know what you have, so take this with a grain of salt.
Look at 'magneto comp' and 'electrical starting mechanism' images. The 'rim' on the magneto in the lower right is where the sprag grabs. The #7 item is the sprag in the electrical starter image.
If yours doesn't look like this, I cannot comment with any sort of authority.
But repeat, most designs do not neet two sprags. I think when the engine is running, the starter gears are stationary, and the magneto/flywheel is of course rotating. Just one sprag to allow that to happen.
tom

[Nieto13]

Thanks again!
Everything you said makes sense. I have a variation of the CG250 engine. That's the problem with unstamped engines, they vary slightly. I looked at the link you sent in great detail and most of the parts are the same. The only difference seems to be the stator on mine is located inside the side generator cover and on the Storm it's located inside the flywheel (magneto). This makes the flywheel different in shape but not functionality. I'm going to order the parts and begin putting it back together. Maybe I'll poke around in the engine while I have it off the frame and screw it up some more lol.

Thanks a million for all your advise.
Andrew