Brozz 250 - 4 Degree Timing Key Install

[tknj99]

Thanks.. having experienced the ultimate failure with the flywheel threads stripping, im wondering if this method could potentially end up stripping the crankshaft threads, and that would be very bad day. I'm probably sounding over paranoid but i think you can understand why.
Do you think it might be safer to use that 3-legged puller and push the puller rod against an M8 bolt that is freely able to be inserted into the crankshaft? In this scenario, it could be a longer bolt with no worry of the bolt head seating against anything, or to be extra safe i could again cut the bolt head off? There is nothing left to strip at this point with this option and worst case scenario i could think if the flywheel still doesnt come off would be that the M8 bolt bends or the puller threads strip, with no damage to the bike.

[JohnC]

Hi, I'm still waiting for the 4 degree key from Joe Henner before getting into this further. I'm not sure what type of puller is best for the Brozz, but just wanted to say thanks for all the discussion before I have to worry about it. I expect a three jaw puller will do the job without issue as long as you are careful.

[tknj99]

Originally Posted by JohnC

Hi, I'm still waiting for the 4 degree key from Joe Henner before getting into this further. I'm not sure what type of puller is best for the Brozz, but just wanted to say thanks for all the discussion before I have to worry about it. I expect a three jaw puller will do the job without issue as long as you are careful.

In my opinion it might be safest to go with the 3 jaw puller, remove the flywheel bolt, cut an M8 bolt head off and cut to length and then push against it. this would ensure that you dont run into the same issue i had with the flywheel threads stripping.
Let us know how it goes, i hope to re-attempt this in the future hopefully with better results

[grumpyunk]

When I removed the flywheel, I had no concern that I would strip the bolt threads. Just did not cross my mind. Inserting a smaller diameter 'slug' to transfer the pressure when the puller is tightened would insure you did not strip the crankshaft threads. You would have to be careful that you did not damage them by having the slug or rod bear against the threads and damage them. IOW, it would have to fig snugly so that it would not bear on one side or the other. I would trust a cut-off bolt that threaded into the crankshaft would not damage the threads. Thing is to get it out after removing the flywheel. It should unscrew readily, but how do you grab hold of it to unscrew it. Six of one, a half dozen of the other.
tom

[Megadan]

I just used the right puller designed for the job ( like the one I previously linked in post 10 http://www.chinariders.net/showpost....9&postcount=10) Flywheel comes right off. No danger of damaging any of the threads. All of this talk of cutting bolt heads off and such are confusing to me. I guess I just need a visual.

[JohnC]

Originally Posted by Megadan

I just used the right puller designed for the job ( like the one I previously linked in post 10 http://www.chinariders.net/showpost....9&postcount=10) Flywheel comes right off. No danger of damaging any of the threads. All of this talk of cutting bolt heads off and such are confusing to me. I guess I just need a visual.

Thanks Dan,


That's the puller I have and expect it should work as designed. But I will be very cautious after all this discussion.



John

[tknj99]

My case may be the 1 in a million hopefully and i hope to still make it a happy ending story at some point

[grumpyunk]

I would have use a puller designed for the job, ordered what I thought would work. It did not, and I was ignorant of what would, PLUS I was in the middle of a mess, so used the three-jaw.
IF you have damaged threads, the designated puller will likely not work. You will be stuck with a different design.
The cut off bolts are such that your puller pressure screw - the one in the middle of the puller - has something to bear on besides the end of the crankshaft or the original flywheel bolt.(still screwed into the crankshaft, but out at least a couple turns)
If you have ever removed the rotor from a gas powered generator, they are similar. The crankshaft is tapered as is the center of the stator, to insure 'perfect' alignment. You insert a rod of custom length into the hollow center of the rotor shaft. You then insert the original bolt that holds the bearing onto the rotor and tighten it to push against the custom shaft which in turn pushes on the crankshaft. It will force the rotor to pull away from the taper. You can also use liquid or grease to form a hydraulic piston/cylinder to raise pressure inside, and again force the rotor from the crankshaft. Somewhat similar to using grease in behind a pilot bearing in a car/truck crankshaft. old tricks.
tom

[China Rider 27]

I know nothing about this, so forgive me if intruding, but am curious given all the discussion. I have never seen the flywheel on a HAWK or Brozz but from the video attached to this thread it appears the flywheel and the end of the crankshaft are threaded. The flywheel retaining bolt is smaller than the hole in the end of the flywheel by about 2X and threads into the end of the crankshaft to secure the flywheel. Now the important part appears to be that the hole in the flywheel is 2X the diameter of the flywheel retaining bolt but it is also threaded to a much larger size (2X at least). If this is all true. Then if you find a bolt the size of the flywheel threads (flywheel puller?) thread it onto the flywheel and tighten it will eventually push against the end of the crankshaft. Because it is much larger than the threaded hole in the crankshaft it should push only on the outside edge of the crankshaft thus when tightened push the the flywheel and crankshaft apart and flywheel from the crankshaft. Is that not true?

[tknj99]

I should have just done that instead of using a bolt pushed into the crankshaft that ultimately led to all the trouble i experienced since it got stuck inside and the subsequent one with head removed bent... For someone doing this the first time, they should buy the M28 x 1.0 RH thread puller, only use the 1" puller piece (remove the M28 socket) and thread it all the way in and then crank down until it pops.

[China Rider 27]

So guy could go to the bolt shop and get a m28 X 1.0 RH probably hardened to prevent any thread issues and do the same thing. Should you try it again I would chase the threads with a good (quote good) tap on the flywheel. Try it if seems like stripping, Grumpyunk makes a point about putting pressure on that flywheel puller bolt and tapping it with a hammer. Not real hard, just about an 8 inch swing to let the weight of the hammer put little force on that bolt while it has pressure on it. I have had to do that a time works good.

[Megadan]

If the Brozz uses the M28 style puller then it is actually a slightly different flywheel center than the Hawks. The Hawk flywheel hub is only threaded internally, and as China Rider mentioned, the M16 center puller threads inside the hub and simply pushes against the end of the crankshaft.

The only difference between the Hawk style and the Brozz style would be the outer puller threading on to the flywheel, and then a center bolt that pushes on the crank. My thing is, you also talk about threading on the inside of the flywheel, so that has me wondering if it also has the same M16 threading like the Hawks, and if it does, it should remove the same way a hawk flywheel would.

If you watch from the 23:30 point in my cam install video to around 24:10, you can see exactly what I mean by how the puller works on the Hawk flywheel.

[tknj99]

The Brozz is the same as the Hawk from your description.. I probably shouldn't have followed that video I linked earlier in this thread, if i handle messed with inserting a bolt in the crankshaft it would have probably worked albeit with much effort as its tight as he'll but wouldn't have been as eventful

[China Rider 27]

Originally Posted by China Rider 27

So guy could go to the bolt shop and get a m28 X 1.0 RH probably hardened to prevent any thread issues and do the same thing. Should you try it again I would chase the threads with a good (quote good) tap on the flywheel. Try it if seems like stripping, Grumpyunk makes a point about putting pressure on that flywheel puller bolt and tapping it with a hammer. Not real hard, just about an 8 inch swing to let the weight of the hammer put little force on that bolt while it has pressure on it. I have had to do that a time works good.

Let me qualify this and say, using a hammer should be a last resort! Use a proper method if at all possible.

Originally Posted by Megadan

If you watch from the 23:30 point in my cam install video to around 24:10, you can see exactly what I mean by how the puller works on the Hawk flywheel.

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There you go. Now I have seen HAWK flywheel and the proper method for flywheel removal. Outstanding video, Megadan!

[Megadan]

Originally Posted by China Rider 27

There you go. Now I have seen HAWK flywheel and the proper method for flywheel removal. Outstanding video, Megadan!

Mediocre video, but thanks lol.

I should also state that it is important to ensure the threads are well oiled. Shouldn't be too hard to accomplish considering everything is covered in oil, but it never hurts to make sure either.