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Old March 13th, 2016, 07:22 AM   #41
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Originally Posted by HoneyBadgerRy View Post
When doing bottom end rebuilds I used to put the engine cases in the oven on warm. Rims are heat treated though, so it would likely be better to prevent them from getting to hot.
I heat wheels all the time during powder coating, and always keep they in a safe range, which for the most part is under 400F.

When you get over 400F, the time you can spend there without altering the heat treating gets pretty short. At 375F to 380F you get about an hour before you start to get close. Most of the time the wheel spends about 15 minutes at that temp. The problems start when people "outgas" the wheels at 450F to release trapped gasses or "burn-off" the existing coating at 800F. It happens.

For bearing installation, I would think 200F would be plenty. At that temp it would take hours and hours to even get close to altering the heat treating.
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Old March 13th, 2016, 07:45 AM   #42
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Just warm is probably good enough. I could still touch the wheels with my fingers and not feel like it was burning. Just a heat gun will warm them enough. Definitely don't heat the wheel enough that is burns you. If bearings are cold the rim is warm. Then the bearings should just push in with you fingers.
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Old March 13th, 2016, 10:22 AM   #43
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So if one rider weighs 120 lbs, and another weighs 260 it doesn't make a difference??
I fat thumb'd the thumbs up, but it's a good learning opportunity.

Eric is dealing with terminal velocities, not acceleration. So all else the same, a difference in rider weight doesn't really factor into the equation. Obviously there's limitations to that statement because the bike does have to accelerate within a reasonable distance before the timing zone, but still. The only factors in terminal velocity calculations are tractive force (power transferred to the road) and resistance to movement (bearing friction, rolling resistance, aero drag etc etc). Rolling resistance IS a function of weight, so technically weight does come into play, but rolling resistance and bearing friction are so small in comparison to the aero drag, that for the sake of our discussion, weight can be dismissed as a concern.
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Old March 13th, 2016, 10:37 AM   #44
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Ahhh okay gotcha
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Old March 13th, 2016, 11:20 AM   #45
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So if one rider weighs 120 lbs, and another weighs 260 it doesn't make a difference??
Aerodynamically - not necessarily.

Sport Rider did an article on aerodynamics and Land Speed Racing a few years ago, and compared a smaller rider and a bigger rider - the bigger rider was more aerodynamic.

That's because he filled the low pressure void better than the smaller rider. It was also on a big bike (Busa I think), so it's not going to be the same on something like a Ninja 250, small bike, or one without fairings.

Just something to consider. The right answer isn't always the obvious one.
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Old March 13th, 2016, 11:33 AM   #46
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The real difference is the tuck. If your back is flat then there is less void behind you.
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Old March 13th, 2016, 11:52 AM   #47
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The real difference is the tuck. If your back is flat then there is less void behind you.
Yes and no, it's more complicated than that. The idea isn't to reduce "voids" as you call them, the idea is to control the flow over over the vehicle+rider body and reduce the about of separation.

Spend your evenings researching on scholar.google.com looking for research papers about CFD and/or wind tunnel tests on motorcycles. Check for sources like SAE or ASME or maybe even AIAA journals.

Look into other topics like trip wires or spoilers when you do your searching. Trip wires are a way to induce small turbulence in order to contain the flow better so it doesn't separate into large turbulent regions. The idea is it will follow the surface of your body longer. Skin friction << form friction, therefore taking a small hit on skin friction ddramatically reduces form friction.

most studies will have fancy pictures like this, not useful for much without knowing their scale/variables/whatever. But they look neat!!!
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Old March 13th, 2016, 01:46 PM   #48
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I have spent many many eavnings researching aerodynamics. What I learned is to take all the fairings off and run the motorcycle in a class that does not use them. The money spent to build paint and mount the fairings on a motorcycle that is only going 125 mph is better spent on engine development. I say that as a joke . But all jokes have there basis in reality.

Each speed has its own aerodynamic sweet spot. So somthing that goes 200 might not work at 100 and it might not work at 300.

The subject is very very complex. And to make it even more confusing the real world of 300 mph motorcycles is totally unexplored .

For me I have to settle for the shape of the 250 ninja. I have done obvious things to smooth out the airflow. But I must look like a 250 ninja.


If you don't mind .
We should take this discussion to the Project X thread . This has gotten away from the Worldwide bearing conversation.
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Old March 22nd, 2016, 05:25 AM   #49
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Trans bearings
The trans bearings are simple to replace if you have the tools. And you have to split the case. So I guess not so simple.

Once you have the transmission shafts out the front bearing slips on and off with ease.

The rear shaft has a press on collar. This is between the bearing and the output sprocket. Before removing the engine you should remove the big nut and output sprocket.

The sleeve will need to be pulled. There is no way to pry the sleeve off. Don't even try or you will damage things.

The threads on te shaft are very fragile so I keep the bolt loosely attached most of the time.

Using a gear puller or a bearing separator is the best way. Any auto shop will have these tools and not charge much to swap the bearing. Just pay attention to the bearing orentation. There is a clip that holds the bearing in the trans. These are half moon clips in the upper case half. Make sure there in place when you go together as they can stick to the old bearing and get lost.

Then just reaassemble the engine acording to the manual.
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Old June 1st, 2017, 07:29 AM   #50
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Front wheel first

After removing the front wheel and the speedometer drive . I find a nice flat serface. Like a work bench or even a piece of plywood on the floor.

Lay the wheel on its side. Brake disc up.
Then carefully remove the dust seals. I use a screw driver and use a twisting action and go around and pry the seal out. It would be easyer to replace the seals. But that is not always an option. First clean everything and get the screwdriver under the actual lip of the seal.

Once the seal is out. Wipe out the grease and you will see a snap ring. This is next. Sometimes they can be stuck. A punch and hammer can be used to carefully dislodge the ring . Put the point in the snap ring hole and gently tap it until you see it spring back. Then use snap ring plyers to remove
Next use a rod to knock out the bearings. The rod I use is 3/8 in diameter and slightly mushroomed. The mushroomed part is what I use to get the edge of the bearing. You put the rod through the upper bearing on the brake disc side. Slide it in at an angle . You will feel the lip of the bearing. Then tap the bearing out.
I know this is an old thread and off topic, but what did you use for the gold finish on this rim? That is the color I am looking for. TIA.
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Old June 1st, 2017, 08:55 AM   #51
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I know this is an old thread and off topic, but what did you use for the gold finish on this rim? That is the color I am looking for. TIA.
I am pretty certain that is a aftermarket aluminum rim.
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Old June 6th, 2017, 01:35 PM   #52
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I used the gold chrome spray paint. I first steamed the rims very clean and then broke the tires off the bead. But left them on the rim. Then taped up the tires. After that I mounted the rim/ tires in a wheel balancer and painted them while spinning them. That's it. Then just refill the tires.
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Old June 6th, 2017, 01:38 PM   #53
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I used the gold chrome spray paint. I first steamed the rims very clean and then broke the tires off the bead. But left them on the rim. Then taped up the tires. After that I mounted the rim/ tires in a wheel balancer and painted them while spinning them. That's it. Then just refill the tires.
Thank you, but what brand paint? I have that color in mind for something.
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Old June 6th, 2017, 01:40 PM   #54
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I don't know. It is the stuff you get at auto zone. Supposed to look like chrome but never does.
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Old June 6th, 2017, 01:42 PM   #55
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I don't know. It is the stuff you get at auto zone. Supposed to look like chrome but never does.
Thanks!
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