Check this bike out and tell me what you make of it

[troybilt]

Is it a CR500 in a 450r? I can't tell dirt bike engines from one another... very clean install from this angle.. still probably vibrates "to beat the band", but looks cool...

saw this on 450r.org

[tt racer]

I bet that it is i rode one before and no thanks its not enjoyable at all!!!!!!!!!!!:(

[troybilt]

Originally posted by tt racer
I bet that it is i rode one before and no thanks its not enjoyable at all!!!!!!!!!!!:(

No joke. I'm thinking its a CR250r motor, the bike seems too small for a 500... but that is just a guess.

[Ruf Racing]

A CR500 engine will fit in the frame. There are a few guys that have done it. I have considered trying, after the last 450r engine carnige I had. The vibration factor is the biggest down side. :(

[250Renvy]

I'm thinking based on the pipe angle that it might be a 250.

Troy, you always have good links and have some knowledge of engineering or are an engineer - do you have any idea what it would take - program wise, designer wise and/or cnc machine wise to make a set of counterbalanced CR500 cases?

I was thinking of approaching the local university to see if they would have anybody interested in taking on a for profit project to design a set of cases and counterbalancer for a 2 stroke motor - I'm thinking KTM or Yamaha since they are still in production.

I just don't know who, or what department yet. All I know is that they are closely tied to a lot of the automotive and casting facilities in windsor,detroit.

I would then take the design, or whatever to a casting plant to see if they could be cast since billet would be way too expensive.

[destey]

curious as to why it doesn't vibrate as much in the 2 wheel bike frame as a quad frame

[jcs003]

Originally posted by destey
curious as to why it doesn't vibrate as much in the 2 wheel bike frame as a quad frame

believe me the bikes vibrate alot. its just the frame connection points and the amount of material to transfer the vibrations is less. more material means more metal to vibrate. also, less connection points allows for a more rigid chassis. my 250r vibrates a bit at idle and my 400ex/250r hybrid is the same. seems the 400ex framed bike vibrates more. either way they both work great.

[fastrnrik]

Originally posted by destey
curious as to why it doesn't vibrate as much in the 2 wheel bike frame as a quad frame

I was always told that the bikes transfer vibration out through the fork tubes and spokes in the wheels.

[troybilt]

Originally posted by 250Renvy
I'm thinking based on the pipe angle that it might be a 250.

Troy, you always have good links and have some knowledge of engineering or are an engineer - do you have any idea what it would take - program wise, designer wise and/or cnc machine wise to make a set of counterbalanced CR500 cases?

I was thinking of approaching the local university to see if they would have anybody interested in taking on a for profit project to design a set of cases and counterbalancer for a 2 stroke motor - I'm thinking KTM or Yamaha since they are still in production.

I just don't know who, or what department yet. All I know is that they are closely tied to a lot of the automotive and casting facilities in windsor,detroit.

I would then take the design, or whatever to a casting plant to see if they could be cast since billet would be way too expensive.

Kevin, I'm an engineer and I can do the work myself and would love too. I have all of the software, just no extra money. Basically what would need to happen is scan the trx250r cases into 3D CAD and do the same for the CR500 cases.. I've already priced this, comes into about $1800 per set from an outside vendor to scan these in correctly.

Second, would need to modify the CR500 CAD models to adapt a trx-"type" counter balancer or one similar, so basically it would be a CR500 motor with a trx counter balancer.

Now the tricky part is the balancing. Its not just simply using the existing counter balancer from a trx, the dynamics of a CR500 is alot different than a trx, and they won't work (effectively anyway) just installing a trx CB into the CR motor. Do this correctly, one would need to do a non-linear modal analysis to determine the order of vibrations you are trying to dampen, usually like 10-100Hz. I've done alot of this on high speed chopper applications in agriculture at my last job. Vibrations from an engine are not only in the plane of the cylinder moving up and down, they radiate outward in spherical (all) directions... The vibrations are caused by the crankshaft actually flexing during operation, and radiate axially from the crankshaft. By dampening the verticle plane (if you will) of the motor i.e. piston going up and down, this is what is called "statically balanced" we need to dynamically balance to work properly. Otherwise you could just make a offset flywheel to dampen the vertical vibrations. A counter balancer vibrates in whats called a "phase shift" of the piston vibrations and the 2 vibrations cancel each other out... i.e. dynamically balanced. Think of it as sound waves which for all intensive purposes look like a sine wave, lay 2 sine waves on top of each other one that is 90 degrees shifted and the 2 sine waves add up to zero... (anyway sorry for the engineering jargon, but the long story short it can be done)

Lastly, is getting the castings made, once a new 3D model is complete. I've already been in contact with a few casting suppliers in Huron, Mi. We current do work up there with a couple good suppliers already. A casting mold or template for this complex of a structure, i.e. lot of features in a left and right case. Estimated cost based on other stuff I've done is anywhere from ~5k-20k... There are some tricks to getting prototype stuff made that are cheaper, say 2-3k, but these methods won't work for production runs.

FWIW>All of this is my best guess as to why this hasn't been done already!

With all that said... I've got other ideas that don't require as much capital expenditure, just some time and a little testing. (as they say... "there is more than one way to skin a cat")

Option 1) Redesign the chassis to dissipate the vibrations from the motor, we do this all the time in machinery design, I guarantee the engineers did this when designing the original TRX chassis, even though there is a CB in the trx motor. Modal analysis of the trx chassis with CR500 motor to determine the low order modes or "resonance frequencies".. i.e. these are the vibrations that seem to get worse or "run away". Google Tacoma Narrow's bridge for what I'm talking about. Anyway, the chassis can potentially be designed to mitigate or channel the vibrations away from the occupant. Alla - CR Chassis design. Having 2 wheels has nothing to do with it. Mount a CR500 engine into a street bike frame and you'll know what I mean. Been done 100's of times and they vibrate like crazy too.

Option 2) Torque dampener, idea => basically mount the motor in a "cradle" isolated from the rest of the chassis and use a torque dampener to dissipate the vibrations. Here is an example albeit a simple one, these are used to dampen vibrations from mega horsepower 4-bangers (a.k.a. rice burners): http://www.lightningmotorsports.com/ingalls_engineering_stiffy.htm

I'm also currently a part-time test engineer, (data aquisition) and it would an interesting project to attach accelerometers on a trx chassis with a CR500 motor to measure these inherit vibrations. Then do the same thing once the "fixes" or design ideas to mitigate vibrations are added or designed into the new chassis.

Sorry for the long post, as you can see I've been dreaming about this myself for along time. These are some of the ideas I had...

T

[1promodfan]

I say its a CR250 motor. I like it, it looks pretty sweet.:D

[destey]

there's no way to cancel the vibration with a small weight on the clutch basket?

[Rich250RRacer]

Originally posted by 1promodfan
I say its a CR250 motor. I like it, it looks pretty sweet.:D

It's a 500 motor. I own one, I know what they look like. The way the two hoses come out of the water pump are the give away.

[Ruf Racing]

This guy has suppose to have done it. Looks good, check it out!

http://www.youtube.com/watch?v=dS_jT8TdHGE

[troybilt]

Old news...
He's posted on the other 250r site... and its not fixed... yet.. Nice work though, cool to see the someone try. I don't believe it would ever work properly anyway, to use a 250r CB on a CR500 engine, I could be wrong though, and hope some can prove me wrong. It may dampen some of the vibrations. The CB mass would need to be increased to counter-act the dynamics of a CR500.

BTW, I read his whole thread on Australia forum that he's on.

This is my dream bike a CB'd CR500, kudos to the one that has the funds to figure it out.

[destey]

Here's the build project (http://www.ozatv.com/forum/viewtopic.php?t=11107&postdays=0&postorder=asc&highlight=trx500r&start=50) for the guy on youtube with the counterbalanced cr500

Says he just got it going a week or two ago, still vibrates but not as much at higher rpm. Says at low rpm actually vibrates more

[troybilt]

Originally posted by destey
Here's the build project (http://www.ozatv.com/forum/viewtopic.php?t=11107&postdays=0&postorder=asc&highlight=trx500r&start=50) for the guy on youtube with the counterbalanced cr500

that's the one.

[250Renvy]

Originally posted by troybilt
This is my dream bike a CB'd CR500, kudos to the one that has the funds to figure it out.

I've got some funds to play with right now and should have more by the end of the year. Maybe we can team up.

Although the CR500 or CR250 or even updated TRX250R would be great, I'm not sure it would be economical enough as they are all out of production and the only way to get parts would be to buy NEW OEM from dealers which would run the motor cost upto $5000+ or strip bikes down, but with the motors getting stripped, the frames and other parts would become worthless.

I like the idea of the KTM 300 or Yamaha unless it's cheap enough to do just a small run of say 50-100 sets of cases and that is it, then I'd go with Honda.

[troybilt]

You know while we are on the topic. The other way to get 500cc of 2 stroke dominating power in a trx frame without using an LT500 or non-CB'd CR500 motor, dual cylinders on common crank, cancels most vibrations.

If you run 2 pistons on a single crank, (banshee style), a counter balancer is not needed... ergo, the twin CR250 jugs, on a custom bottom end. Trick racing has done it with 2 Cr500 jugs, but dual CR250's might also be an option on the table... food for thought, carry-on.

[troybilt]

Originally posted by 250Renvy
I've got some funds to play with right now and should have more by the end of the year. Maybe we can team up.

Although the CR500 or CR250 or even updated TRX250R would be great, I'm not sure it would be economical enough as they are all out of production and the only way to get parts would be to buy NEW OEM from dealers which would run the motor cost upto $5000+ or strip bikes down, but with the motors getting stripped, the frames and other parts would become worthless.

I like the idea of the KTM 300 or Yamaha unless it's cheap enough to do just a small run of say 50-100 sets of cases and that is it, then I'd go with Honda.

Also, have you considered Maico? Awesome motors, and they have no intentions of going 4 stroke. Nothing like German engineering... LOL.. Zabel is the other one, a dude from Maico went off and started his own 2 stroke motor company. And builds motors, to the tune of 700cc's... They use these in side car motocross, (which is absolute crazy sh$t, but that's another story), anyway the vibrations must be dealt with on those bikes too...

Zabel Engines (http://www.zabel-racing.de/en/10.html)

Sidecar motocross:
balls the size of pickle jars (http://www.youtube.com/watch?v=EPvesXbuer4)

[Ruf Racing]

Originally posted by troybilt
Old news...
He's posted on the other 250r site... and its not fixed... yet.. Nice work though, cool to see the someone try. I don't believe it would ever work properly anyway, to use a 250r CB on a CR500 engine, I could be wrong though, and hope some can prove me wrong. It may dampen some of the vibrations. The CB mass would need to be increased to counter-act the dynamics of a CR500.

BTW, I read his whole thread on Australia forum that he's on.

This is my dream bike a CB'd CR500, kudos to the one that has the funds to figure it out.

Sorry to have reposted that. Even if a 250R counterbalancer took out half of the vibration, it would be a major improvement. Good luck!

[troybilt]

Originally posted by Ruf Racing
Sorry to have reposted that. Even if a 250R counterbalancer took out half of the vibration, it would be a major improvement. Good luck!

I've never rode such a beast so I don't know "how bad" the vibrations are... but if a certain range of rpm vibrations were mitigated it would be worth pursuing...