Let's talk cams...

[AK47KID]

As the title says....

I keep hearing that an xr200 cam is better than the 200x cam why is this?

Wanting to build a autox with 200e engine and am wanting to do everything I can to make it get the most out of it.

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[barnett468]

If you want suggestions that are specific to your build, you should post exactly what you want it to do . There are many good cams out there . Two of the main cam mfg's are below.

http://www.webcamshafts.com/

http://www.megacyclecams.com/


Compression is king, but unless you want to run some type of race gas or E85, you are best to limit your static/uncorrected compression to around 10.5.


PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[arlaunch]

Buying a 350X would be easier and cheaper. There is more to it than just throwing an XR cam into a 200.


The bigger the cam lobes ie: height and width means the more open duration. The more open duration the higher the engine can rev vs. one with less duration as the bigger cam can breath better at higher RPM's.

The disadvantage to the larger duration cam is less low end power. This is because the motor gets to much of a good thing at lower revs were the smaller duration cam will make its torque and HP earlier at a lower RPM.

The smaller duration cam could be an advantage with a heavier vehicle. This makes drivability a little nicer.

And this is exactly why they put a higher RPM cam in the XR200 and the lower RPM/Lower Horsepower, Better Drivability Cam in the ATC 200X.

The XR200 is lighter and does not miss the low end power because of weight.

You never put a hot rod mustang cam in an F250. This of course has nothing to do with the XR vs 200X camshaft.

Here is a link to a fun read

http://www.3wheelerworld.com/showthread.php/121328-200x-Racer-The-Engine-Build

[AK47KID]

Buying a 350X would be easier and cheaper. There is more to it than just throwing an XR cam into a 200.


The bigger the cam lobes ie: height and width means the more open duration. The more open duration the higher the engine can rev vs. one with less duration as the bigger cam can breath better at higher RPM's.

The disadvantage to the larger duration cam is less low end power. This is because the motor gets to much of a good thing at lower revs were the smaller duration cam will make its torque and HP earlier at a lower RPM.

The smaller duration cam could be an advantage with a heavier vehicle. This makes drivability a little nicer.

And this is exactly why they put a higher RPM cam in the XR200 and the lower RPM/Lower Horsepower, Better Drivability Cam in the ATC 200X.

The XR200 is lighter and does not miss the low end power because of weight.

You never put a hot rod mustang cam in an F250. This of course has nothing to do with the XR vs 200X camshaft.

Here is a link to a fun read

http://www.3wheelerworld.com/showthread.php/121328-200x-Racer-The-Engine-Build
If I'm understanding correctly. Work trike it is better have a small cam play around trike it is better to have a bigger cam

For a autox with a 200e engine I'm wanting to build a work trike out of it ( it's for the women mostly) so I would be better off with the stock cam or a smaller one.

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[AK47KID]

If you want suggestions that are specific to your build, you should post exactly what you want it to do . There are many good cams out there . Two of the main cam mfg's are below.

http://www.webcamshafts.com/

http://www.megacyclecams.com/


Compression is king, but unless you want to run some type of race gas or E85, you are best to limit your static/uncorrected compression to around 10.5.


PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR
Things I hope to do

1: mid/high compression piston probably 10.5.1

2: stroker crank

3: lighten fly wheel

4: 200es head for the hot start release to help relieve stress on the starter or my hand when starting.

5: bore .20 out (by John tice)



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[fabiodriven]

If I'm understanding correctly. Work trike it is better have a small cam play around trike it is better to have a bigger cam

For a autox with a 200e engine I'm wanting to build a work trike out of it ( it's for the women mostly) so I would be better off with the stock cam or a smaller one.

Yes exactly.


Things I hope to do

1: mid/high compression piston probably 10.5.1

2: stroker crank

3: lighten fly wheel

4: 200es head for the hot start release to help relieve stress on the starter or my hand when starting.

5: bore .20 out (by John tice)

You are talking about two different machines now, yes? You never made reference to two different machines but you've just gone two completely opposite directions with this.

Also I'm curious. You post here a lot and ask a lot of questions which is good. You're a young guy who is also into trikes which is also good. However, personally I don't recall seeing much of you actually doing anything hands-on, such as riding a three wheeler or working on a three wheeler, just tons and tons of speculation. Why don't you get your hands on something and then see what you're dealing with? You'll learn a lot more.

[Scootertrash]

The XR200 cam and carb is a nice improvement over the stock 200 set up. I've got that combo in my 200S, I can walk all over any stock 185/200 that my buddies have. It's not so hot that ladies couldn't use it for "work" and it's plenty peppy for me to have fun when the ladies are done "working". I have most of the parts accumulated for a 200 Auto-X build or 3, but I'll probably go for a newer Keihin or Mikuni carb.

A 10.25:1 piston won't necessarily give you 10.25:1 compression. Your corrected compression ratio is determined by the cc volume of your head, the bore and stroke of your cylinder and piston, and the thickness of your head and base gaskets. Adjusting your ccr can be accomplished by using different thickness base and head gaskets, if you really want to go that far.

My 200S build thread, post number 3 has the measurements of the cam lobes from the 200S and the XR200:

http://www.3wheelerworld.com/showthread.php/140489-Scootertrash-s-85-200S-build?highlight=200S+build

[barnett468]

If I'm understanding correctly. Work trike it is better have a small cam play around trike it is better to have a bigger cam

No, it is not that simple . It all depends on where you want the power for each application and not all people want the same type of power for each app.



For a autox with a 200e engine I'm wanting to build a work trike out of it ( it's for the women mostly) so I would be better off with the stock cam or a smaller one.

Hopefully the following will help you narrow down what you want and not be too confusing.


ENGINE SIZE

First of all, there is no replacement for displacement . The bigger the displacement, the sooner in the rpm range it will have power if all else remains the same . Also, it will have less max rpm . Basically, if only the size of a particular engine is increased, the rpm range over which it operates best will be lower and it will develop more torque.


CRANK & FLYWHEEL LIGHTENING

Lightening the crank or flywheel will reduce torque over the same rpm range . In other words, you will have to rev an engine with a lightened flywheel higher to get the same amount of torque out of it that it had with the unlightened flywheel . If you want to tow stuff, you do not want to lighten the flywheel.


COMPRESSION

In general, the higher the compression, the more volumetrically efficient the engine will be . It will produce more torque and have crisper throttle response throughout the entire operating range.


GEARING

Installing numerically higher gearing will lower the entire rpm range over which a vehicle operates best.


CAMSHAFT THEORY

Way too complicated to explain.


VALVE MODIFICATIONS

One modification that can often be done that will increase the power a little is to have the intake valve "back cut" if it isn't already . A shop might charge you around $15.00 to do this

.................................................. ...............http://i79.photobucket.com/albums/j143/oldeskewltoy/MOmo/backcutintakecomparison.jpg

........................................http://www.ws6transam.org/Backcut.jpg


You might consider modifying the bike in stages so you don't do something unnecessarily or that makes it run differently than you want.


GEARING

You might start by installing a countershaft sprocket that has 1 or 2 less teeth on it . This is cheap and easy to do and it will hopefully give you a better idea of just how much more power you want to put into the engine . After this test you may decide that you don't need a big increase in power and that just a big bore kit with a little more compression will likely get you the additional increase in power that you want.


EXHAUST

If the girls are going to ride it and you have the stock exhaust, you might want to try that with the other mods before spending a wad of cash on a loud system unless they like that sort of thing.


CARBURETOR

Try what you have with the new mods before you buy a bigger one.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[Scootertrash]

Also I'm curious. You post here a lot and ask a lot of questions which is good. You're a young guy who is also into trikes which is also good. However, personally I don't recall seeing much of you actually doing anything hands-on, such as riding a three wheeler or working on a three wheeler, just tons and tons of speculation. Why don't you get your hands on something and then see what you're dealing with? You'll learn a lot more.

It's easier to ask questions and wait for people to answer questions that have been asked multiple times in the past than it is to use the search function to find the info hisself:

In less than 5 minutes I found:

http://www.3wheelerworld.com/showthread.php/179148-Hot-Reliable-200s-Engine?highlight=200+camshaft

http://www.3wheelerworld.com/showthread.php/180694-84-200X-camshaft-and-clutch-sizing?highlight=200+camshaft

http://www.3wheelerworld.com/showthread.php/152505-Cam-talk-Need-numbers?highlight=200+camshaft

http://www.3wheelerworld.com/showthread.php/131527-modding-a-200s?highlight=200+camshaft

http://www.3wheelerworld.com/showthread.php/127619-1985-200x-cams!!!!?highlight=200+camshaft

From the last link above:


Hi cupcake :D

OP, we have a ton of threads on an XR200 cam being an upgrade as well as exhaust/air box mods, etc etc.

[Dirty200]

No, it is not that simple . It all depends on where you want the power for each application and not all people want the same type of power for each app.




Hopefully the following will help you narrow down what you want and not be too confusing.


ENGINE SIZE

First of all, there is no replacement for displacement . The bigger the displacement, the sooner in the rpm range it will have power if all else remains the same . Also, it will have less max rpm . Basically, if only the size of a particular engine is increased, the rpm range over which it operates best will be lower and it will develop more torque.


CRANK & FLYWHEEL LIGHTENING

Lightening the crank or flywheel will reduce torque over the same rpm range . In other words, you will have to rev an engine with a lightened flywheel higher to get the same amount of torque out of it that it had with the unlightened flywheel . If you want to tow stuff, you do not want to lighten the flywheel.


COMPRESSION

In general, the higher the compression, the more volumetrically efficient the engine will be . It will produce more torque and have crisper throttle response throughout the entire operating range.


GEARING

Installing numerically higher gearing will lower the entire rpm range over which a vehicle operates best.


CAMSHAFT THEORY

Way too complicated to explain.


VALVE MODIFICATIONS

One modification that can often be done that will increase the power a little is to have the intake valve "back cut" if it isn't already . A shop might charge you around $15.00 to do this

.................................................. ...............http://i79.photobucket.com/albums/j143/oldeskewltoy/MOmo/backcutintakecomparison.jpg

........................................http://www.ws6transam.org/Backcut.jpg


You might consider modifying the bike in stages so you don't do something unnecessarily or that makes it run differently than you want.


GEARING

You might start by installing a countershaft sprocket that has 1 or 2 less teeth on it . This is cheap and easy to do and it will hopefully give you a better idea of just how much more power you want to put into the engine . After this test you may decide that you don't need a big increase in power and that just a big bore kit with a little more compression will likely get you the additional increase in power that you want.


EXHAUST

If the girls are going to ride it and you have the stock exhaust, you might want to try that with the other mods before spending a wad of cash on a loud system unless they like that sort of thing.


CARBURETOR

Try what you have with the new mods before you buy a bigger one.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR
whats the benefit of the backcut???

[yaegerb]

whats the benefit of the backcut???


Improves flow around the head of the valve.

[barnett468]

.

...at lower lift levels.

The more the valve opens, the less affect a back cut will have . It will not make a significant increase in flow/power, however, if you are looking to get the most from an engine, it's a very low cost upgrade . Plus it's another cool thing to tell people about your engine. http://www.mustang.org.au/forum/Smileys/smilies/thumbsup.gif


PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[AK47KID]

Thank you all for the replies. I'm gunna think about it and make a list

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[Dirtcrasher]

Sounds like you need about 700 bucks or so for those mods. I prefer the "shrunken rod technology" stroker cranks versus using a spacer plate....