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421 cheetah p.v v.s 421cub


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Everyone is saying good info... Maybe good personal testimony but this guy obviously had issues he never figured out. My 392 cheetah WITH pv's runs awesome and I've never had any problems since we fixed what trinity did. So, to say the 400's are junk is incorrect. I understand you had a shitty experience, and I'm not taking up for trinity in the least, but you obviously had issues you never worked out because these motors can run good and do. I dont want to get into an argument about pv's because you wil just claim to have learned from and quote from the pro's, but the are not bad as you make then out to be. If properly tuned they will be up and out of the way so there is no way they wil hurt top end power like you say. Sucks you had all that bad experience with all your motors, but they aren't junk like you portray then to be.

 

Even when completely opened up, the powervalves will still cause turbulence in the exhaust port. I run the PV's in my 485 so I agree with you that if set up right the powervalves make for a very nice ride. I am very happy with the power and the way the power comes on with my cheetah. But at the same time I have not tried it with block-offs, so my argument is one-sided so far. If anyone has a set of blockoffs for a 73 bore cheetah I would like to buy them and give it a shot.

 

-Jared

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Everyone is saying good info... Maybe good personal testimony but this guy obviously had issues he never figured out. My 392 cheetah WITH pv's runs awesome and I've never had any problems since we fixed what trinity did. So, to say the 400's are junk is incorrect. I understand you had a shitty experience, and I'm not taking up for trinity in the least, but you obviously had issues you never worked out because these motors can run good and do. I dont want to get into an argument about pv's because you wil just claim to have learned from and quote from the pro's, but the are not bad as you make then out to be. If properly tuned they will be up and out of the way so there is no way they wil hurt top end power like you say. Sucks you had all that bad experience with all your motors, but they aren't junk like you portray then to be.

 

Ok, you are being polite and I will too.

I didn't say 400's are junk....I said MY 400's were junk. :lol: As you read, I didn't do any repair work to the 400's from how Trinity shipped them. AS SHIPPED from Trinity...it was junk.

Now once I got into the 472-492 motors...I wasn't going to keep buying pistons every time the motor detonated, so that's when I started having top people do custom domes and work on porting the motor.

I did have issues that never got worked out with the 400 motor. But the 4 mill motors got more R+D time than anyone in their right mind would ever do. (Not having to pay for dyno time has made it possible for me to test the snot out of just about every thing you would want to try.)

 

Now I'm going to throw this out there and I don't want anyone to take it the wrong way, so please listen to the point I'm trying to make. (I'm speaking in general...not directing anything at anyone.)

My friend has a 65HP bike that RIPS.

My wife has a 63HP bike that RIPS.

Both those bikes consistently beat a very nice looking high dollar 421 cub.

I say that because a bike can "Run Great" or "Rip" or "Break the hearts of bigger motors" and leave the owner VERY HAPPY with the bike. Yet it can be down on power from what others might think it should make. For instance, the guy with the 421 cub thinks his jetting is mint and thinks the bike rips. He also thinks he's making 88-90 HP But we know otherwise. This would be a big reason why he's getting beat by smaller motors.

The overall point I'm trying to make here is that I've found many people who come in with Banshees that are strong running bikes and after the first couple of passes on the dyno, find the numbers are 20HP lower than they had convinced themselves that they had. Now I'll admit that the simple number a dyno shows has ZERO value in the seat of the pants. (If a bike is scary fast and making 55HP...finding out the number changes nothing.) But if you KNOW other motors like yours are making 70HP...than you have learned you have room to improve.

Satisfaction with your bikes power is a personal thing. For the money and knowledge spent on my Cheetah motors... I found it was relatively easy for people with OTHER cylinders to make the power levels that I was struggling to make.

 

My statements are not being made to lower your level of satisfaction with your motor. If your bike runs great then I'm glad you have found the level of satisfaction that your looking for.

I found the Cheetah motor design required all the best work from the best people to get it to perform to the same power levels of smaller motors. (Highly built 492 = average builders built 421 cub.)

This lowered my satisfaction rate because I could have had a lot more power with a lot less work and cheaper rebuilds had I never gone with the cheetah motor.

 

I choose not to debate power valve theory because in the right situations, they can be made to work well. (As I have stated) But I found in both dyno testing and seat of the pants riding, that the block-off plates far out performed using the power valves. (Yes I spent days messing with cutting P.V. springs and tuning them.)

I find the Serval power results to be a much better path to the type of power you would want from the P.V. motors. A 10 mill Serval can be bought in a kit from your average back yard builder/internet/site sponsor and will make better power, and cheaper than a full custom 4 mill P.V..

 

I've put my money where my mouth is because I've sold my 492 Cheeath and dropped to a 465 Cub. Now I've just explained how I feel about the Cheetah motors....(And in doing so in this latest response, I have voiced more "Opinion" than in the previous posts.) But my opinion is entirely based on the information that I gathered from years of trial and error as well as dyno testing and tuning.

Trust me when I say....you don't drop the coin I have, for as long as I have...If your not totally committed to being a Cheetah owning nut swinger. ;) But unfortunately I was dissatisfied with the design after the massive effort that went into "finding that motors potential."

 

My statements are in NO WAY meant to bash anyone's bike or decisions. I have only shared info to better inform others of the things I have learned. (Nickisgod) has a fresh 485 P.V. motor and is driving from NY out to meet with me and dyno his bike on our dyno, then spend the weekend duning at Silver Lake Michigan with me. He was given all the free info I could to help him find satisfaction from his motor. I'm sure he'll be posting dyno numbers at some point for all of you to look at. (His latest 485 is a Trinity/F.A.S.T motor.)

 

See......now I just can't find a way to tactfully explain the how's and why's of things I say without it taking up a lot of space. I'm trying to avoid offending anyone while still passing on free info. :shrugani:

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:jesterlaugh: And you had to quote the whole thing...... :rolleyes: You KNOW Tyler deletes any thing I say that's more than 3 sentences long. :o Now your just tweaking him. :lol:
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I feel windys posts are good for the most part .. and have talked to him seems like a good guy although I know alot of people say other wise ??

your 492 is up and running matt put it together for tito and it runs great he did put the pv in it thou..!!!

 

cant wait to get my 535 pv running

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Wow, now that was a long post, lol. But, worth reading and very well put. I guess I am a cheetah nutswinger as you mentioned, but I guess its hard not to be when you invest so much time and effort into anything. I have been on my phone for this while post so couldn't go back and read it when I replied, but yes, trinity 400's ARE junk, lol. Didn't mean to mis-quote you. Wish I had free dyno time like you just for shits and giggles to see what my motor looks like, unfortunately, the only one I know of near me charges $50 for 2 pulls, no tuning time really. Its popular with the 4 strokes, haha.

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I feel windys posts are good for the most part .. and have talked to him seems like a good guy although I know alot of people say other wise ??

your 492 is up and running matt put it together for tito and it runs great he did put the pv in it thou..!!!

 

cant wait to get my 535 pv running

How did it do compared to Matt's motor? (I know Matt has the best tires for the coal....but did they ever shake them down in a drag?)

I tried to talk him into skipping the whole P.V. install and just running it the way I had it set up....but those PA guys really like the P.V. motors. I figured it found a happy home.

When are you guys going to go dyne some of your motors? Talk someone into a group rate, or rent by the hour and be ready for speedy jet changes. B)

 

What did you end up doing as far as your build with the 535? (I smell a HP war coming in the PA.) :lol:

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How did it do compared to Matt's motor? (I know Matt has the best tires for the coal....but did they ever shake them down in a drag?)

I tried to talk him into skipping the whole P.V. install and just running it the way I had it set up....but those PA guys really like the P.V. motors. I figured it found a happy home.

When are you guys going to go dyne some of your motors? Talk someone into a group rate, or rent by the hour and be ready for speedy jet changes. B)

 

What did you end up doing as far as your build with the 535? (I smell a HP war coming in the PA.) :lol:

 

They never drag raced Matt's is always in good tune.. It would be cool to get them all dynoed!!! It's not a war I really want more tourqe and mid range ... I like roll on power

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This is all great info as I have read. Camatv also gave me a lot of insight on the cheetah setups. I got the 421 cheetah pv but still have to get domes cut,cases ported,block ported. I also just got a 10mil cheetah pv that is drag ported by Cameron at redline, but have to get cylinder repaired by millennium. I guess my question is shud I trade my 421 cheetah pv for a 421cub?

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In the smaller engine sizes (anything below the 10mil cheetah) the larger intakes actually lower your CCR (crank-case compression ratio) and can actually adversely affect the way the charge is forced into the transfers and slow everything down. (learned that from calvin from CP Industries over on planetsand)

- Jared

 

ive read the same info from him on ps and found it very informative. i think he said that in motors under 120hp, the cub wins because of the smaller intakes. pretty smart dude.. :cheers:

Edited by volfan537240
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