possum Posted June 11, 2012 Report Share Posted June 11, 2012 Very interesting info here: keep it coming....loving this thread.....because it's no BS in it......need more threads like this. This! Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted March 30, 2015 Report Share Posted March 30, 2015 Bump for all the great faces. Quote Link to comment Share on other sites More sharing options...
Skibum4106 Posted June 12, 2016 Report Share Posted June 12, 2016 If done right your well built P.V. Cheetah will have lower overall power than a cub. Not just peak. Some of us have spent YEARS doing a WIDE VARIETY of porting, timing. compression, dome, pipe research to figure out that the Cheetah dose NOT have a lot of hidden potential. (BigRed you have a chance as power with your 535 10 mill) But if we're talking about a 421 P.V vs a 421 cub.......The 421 P.V. motor will be hard pressed to make 4 mill stock cylinder numbers. I've owned - 400 Cheetah with block-off plates 400 Cheetah with Power Valves 472 Cheetah with Power Valves 472 Cheetah with block-off plates 492 Cheetah with block-of plates 6 different sets of domes from 3 different builders Trinity, CPI and Shearer pipes and the bike and motors have had more dyno time that a NASCAR restrictor plate motor. (I've got access to a dyno, I've got a key to the place, I pay nothing for dyno time....I'm not talking out my ass. I've burnt many a jug of fuel to learn what I know first hand. Was that short enough for you Tyler? Well what did you learn then? I want to built a stronger street Engine for my Yamaha RZ-350 road bike. I did not want to give up the power valve exhaust ports of the stock engine .. Then I see that Trinity makes an after market power valve jug. So what did you learn with all of your Dyno Time ? Quote Link to comment Share on other sites More sharing options...
Skibum4106 Posted June 12, 2016 Report Share Posted June 12, 2016 Ok, you are being polite and I will too. I didn't say 400's are junk....I said MY 400's were junk. 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. I was looking for a newer Vintage Yamaha RZ 350 Jugs .. the 84-85 Jugs with Power valves made 47 HP with a very restrictive exhaust .. The later Engines with better porting in Canada made 63 HP stock. So being new to the RZ=350 and Banshee 350 world I am not up on various aftermarket Jugs available .. I did find one manufacture that makes a Cool head that with use the RZ-350 Thermostat which I want to keep using .. The guy that started Trinity Racing now has a business called McDermott racing .. McDermott Racing Formally Trinity Racing Inc. Quote Link to comment Share on other sites More sharing options...
bigweav81 Posted June 12, 2016 Report Share Posted June 12, 2016 Wtf is the point here? Sent from my SM-S820L using Tapatalk Quote Link to comment Share on other sites More sharing options...
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