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Discussion Starter · #1 ·
Well after finding out my VDI has crapped out on me I swapped over to the dyna and the bike ran beautiful. It was a friggen rocket. I got some nice video I'll post later.

We didn't win, my jockey red lit. I swear the kfx bikes have red lit more than all the other bikes combined.. ha ha. I think it is because we all know the race is won at the starting line and not the finish line.

Casey red lit, let off the gas, thought about it a moment and then got back on it. He was still able to run down one of the other bikes and finished 2nd. In the video it sounds like he left off right before the end so the other bike got away... awww well.

Ok that was the good news, here is the bad.

The Dyna has advanced timing, I have never run that much timing with the bike. It seemed to love it, ran SOOO good.... but then.....

It blew the cases even worse than Rockcrawler. I got a 4/5 inch crack running right through where the oil filter connects to the bike. EXACTLY where rockcrawler blew his (are you listening Camo?)

I was going to get it welded but it looks like too much damage.

Maybe it was the advanced timing, maybe not. Either way the bike is down for a while.... again!

I have a a question. Does a brute force motor actually mount to the frame in the same way a kfx motor does? Someone said they have never heard of a brute force breaking in that spot. With my bike that makes 3 kfx bikes that I know of that have broke in that exact spot.
 

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you have a spare set of cases still ?

you got a lot of abuse out those
 

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Dude, I'm so sorry to hear about the cases. :( Too much timing could have caused it. I have been running a conservative MAP cause I am skeared. I check mine around the oil filter quite often.

If I had the thicker brute cases, I'd ship them down. No other way to put it... SUCKS ASS!!!
 

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I hate to read this. I have a set of stock cases if you need em...
 

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Discussion Starter · #7 ·
I have spare kfx cases thanks to tom but let me ask you guys this. Are the brute cases really thicker? They appear to mount the same way... is it worth it to switch over for real or is it just a myth that they are thicker?
 

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Discussion Starter · #9 ·
Thanks Cajun, is there anyone who wants to disagree? I am just making 100% sure that I need to spend the money. Speak up now if you think they won't help.


Here is a warm up video... the green raptor had trouble and Casey wasn't staying on the throttle the whole time...

Like timing much? Bike sure liked that CDI.

 

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That sucks E looks like it was running good
 

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The Brute force cases are DEFINATLY thicker. about 1/8th of an inch thicker all over. some more in areas.

The cases seam to break when you hit about 100-110 RWHP.

they all crack right up the left side case 1/2 through the oil filter area. I believe this is from the Motor wanting to torque to the clutch side with the driveshaft torque and just 2 mounting points on the motor.

it may have also been the timing. but you should be able to see spark plug detonation white melted spots and piston pitting. you'd hear it as well. sounds like marbles under load and it looses some power.

I've never seen a brute 750 Case break yet. the Teryx cases are the same as the Brute cases and they carry a tom of weight and still mount exactly the same.

You know when you've reached this point, that you were doing somehting right and making the power.

You could always throw a stroker in there while you have it apart.

Definatly get 750 cases

John
 

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I don't think I never seen her running that strong...or maybe is my new computer speakers, they are loud! :p
 

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I think the cases break with the hard hit of nitrous or supercharger (timing could also be an issue here). The turbo has a more linear take-off and may be easier on the cases. I have V cases. I may retract this statement if I break mine.
 

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Discussion Starter · #15 ·
thanks for all the info cajun and John. Looks like I am going with brute cases... anything I should know about the change over?

I like the advanced timing, maybe back it off a little and leave it. I remebered when I first started testing the 840 a year ago I ran it once with that CDI, blew the gaskets but it felt awesome.

This time the gaskets held and the cases went...LOL

working on the video BTW
 

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thanks for all the info cajun and John. Looks like I am going with brute cases... anything I should know about the change over?

I like the advanced timing, maybe back it off a little and leave it. I remebered when I first started testing the 840 a year ago I ran it once with that CDI, blew the gaskets but it felt awesome.

This time the gaskets held and the cases went...LOL

working on the video BTW
it's all straight forward. I have both sets of cases apart at the shop If I get time tomorrow I'll snap some pics of them. it's easy to see the difference.

In a small way I don't think it could have been timing. All the broken v cases none of them had bad headgaskets or any burnt pistons?? I don't think so. but I don't know.

I know the 700 prairie's crack the engine cases(same as V cases) in the back right thru the shifter area if the motor mount's work loose or the frame cracks by the battery.

This is why I think it can be a HP/LOAD on the motor and it's front mount area. but it's very hard to say. with the torque angle of the driveshaft it'd want to lift that area up and pull the motor over to the left.

When you Split the motor. let us know if the crack extended right up to the crankshaft bronze bearing. if it was timing. it would have to be broken in that area to push down with enough force on the crank. but I think at that speed the motor is running you'd break a rod and at least have rod bushing wear. and it would have to have focused from the rear cylinder.

John
 

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Discussion Starter · #17 ·
Sure thing, you know me. I post pics and video of everything. Thanks! Hey if I buy used cases and the left side bearings are bad can those be replaced?
 

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Someone should mod the motor mounts on the frame and put some rubber or poly bushings/mounts in place to allow some motor flex within the frame.
 

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Discussion Starter · #19 · (Edited)
Good idea heathen, might be worth a try I guess.

Here is the video, I know I missed a bunch of classes but I am walking around, shooting other stuff and getting my bike ready. I wish I could include them all. I am pissed I missed the predators racing. I like watching those you don't see enough of them.

The video is real ugly right now, when youtube finishes with it will be 1080p. Might take an hour or so. I am also uploading to vimeo in case youtube doesn't like this song.


vimeo is still converting too...
http://www.vimeo.com/8808133
 
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