OOPS!

[lakercr]

Well, I finally got a few miles on the new engine/turbo and decided to dial it up a bit yesterday. Started at 14 lbs and was pulling into the 130's on GPS. went to 20 lbs, checked my A/F on a few quick pulls and then tried it out of the hole once, and I mean once...

F7 skid does not match well with 20+ pounds of boost.

 

[tko47]

sounds like to much power?

 

[REXX]

F7 skid does not match well with 20+ pounds of boost.

All the rest are "just toys". That's why they break so easily.

REXX
-------------------------------------------------------
'07 Apex mtn SE turbo+
Western Canada

 

[lakercr]

sounds like to much power?

I had the limiters sucked up almost all the way and I doubt there was more than 8 inches of track on the ground when I pinned it. Sled is really tippy with only 2 rear wheels and it puts a lot of load on the rear part of the rail. You can see in the one pic where it just snapped. I'll make a better rear axle for it this week and add the other two wheels. Also going to relocate the skid in the tunnel a bit to deal with the transfer.

No such thing as too much power!!

 

[TWIN TURBO]

And I thought my Wall suspension was bad?
No Harm intended but, It just sends shivers up my spine, How can so many guys put that cheap Arctic junk on a Yamaha? You of all people should know better.

 

[Srxspec]

Is that a 2003 rear skid? They had updated rails in 2004 with thicker material to keep that from happening!

 

[lakercr]

And I thought my Wall suspension was bad?
No Harm intended but, It just sends shivers up my spine, How can so many guys put that cheap Arctic junk on a Yamaha? You of all people should know better.

Keep in mind this is an '03 RX chassis. Not much to brag about from Yamaha on the quality/performance of the stock skid. The Pro Action was swapped out 4 years ago for the Cat skid, and it has worked very well up until now. To be fair to AC, the rear of these rails have been modified a bit (some material removed) when I was playing with different wheel sizes/drivers/ skid location. Nothing too drastic, but apparently enough...

Fundamentally, I don't think there is anything wrong with the design of the AC skid. It is almost infinitely adjustable, has zerks everywhere they should be, and uses substantial brass bushings in places Yamaha chooses to use plastic. It also doesn't lose track tension on transfer like the stock Pro Action does. This skid has been in/out of the sled probably a dozen times in the past few years and I've yet to clean up a weld or fix a hairline crack.

Anyway, no offense taken. You're right that I probably should have known better than to run the skid in it's current config. It has been working so well for so long, and there is so much that is new on the power end that I guess I'm a little myopic on where the potential problems are going to come from. I'm not going to post my gearing/clutching set-up, except to say that Turk knows what I'm running and I think he's more than a bit surprised at what it is taking to keep off the rev limiter. There is a LOT more under the hood than just a new turbo.

I'll post some pics of the skid mods that are done to it this week, feel free to offer additional comments.

 

[lakercr]

Is that a 2003 rear skid? They had updated rails in 2004 with thicker material to keep that from happening!

The skid is from isle 18B? at Haydays. Who knows what year it is from...!

Might want to call you buddy in Roseau today. Can you send me the # again?

 

[Srxspec]

2003 F7 rail in these pictures (and the one that broke put me through the traps side ways at 88 mph on our grass test track). The updated rails were substantially stronger.

 

[lakercr]

Was that with just the 2 rear wheels, or all four?

 

[Srxspec]

2 rear wheels.