Jump to content

Cool head and re gear for better GP lap times


TIM LUTZ

Recommended Posts

So I raced my first GP Saturday and 80% of the time I'm in 1st gear maxed out screaming thru the woods. Pretty scary thru tight woods but second is just a little too tall. Only time I used 2nd & 3rd was on the MX part of the track.  I'm going up one (14 to 15) on the counter sprocket and throwing on a Chariot head with 20cc domes.  This is the first time I've done 2 mods at once but I'm pretty  sure one will

complement the other.  Due to my port job and stock head I'm only around 120 PSI on a fresh top end so going to 160 PSI and 50/50 94 and cam2 should give me a nice boost out of the corners and more useable power thru the woods.  Thoughts?

Link to comment
Share on other sites

you MAY.....and I say MAY be able to get away with just 93 pump fuel with your set up.  I know last season I was running my dune/play port from Jeff, with 20cc domes and I was on 93 pump.  I did lean the shit out of my motor and suck up some serious dirt and destroyed my motor when one of my air filters came off after a very large bump.  However when I sent my cylinders back to Jeff for a bore/hone.....it gave me the chance to ask him to look for any signs that I had missed indicating detonation.....so he had me send my worst piston and that pistons dome along. 

 

After he got my cylinders all done, he gave me a call and asked what domes I was running and I told him as he inspected my piston and dome....even to his eye he could not see any signs of detonation on that side.  My compression was at 156 on both sides and still running on 93 pump.

Link to comment
Share on other sites

Thanks for the input.  I think when I play ride I'll be OK with pump but to be on the safe side I'm blending for race day.

What have you all seen in power when adding your cool heads with this big a bump in compression?  I'm looking for

anything that will give me more torque and wider power band.  My next mod is going to have to be a set of V3's

 

It may be denial that keeps me on a Banshee or the joy of blowing by a TRX450R on a 50 yard straight BUT,

I'm starting to think I could be turning better lap times on a YFZ450R.  I've had my Shee for 14 years and will

be buried with it.

Link to comment
Share on other sites


 

 

You sir are a prime candidate for a yfz450 hybrid!   

That would be sweet.  If I did that I'd put a CR or KX 500 motor in it. Them things had so much damn torque.

How bout a timing plate?

Runnind a 4 degree key.  yea, a plate would me much better.

Link to comment
Share on other sites

Why not add 2 teeth to your rear or go one smaller on the front? That way instead of spending your day in first.... You can pull second.

 

Try 13-41 if 14-41 was doing what you said.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...