Motorcycle Racing Forum

Racing Discussion => Racing Discussion => Topic started by: grasshopper on October 09, 2006, 10:46:41 PM

Title: KX500 Motor in Hawk Frame...
Post by: grasshopper on October 09, 2006, 10:46:41 PM
Anyone notice that machine at Gingerman last weekend? What a contraption. He had the whole entire exhaust hanging from safety wire.  :banghead: The thing sounded bad ass and it looked like the motor was fitted properly. I didn't get the guys name but after his last race he put it in his van and the threaded part of the clevis on his shock snapped off and his whole motorcycle collapsed. HOLY CRAP!!!! Can you imagine if that would have happed on the track? That could have been a disaster for him and who knows who else?  :err:
Title: Re: KX500 Motor in Hawk Frame...
Post by: HAWK on October 09, 2006, 10:52:08 PM
Scott Schafer from MO. H usually runs his regular Hawk but since he's taking to Daytona didn't want to risk tearing it up this weekend. He seemed to have jetting problems which weren't helped by being running off the track in 3 to avoid another riders highside. Not his best outing him and I usually run pretty close on our Hawks.
Title: Re: KX500 Motor in Hawk Frame...
Post by: Un-retired_racer on October 28, 2006, 04:28:28 PM
I battled with Scott at Daytona but couldn't track him down in the pits afterwards.  Anyway, nice race, bro, and hopefully we'll do it again next year.

BTW, one of the photogs got a couple pics of our race.  Check out images 4620 and 4644 at http://motorsportsarchives.com/Standard/Login.jsp

Tom
#96
Title: Re: KX500 Motor in Hawk Frame...
Post by: Super Dave on October 28, 2006, 08:28:02 PM
500MX motors were done in Hawks in the early 90's.  Dr. Bob Meister did it with a CR500.  Safety wire for the chambers is common because of the vibration;  everything cracks if it's mounted too solidly.
Title: Re: KX500 Motor in Hawk Frame...
Post by: 123user on October 30, 2006, 01:38:04 PM
Actually, the shock rod did break during race.  On the last corner of the last lap the whole bike came around and I almost highsided.  It was only gravity and my weight keeping it together.  I didn't realize this until I picked up the subframe and the bike fell apart... very scary.  I guess there was some flaw in the threaded portion of the shock rod. 

The expansion chambers are very difficult to design and mount in these applications.  I was very glad that the safety wire was there, during the race, the pipe developed a major crack and the lower mount broke. 

I was a little disappointed with the performance during the race, on Saturday's practice it would almost stay with slower 600's.  By my race, a combination of problems made it slower that my regular hawk.  Not only did the pipe develop a crack- killing the top end, the pipe was being blown off the cylinder... with 3 very heavy springs!!

I went through three iterations of mounting the motor.  The first was a solid mount and the bike was all but unridable due to vibration.  The final design is a "floating" motor.  It is rigidly mounted through the swingarm pivot, but uses 10 "isolation mounts" for the other three mounting positions.

I don't think vibration caused the shock to break, I think I just had a bad shock... and the vibration didn't help.

You should get a chance to see it next year, I've binned my regular Hawk in favor of a 2006 1000ss, but I'll continue to run the KX500 for ultra-light (if the class exists next year)
Title: Re: KX500 Motor in Hawk Frame...
Post by: benprobst on October 30, 2006, 07:44:28 PM
1000SS . cheater :biggrin: Are you going expert or staying AM next year scott.
Title: Re: KX500 Motor in Hawk Frame...
Post by: 123user on October 30, 2006, 09:48:53 PM
Well, seeing as I'm riding a "cheater" bike, I suppose I should be an expert, it wouldn't be fair to ride against amateur's with a clearly superior machine.

No, but seriously, I guess I'll just see where CCS puts me.  I don't really care, if CCS keeps me in amateur I probably won't do a lot of motor work.  If I'm classed as an expert... I'll see what I can afford

Remember, a stock SS weighs near 450lbs wet, and I'm pretty fat.  The rumors of the Duc's power advantage over the SV are somewhat exagerated.  I'd have to spend some money to get it anywhere near the XB-12R powerwise.

I still think winning is 90% rider, 5% bike, 5% luck... unless your on a Hawk, then it's fair to blame the bike.