Stealth Hawk

Stealth Hawk

This is Deon's Stealth Hawk

The Stealth Hawk:

A. The Engine:
  1. Mildly ported stock valved heads.
  2. Really good valve job, stock valve springs. ( Thank you Dave Weaver.. )
  3. MegaCycle 174x-8 cams, dg'd at 104dg. ( Dave's idea.. )
  4. 3mm over Wiseco pistons 12.1 to 1 compression, with base gaskets removed from cylinders ( again Dave weaver's idea.. ) and skirts shortened. 696cc ( slightly smaller combustoin chamber due to removal of base gaskets ) with base gaskets was 11.8 to one comp, and 697cc.
  5. Carrillo rods
  6. Costa Mesa ballanced and lightened crank.
  7. Mike Velasco Racing dual diameter header
  8. Oil pressure bumped up.
  9. Stock carbs, airbox bottom, with Uni Foam replacing paper plate filter, dyno Jet stage 7 race needles.. ( didn't use HRC kit as lost 4 hp on top.. ) shimmed stock needles will work too..

B. The Chassis:
  1. Progressive fork springs, 10wght oil, oil 5" from top, measured with no springs and forks fully bottomed.
  2. Cartridge Emmulators ( variable compression damping for damper rod forks )
  3. F-2 preload caps
  4. F-2 front wheel and spacer
  5. Dual 316mm Hawk rotors
  6. VFR master w/ Hawk mirror mount installed
  7. Braidedbrake lines, rear through swingarm..
  8. Rear brake resevior replaced with plastic tube resevoir from an RS250 gp bike
  9. VFR five spoke rear wheel ( from the current VFR750 )
  10. Fox multi adjustable shock ( spring pre-load, comp and re-bound damping and ride hight )

C. The Rest:
  1. Kiyo Watanabe Carbon Fiber 5.3 gallon tank, with pressure relief valve installed.
  2. Hand pollished frame
  3. Black painted fork legs, rotor centers, and body work..
  4. F-2 handle bars

When I bought the Hawk new in 89 it was my first street bike and I was looking for something I could learn on, that would be fun in the twisties and able to grow with me. In '91 I began moddifying it. Out came the stock pistons in favor of 3mm over high compression Wiseco's. On went a Muzzy slip-on, replacing the stock shorty, which was as heavy as a boat anchor. I re-jeted the stock carbs, and shimmed the needles. I also replaced the fork springs with progressives, and ran 10 wght fork oil rather than the stock 5 weight. And of course stock brake lines were replaced with stainless braided lines, the rear routed through the swingarm. I aslo hand pollished the aluminum frame. Went through tons of wet dry sand paper and Mothers pollish. Shines like a mirror even now, though I have to pollish the oxidation off every week or so. Adds to the sattisfaction of detailing the bike before riding weekends.. That state of tune lasted around 1500 miles, before I'd ruined the stock rods. As I was doing the motor work on my own, learning as I went, I wasn't aware that the Wiseco's longer skirts would hit the opposite cylinder's liner. Scratch one pair of stock rods.

Next I replaced the pistons again, stuffed Carrillo rods in, after I sent the crank, rods and pistons to Costa Mesa for ballancing and lightening of the crank. A Two Brothers pipe replaced the Muzzy slip on. I had the heads ported and installed 1mm over intakes and 1.5mm over exhaust's. In went Megacycle 174x-2 roadrace cams, and the stock carbs were replaced with 39mm Keihien FCR's. When the motor was re-installed I also mounted Marchisini's. An F-2 front ( Marchi ), and a Hawk rear ( Marchi ). With the F-2 front ( Marchi ) I installed a Honda CB-1 right side fork slider which is identical to a Hawk's, but carries the mounting boss's for a calliper ( hawk's only have left side boss's ), and the brake from a CB-1 along with a second 316mm Hawk rotor. And of course a Fox rear shock replaced the awefull stock shock. I have the rear ride hight raised around 2 inch's to increase the steering rake, and reduce trail. ( stock hawks have a lazy 27dg steering rake, mine's now 24dg )

After that motor was installed I had a HUGE midrange hole, through which I couldn't get it to run. It wailed on the top end, but had nothing below 6 grand. Absolutely un- rideable. It turned out to be WAY overly ported heads, but I didn't figure that out till I'd replaced the TBR pipe, and Megacycle x-2 cams with an MVR pipe and 174x-8 cams.

Once again the motor came out. This time I had a friend do the work, someone who's been racing Hawks forever, and knows exactly what works and what doesn't. Dave Weaver's his name, he ported the heads, did the valve job, came up with the 104 dg idea for the cams, and decided to try leaving the base gaskets out rather than mill the cylinders.. He replaced the over ported big valved heads with stock sized valves and a his own head porting and valve job. Degreed the cams at 104dg, rather than the specified 106dg, trying to move the power down the rev range a bit as well as increase low end tq, trying not to make the mistake of having a Top End only Hawk again. Also left the cylinder base gaskets out. Leaving the base gaskets out is simmilar to milling the cylinders, something Hawks respond really well to. ( don't mill the heads on a Hawk, do the cylinders as milling the cylinders changes the shape of the squish erea in the cumbustion chamber by moving the piston's crown further into the head. Makes a big difference in Hp and Tq.. Far more than just milling the heads the same amount would... )

When I re-installed the motor, I also re-installed the stock CV carbs as I couldn't filter the FCR's. I'm runnning Dyno Jet needles, the airbox bottom, with stock filter ellement holding Uni-foam instead of the paper pleates.. Works as well as Uni Pods, but allows me to hook the crank case breather to the airbox bottom, and get rid of the oil splashed out of the breather onto my right leg. I also replaced the F-2 / Hawk Marchisin's with the above mentioned F-2 front wheel ( same offset as a Hawks brake rotor, the swap only requires changing the wheel spacer from a Hawk's to an F-2's.. Retains the mechanical pick up for the speedometer.. ) and a VFR five spoke rear. The Marchisin's were absolutely gorgeous, but rather fragile and I didn't want to ruin them here in pothole riddled mid western Pennsylvania.. Stock rims were ugly as sin to me and the VFR/F-2 combo is much better looking ( no more Hawk egg beater looking rims ) and allows the fitment of modern sporting 600 superbike rubber. 3.5" front, and 5" rear wheel as apposed to 2.5" front and 4.5" rear.. With the new ( again ) rims, I installed a set of Cartridge Emmulators in the front forks.. Much improved front end, to go along with the improved fox equipped rear.. I also ironed out the brakes, and now have a VFR 5/8's master pushin' the brake fluid. The hawk's 1/2" master was too small to push the doubled fluid volume.. I removed the mirror perch from the stock Hawk master, and JB welded it to the VFR master to retain the right side mirror assembly. Using the VFR master also allowed me to utilize the stock brake lever ( or an adjustably VFR, another mod for the near future.. ) as well as the stock brake light switch. It was a bolt on affair. My instincts told me it would work well, and boy oh boy does it. I now have doubled ( dual 316mm rotors ) the stock Hawk's swept brake erea, and she STOPS!! Just last night ( 10/19/96 ) I replaced the stock gas tank with a Kiyo Watanabe Carbon fiber affair. 5.3 gallons verses the stockers tiny 2.9 galon tank. Kinda brutish looking, but light as air. even with almost two gallons in the Kiyo, it's lighter than an empty stock tank ( stock tank minus gas cap, petcock, and rubber stuff even!! )

So, that's where my project stands. How does it run? Well, in a word absolutely fabulously!! stock Hawks are fun little commuters, reliable as can be. Moddified Hawks are absolutley intoxicating fun. Mine carves corners with abandon, lofting the front on tight second gear exits. Stops nosebleed eyeballs on your face shield hard. Like harder than a CBR900rr!! ( dual 316mm disks, as apposed to 296 disks. Swept erea rules.. ) And my gamble with running the cams at 104 dg rather than 106 dg worked really well. It's a torque monster, pulls like freight train from the very bottom. Even so, the top end is awesome. It lofts the wheel from any rpm in first, and with a rider that has ballance will carry it through fifth gear on the rear wheel. It even picks the front off the ground about eight inches or so on hard first to second shifts. Slam left/right/left through a tight set of switch backs and the rear is the only thing touching ground through the middle turn. I won't say a Hawk will ever out run an inline four in a straight line, but when your carving corners, especially tight ones, there aren't many bikes that'll lose a well ridden, moddified one. Really fun bikes if you like corners..

I'm pretty close to being finnishded with this project Hawk. In the future, I may re-install the FCR's, and might try another pipe. Am going to try to fabricate a ram air system, and probably install an oil cooler and maybe a larger radiator. Eventually I hope to score an Africa Twin crank and will bump it to roughly 800 or so cc's, as well as fabricate an additional crank bearing. It will remain naked though, as I don't want Super-Bike riders to think it's anything special.. And I really like naked muscle bike looking sleds.

For now I'm out enjoying the fruits of many years labor, roosting around the northeastern states, preying on un-suspecting Super Bike riders. Just me and my Stealth Hawk. ( Gee Willy, that un-assuming little unfaired bike doesn't look like it could make my all conquring [ insert name of current all conquring sport bike here ] eat dust! How'd he do dat?!!? ) Tight twisties are what Hawks are all about...

© 1997 by Hawkland