Dirt tracker mods

verticaltwin · Posted: June 27, 2005, 11:36 am Post subject: Dirt tracker mods

I've been wondering what to do with the couple 77 650's I picked up a while back. I want to do one for street use, but the other I have no title for. Well this weekend I went to the local dirt track and watched some great racing, several riders on xs650 motored bikes. They did really well against other vintage twins. I'm going to try to hook up with a couple of the racers in the local vintage circuit and see what they've done to the bikes, but I thought I'd pop the question here as well.

Any dirt trackers out there?

What does it take to get a stock motor competitive with out draining my wallet?

Any frame suggestions?

Thanks,
VT

robertpokerplayer · Posted: June 29, 2005, 5:51 am Post subject: Re: Dirt tracker mods

I've not had the chance to see any XS's on the track but heard that they did well. I saw something awhile back on making a dirt/flat tracker but can't remember where, I'll look around to see if I can't find it again. Anyway, over at 650central there are a couple of thing that you may want to check out. Here are the links: www.650central.com/fla...racker.htm
www.650central.com/tec...onmods.htm
That bottom one I think all XS owners should look at, it has some really good info in it (it might help you with your street machine too!!).

verticaltwin · Posted: June 29, 2005, 7:23 am Post subject: Re: Dirt tracker mods

Thanks for the links, thats what I'm talking about! Unfortunately I can't afford the top notch racing gear they put in that bike. I found some info on a flattrack website about setting up a Yammy 650 for a starter bike. It was on a forum where the person was asking a pro about the viability of starting racing on an xs650 and what he should do to the bike. Here's the reply:

"The Xs650 is a great place to start. Personally I would do the following
few things if you want to run a stocker (I suggest you do) to get
started. Performance mods should be concentrated on getting the machine
to handle. The stock frame and stock engine can work fine, spend your
money on suspension! Get some adjustable rear shocks built to the
swingarm dimensions, bike and rider weight. Send the front forks off to
a specialist for dampening and spring mods to suit the machine and rider
weight as well. I am not solid on the rake and trail on this unit but
Davey Durelle in Fountain Colorado could probably square you up on
whether the triple clamps need relpaced as well as handle most all of
the suspension mod needs. Davey has kits for Yamahas). As far as the
engine goes, dump all the intake crap and get some foam or K&N paper
elements so this baby can breathe, AND, the number one need is to get
the left side alternator/primary cover modified so you can lean this
bike left without lifting the rear end off the ground. This is one of
the most common oversights on the Yamaha and will end your career real
early if not attended to properly. I have not mentioned any engine
modifications as the Yamaha puts out plenty of useable power starting
out in stock form. This engine has little useable fywheel effect as it
is and all mods simply put the performance in the light switch category
causing frequent underwear change stops as you try to get the power on
and off while still maintaining control. Another solid $400 investment
is a cdi ignition ala ARD and other brands. Getting rid of the battery
makes life simpler and the bike lighter as well.
The low cost of operation is a primary reason to start with the Yamaha.
The Brit bikes on the other hand are more expensive to set up but they
are a natural for flattracking from a controllability standpoint.
Good Luck...."
ike Zbrozek

Sounds promising!

VT

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

If your attentions are to turn this motor past the factory redline,you better be welding the rod pins to the crank halfs or you'll be picking bottom parts and possibly human parts off the track due to crank half seperation. THIS IS a COMMON PROBLEM with XS anytime you exceed the limits of the bottom section,They will seperate and this is a must for your safety............and keeping the motor from exploding..........Jack

verticaltwin · Posted: June 30, 2005, 9:12 am Post subject: Re: Dirt tracker mods

Thanks for the warning. I'm not that hard on bikes, usually... Hope to get max torque out of the mid range rpms, if I can tune/tweak the carbs right.

VT

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

You'll gain more engine performance in the header,muffler combination than through the carbs but for any improvement that boost engine output can be rendered useless if the motor isn't allowed the breath through exhaust port of the XS head. If ya want most bang for the buck along with the exhaust system........port the heads and you'll be amazed at the out come in performance..............Jack Wink

verticaltwin · Posted: July 1, 2005, 9:41 am Post subject: Re: Dirt tracker mods

Thanks for the advice.... Though I have to keep the $$ down right now. I need to move a project or two to free up some fundage...

VT

sportydriver · Posted: July 11, 2005, 8:38 pm Post subject: Re: Dirt tracker mods

Who do you send heads to for porting/polishing?

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Go to the porting section in engine mods Wink

..Jack

sportydriver · Posted: July 14, 2005, 8:16 pm Post subject: Re: Dirt tracker mods

Hey Jack,
Thanks but I was really looking for a pro to send my heads to. I'm mechanically inclined enough to change bearings and bushings and such, but with only one engine, I really want to leave this to the pros.
Anybody know a good shop in the southeast? I'm just outside of Atlanta.
George

Barrett · Posted: January 22, 2007, 11:29 pm Post subject: Re: Dirt tracker mods

They also make some classes for the Vintage Flat Track racing for stock CV carbs and another for aftermarket/mikunis. At the last race I was at, the XS's whooped up on everything except a couple of XR-750 Harleys.

Get big filters, there is this whole physics deal about moving as much air as the motor displaces...(no little cones)

Dirt trackers use 19 inch wheels, the cheap way is an adapter for a front wheel that uses quick change sprockets/rotor/bearings. Dunlop makes an 18" rear tire(if you have an 18" off of an XS 400)

VDTRA guys have all the secrets about the heads, valves, and guides. Something about moving the guides/angles or something

ost balance around 61-65% and then Tig a stich or two to keep the flywheels from shifting(next time it is apart, or if your build a hotter motor)

All the racers I know with stock frames use the plain XS frame over the special(the ones with a 16" rear and plastic side covers). Apparently there is a few degrees difference in the rake.

Hard core guys move the shifter over to the right as well(left foot on the ground, right on the bike...)

Get a SHELL #1 cam, if you do any engine mods, that is the choice cam with springs. Works with the 750cc too.

spickett · Posted: March 27, 2007, 5:16 pm Post subject: Re: Dirt tracker mods

If it were me I would save most of my cash for good safety gear like leathers and boots and a good steel shoe. Then attend to the wheels and tires. Go 19" on both ends and the quick change setup is the way to go. The stock front wheel is fine in either mag or spoke. I bought a new quick change barnes from First Klass Glass for $465 complete with adapters and nuts. Go to a 17 tooth front sprocket for a 520 chain from mikesxs and rear sprockets run about a dollar a tooth from most race suppliers. Then put the bike on the track a lot! Attend American Supercamp if you can to really learn to slide and then see how much you like it. You may find that you love it and want to get rid of some stuff to raise cash and really make it go but as you start out the stock engine is much easier to ride. AHRMA has a couple of classes (750 Sportsman and 70s twin) and most AMA events have whats called the Vintage Heavyweight class to ride in. Just know that you will run against the later TT500 singles and they are hard to beat on a 650 twin. I hope you have as much fun as I do at it. I am going to try to get to Greenville SC this weekend for a SE Regional AHRMA race.

dpmphoto · Posted: May 2, 2008, 5:58 pm Post subject: Re: Dirt tracker mods

what does it take to make your bike competitive without draining your wallet???? Impossible

What Happened to 650rider.com?

Yamaha xs650