XR100

Hi Guys

Been awhile since I looked in.I've been helping my son Trey run a Flat track bike this winter.Started with a XR100 have the chassis working very well now.He has gone from getting lapped in his first race,to two feature wins in a row.Of course he has rode alot in his short life but his progression has been amazing to this proud dad.Any way why I decided to post here and ask has anyone ever built a honda 100 for hp?Its time now to look for a few more since they only come with about 5.

Glad to read up on everyone stay safe in your projects.

Munday

Is that still the old 80's four stroke XR series or did they carry the XR label on to newer models as well?

We used to build some old hondas up but it was mostly aftermarket higher compression oversize pistons, cams and porting work. Are there any limits to what you can modify for the class?

index the spark plug....

Don't forget about gearing. It's a trade off between top end speed and acceleration but try experimenting with different sprocket sizes until it suits your specific needs best. Remember:Bigger rear sprocket, smaller front sprocket=more acceleration, the opposite is true for more top end.

When Ricky Carmichel was little I saw him race a big wheel 80 in the 250 open and come in 3rd. That guy's the MAN !

We race dirt bikes on the lake in the winter here. Informally for us, but a blast nonetheless. We will plow a track on the lake with our 4wheelers. Mine are usually about .4 to .5 mile. This year has been a pain in the ass due to all the snow an wind so my track is pretty much gone at the moment. Zman has a .8 track at his house that is amazing. turns, sweepers, shicayne (sp) and straights.
The little bikes are way more nimble. I have a Honda CRF150R. 16/19 wheels. It hauls ass. We have a guy that makes tires for us. Like 500 ice screws in each, thru the lugs and into a liner.




My son rides MX on a YZ250F. We have a track on the back of our farm. He is insane. And is recovering from a pretty horrible knee injury he suffered last July. Came down kittywampus off a triple and landed on his right knee. Shattered kneecap, 35 stitches. Opened her up from side to side.

Hey guys thanks for the replys,Trey ran a distant second last night.Rider error,he is suppossed to run this little short track in second gear.A third gear start was a bit boggy and he never did figure it out,So rode the whole feature in wrong gear.In his defence he did change his line well making it a more round track and running the corners high to keep his speed up,passed five after the poor start but the leader had checked out by that time.

Rules allow for upto 140 cc 4 stroke in his class and I've read most of what is on the net.Yes the xr's of today are the same as yesterdays accept electronic ign. since 94.
Like Joe said I just thought there might be a guru in this group,which I hold in higher regard than any other I participate in.

I have procurred an additional motor and I'm gonna try over bore and sleeve.Gonna try to straighten the intake tract a bit also and play with the cam timing.

I'd love to try ice riding we get out and tear up the snow anytime we get a bit here in Oklahoma.Sorry about your boys knee Mike,I know my back would be alot better if I'd never rode MX but when your young and bullet proof racing is such a rush.

Off to Tulsa to watch the Chili Bowl midget race next tuesday y'all be good

Munday

If I'd ever dreamed I'd live this long I woulda taken better care of myself...

Sean

Good advice on Thumper talk.Learned alot after figuring out who knew and who was full of ship.

What we ended up with

Extra motor (we are in points chase we a 3 pt. lead)

Stroked crank
Big bore kit
Mega cycle cam
Super head
big carb but not to big
inner rotor ign (Basicly no fly wheel)
jemco down pipe

This set real runs well,almost to much for my kid,so I changed the cam timing a couple of degrees to move some of the power to the bottom

Hope all is good with your projects,barely holding on here in snow and ice.Come on summertime

Munday