Race bike

graydog8josh said:
So i finally have gotten a bike i think could possibly keep up wiht the pack.
I have been getting up to the lower 40's pretty consistantly riding through town every day.
i think i might try running a 24" tire in the back with the cst cyclops fatter tire in the back and a 34t sprocket.

36t sprocket


So im reopening this thread for suggestions as i am planning on taking vacation time to go out to the races in october if they have them.

Also have gained some weight since last posting and want to get myself back down to about 170 for the races too to maximize my experience on the bike.
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No if about it.
Sat October 18th is the date at Grange Motor Circuit.
Be there on Friday afternoon for the best time and camp over.

36 tooth is too small for the track. Get about a 40 tooth.
Plan on jetting for 3200' elevation.
 
40 tooth? that will surely increase my acceleration. Is that 40 tooth on a 26" wheel or a 24" wheel? im at about 200-300 ft elevation right now
 
MotorBicycleRacing said:
Huh?

You said 26"?


I am confused. 4 words don't cut it.
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I think im going to get the triple tree forks with front disk brakes from bicycledesigner.com and im going to run a disk brake set up on a 24" wheel in the front and lower the forks until my pedals are nearly scraping on the sharpest turns im willing to take.

In the back im going to run a 20" 2.4 bmx tire with the 32T sprocket.

next im going to see if there are ways i can manipulate the seat to get me low as possible, maybe switch to a scooter seat or a cafe racer style seat.
Havent done any welding or anything to the bicycle yet but if it comes down to it i may start chopping on it to get it low.

what size chain do racers use in the china class. does everyone run a #41 chain or a 415. Can a 410 bmx chain handle the power of a modified china?
 
got the new kickstand installed.

found some 30mm(34?) hex bolts for the ragjoint, the ones that were on there were much too long and i think i can get better balance with shorter higher quality bolts than the kit provided. Maybe some weight reduction too, i dont have a scale yet though
 

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You will likely get the bike to handle better with the same sized tyres all round?
20" tyres may require shorter crank arms.
I would personally go with 24" front and back.
.
 
You should settle on either 24 or 26 inch tires & wheels. You want the same size front & rear.

Plenty of either size are run at the Grange. Even with a 26, you need to phase the pedals in the turns. Watch some of the race videos.

I think it is great that you are taking the time to come play with us in October. Get your bike together & sorted out so that you can enjoy the time at the track.

Take the advice offered on gearing, been a lot of china girls run around that track.

We took a gaggle of beginners out there with stock china girl kits that were almost new. They all had fun, but there were the usual little hiccups - dead CDI, plugged jet, etc. Mostly they all ran well, and everyone had fun.

looking forward seeing you in October. Sort the bike out, and make it reliable first.

B
 
gauges not really sorted out how i wanted. reached 238 f on the ride home and 32.8mph at 7200 rpm on the short blast down the road
 

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graydog8josh said:
got the new kickstand installed.

found some 30mm(34?) hex bolts for the ragjoint, the ones that were on there were much too long and i think i can get better balance with shorter higher quality bolts than the kit provided. Maybe some weight reduction too, i dont have a scale yet though
Click to expand...

You don't really want or need a kickstand on a race bike.....ya just don't.
 
today i greased my headset bearings and oiled my forks.
I was having poor damping from the used 1" suspension fork im running so i tried working it with a lot of oil to see if it was sticking or bottomed out. i still havent ridden it since taking things apart and cleaning them up. I dont konw if its a function of the bike itself or the weight or the balance but when i look down at my wheel i can see the fork dropouts vibrate a bit. maybe that will take up some of that vibration with everything regreased and snugged up. (im not really sure how else to describe what ive got going on.
I also found i had a pinhole leak in my thornproof front tire, and replaced that tube wiht a 26" 2.4 rubena downhill tube that has the metal threaded stem with a locking nut on it. the tube looks kinda weird, it didnt look round whenever i took it out of the package. but it fit in just fine so i guess im okay.

I made a very big list of things i wanted to check, grease, inspect etc.

there are also some things i would like to improve, namely my exhaust mounting technique carb tuning for winter riding and braking power. I'll be addressing those things as i get more time to work on the bike. Ive been up 4 hours working on teh front suspension fork, wheel, tube problems.
 
made a clamp exhaust mount for the rear of the snake pipe, the pipe can move a little but not nearly as much as it could when i had it tied on with zip ties.


thinking about ditching the cloud 9 seat and finding a comfortable seat that lets me move around and shift my weight more.
 
Sent my motor off to get rebuilt by fred. Want to see what a balanced motor will do versus one that was put together with stage 2 parts. Also somehow i loosened my brake pad and it ate through my front 26" cyclops tire, so i ordered another one.
 
got tired of messing with v brakes so ive ordered avid bb7 disk brake and im going to swap my front fork for the adjustable chopper fork triple tree from bicycle designer. my v brake pads fade pretty fast. Im looking forward to the superior power of disc and the ability to put a 24", 26" 29" 20" 16" whatever size i want.
ive been running 26" front 20" back and it looks funny to people the 6 inches difference. I think the 24"/20" will be a lot more normal looking, although ive felt like 26" 20 isnt too difficult to steer. i can also get lower to the ground.

Ive been phasing my pedals since putting a 20" wheel on but ive never had my pedals hit the ground in a turn yet.
 
still running cst cyclops front and back and feeling pretty comfortable on them. disc brake works pretty good too.
 

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