shifter kart

[That One Guy]

When you ride a four stroke for the most part, it's smooth all the way; when you're mobbin' on a two stroke, it's like after you twist the throttle to a certain point... NITROUS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Except for not really, but you know what I mean.

 

[redsox985]

428 and 40 aren't the same. the roller diameter is different

Correct, they aren't the same but the differences aren't significant

Chain No. Pitch Roll. Dia. Roll. Wid. Sproc. Thick.
40 1/2 5/16 5/16 .284"
428 1/2 .335 5/16 .284"

P.S. 5/16 = .3125

 

[bigair49]

Vary Good! Thanks guys.. Now back to my question about sprocket sizes would 40 to 50 teeth be too much does any one have that info ? Ok I'll go mid way on the counter sprocket so lets make it 15 what size would work best for a nice wheel popin 1st gear right on through to killer top end? I'm new to these little 6 or 8 inch wheels so I need all the advise I can get with the gearing THANKS!! Now I have been repairing,building and modifying 2 and 4 stroke small bore engines for 25 years now and Own/Operate a small business Called BOMAR RACING we specialize in pitbikes and going FAST most of the bikes today are 4 strokes the younger kids are running 2 strokes but quicky jump to the 4 strokes as they progress. My son really likes the Karts so I need to start learning the basics ........
Thanks
Jess

 

[modelengineer]

Well my kart with a 500cc bike engine has 14 tooth on the engine and 50 tooth on the rear axle, but I have normal car tyres which are pretty huge. Also, the gearing in the transmissions will be different between our engines, and your lighter weight will mean you can pull higher gear ratio's.

 

[That One Guy]

I was stoked when the AMA said they'd allow two strokes to come back into supercross and motocross, but no one has done it yet -_- But yeah, everyone uses four strokes nowadays.

 

[redsox985]

I would keep the ratio as close to possible as what the bike ran, maybe a bit lower because the kart is heavier than the bike. It may be too much strain on the motor.

 

[Kaptain Krunch]

I would keep the ratio as close to possible as what the bike ran, maybe a bit lower because the kart is heavier than the bike. It may be too much strain on the motor.

It actually depends on tire size. My ratio for my shifter kart is much higher than the bike's original, because my tires are nearly half the size. If i left the gear ratio alone, i would be redlining at 50mph in 6th with tons of power left.

 

[redsox985]

Very true Kaptain. I didn't think about that. The kart I planned on putting the XR100 motor on would've had 18" tires close enough to the bike so I planned on gearing it with like 5 teeth more but with the small tires you are right.

 

[anderkart]

bigair,
CR80 powered shifter race karts usually run between 21 to 28 tooth rear sprockets and 13 trough 20 tooth engine sprockets in a #428 size.

You'll find most rear sprockets for shifters are direct mount and don't use a separate hub because the diameter is so small. This place has a pretty good selection of shifter sprockets: http://sharkshifter.com/zc/index.php?main_page=index&cPath=45&sort=20a&page=1
(I'd suggest you first measure the diameter of your axle, and also the circumference of your rear tires, and then contact them for more detailed gearing advice)

 

[bigair49]

Thanks Anderkart, thats what I was looking for!! I wasn't able to convince the owner to go with the two stoke CR 80 so the XR will get it's chance to shine.
I got over to where the Kart is on the weekend and it's in pretty ruff condition here are a few pics I took

 

[bigair49]

The axle 1- 1/4" and the tires are 10"

This was hanging around as well

 

[That One Guy]

What happened between that kitchen pic and that?

 

[bigair49]

I'm guessin about 4 years of sitting in a damp shed with no one to wipe it down after the dishes and wiping off the table.. but no worries I will show this old Kart some love!!

At least the tank is aluminum and still looks nice and shiny on the inside!!

 

[That One Guy]

Yeah... That'll do it! That tank does look nice. Colour plans?

 

[bigair49]

Well I had to finish some other projects but now I'm back into this one

 

[fowler]

wow thats a serious delay


what other projects

 

[bigair49]

You asked,long story short this one project.
I scratch built bike for my Daughter over the winter
here's some pics

Here's the paint

 

[fowler]

thats cool

 

[anderkart]

Yeah, that's really freakin cool, nice job man!

 

[bigair49]

Thanks guys!
I got some nice 1" aluminum tubing for the seat