Sprocket ?'s Birel shift kart,yz125

[ia-turtleboy]

i have a birel shifter kart that uses a yz125 engine. i have 2 of them and both have the same front sprocket. they have 13 teeth, and a 17 mmm gap from tooth-tooth.

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the screen on the second pic says 13mm

now the sprocket on the axle of the kart has 24 teeth and a 13 mm gap from tooth-tooth.

the chain has a about a 4.15 mm gap for the tooth to fit in.

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now the chain fits the karts sprocket but the sprockets on the engines wont fit the chain. what should i do? ps. the measurements may not be exact.

i have another yz 125 engine and its real nice but it is left hand driven(sprocket on the left side of motor) if somebody wants to trade for a good right hand driven motor let me know.

 

[stonny9]

There. Are. Several different types of chains for carts. I believe they are labeled with a number for size. Your stock yz sprocket is not going to be the same as the shifter cart sprocket on the axle. Bmicarts and tsracing are a couple sites to look at for the correct size.

 

[ia-turtleboy]

i think i need a 520 rear sprocket for my axel but none of the companies ive contacted have replied

 

[christeeezy]

http://www.gokartgalaxy.com/uni-hubs_&_vari-hubs.htm

There is where I'm going to get my 520 rear sprocket and sprocket hub. Just scroll down about midway.

 

[anderkart]

the sprocket on the axle of the kart has 24 teeth and a 13 mm gap from tooth-tooth.

Sounds like your current axle sprocket is actually the #428 size. (#520 is 15.88mm from tooth to tooth)
This link: --> http://www.wemoto.com/info/Chain_Dimensions/ shows the #428 pitch, width and chain roller dimensions you could use to re-measure yours and confirm.

Your rear sprocket looks to be in good condition, so If its a #428, you could buy a #428 engine sprocket to match it here:--> http://sharkshifter.com/zc/index.php?main_page=index&cPath=76&zenid=da9550fec8fd03e1d75548ee2c7c1c74. Changing the engine sprocket would be much easier and cost less, just make sure it fits your countersprocket.

 

[ia-turtleboy]

Sounds like your current axle sprocket is actually the #428 size. (#520 is 15.88mm from tooth to tooth)
This link: --> http://www.wemoto.com/info/Chain_Dimensions/ shows the #428 pitch, width and chain roller dimensions you could use to re-measure yours and confirm.

Your rear sprocket looks to be in good condition, so If its a #428, you could buy a #428 engine sprocket to match it here:--> http://sharkshifter.com/zc/index.php?main_page=index&cPath=76&zenid=da9550fec8fd03e1d75548ee2c7c1c74. Changing the engine sprocket would be much easier and cost less, just make sure it fits your countersprocket.

cool ill check that out. you wouldn't happen to have known a Lowell Jensen would you?

 

[anderkart]

Maybe but I cant recall the name, does he race karts here in Phoenix?

 

[anderkart]

i have another yz 125 engine and its real nice but it is left hand driven(sprocket on the left side of motor) if somebody wants to trade for a good right hand driven motor let me know.

You should be able to relocate your rear sprocket inside of the axle bearing to use this engine.

Like this Birel shifterkart:

(your axle would just need to have a keyway for the sprocket in that area, but most do. If not, a machine shop could broach a new keyway into your axle)

 

[ia-turtleboy]

cool thanks

 

[ia-turtleboy]

ok so i like that design.my motor almost works but i need a motor mount for the rear.front bolts up and shift lever seems to align right but the sprocket does not line up at all.im just lost at this point, im a 19 year college kid and never did any thing like this before. help?

here's where the motor mount would bolt to the frame.

here's where you can see the sprockets wont line up.

 

[anderkart]

You need to buy or build a motor mount similar to this pic:

They simply clamp around your 2 frame rails and locate the engine much closer to the seat so your 2 sprockets can line up. You might find a lower price if you shop around, but you can buy a 125cc. Yamaha mount here: http://sharkshifter.com/zc/index.php?main_page=index&cPath=76&zenid=da9550fec8fd03e1d75548ee2c7c1c74

 

[babzog]

Can the lower part of those kinds of mounts ^^^^^ be had? I was missing one from the cart I picked up on the weekend.

 

[anderkart]

Can the lower part of those kinds of mounts ^^^^^ be had? I was missing one from the cart I picked up on the weekend.

Yeah, they usually call those motor mount clamps or butterfly clamps. Most shops that sell racekart parts will sell just the clamps. You'll just need to measure your frame rail spacing to buy the clamps that fit. You'll find some info about measuring (to see if you need the American or International style) and some clamps for sale here: http://www.cometkartsales.com/store/mount/mounts.htm (click on all the different motor mount brands, some offer just the clamps)

More clamps here:
http://www.out2win.com/catalog/mount_chassis.html#clamps
http://jcspecialty.net/ (check catalog pages 124-126)

 

[ia-turtleboy]

got a motor mount and sprocket for the build,gettin real close here.

 

[fourtogo]

For MX engine stuff you can also check with QRC Outlaw karts. Motor mounts chain hub/sprockets

 

[voided]

I got my motor sprocket cheap from pbi sprockets

 

[ia-turtleboy]

been a long time snce i worked on the kart but i finally got the sprocket,and motor mount .i just need a 428 chain, fuel lines, new air filter and a fuel pump. allright so here's my next round of ?'s how many links of chan do i need to generally order? what air filter do i get for the yz125 engine on my kart(1999) and best fuel pump/ cheepest route i should get.thanks!

 

[anderkart]

You'll need to use a tape measure around both sprockets to estimate your chain length.
(Each link of #428 chain is 1/2 inch long...)
I'd suggest taking the measurement with your motormount in the center of its adjustment range, then order your chain with at least a few more links than you will need, just in case...

For your air filter, I'd suggest you start by measuring your carbs flange where the air filter clamps on.
Then go to this link: http://www.unifilter.com/clamp-on/ and find the listings for all the "CLAMP-ON DUAL LAYER "POD" FILTER" models UNI sells. Then match your carbs flange size to UNI's "I.D. in." to find your UNI part number.

I'd order the: Part# 'MIK-DF52' Mikuni Fuel Pump Double Outlet. HIGH VOLUME
You could shop around the net for the lowest price or just order one from here: http://www.out2win.com/catalog/fuelpump.html
I'd order about 10 feet of clear 1/4" fuel line from wherever you get your pump. That way you'll have enough to install a return system in case you run into carb flooding issues from too much fuel pressure.

 

[OzFab]

Each link of #428 chain is 1/2 inch long...

Sorry to correct you but, technically, each link of #428 chain is 1" inch long, being that 2 sections = 1 link.

This is where it gets confusing because, some people measure chain links as 1 section (pin to pin), others measure by 2 sections & it's hard to tell who's who so, when ordering chain, give them a measurement, not number of links...


This is called a half link:

 

[ia-turtleboy]

thanks for the help guys!!

ill get my measurements and start saving for the last bit to get her runnin.as soon as get stuff figured out i'll let y'all know.thanks everybody for helping me get this far!