yd reverse from BMI?

[TheFauxFox]

what about this?

http://www.*************/Go-Kart-Reve...le_p_1031.html

i have no idea about splined shafts. I just know that it's the engine shaft. How do I figure out what my spiderbox has?

[2SlickNick]

I think that is for a lawn mower type engine.

[jmansracerocket]

Yeah won't work on a gy6

[TheFauxFox]

Awh...but...but...ok...

[Davcruz]

I am not so sure that would not fit a GY. I think it may fit a GY, looks very close to what I have on our Spiderbox, the picture is bad and not very helpful for identification though.

Call them and ask. You would need the long output shaft for your gearbox rather than the stubby unit that is on it now.

[Masteryota]

I don't know, it might work, and I quote- Reverse drive assembly for 150cc go-karts. Used on most models with external reverse.

I don't know any mower engines that are 150cc and used on go karts. Best bet is to call BMI directly and ask, their customer service is pretty good, I had to call about shipping times on the axle I ordered from them.

[2SlickNick]

Ahhh... I didn't see the description. It is for 150cc. Cool!

[ckau]

Don't know about this one. Though it appears very similar to a gy6 reverse unit. there's few differences. The sprocket count is off. 18 tooth is a very tall gear. Second it's set up for the 400 series chains... go kart stuff.
They seem to have been destined for some obscure application. I guess BMI got a deal on a boat load of extra units.

[TheFauxFox]

So, if I somehow managed to get that on my kart all set up, I would probly have to re-gear to what? 44 tooth or something? How can I calculate this?

Edit: After doing some research on the type of chain it takes, I don't think that I want to downsize my chain just so I can save some money...Nuh uh!

[x-bird]

I had the same thoughts as ckau, especially since they use a splined shaft. Not a mower engine, but 40 series chain. maybe they're actually for 110cc engines? Not sure of the chain size on those. crappy picture, makes them look a lot narrower than a 150 unit. if all it took was a sprocket swap, then they'd be worth the savings.

[TheFauxFox]

Originally Posted by x-bird

I had the same thoughts as ckau, especially since they use a splined shaft. Not a mower engine, but 40 series chain. maybe they're actually for 110cc engines? Not sure of the chain size on those. crappy picture, makes them look a lot narrower than a 150 unit. if all it took was a sprocket swap, then they'd be worth the savings.

I was thinking that I its just a sproket swap needed, it's a great deal, but I was reading on some dirt bike forums that they would "never use a 420 on anything but a 50cc bike" and this is a bike were talking about! Not a kart, so I'm a little concerned with chain strength if I did this. Also, when te engine shaft Is splined,
Does it just mean that it has X number of ridges for the front sproket to fit onto?

[x-bird]

Just happened to be working on a reverse unit and took the time to check the output shaft (150 cc) -- it's a 19 spline, 20 mm diameter shaft. Not a bad deal if one just needs to grab a 16t 50 series sprocket to put on it. You want to work the the drive sprocket and not your axle sprocket, so you'd keep your stock chain size.

someone needs to be a guinea pig.

just remember, if you're going to put it on a yerf, you're going to need a new output shaft as well, and that can get to be a bit tricky. The spline depth, shaft length and thread length, reverse box internal spacers and bearings all have to land in the right places.

[TheFauxFox]

LOL, just like Davcruz, there is a local guy here that has the gy6 off of a talon with the external reverse. He's asking 75!!!!! So, I'm gonna go call him now and get that thing as fast as possible! And maybe I can get his airbox too... (mine is cracked)

[Davcruz]

Totally different airbox, it may fit in the swingarm for the Yerf but I like the unit for the Yerf better anyway.

[TheFauxFox]

Shame...good to know, however! Ironically, his engine got some gunk up in it, and he burned it out, too! It didn't catch fire though (as far as I know). Said he planned on putting a big bore kit on the engine, but never got around to it. But, I'm only interested in his gearbox. Didn't you also have to grab the longer output shaft from the engine as well?

[Davcruz]

You need the output shaft, the spacers, everything from the Talon trans. It will take some fiddling to get it right, you will also have to space your axle sprocket over to the left about 10 mm for the chain to line up.

[TheFauxFox]

Ok, so I can't just use any old washers (even grade 8) to space the sprocket over, right? I have to go buy a specific axle spacer? If so, that's sounds fine to me...

I'm just worried that when I go to put it on, something is gonna slip or something and I'm gonna have a stripped output shaft or whatever the heck, but I'm sure it will work out fine. The guy lives about 45 mins away, so it's a bit of a haul with this being mid-terms week and everything is due like...now.

By day - he is a student - and by night... nope! Still a student...

[Davcruz]

I used the metric 10.9 grade washers and bolts/lock nuts, I also went up a size on the bolts, they just fit trough the holes. No issues as of yet. My fix was temporary by design as I intend to at some point this winter modify the swingarm to accept the Talon rear axle at which point I will move the caliper/sprocket mounts to the correct locations on the axle to line up.

The Talon axle is bigger diameter and just seems stronger than the Yerf axle. Plus the original axle on our Yerf had the stub end on the drivers side welded as it obviously broke at some point.

[TheFauxFox]

Alright...so washers it is!

[x-bird]

if you can cut a deal, you may be better off taking the whole swingarm and engine. Mating the talon to the yerf might require moving shock and swingarm mount tabs, but a better axle setup is nothing to walk away from.

[TheFauxFox]

If only... He only has the engine for sale. nothing else.

edit: gearbox, airbox, etc also with it

[Davcruz]

Originally Posted by x-bird

if you can cut a deal, you may be better off taking the whole swingarm and engine. Mating the talon to the yerf might require moving shock and swingarm mount tabs, but a better axle setup is nothing to walk away from.

This is exactly what I should have done with ours! In hindsight (I thought of it about 24 hours after I ditched the swing arm) it would have been MUCH easier to mount the Talon swinger on the Spiderbox chassis than modify the Spiderbox swinger to accept the Talon axle...oops.