Gx 270

[wyattpowers]

Hi. I have a gx270 with a wet clutch. Came from a gokart track. I'll include a pic. What comes next? The shaft is 7/8. I'm currently running a gc160 with a 420 chain and I think 72 tooth sprocket and just a regular little clutch. Pardon my lack of proper terminology.

 

[jamyers]

Hi! Those GX270's aren't any good, especially with wet clutches. You should send it to me for proper disposal, hahaha

 

[Karts of Kaos]

well first things first, welcome to the forum! now onto the engine. you will need a new mounting plate I think, and also sometimes there is a gear reduction the the clutches so you may have to change your final drive. then also that engine is much bigger that your previous and you can achieve speeds over 50mph! which could be dangerous. the 270 has much more torque so that could also cause problems. and I can't tell form the pics but if you have a one wheel peel then you should not do the swap. also ditch the seatbelt without a roll cage it is dangerous to use.

 

[Budget GoKart]

Ignore what he said ^ bigger motors mean more fun your gonna have to mount it differently and gear it differently and find a sprocket hub and sprocket at a local tractor parts type store personnally i plan on building a gx390 1 wheel peel. Also get rid of the seat belts until the kart has a cage that is very unsafe

 

[Karts of Kaos]

Ignore what he said ^ bigger motors mean more fun your gonna have to mount it differently and gear it differently and find a sprocket hub and sprocket at a local tractor parts type store personally i plan on building a gx390 1 wheel peel. Also get rid of the seat belts until the kart has a cage that is very unsafe

and you will be replacing your drive wheel every 30 seconds or so.

 

[wyattpowers]

First and foremost, let me say thank you for your time.
So, let's say all the stars were in alignment. I was simply missing one component. That one that connects to the shaft. What is that called?
I gotta put a sleeve on it too. Right? To bump it up to 1inch. Right?

 

[Budget GoKart]

Find out what your local tractor store sells for hubs they usually sell one for each size shaft

 

[Karts of Kaos]

I think that you just need a sprocket that it 7/8' inch dia and gets you to you desired speed.

 

[wyattpowers]

So the hub goes on the crank shaft and it bolts to a sprocket with 12 or so teeth. And a chain connects it to another sprocket that is bolted to a hub?

 

[Karts of Kaos]

why do you need a hub for the pto output?

 

[anderkart]

The output shaft on most (possibly all?) of these 2:1 ratio Honda wet clutch's are 22mm. diameter...
7/8" is close to 22mm. but slightly smaller...

So I'd suggest you start by accurately remeasuring the output shaft using a caliper tool.

Then to help confirm things, you also need to measure the width of the keyway in your output shaft with a micrometer. I've got a feeling you'll discover its exactly 7mm. wide.

Then if I'm right, here's a link to some drive sprockets that'll fit your engine: https://www.bmikarts.com/428-Sprocket-with-22mm-Bore-7mm-Key-12T-18T_p_30602.html

_______________

But before you order a drive sprocket, we need to figure out the best gear ratio for your situation:

1- Measure & post how many inches tall your rear tires are when they're fully inflated.

2- Get an exact tooth count on your axle sprocket.

3- Tell us what type of terrain you plan to ride your kart on?
(like will you be doing a lot of low-speed/stop & go driving in a small area, or riding the kart off road through deep mud and/or constantly climbing steep hills? ~ Or will you be pretty much only be riding at top speeds on large flat hard surfaces like paved roads or parking lots?) This is a very important aspect in selecting your gear ratio, because you can gear the kart for good acceleration & good hill climbing ability; but that'll result in lower top speeds. Or you can gear the kart for higher top speeds, but that'll result in less acceleration and hill climbing ability...
___________

Then we'll be able to determine the best gear ratio for you, but it'll be a little trickier than usual because we'll be compensating for the 2:1 gear ratio wet clutch on your engine.

 

[wyattpowers]

Thank you so much. I'll be back with the measurements.

 

[wyattpowers]

Yep. 22 and 7. Never doubted you for a second. As far as the sprocket. I need to replace it. It's as crooked as a politician. My rear tires are 16" tall. I want low end torque. So, I'll order from the link you provided. How many teeth do I want? On the axle sprocket also, how many teeth?

 

[wyattpowers]

I appreciate the help very much.

 

[jamyers]

Go this forum's home home page, on the left theres a link to a gearing calculator. I'd use the numbers from your old engine/gearing setup and shoot for something similar, assuming the old setup's top speed was to your liking.

With that gear reduction / clutch setup, be sure and use it's output shaft rpm instead of actual engine rpm.

 

[anderkart]

If it was my kart, I'd order the 18-tooth drive sprocket.

I forgot to ask if you've removed the engines governor or not, but at 3600rpm & going with the 18-tooth drive sprocket & a 60 tooth axle sprocket: ~ You'd end up with an estimated 26mph top speed and still have some fairly descent low end torque.

Or substituting to a 72 tooth axle sprocket would increase low end torque but drop your estimated top speed down to 21mph...

Here's the link to our forums speed calculator if you wanna calculate some other gear ratios: https://www.diygokarts.com/speed-calculator.html
This speed calculator wont be accurate for your engines wet clutch with its 2:1 gear reduction, but you can compensate for that by simply entering 1/2 as many in the "Teeth On Clutch" window. Or enter the correct # of teeth and simply reduce the MPH reading to 1/2 of its results.