Gx390 on birel r30 style?

I have issue with clutch coming in contact with seat bracket ,what should I do any special motor mounts move out a 1-1/2" ? I'd like to get it in but no welder or way to make mounts myself I could if I had the tools.
 
I have the exact set up on a Birel and a Tonykart. Two words: Jackshaft.
Can you post a photo of your jackshaft set-up for others to see?
I get asked this question a lot, and sometimes a photo is worth a thousand words.

I recently built an open 390 with jackshaft for an oval kart customer using the Burris big block mount and jackshaft kit.
I got a different shaft for it from Burris that enabled a Bulley clutch to be run outboard (ie keyway not splined shaft.)
I think the customer ended up using a shaft from Buller to run it inboard to fit his chassis better.

There are different ways to go about it, but it seems like it always ends up a hodgepodge of parts with no one "bolt-on" kit that works with all.

The other word of caution is to get the jackshaft ratio and clutch to work together.
Unless they're both on the same page, you'll go through some clutch discs. Compu-kart can educate you on that as well!


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
I wish I knew the actual model but I don't see anywhere besides tag in photo and also there wasn't number anywhere that birel PDF file shows to I.d kart
 

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The engine isn't completely bolted down so it would bypass if sitting as photo shows but it's an inch to close to seat bracket,thanks everyone
 
So is there benefits to jackshaft? I'll try your clutch idea, I feel the gx390 is heavy and is not a big improvement vs a built gx200 or similar but I'm 260lb so I hope torque will be helpful
 
The benefits of a jackshaft are several. Clearance of the seat struts, getting the weight of the clutch off of the crankshaft, a lot less wear on the clutch discs and the ability to fine tune the gear ratio. The expense of getting one will pay for itself in less than a season.

Getting the weight off of the crankshaft is important because at speed the crank will flex with the extra weight. This will affect the alignment of the drive belt (or chain, your choice) and eccentrically wear it and the sprockets. Additionally this will also prematurely wear the clutch discs dramatically. Changing them after every race gets expensive at $80-120 a pop.

As far as comparing it to a built gx200. I've driven both for years. There is NO comparison, and by that I mean ZERO comparison. The big block gives you more torque than you need the instant you hit the gas. The lower rpm means more time between rebuilds too.

After looking at your pix, keeping the gx200 and inboarding the clutch (turning it around, or putting it on "backwards) seems like a reasonable solution if your not planning on running sanctioned race events and you have the clearance to move the rear sprocket carrier to the right.

I'll post pix of my jackshaft setups when I get to the shop this friday.
 
The benefits of a jackshaft are several. Clearance of the seat struts, getting the weight of the clutch off of the crankshaft, a lot less wear on the clutch discs and the ability to fine tune the gear ratio. The expense of getting one will pay for itself in less than a season.

Getting the weight off of the crankshaft is important because at speed the crank will flex with the extra weight. This will affect the alignment of the drive belt (or chain, your choice) and eccentrically wear it and the sprockets. Additionally this will also prematurely wear the clutch discs dramatically. Changing them after every race gets expensive at $80-120 a pop.

As far as comparing it to a built gx200. I've driven both for years. There is NO comparison, and by that I mean ZERO comparison. The big block gives you more torque than you need the instant you hit the gas. The lower rpm means more time between rebuilds too.

After looking at your pix, keeping the gx200 and inboarding the clutch (turning it around, or putting it on "backwards) seems like a reasonable solution if your not planning on running sanctioned race events and you have the clearance to move the rear sprocket carrier to the right.

I'll post pix of my jackshaft setups when I get to the shop this friday.
Thank you that's very informative and very helpful, along with everyone who commented about this. I did drill plate a bolt width and it now clears seat support. So I'll see what I can do with the info given . Thanks again
 
Can you post a photo of your jackshaft set-up for others to see?
I get asked this question a lot, and sometimes a photo is worth a thousand words.

I recently built an open 390 with jackshaft for an oval kart customer using the Burris big block mount and jackshaft kit.
I got a different shaft for it from Burris that enabled a Bulley clutch to be run outboard (ie keyway not splined shaft.)
I think the customer ended up using a shaft from Buller to run it inboard to fit his chassis better.

There are different ways to go about it, but it seems like it always ends up a hodgepodge of parts with no one "bolt-on" kit that works with all.

The other word of caution is to get the jackshaft ratio and clutch to work together.
Unless they're both on the same page, you'll go through some clutch discs. Compu-kart can educate you on that as well!


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com


Carlson knows my pain in getting the jackshaft set up correctly. In my learning curve days I burned up a brand new 4 disc Bully clutch PULLING OUT OF THE PITS!!!
Luckily he rebuilt it, I recalculated the CORRECT ratio and it's been a solid performer for two or three years.
 

IRQVET

Member
I’d set the clutch inboard, if you can. Can’t make out in the picture if you have a third axle cassette that would get in the way and otherwise prohibit you doing that. I have that issue on my chassis, where I can't run inboard.
 
You can also shorten or add links to the chain and move the engine back or forward to see if the clutch will clear the seat post.

Also, add a larger diameter exhaust pipe and enjoy the extra power.
 
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