GS450 Carb upgrade, whcih carbs?

[djg42]

Hello,
I want to get a nice upgraded set of carbs for my 1980 GS450. Any suggestions? Is round or flat slide better? Heres a good selection of mikuni slide carbs, but are these worth upgrading too?

http://www.nichecycle.com/Items.aspx?code=CARBSING&key=cat

Thanks!

[Steve]

What's wrong with the carbs you have on it now?

They will already flow more air than the stock engine can handle.

.

[Dave8338]

What's wrong with the carbs you have on it now?

They will already flow more air than the stock engine can handle.

.

NO...NO...Steve ! More air/fuel...more POWER !

Unless you have a cam, head work, and plan to spin the thing into the double digits...different carbs won't do you much good. Add to it, that the displacement of a 450 will also limit what you can expect for power.

[djg42]

I want better carbs that are easier to tune, and for better performance.
Im boring it out and using GS500 pistons.

[Billy Ricks]

You can probably find a couple of TMs on Ebay if you take your time.

[pete]

Alternatively the GS500 carbs I believe are a bolt-on, but I don't know that will be an upgrade as such...

[rapidray]

I put FCRs on the 93 GS500 we used to road race but don't know if those will work on the 450. Ignore the guys that AREN'T engine builders or tuners! Carbs, even on a stock engine, are a good source of more power! I speak from EXPERIENCE!!! Ray.

[Billy Ricks]

I put FCRs on the 93 GS500 we used to road race but don't know if those will work on the 450. Ignore the guys that AREN'T engine builders or tuners! Carbs, even on a stock engine, are a good source of more power! I speak from EXPERIENCE!!! Ray.

A good set of mechanical flatslides will wake any bike up.

[pete]

Hmmm... Ray... was there a specific type/size of FCR? I believe the 450 and 500 share the same intake boot diameter so I'm guessing that they'd work for the 450 as well...

I'm just thinking for Dennis as well as for myself if I happened across a pair at the right price...

[Billy Ricks]

Hmmm... Ray... was there a specific type/size of FCR? I believe the 450 and 500 share the same intake boot diameter so I'm guessing that they'd work for the 450 as well...

I'm just thinking for Dennis as well as for myself if I happened across a pair at the right price...

2mm over stock is plenty and will usually fit the stock manifolds. Slide type carbs flow more air so you don't have to go ginormous with them.

[pete]

2mm over stock is plenty and will usually fit the stock manifolds. Slide type carbs flow more air so you don't have to go ginormous with them.

Cheers Billy! Dunno about Dennis but I'm a noob when it comes to that stuff... but it's real fun learning

[djg42]

yeah, thanks! Greatly appreciated. I guess ill go with a mikuni flat slide?I can get 34mm, or 33mm with accelerator pump($100 extra per carb)
Also, is there a way to figure a range of jets to start with, based on my stock carb set up?
I have 150 main jets (117.5 stock)
and 25 pilot jet (either 15 or 17.5 stock)

[Billy Ricks]

yeah, thanks! Greatly appreciated. I guess ill go with a mikuni flat slide?I can get 34mm, or 33mm with accelerator pump($100 extra per carb)
Also, is there a way to figure a range of jets to start with, based on my stock carb set up?
I have 150 main jets (117.5 stock)
and 25 pilot jet (either 15 or 17.5 stock)

They'll probably be jetted close enough that all you might have to do is play with the needles and maybe change mains. I'm not sure what the stock carb size is, most likely 32mm. Either of those sizes would do if that's the case. The pumps are nice but not essential.

[djg42]

Thanks! The jets in my stock carbs fit into the TM's?

[Billy Ricks]

I believe the TMs use the hex shaped mains.