WTB 91 waverunner 500 SBN carb

[superhondaz50]

Need a WR500 sbn carb for a Kawi 300. Thanks

 

[Myself]

Is that just a regular 38mm SBN?

 

[superhondaz50]

I think but am not entirely sure

 

[superhondaz50]

I could do a sbn38 and could prob figure out jetting

 

[WFO Speedracer]

The difference is it will directly hook up just like a 38BN carb and the WR500 jetting works perfectly on a JS300 engine, I would know I came up with the idea , at any rate any of the Seadoo 38SBN carbs off of a 587 should also work with a different throttle drum plate and using a Primer setup , the WR600 jetting specs are 77.5 pilot , 80 main jet and most likely a 1.2 needle and seat size and maybe an 80 or 95 gram spring.

https://www.pwctoday.com/forum/technical-discussion/vintage-skis/133674-

 

[superhondaz50]

WFO, awesome info. I wasn't sure if the WR500 venturi size was different from other SBN38's like one off a Seadoo. Do you know what throttle plate is needed?

 

[nwcitizen]

1989 Yamaha Waverunner WR500 Carburetor Mikuni Freshwater Only W/Flame Arrestor | eBay

I HAVE FOR SALE A 1989 YAMAHA WAVERUNNER WR500 CARBURETOR MIKUNI FRESHWATER ONLY W/FLAME ARRESTOR. HAS BEEN SITTING ON THE SHELF AND WILL PROBABLY NEED REBUILDING. THANK YOU FOR YOUR TIME

www.ebay.com

 

[superhondaz50]

Found what I needed. Thanks guys

 

[WFO Speedracer]

I had a pretty hot running 300 in my 300SX fixie , I had a pipe and the OEM boost box intake on it, WR500 carb and the 650SX cut down head gasket mod , also ditch the rubber surround for the rear exhaust exit around the pump , it's restrictive and sucks up HP.

 

[superhondaz50]

I had a pretty hot running 300 in my 300SX fixie , I had a pipe and the OEM boost box intake on it, WR500 carb and the 650SX cut down head gasket mod , also ditch the rubber surround for the rear exhaust exit around the pump , it's restrictive and sucks up HP.

Nice. This is in a JS, so only has the side exhaust

 

[WFO Speedracer]

Nice. This is in a JS, so only has the side exhaust

The engine runs a little better in the JS hull than it does in the SX hull stock for sure .

 

[superhondaz50]

The engine runs a little better in the JS hull than it does in the SX hull stock for sure .

Go figure didn't know that. I'm building this JS300 for my niece and have a finished 300sx for my son. Both are young (12 and 10) so figure a 300 is a good first ski.

 

[WFO Speedracer]

That rear exhaust tube on the SX is really small , when you add the rubber tube to the back it gets really restrictive, I see these guys trying to build freestyle skis out of SX's , putting big motors and pumps , but not replacing the rear exhaust tube, I always have a good laugh on that one, been there , done it , have the t-shirt .

 

[superhondaz50]

I say leave the 300sx as is..if you want a freestyle hull, buy one haha

 

[superhondaz50]

Hey @WFO Speedracer , what pop off are you running on that SBN?

 

[WFO Speedracer]

I honestly do not remember , whatever spring came stock on the WR500 worked out perfectly for mine.
I have looked but I have seen no way to cross reference the OEM part numbers on the springs with Mikuni parts numbers for their springs, if I was to guess I wouls d say it's either an 80 or 95 gram spring.

 

[superhondaz50]

I'm gonna start with a 95 I assume with the stock flame arrestor it'll have a bigger pop off due to higher vac

 

[WFO Speedracer]

I'm gonna start with a 95 I assume with the stock flame arrestor it'll have a bigger pop off due to higher vac

correct