[scwaterboy]

ok, im in the middle of carb rebuild for my 1998 xl1200. It has the square body. Got the kit from SBT and kit is for the 38 and 44 sbn. when reassebling, im confused on the pulse side. from the mikuni site pics, it looks like a bn38 and was pulled apart like a 38. it ran like crap when i bought it. should i reasseble as a 38 or 44? please help, i would like to work on them in the morning. see it here = http://www.mikuni.com/pdf/sbn_rebuild-kit.pdf

 

[Youdog99]

I'm a shade-tree mechanic so take my comments with a grain of salt....

I just did the same thing on my '95 Wave Raider 700 and had the same problem. Everything said my ski has 38s but the exploded diagram much more closely matched the 44s. I also have the the Clymer Shop manual and the Yamaha Service Manual. All of the diagrams matched what is described as the 44sbn in your pdf.

Dont know if you did it but I soaked my carb bodies over night and blew out the various galleries and channels. Lots of crud came out!

I followed the 44 sbn exploded view to reassemble. What wasn't documented anywhere that I could find, is the reassembly of the front carb's pulse side that didn't have a diaphragm assembly.

Once I reassembled, it started very quickly. (It had been a hard-start previously). On the stand, it definitely seems to run better. Previously tended to run away, bogged under acceleration, needed ether to start that first time of the day, etc.

Just my humble opinion. I defer to the more experienced posters on this board...

Greg

 

[gkecorp]

I'm a shade-tree mechanic so take my comments with a grain of salt....

I just did the same thing on my '95 Wave Raider 700 and had the same problem. Everything said my ski has 38s but the exploded diagram much more closely matched the 44s. I also have the the Clymer Shop manual and the Yamaha Service Manual. All of the diagrams matched what is described as the 44sbn in your pdf.

Dont know if you did it but I soaked my carb bodies over night and blew out the various galleries and channels. Lots of crud came out!

I followed the 44 sbn exploded view to reassemble. What wasn't documented anywhere that I could find, is the reassembly of the front carb's pulse side that didn't have a diaphragm assembly.

Once I reassembled, it started very quickly. (It had been a hard-start previously). On the stand, it definitely seems to run better. Previously tended to run away, bogged under acceleration, needed ether to start that first time of the day, etc.

Just my humble opinion. I defer to the more experienced posters on this board...

Greg

You ahve a mikuni bn44!! go with the 44

 

[scwaterboy]

It seems you dont know what you have until you take it apart. Carbs work great now.

 

[Youdog99]

Yep - Mine turned out real well too. Whomever recommended I rebuild them was right on. Starts right up, only takes a few cranks with choke and off it goes.

 

[GeorgeDuke]

I also have two Mikuni's. Is there a simple way to tell the BN38 from the BN44? The numbers must refer to a metric measurement -- say the minimum diameter of the venturi? Basically, how can I tell which carbs I have? Thanks. ==George