'99 M750 carb issue

[ducpainter]

Here's part of the problem. Would this cause a run away idle?

It is a vacuum leak.

It usually causes poor acceleration and fouled plugs.

[MotoPsycho]

I'm pretty sure it happened when I changed needle jets. That's off the front cylinder side. That's the one that was running 2x hotter than the other cylinder. Now I just have to find a new diaphragm.

[garryc]

Not sure of the cost stateside but from Italy the diaphragms are 98 euros.
For 110 euros you can buy a new set of carbs
http://www.ebay.it/itm/CARBURATORI-CARBURETORS-DUCATI-MONSTER-MIKUNI-38mm-/380676933264?pt=Ricambi_e_Accessori_Moto&hash=item58a21d0690&_uhb=1

[ducpainter]

Diaphragms are expensive here too.

Someone just found a source for a better price.

Let me look.

here... http://www.ducatimonsterforum.org/index.php?topic=61712.msg1156208#msg1156208

[Howie]

Diaphragms are expensive here too.

Someone just found a source for a better price.

Let me look.

Yamaha dealer?  TDM850
Maybe give SUDCO a call?  http://www.sudco.com/

[MotoPsycho]

Diaphragms are expensive here too.

Someone just found a source for a better price.

Let me look.

here... http://www.ducatimonsterforum.org/index.php?topic=61712.msg1156208#msg1156208

Just found out about the DR650's yesterday. Yamaha parts fiche shows theirs as slide and all. $270 is what I was told for one assembly. Hell no. I'll sell off my old parts and one of 4 guitars and get FCR's before I take one in the butt like that.

[koko64]

+1 on SUDCO .
If not theres every chance a forum member will for a good price.

Mind you, nows your excuse for those FCRs!   

[MotoPsycho]

Mind you, nows your excuse for those FCRs!   

That's on my long term list. With a baby coming the 24th I gotta be on the cheap for a while.

[MotoPsycho]

Tried looking at sudco. What exactly is the nomenclature of these carbs? AFAIK they're Mikuni BDST 38mm carburetors. If they're there I didn't see if its called something else. The Yamaha dealer here (fz1000) said $270 and the Duc dealer in Honolulu said $175. But that's for the diaphragm boot AND the slide, which I don't need. Plus I figure I might as well get 2 and be done with it.

[ducpainter]

Did you look into the Suzuki part?

[Speeddog]

I stumbled across these guys a while back, and bookmarked them.

http://jbmindustries.com/Dimensions.html

Haven't searched their site yet for ones that fit, so maybe a red herring.

[MotoPsycho]

Did you look into the Suzuki part?

His mechanic took my number in case he ran across anything but he said the same thing Yamaha and Ducati said. Slide and all. He's the one that called Oahu for me.

I stumbled across these guys a while back, and bookmarked them.

http://jbmindustries.com/Dimensions.html

Haven't searched their site yet for ones that fit, so maybe a red herring.

Thanks. I'll look into that one.

[MotoPsycho]

I can get Suzuki diaphragms local I found out today. Not from the dealer. He didn't want to touch them. If they're the same part number through Mikuni then I'm in business. DP, thanks for that link that says they cross reference. I'm pretty sure it'll work but I wanna make absolutely sure.

[MotoPsycho]

I found this place today. Might help out some others looking for the same thing I am. 22.50 euro which translates to $30 per.

kedo.com/products/41454.html

[MotoPsycho]

OK, so here it goes...

I can confirm the Suzuki DR650 diaphragms work. Done.

But, the floats had me scared to death. I've never ever had good luck with carburetors. Auto OR moto. But after reading reading the FP and Ducati Suite pages on adjusting floats, it seems a lot easier than it reads. Here's what I did. Please tell me if I did this procedure correctly.

1.Stood carbs on the vacuum chambers so the floats pivot freely when moved.
2.Rest floats on the flat needles as not to compress the springs inside.
3.Take measurement. (I got 12mm on both sides.)
4.Push tabs down to make resting float depth higher.
5.Take measurement. (I got 14.00-14.10 on the first try)

Now, that being said, how critical is the .10mm ? I guess it's just a matter of trying out some fresh gas and giving it a go to see what happens.

And as far as balancing carbs go, I know its crucial, but is it sufficient to go off of sound initially? I've played guitar for 23 years so my ear is pretty tuned to subtle changes in pitch. If I'm off by a little bit without using a manometer, it's not going to fry the motor, right ? In other words if I can get it pretty close by ear will that buy me enough time to ride 16 miles downhill to get to a set of gauges?