Since my last post I have done the following:

Remove the petcock and cleaned the filter and gas tank.  There was some residual rust from the tank at the base of the filter but I did not see anything which would restrick the gas flow.

Replace the vaccum line.

When neither of those improved the bikes performance.

I removed the carburator and disassembled it.   Cleaned and soaked with carb cleaner even thought the card looked new on the inside.  The filter on the inside of the carb was clean no rust ect.  
I inspected each component of the carb as I reassembled it.  I found the "Pilot Air Jet" to be completely blocked.  I removed the blockage  reassemble and road about 100 - 150 miles with out any problems that couldn't be fixed without adjusting the choke.  

Got back on it last  night, the problem showed back up when the throttle position was 1/8 to 1/4 turn.   If I open the throttle I have good response.  

With the throttle position between 1/8 to 1/4 turn.  I adjusted the choke from full to half.  It would get better for about 30 sec. then it got worse.  Adjusted the choke again back to full,  better then worse.  Swiching from main to pri on the petcock reduced the stalling/hesitation but, didn't get rid of it completely.  I could still feel a small amount.  Swiched back to main and the stalling/hesitation got worse.
After riding for 20 to 30 min the choke was off, the petcock position was in the main position, the stalling/hesitation felt like it did when the petcock was in the pri position.  The bike was running good again.

I adjusted the pilot screw an additional 1/2 turn out from base at one point in this adventure thinking that it would affect the running of the bike when the throttle position was between 0 and 1/4 turn.  It kinda sorta did help a little.   I am wondering what part of the carb circuit affects the bikes performance between 0 and 1/4 turn on the throttle.  

The pilot screw does for idle.  
Does the needle position(white spacer) have an affect how the bike performs between 0 and 1/4 turn?

I am wounder if adjusting the white spacer thickness will reduce the stalling/hesitation 0 and 1/4 turn.  

I also noticed that the stalling/hesitation seems to occure when it is a little cool out.

Any thoughts?

On my FCR mix up to 1/4 throttle is dominated by the parallel portion of the needle.

Clive W  

Bottom of page 188 of the clymer manual.

The Mikuni BS40 is a hunk of junk. You should have 3 or 4 choke settings in addition to off (no choke). Run a couple tanks of fuel with 2-3 ounces of two stroke oil mixed in. If the bike runs better, your problem is the all too common "galled" AKA "FUBAR" carb slide. The newer replacements have a better nitride coating than the older (pre-2K) ones.  
-WD

Don't get the wrong impression, other than the carb, I pretty much love my 98 custom.  Oh, and change the fuel and vacuum lines at least once a year. Cheap insurance. And run two stroke oil at least every other tank. Or else.

WD wrote on 12/31/69 at 16:00:05:


Hey WD;
I got the impression from one of your previous posts that you did not work on carbs!
My "Hunk of Junk" BS40SS constant velocity carb has given me absolutely flawless, maintenance free service for the past 20 years.
Since I rebuilt the engine and added some modifications:
i.e. Punched out cylinder and installed .120" oversized piston, Installed large K&N pod filter, opened up exhaust and installed very free flowing (tuneable) muffler, I had no choice but to rejet the carb.
Through small increment increases in main jet, pilot jet, and pilot air jet sizes, and raising of the jet needle in .025" increments, and most important of all - READING A NEW PLUG - after each test drive, was I able to "PROPERLY" dial in the carb. All of this applies to any make of roundslide or flatslide constant velocity carb.
As a point of interest, the following is what I ended up with: main jet - #175, pilot jet - #52.5, pilot air jet - #75
midrange jet needle raised .085"
Nothing in town will touch it up to 150 km/hr. including stage 4 HD's (that is as fast as I've had it up to and it still pulls like hell at that speed)
All I'm saying here is that if you take the time, and take advantage of all the resources available on the web, the Mikuni (roundslide) BS40SS constant velocity carb can be dialed in and compete easily with any of the newer generation flatslide carbs, including Khein, Edelbrock, Mikuni, etc.
The BS40 has been used in the Savage since day one! Why change a good thing.

I've opened up 4 BS40s in the past week. No choice, they were customer carbs. Every single one of them had a galled slide. 2 1998, 1 1996, one 1995. Ended up sending them to the Internet to order replacements, as the Suzuki dealer closest to work is horrible. They carry Suzuki, Honda, and Polaris. They know the Honda and Polaris stuff real well, but their Suzuki customers are treated terribly.

What ever happened to normal motorcycle carbs? With a throttle butterfly flap and no slide? Like old Linkerts? Or Del'orto, Weber, SU, most S&S? Or the cable operated slide Amals? Mikuni has made some very good carbs in the past, but even the big bikes that run modern Mikunis have stumbling issues. Dollar for dollar, if you're going to run a CV carb, the Keihin units are better quality than the Mikunis.

As for the fuel tap, the VS800 Intruder mechanical unit should be a direct swap. FWIW though, even the one replaced under RECALL on my wife's Intruder leaks, and it is the "updated" version that shouldn't leak.

As for working on the carb, if you have the patience to go through the needle swap and test procedure(s), more power to you. My 98 pops like it is lean, but the plug comes out showing rich.  ??? Who knows, I sure don't.
-WD

I have found my problem to be the vaccum petcock.
For the past 2 - 3 weeks I have had the petcock in the Pri(prime) position.  That position doesn't require vaccum to allow fuel to flow into the carb.   I have not had any stalling or hesitation problems since I did this.

I have modified my petcock in accordance with the following forum link and am still problelm free.

http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1113631...

WD wrote on 12/31/69 at 16:00:05:


You change out that air filter yet? I believe it was called filthy