Author Topic: Couple questions re: carburetion and exhaust (Read 2472 times)

92mx83 · « **on:** April 20, 2007, 08:43:06 PM »

Hi, everyone...

I have a 1991 B4 which I just took to get serviced by my local Suzuki dealer. Because my bike idled at 2K before the service, they brought the idle back down to about 1500 rpm. Now my engine shuts down intermittently when I clutch in at speed (which is really irritating when it occurs). They did a basic tuneup and fluid change (yeah, I can hear the gearheads groaning, but I work for an accounting firm and it's busy season), and so I was wondering what could be the cause of it?

I also have a horrendous flatspot at speed from 2K to 3K rpm. Really bad. Like mopeds beating me kind of bad. Do I need to have my carbs overhauled? The bike did sit outside due to the previous owner's neglect for a time.

Also (and this may be a related problem), I have a stock muffler, which is very loud. In fact, it sounds pretty damn good above 12K, but when I'm droning along at 6-7K on the freeway, it's more than just a little irritating (and I do wear earplugs). Apparently, in the 12,000 miles it has stomped about this Earth, the muffler packing has been rendered useless. It appears the stocker is un-repackable, so I am in a bit of a quandary. Is there any decent alternative to shelling out huge dollars for a factory replacement, without making enemies out of all the car drivers and my neighbors? I even considered slipping on a stock muffler from a GSXR 600.

Your advice is greatly appreciated. I am not new to motorcycling, but I may as well be, since I took a 12-year hiatus from it, and I just picked up my B4 last month.

Thanks in advance,

Craig

BrianM · « **Reply #1 on:** April 20, 2007, 09:46:08 PM »

The stalling and flat spot are both related to the same issue... the carbs are running rich. This could be related to 2 things... if you're above about 3k in elevation, the pilot jet is too rich and you need the next size smaller (30). But more likely is that all the damn rubber parts in the carbs are completely trashed due to age and need replacing. When they're rotten, they allow too much fuel into the system and you get stalling at idle and a nasty 'dead' spot in the lower RPMs.

for the exhaust, I'm in the same boat. I want something as quiet as possible. "Quiet" and "Aftermarket" are NEVER 2 words that go together, unfortunatally. I'd fit something from another stock bike, but I really like the look of the OEM B4 muffler and pretty much dislike damn near everything else out there... actually, if I could find Anything I liked, I'd already have it on the bike. I could really go for a 4-2-1-2 setup.

Good luck with getting the shop to fix your carb issues.

92mx83 · « **Reply #2 on:** April 20, 2007, 10:24:54 PM »

Thanks for the reply, Brian. I actually thought the flat spot was a lean stumble. I am actually at sea level, so I s'pose it's not the pilot jet. Since I'm not that mechanically inclined, I'll probably take it in to a tuning shop to have the carbs rebuilt/rejetted.

gsxr400 racer · « **Reply #3 on:** April 21, 2007, 12:05:33 PM »

Quote from: "BrianM"

The stalling and flat spot are both related to the same issue... the carbs are running rich. This could be related to 2 things... if you're above about 3k in elevation, the pilot jet is too rich and you need the next size smaller (30). But more likely is that all the damn rubber parts in the carbs are completely trashed due to age and need replacing. When they're rotten, they allow too much fuel into the system and you get stalling at idle and a nasty 'dead' spot in the lower RPMs.

for the exhaust, I'm in the same boat. I want something as quiet as possible. "Quiet" and "Aftermarket" are NEVER 2 words that go together, unfortunatally. I'd fit something from another stock bike, but I really like the look of the OEM B4 muffler and pretty much dislike damn near everything else out there... actually, if I could find Anything I liked, I'd already have it on the bike. I could really go for a 4-2-1-2 setup.

Good luck with getting the shop to fix your carb issues.

here is your 4into1 into 2
http://www.okshon.com/v.cgi?YYurl=http://page13.auctions.yahoo.co.jp/jp/auction/r35841827

Herr Tod · « **Reply #4 on:** April 21, 2007, 07:59:05 PM »

I've seen that one too, I'm thinking of buying it. But I will take it apart and reweld it, to make it lighter. The GK76A 4-in-1 weighs 5.3 Kg, I don't want to know what the 4-1-2 weighs