Author Topic: Surging (Read 8330 times)

bbb-bandit · « **on:** March 07, 2005, 02:13:38 AM »

I have a '97 B12 that "surges" at constant throttle between ~3000 and 4000rpm. I call it surging because I don't know what else to call it, it acts a little bit like its starving for fuel. Below ~3000rpm its fine, and above 4000 its fine (runs awesome). I just had it to the Seattle Suzuki shop and they did a full engine service including valves and carbs. Has anyone else experienced this? Am I crazy?

Thanks,

Red01 · « **Reply #1 on:** March 07, 2005, 03:35:46 AM »

Does it still have the stock jetting?

gsxr400 racer · « **Reply #2 on:** March 07, 2005, 11:09:39 AM »

bingo

FreediverGa · « **Reply #3 on:** March 07, 2005, 11:33:05 AM »

yeah my does the same thing and I still have the stock jetting with only a scorpion slip on. The slip on already killed the gas mileage. So I'm reluctant to put in a jet kit because it will take even more of the mileage I would like to keep!

BBurton · « **Reply #4 on:** March 07, 2005, 11:47:24 AM »

A jet kit will more than likely help your gas mileage. I also have a scorpion slip on with factory jetting and my bike runs like a scalded dog, no surging or flat spots anywhere. I'll do a stage 1 kit eventually...

B6Matt · « **Reply #5 on:** March 07, 2005, 01:54:08 PM »

Probably a lean stumble due to stock jetting.

FWIW, my gas mileage was not adversely affected by adding a Yoshimura slip on and midpipe with Holeshot Stage 1 jetting and timing advancer. If the mileage decreased any at all, it's because I'm constantly cracking the throttle wide open :mrgreen: because it's running so well. No surging and much smoother powerband with this setup.

bbb-bandit · « **Reply #6 on:** March 07, 2005, 02:48:25 PM »

I really appreciate all of the feedback.

So it sounds like a jetting problem from the responses. Is Holeshot THE place to get a jet kit? I have the stock exhaust and jets, is it going to be a problem to just do the jetting with no exhaust mod?

I just want it to run perfectly!

Just curious, does it seem strange that my bike would do this with an all stock set-up? The previous owner did drop the bike at low speed and grind the corner of the can on the ground, could this have effected the flow of exhaust and cause something like this?

Thanks again for all the feedback!

ray nielsen · « **Reply #7 on:** March 07, 2005, 05:57:27 PM »

If the first generation Bandit uses a throttle position sensor it might be the culprit.

My 2003's TPS was badly misadjusted from the factory and my gas mileage didn't improve from 33 MPG even after break in .

Using the factory manual, I adjusted it -- you'll need an ohmmeter, but otherwise it's very simple. Basically youi measure the over resistance of the TPS from end to end terminal and then set the end to center resistance to a percentage of the total. The key is a percentage, not a specific resistance value.

My gas mileage went up about 18% and the bike ran better.

Lately I've installed a Scorpion slip on and the mileage is now about 44 MPG, but I'll wait to see if that's consistent over a longer time period. The bike runs better with the Scorpion; the choke can come off sooner and the idle RPM seems just a bit higher too, maybe 50-100 RPM.

Red01 · « **Reply #8 on:** March 07, 2005, 06:30:05 PM »

No TPS on the 1G.

FreediverGa · « **Reply #9 on:** March 11, 2005, 03:32:40 AM »

I need to get around to checcking TPS on my B6 before Ralley in May!

You guys are making a holeshot jet kit sound more interesting every day!

FreediverGa · « **Reply #10 on:** March 11, 2005, 03:38:21 AM »

Quote from: "BBurton"

A jet kit will more than likely help your gas mileage. I also have a scorpion slip on with factory jetting and my bike runs like a scalded dog, no surging or flat spots anywhere. I'll do a stage 1 kit eventually...

I have b6 unstead of b12! That scorp sounds really nice huh? When I got some new tires in December The guy road off for a test ride. That was first time I heard the can on my bike with someone else riding it and I was like is that what my bike sounds like to other people. sound like damn race bike going by! Me likey !!!

BBurton · « **Reply #11 on:** March 11, 2005, 11:23:54 AM »

The scorpion is a sweet sounding can, and a sweet deal as well. I like the looks of the race oval can and the fit and finish is very good!!

Slider · « **Reply #12 on:** March 14, 2005, 04:15:39 PM »

I have a 98 12S which ran poorly with a Yoshi slip on. I went to one dealer who said I needed a jet kit for $275Cdn + labor. I asked him if he had ever put one in & configured it. Nope.
I went to another dealer, (larger), and asked the same questions. He said if I bought a jet kit he would give me most of the parts back after instal. He said you didn't realy need the kit unless you were going the more radical route, ie GSXR cams, piston kit and or timing changes etc.
He proposed & did a milder route. I decided to do it when I asked him how many of these they had done and it was at least ten.
I believe he raised the main jet needle a notch. He did drill out the low speed jet covers and richen these. I spent the same on labor and it runs beautifly from 1500 rpms up. I did not detect any significant change in mileage.
He said all bikes are set very lean for emissions and the slip makes it worse. Good luck.

Mike