Author Topic: Carburetor - Timing? problem.... Need help diagnosing (Read 6535 times)

sloow · « **on:** August 19, 2005, 12:59:07 PM »

I just did my first valve clearance adjustment on my Bandit 600 '02, and had the carbs cleaned while I was at it. A friend who rebuilds older bikes did the cleaning. Well, now the bike doesn't run as well as before the tune up, which is disappointing. I was just happy to get it all back together without having any extra bolts sitting around.

2 things

1 -The bike idles more roughly than before, except when it is completely warmed up.

2 - on acceleration, with the throttle opened slightly it seems to accelerate accordingly, but if I open it up, it loses all its power between say 4000 and 5500 rpm, and just stumbles along.

Is this a timing problem.. I can't see how, I didn't touch anything there.. unless the carb throttle position sensor was damaged, but it looks OK from the outside. I don't know what it does really.

Is this a carburetion problem? I don't think the cleaning was that extensive, i.e. the carbs weren't completely taken apart. They weren't that dirty But what should I look for?

I also installed a K&N air filter.

Help.

Red01 · « **Reply #1 on:** August 19, 2005, 06:47:28 PM »

If you didn't rejet, stick the stock air cleaner back in. The K&N filter for the 2G B12 (and 600) even causes problems for some jet kitted bikes.

sloow · « **Reply #2 on:** August 21, 2005, 03:22:50 PM »

That was totally it!!!

Amazing. I think it just goes to show that it's better to make one change at a time. It would have been easier to figure it out if I hadn't made three changes in the same session.

Anyways thanks very much, you saved me a lot of time!

Paul

tbot · « **Reply #3 on:** August 21, 2005, 03:30:21 PM »

Quote from: "Red01"

If you didn't rejet, stick the stock air cleaner back in. The K&N filter for the 2G B12 (and 600) even causes problems for some jet kitted bikes.

I was just about to pick up a K& N filter for my bike, what's the story??

sloow · « **Reply #4 on:** August 21, 2005, 03:36:19 PM »

The story is that when I put the filter in, the bike either got too much or too little air. I think it's too little, so when you open up the accelerator, more than half way for example, nothing happens. From idle to say 2000 rpm it seems OK, but after that... the engine kind of sputters and stumbles like it does when you have to switch to reserve, or have run out of gas.

Paul

PeteSC · « **Reply #5 on:** August 21, 2005, 03:38:43 PM »

Tbot, the Kand N will be fine on your '98 B12. The newer bandits have a slightly redesigned aribox....which somehow the K and N doesn't work well in.

Red01 · « **Reply #6 on:** August 22, 2005, 09:55:45 PM »

Don't you have to do a little carb tweakin' on the 1G to run the K&N, too?

Landry · « **Reply #7 on:** August 23, 2005, 03:08:51 PM »

Quote from: "sloow"

The story is that when I put the filter in, the bike either got too much or too little air. I think it's too little, so when you open up the accelerator, more than half way for example, nothing happens.

It's letting too much air. Those K&Ns let in a BUTT-load of air, compared to the stocker. Maybe not a butt-load, but definitely enough to upset the air/fuel balance in a bike that has been tuned lean from the factory to appease the EPA sissy-boys.

Mongo · « **Reply #8 on:** August 25, 2005, 10:02:32 PM »

I was considering doing the K&N on my 02 1200S but I'm starting to think twice about it. I replaced the stock can with a Yoshi RS3 and still seem to be running fat given the amount of carbon on the exhaust.

I figured the installation of the K&N would help lean it out; we went through and synchronized the carbs over the weekend and placed vacuum lines between the number one and two carbs and joined the number three and four. This seemed to help the idle and performance of the bike still feels good.

While I was in there I noticed the air filter had seen better days so it got a good blow down and was place back in, now I need to figure out if I want the K&N or stay stalk.

Steve · « **Reply #9 on:** August 26, 2005, 04:21:09 AM »

The K&N can work fine, on mine it just took a little tweaking. '01 b12s w/ Ivan's kit and a Yosh slip on. No problems here. The K&N will pass more air (leaner) than the paper element and I have read many (BMW car & bike) sources say that it also passes more crap into the engine.

I run the K&N on my b12 & sr500 (and a Pathfinder) and took one out of my R100rs (and would NOT put one in my e-23), go figger.

Steve

Mongo · « **Reply #10 on:** August 26, 2005, 09:54:14 AM »

I think I'll go with the K&N and if necessary I'll re-jet but, with the looks of my exhaust I don’t think jetting will be an issue.

I've run K&N filters on all of my vehicles and have become a firm believer in the product. Hopefully things don't get to strange on my bike!

land_shark · « **Reply #11 on:** August 26, 2005, 11:21:03 AM »

Quote from: "Mongo"

I think I'll go with the K&N and if necessary I'll re-jet but, with the looks of my exhaust I don’t think jetting will be an issue.

I've run K&N filters on all of my vehicles and have become a firm believer in the product. Hopefully things don't get to strange on my bike!

I hope so too! I think the exhaust will help a little bit, but with a factory-jetted bike you're already running pretty lean. You'll have to re-jet to put more fuel into the cylinders to keep up with the increase in air from the K&N. Otherwise, you'll get stumbling, and can cause long-term damage by overheating your cylinders. I'm pretty sure the other members will back me up on this

....I hope!

Sweet mailbox, by the way!!

tacoman · « **Reply #12 on:** August 26, 2005, 01:13:45 PM »

On the 1G B6, Dale's kit comes with a K& N, so he set up his kit around it I presume. There's been lots of talk here about the KN compared to the stock filter. The KN flows more air but doesn't filter as well. If you ride in dusty areas stay with the stocker. I like the KNs because they're reusable. The B6 filter isn't too bad stock but filters for my diesel ford are huge $$. The KN paid for itself after 1 change.

Mongo · « **Reply #13 on:** August 26, 2005, 04:49:58 PM »

Sweet mailbox, by the way!!

[/quote]

Thanks for the advice I think I'll hit the local shops (cycle gear, star cycle, etc) and see if I can pick up the K&N and a jet kit this weekend. I checked out there web pages but they were weak.

Land shark if you thought the mailbox was sweet go back into my photos and check out the trashcan

Mongo · « **Reply #14 on:** August 28, 2005, 06:13:09 PM »

I was able to find a K&N local thanks to the folks at Star Cycle and installed it this morning. I took it out for a short run and found no real issues with stumbling or a lean pop. Unfortunately I tweaked my back yesterday and was in no condition to give it a good shake down for the long haul. I was able to give her a pretty good run through the gears and every thing seemed to be fine!

I think I’ll spend the rest of the day nursing this back of mine with my friends Bud and Jose Cuervo and a bottle of Aleve and watch the AMA Super Bikes on Speed. Hopefully I’ll be able to give it a good run tomorrow on the way into work!

I’ll let you all know if I run into any problems!