I swapped Stock exhaust, now a question? 01' 1200S

[britxbike]

So I’ve had my 01’ 1200 for about 5 months now and thought it was time to start upgrading. This is a bone stock bike that I ride just about every day with less than 8k miles.

The bike ran like crap, when I got it, b/c it was sitting for a year. Thus I pulled the carbs apart and cleaned them out. Afterwards she ran a little rich but nothing I was worried about. I thought about it and determined if I got an aftermarket Can then it would lean out and even up. Purchased a Jardine race core can off eBay and installed it the day I got it, which took about 10 minutes.  

Now my question. After the install and about 200 miles she pulls great and screams whenever I’m on the throttle BUT when I let off she sputters like there is not enough restriction. I’m not worried about this more than I am curious why she sputters. If I went up in main jets would this resolve the sputtering when I let off the throttle or would it be something else?

[JayRo]

The carb thing is strange to me.  If you have a bone stock bike, and all you did was clean out the carbs, why is it now running rich? You should be running lean.  Are you sure your bike is bone stock? Are the cover plates over mixture screws still in tact or are they drilled out?  I thought my bike was all stock when I first got it until I had fouling problem and I took the carbs off.  Someone put in 127.5 mains in when stock is 102.5 for my 1G. According to my book, you should have 100 mains and 15 pilots in yours, but someone with a true stock 2G would be able to tell you better.  I would pull all those plugs again and see what they look like.  See at least if they are all the same.  I also had some carb sync issues, which made it run rough, and it was more noticeable at idle.  
Don't overlook the obvious stuff also like the air filter.
Good luck

Jason

[britxbike]

Ok I checked and the mains are stock along with everything else.

It's just weired b/c the bike runs great but when you let off the gas it sputters with the after market can. Anybody have any other ideas?

[Tx Redneck]

Purchased a Jardine race core

There's your problem. Mine is doing the same thing after I put on a Yosh can. From what I've read here these bikes are setup to lean from the factory. I ordered Iban's kit to correct this. Just to reaffirm I put the stock can back on & it doesnt do it with the stock setup

[StangMATA]

The reason that you are popping when you let off the gas is due to "engine braking". You are causing the engine to rev without feeding it fuel.

Think of it this way. Usually, you cause the engine to rev by feeding it gas and air which then drives the rear wheel. This pushes exhaust out...

Now, when you cut the gas (with the clutch still engaged), the rear tire is driving the motor which is causing it to draw air. Part of that is drawn through the exhaust.

Now the stock can is restrictive not allowing much air to enter the can and make that "popping". Your new aftermarket can is MUCH less restrictive in comparison which allows it to suck in air and blow it back out making that "popping" sound.

It's normal and there is no worries. My D&D pops like a m'effer when I chop the throttle.

Next.

W/ stock carbs and jets, there is no reason that you should be running rich unless you don't have your air/fuel mixture screw adjusted properly.

Also

A can doesn't really lean out the bike much. A full system is a different story. 90% of the time, you don't need to rejet for a can.

Did that help answer your question.

[britxbike]

Thanks for the response Ian. After some research over the BB what you said it makes total sense. I should edit my first post as I know I was imagining things when I said it was running rich b/c the air screws haven't even been drilled out. Thus my solution to this will be me purchasing an Ivan kit. Most posts put Holeshot and Ivan pretty even but I'm going with Ivan's setup.

As if I didn't think this bike was fast enough!