Studders and bucks under 4000rpm

[tyler2569]

After leaving the bike outside for 1 month with out riding i go to start it and its running real rough, had the throttle wide open and it was bucking and kicking in all the RPM ranges. Looked at the carbs and saw gas was comming out of ( which i belive is) the poilet air jets, in the front of the carbs where air box attaches, on the 2 left carbs.
The shop said dirty carbs, so they cleaned and i guess rebuilt them. Now i get it back and ride it, running great i high RPM's but at 4000 and under it was still bucking and kicking. When i try to take off from idle it bucks real bad and studders, once over 4000 RPM its great, tons of power. Shop said its because of the stage 3 jet kit, no air box only k&N's and the headers. I found that hard to belive becasue i BOUGHT THE BIKE 3 YEARS AGO WITH THAT EXACT SETUP and it ran like a champ, i havnt changed anything. So i give in to them and let them install a stage 2 jet kit, put the sock air box in with a K&N. Now still same thing, but now its not quite as bad, but the problem still definatly exists. Also bike will not run with choke on full. Yes it idels but not awsome, when its ideling and i give it a quick rev it seams like it hesitates, and just sounds funny when holding throttle keeping bike under 4000 rpms. seams like the bike is eating gas a bit quicker then i remember. Also i see some black smoke on inital startup, but with the stage 3 installed it was black smoke when riding. I know that means rich but now im on stage 2 and it was black real quick only on startup. Before the bike broke, it never had black smoke... ever.

So the shop is scratching their heads, and im getting close to getting my bike returned to me yet still broke because they dont know whats goin on.

[arsenic]

okay here's what you need to do, I can't tell you why it ran good before and now it doesn't. Forget the Dynojet stage 2 and 3 crap. Get a Factory Pro stage 1 kit. Forget the K&N air filter period, use an OEM filter. With factory Pro Stage 1 and OEM air filter, I am sure it will run right.

[tyler2569]

Well at this point, im not spending anymore money. stage 2 is the best its gona get. The bike ran awsome before even with stage 3, and no air box and headers, actually its my first bike , so i learned on it, not realizing it had stage 3. All i know is it ran great for 3 years, now it dosnt. nothing has changed. Theres gota be an answer out there somewhere, something is being overlooked, and i cant accept that it is because of the mods, it ran great with the mods for 3 years.

[tyler2569]

Ok.. shop just called and said it should be all set, they said they made some minor adjustment.. I dont belive it, this is the 3rd time now.. but ill find out in bit.

[The CyberPoet]

(A) Swap the DynoJet diaphram springs back to the OEM diaphram springs. This will help get rid of the studdering on small throttle openings (coming off idle);
(B) If you're going to park your bike for a month at a pop, start using a fuel stabilizer (like Stabil). Fuel evaporates it's lighter compounds and then doesn't like to detonate well; the stabilizer will help keep that from happening.
(C) Get in the habit of using a fuel system cleaner to help keep your carbs clean, esp. if you ride hard and put it away hot then ignore it for a week or more at a pop.

Good luck
=-= The CyberPoet

[md86]

Let's work with what he's got since supposedly it ran fine before , right .....
Check your plugs yet ? Run any in the tank cleaners ? You SURE none of your o-rings or anything in the carbs is worn ? Also , you have your battery tested ? Auto Zone does that for free . They don't like to work with bieks , but I imagine if you JUST brought them the battery , they might work with it .....

[tyler2569]

The shop said that they adjusted my air/fuel ratio to go leaner, which brought my ilde up so they adjusted the idle screw to bring it down. It idles good now, but still the studders remain below 4000, when i cost from say 7000 rpm down to 3000, sounds smooth untill it reaches 4000rpm, i hear a noticable difference as soon as it reaches 4000 and below. After i got it from the shop the first time i still had a stage 3 kit, yet same thing, sounded great above 4000, but when costing down as soon as it hits 4000 and below it became rough. Now with stage 2 and stock airbox i dont want the bike, they took the beast out of it, member this is my first and only bike, i learned how to ride it when it was on stage 3 with no airbox, now its so tame i cant take it.
Also now it sputters in the high rpms, 9000 when im trying to ride fast.

Im bringing it back to the shop and telling them to check everything u guys are saying, i have no confidence in this shop, only reasion i keep bringing it there is they have my money and i just dont have anymore to pay someone else to try and fix it.
Suposedly the carbs were rebuilt.
Is it possoble to have a coil failing?
How about a float issue?
Sence they leaned it out the studder are not so violent anymore, but seams to be lacking power.
I have trouble going up a steep hill from ilde, when im in trafic i can't just romp on it and fly up the hill, i have to go with traffic but the bike starts kickin and studdering
Is there any specific adjustments to make that conrtol the bike at 4000rpm and below?

Plugs are new, battery has been on a charger.

[The CyberPoet]

The shop is probably trying it's best. But if the shop doesn't have a dyno with an exhaust analyzer, they're just pissing away your dough (if they do, it's a different story).

Getting fueling right with aftermarket filters, exhausts and jetkits is often difficult, and it's very typical that the more complicated the add-ons are, the more likely it will be that the fueling will be off in some range of RPMs. Fact of life. Reliability always lies in the stock configuration, after that it's a trade-off, all-though I've been graced by the good nature of Ivan to dyno-test his configs to the ends of the earth on his in-house dyno before selling it to me (not an option on your year, sorry).

Cheers,
=-= The CyberPoet