Alright guys here is the problem. I have an 02 f4i with 15000 miles on it. I have problems first thing in the morning with this bike. It will start fine and shoot to about 2k rpms but about 10-30 seconds later it will drop to 1k then continue to drop to 500 and then die if I let it. So what I have to do is hold the throttle for about 3-5 mins at about 2k until it warms up and then it will idle fine. I have swapped the throttle bodies cause a friend said it could be the tps. I also put new plugs,new oil, and new gas. At one point I unhooked the vacuum line to the map sensor and it idle fine just didn't run very good. so maybe that is the problem. The second thing is I think it is missing at low rpms. In first gear at about 5k it kinda bounces back and fourth then if you hit the throttle it will clear and take off. haven't really noticed in any other gears. maybe slightly in second. I am thinking about taking it to the dealership just wanna get some ideas first. Also I replaced the CCTL with a oem one. Could it be the timing or the valves?

 

it very well could be the valves needing adjustment as you suspect. Bikes don't like the cold, but once they are started, they shouldn't have any issues as long as your giving the bike plenty of time to warm up before riding it. But those are signs of valves out of adjustment.

i doubt its your timing. Unless its was messed with at some point.

Another thought, only because its an f4i, would be to check the FPR. Pull the vacuum line of and see if there is any trace of gas in it. If there is, replace it. Its a common problem with that series of bike.

Do you have a power commander on it? Aftermarket air filter? Other mods?

When did it start having this issue? Only since its been cold? or after a modification or replacement part?

 

Thanks for the fast reply. The bike is stock. I just changed the FPR with a brand new one. I don't have a power commander. The next thing I plan on doing is replacing the vacuum lines.

 

Ok so here is the latest news on this bike... I got to messing with the vacuum lines today. Oh I forgot to mention. The bike has the clean air mod. Anyways I was messing with the lines to the map sensor and to the air box. I took the map sensor line off first and started the bike. It didn't seem to help. It actually made it worse. So then I put that back and took off the right vacuum line that runs to the right side (if your sitting on the bike) to the airbox. its the one that is a quarter inch and it hooks to the back of the airbox. No change actually got worse also. so I hooked that back up and took the left quarter inch vacuum line off and walaa, the rpms went up and the bike sounded normal. So I let it cool down so there was no temp reading. Started it back up and it went to 2k for till the temp reading got to about 100 degrees then slowly came down to 1100. So I let it warm up and adjusted the idle to 1300. So any Ideas what it might be? I am going to let it sit tonight cause i usually have the most problems first thing in the morning after it has cooled off all night. This leads me to believe it something air related. Any help would be appreciated?

 

yo, i know this thing is ancient , but my bike was down for about 2 year had to replace the pump, and fpr and carb synch, it finally crunk, the wax unit engaged, so i needed to adjust the idle, so i did and after i did let the bike sit ,it got cold now i have this problem every time i crank it cold it will stall and flood every time, ever figure this out, or do you just ride with that vac line unplugged?

 

Hey, I had this exact same issue which eventually turned out to be a vaccum line issue. I am 99% sure you have a vaccum leak somewhere, in one of your throttle body vaccum lines.
It could be a leaking hose feeding vaccum to the scottoiler V system even(in my case). So check all you vaccum lines on the TB for leaks/cracks or they could be lose?
The explanation for cold start issue caused by vaccum lines is this-

When the you start up on a cold winter morning the autochoke would ensure the throttle body valves are wide open(the fast idle wax unit ensures this as the more the cold outside the more it contracts/shrinks hence opening the starter valves more) . This ensures more air is sucked in to burn the extra fuel the ecu dumps during cold startup to warm the engine up, hence the tach shoots up to 3-3.5 rpm. The throttle position sensor has no role to play here.The ECU, I think purely relies on the coolant/engine temperature to calculate the fuel needed.
May be there is a cold startup map on the ecu.
So in a way, in the absence of readings from the TPS as there is no throttle input, the Fuel dumped by the ecu is based on only the temperature. The throttle body starter valves and the fast idle mechanism together are calibrated to burn the fuel the ECU is dumping at the startup So, we have 0% control on startups on the fuel delivery.On FI bikes, the only way a rider can influence the ecu is by throttle inputs anyway(okay newer bikes you can may be interact by leaning, wheeling, launching, ham handedness or whatever but I digress)
The ECU has no way to tell there's a vaccum leak and the engine is not able to suck up all the air through the starter valves so it keeps on dumping fuel which eventually fouls the plugs and your revs drop leading to a flooded engine.
If you give some throttle during startup, you are providing more air to burn the fuel so it helps . As the engine temp rises the wax unit expands and shuts the starter valves down, The ecu also reads the temp and lowers the fuel supply, so assuming your vaccum leak is not huge(not all the pipes are cracking hopefully), the bike is able to cope with lesser air.
But the leak would still affect the riding-loss of power and pickup, pathetic fuel economy(are you getting substanitailly less per tankful?).
The above is what I have interpreted/thought of and is not gospel