Hi all,
Before I get into this, I understand that this is a thread title that always graces the forum, but I have done a lot of searching and cannot find a situation like my own as of yet.
TL;DR: Possible weak battery to start with, but changed spark plugs and oil, then ran the bike with no issues. Took out the carbs after a hell of a time trying to get them out, cleaned them according to a Youtube video
https://www.youtube.com/watch?v=Ksh-hcmz3U4&t=895s , replaced everything, had a weird time with the flimsy diaphragm rubber, but screwed the caps back down on top of them. Ran the bike again, hiccups/hesitation, eventual stall on a downhill even with WOT, got it started and back to the garage it went. Disassembled, tried to carb sync via two-bottle method on a slightly warm engine, bike would not start (out of gas symptoms), noticed water in tubes that lead to vacuum nipples on carbs, reattached everything and just tried to start bike numerous times, when it was started, it could only do so at full choke with steady RPMs at 4-5k, any change in choke or throttle killed the engine. Could get it to crawl by letting out clutch, but was unsteady and sounded like it wanted to stall, and any throttle still killed the engine. Ordering a new battery, I eventually killed my current one, need help on diagnosing and what to do going forward.
Background:
Before my spring break (early March, for a week) I was running my 250 intermittently, and was starting to think about the maintenance the bike would need, not having known when it had last been done (the oil looked very dark and it worried me). Started to hear sputtering from the engine, more so at higher RPMs, and noticeable lack of midrange power, and after forum searching, I bought some Chevron Total Fuel System Cleaner and added the necessary amount and ran it until reserve, and did notice an eventual disappearance of sputtering. Before break (and a full tank of gas) I poured in some more cleaner to the engine since I would be gone for the week, just wanted to cover my ass, and ran the bike (just idling while revving in neutral). Come back, have issues getting it started (around 30-45 degrees throughtout the week), assuming just a cold battery, resorted to setting choke fully on, open/close throttle while starting until I get it going, let it warm up, then take off. Eventually did not have to do this if the bike sat out in the sun or got to warm up long enough while it was running. Then I got around to purchasing all the components necessary for the maintenance I planned on performing (oil change, coolant flush, spark plugs, carb clean, carb sync, valve adjustments) after getting the green light to work on my bike at my friend's house. I have a 2006 Ninja with 5002 miles and finally approached the task having not known when it was last done and having some mechanical experience with cars.
To start I did not get to do everything. First, I got to changing the spark plugs and changing the oil, which I then ensured was okay by taking it for a short ride down the street, no issues there.
Next came the carb cleaning. I knew the Fuel System Cleaner was not a end-all solution and wanted the peace of mind of having cleaned my carbs. Looked it up on YouTube and had ninja250.org pulled up alongside, soaked the jets, sprayed everything down, air/fuel mixture to 2.5 turns out, removed the diaphragms and sprayed them and everything within, replaced them (unsure if i did it correctly, but I made sure the cap covered the rubber, some excess was hanging out in one area more than others after tightening), and went about hooking everything back up to the bike. Now, I got everything back in, all the boots in place, hoses in place, tank reattached, and I go to start the bike, fully anticipating that it will need some cranks before starting, also knowing I have had battery issues recently that required bumpstarting on occasion after leaving the keys in the ignition. Ended up getting the bike started with full choke by jumping it with a jumpstarter box that was not at max charge, 4kish RPM's in neutral. Next, took the bike out to the street again, only to find hesitation/hiccuping, which I did not take too much mind to having replaced the carbs and trying to get gas back flowing in the engine, but when I was coming down a hill I noticed a sharp drop off in power to where WOT would not bring me above 2k RPMS until it stalled out. Gave the bike a second and then started it back up successfully with the choke and hurriedly brought it back to the garage, assuming I needed to now sync the carbs, and went about doing so with the two-bottle method as suggested from ninja250.org. Now, I had the bottles set up, sealed and seated nicely to where I could read them, and tried starting the bike (it had cooled off slightly because I had to make the manometer), kicked up but died shortly after because of what I assume was a lack of gas, although I thought the carbs could hold enough gas to idle temporarily. Tried to start it up a few more times, battery was too weak to continue and died out. As I tried to plan my course of action, I noticed water droplets in the hoses connected to the nipples on the carbs that were meant to measure the vacuum from each cylinder (they were not immersed in the water within the bottles, only the hoses connecting the two bottles were), later finding out that water can mess with things in the carbs should it get in, but I carried on assuming it did not make it in.
I took a break, and reapproached, going over everything to see if everything was connected (it was), but I noticed the hose coming from the tank (one that is hidden by the seat) was kinked, but realized it only led to the bottom of the bike. A few failed attempts at bumpstarting later, I jumped it eventually using a car that had to be turned on just to get the bike going (I know it should be off as to not overload the battery, but I was not making progress, I could hear the clicking of my battery and was desperate). Bike then kicked on after many attempts at starting later and instantly spiked to 4k rpms, and I then went about trying to reduce choke from full, but any reduction will instantly kill RPMs, and I'd have to catch it with the choke. With more minor adjustments, I could get it below 4k only for a short time before RPMs began to hunt and bog the engine. After letting the bike sit for about an hour, I tried intermittently to start the engine with full choke to hopefully restore life into the battery, any attempts to open the throttle killed the RPMs instantly. I tried adjusting idle RPMs, no change, and it is worth mentioning that the temp. did reach its minimum running temp. and I could not let off any choke. Bike could crawl by letting out the clutch at this point slowly, but RPMs and noise told me the bike wanted to stall, and any throttle input from a crawl would kill the bike as well, even with the help of a hill.
Another hour later I gear up and try to see if the motorcycle gods worked a miracle on my motorcycle after starting it (reluctantly) with full choke yet again, 4k RPMs, sometimes 5k, and temporary crawling. Tried rolling throttle: dead. Bike would then refuse to turn on, I tried opening throttle just to get a start, nothing, eventually killed the battery to the point of no return, no click, just a brick.
I was doing the work at a friend's house, had to go back to campus Sunday night, now it is just sitting in his garage. I'm going to order a Scorpion replacement battery (probably needs a new battery anyways), and would like to know what I can attempt to do going into the next weekend.