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Discussion Starter · #1 ·
So I've been running into a few problems on my Suzuki Bandit, before yesterday it would just idle rough and had power surges, summed it up to be running lean and didn't quite know the issue, ran some injector cleaner and it seemed to help but still would stutter. Go for a ride yesterday and immediately know something's up, it's idling at only 100rpm lower, but still I could tell the difference. Wasn't idling choppy this time, just slightly lower and more smooth. Opening it up in any gear was just very saddening yesterday. First gear normally a little under half throttle your front wheels Poppin up, today I cranked the throttle fully and just felt the lag and accelerating so slow compared to normal. First idea was fuel pump/filter but I've came to the conclusion I think it's the stator. I just replaced the rectifier as the old one was fault. Bike has 5000 miles, just got it with 3000 last month. On a bandit forum someone was talking about revving the bike and smelling for a burning smell like plastic, and that is the stator burning up, I did this and smelled the burning smell.

Main question is does this all make sense and would a new stator make my bike idle normal and accelerate properly? Would this be the culprit of me thinking my bikes running too lean?

I'm going to test the stator here shortly After I get some coffee, And possibly take it apart to inspect the coils to see if theyre toasted. Basically ruled out plugs as they only have 5k miles, rectifier is ruled out, battery is brand new, injectors are clean, really just think it would be the stator or either fuel pump, but if it's the stator then the fuel pump wouldn't get proper voltage to operate correctly

Does this all make sense? Thanks for any insight
 

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Discussion Starter · #2 ·
Update : tested the stator and it doesn't seem to be the problem, although I couldn't find what it was suppose to read, all readings were the same, which I was told is what should happen.

Went for a 3 mile ride to get gas, started backfiring like mad it you let off around 4-5k RPM, big triple gunshot backfire. Now I have a Chinese rectifier on the bike, do you guys think this could be the culprit? The bike seems to still be running a bit lean, so fuel pump is #2 behind stator or rectifier right now I just don't know which it is

Advice would be welcomed, really trying to stay out of the shop but if it's too far gone I'll do it, I just feel it shouldn't be catastrophic as the bike has 5.2k miles on it
 

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Discussion Starter · #3 ·
I changed battery and RR around 4k miles cause the OEM one started smoking up my battery, have been good with the battery but could the chinesium stator cause the bike to backfire, idle rough, and not accelerate hard?

I was on a closed road in Mexico yesterday when I discovered the issue, bike tops out at 122 on the dash which is really 115 cause it's generous, anyways a bandit 1250 should too at like 165 on dash or 155 actual. Just wanna ride my bike
 

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You're going to fry your motor if it is fuel pump, you'll go just lean enough to melt it. Not charging parts if the battery stays up, and a $10 voltmeter will tell you. 12,4 -12.8 volts and charging is fine. Also, low voltage makes bike run RICH not lean, at least until it begins to mess with the electronics. Sounds like dying fuel pump to me. A pressure check would tell the tale.

You have an electronic bike with no code reading ability? The computer will tell you what's wrong.

If you run ethanol fuel even more likely it is the pump.
 

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Discussion Starter · #5 ·
You're going to fry your motor if it is fuel pump, you'll go just lean enough to melt it. Not charging parts if the battery stays up, and a $10 voltmeter will tell you. 12,4 -12.8 volts and charging is fine. Also, low voltage makes bike run RICH not lean, at least until it begins to mess with the electronics. Sounds like dying fuel pump to me. A pressure check would tell the tale.

You have an electronic bike with no code reading ability? The computer will tell you what's wrong.

If you run ethanol fuel even more likely it is the pump.
No ethanol, I only put in ethanol free.Thanks for input I got no clue what is wrong I'm just comparing my issues to other bandit forums and guys have had similar issues saying fuel pump or stator/RR.

I don't have a code reader for a bike, I never had to wrench on one until buying this one. So check fuel pressure, rule that out or replace it if problem, scan bike for codes?

Thanks for pointing me in a right direction
 

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Might be time to invest in a diagnostic computer, if you want to know what is going on. If you do, get a good one, that can read fuel trim, pressures, voltages, and not just a code clearing device which are most of them on the market. Sadly I would recommend talking to your Bandit guys for that recommendations as I do not own a bike that requires one only cars. I have some pretty sophisticated ones for my cars (each their own) and they where not cheap.
 

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Yes. Cars are easy as most scanners use OBDII but bikes may well use proprietary software and harder to find readers for that. You'd have to find what protocol Suzuki uses there and a device that reads it. You need one that reads real world live data coming out as the computer reads the engine to be able to tell what the engine is doing, you can keep snapshots of the data to show to the techs.

I too do all my cars myself and nobody ever touches them but me. Got like 3 scanners to use.

If you are clever enough to rig some sort of a tee fitting into the fuel manifold without damaging it you can use an old school fuel pressure gauge to read the pressure. I've done it on other makes but the set up is different for every situation, you have to make it up out of thin air.

Why I tell people to listen several times to their vehicle spinning the fuel pump up to recognize how it sounds, often a pump working but tired will spin up sounding different and if you knew what it sounded like when normal and working right then it becomes obvious something is wrong with it. Noises like hesitation to spin, or not at all for too long, or lagging or pulling up slow or squeaking all tell you likely a pressure problem could be there.
 

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Basically ruled out plugs as they only have 5k miles, rectifier is ruled out, battery is brand new, injectors are clean,
If you had to clean the injectors and it seems like there were electrical problems too... I'm thinking try replacing the 5000 mile old spark plugs.

S F
 

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Discussion Starter · #9 ·
If you had to clean the injectors and it seems like there were electrical problems too... I'm thinking try replacing the 5000 mile old spark plugs.

S F
Worth a shot for $40 it's not gonna break the bank. Just got the bank back on, took apart the pump and cleaned the filter in it, no difference at all, it actually is running rougher. The bike idles fine now, not jumping or surging, but the exhaust is popping, like very loud. Smells like burning or like soot from the exhaust too. Tested the rectifier cuz I have an ebay one on it right now, and it's working perfectly so it isn't a stator or RR which I thought. It could still be pump or plugs and now it's kinda out of my comfort zone, at the point where I just wanna pay someone to make it right now.

Still sounds like it's lagging in every gear, you go to accelerate and it just sounds like it's lagging or sucking in air. Big backfires when your decelerating or even letoff gas in higher rpms.

I don't wanna invest in a nice obd for bikes, cause one thats nice is about 300, and cost to get bike fixed at a shop my guess will be about $700, just pisses me off bought this bike last month
 

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Unfortunately what computer bikes do best just like cars. The clarity of what is wrong pretty much disappears to have any one of 30 things that can go wrong all produce the same crummy symptoms, ergo, the vehicle just runs like a piece of junk. The symptoms commonly sound about the same.

All the popping and banging likely screams your plugs are wet or black to be fouled. Changing will fix that for a minute but if the fouling issue is still present you simply refoul the new plugs in minutes.
 

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I'm just thinking finally try simple.

Apparently the spark plugs have been in the bike since new and apparently there were electrical and may (?) have been fuel problems in the past while running the same spark plugs that are in the bike now. The same spark plugs that during 5000 miles may have seen abuse. They're due for replacement soon anyway.
Apparently the spark plugs haven't even been checked... It's just S.O.P. when troubleshooting to get a look at the spark plugs and change them if there is any question.
BTW.
The spark plugs in that bike run clean, clean, clean. If you find deposits that look "normal used" for an older two valve engine... They're probably fouled.

S F
 
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