Weirdo, need help!

[badidou]

First of all i cannot log in to the discussion group using my previous username and password. I had register again.

Anyway! that's not a big deal it took me only 5 minute to do it.
My main concern is the byke. After i finaly got a new CDI and it  worked fine for almost two weeks a couple days ago, the byke started acting weird.

1- It died on me on low RPM, however worked great on high RPM. I had to keep acclerating so it wont die on me at a light.

2- second day, could not start the byke using the choke. had to accelerate using the throtle to have it start. However was still runing perfectly on high RPM(still died on me at a light).

3- afternoon same day, was running very slow even on 5th or 6th gear I had the impression that it was running only on 1 cylinder, it was also making a very loud sound. it also died on me at each light or stop sign. Even when using the throtle, the byke was dying on me and had to restart it each time.

4- in the evening, did not want to start anymore!

I have sparks on all the 4 cylinders, i opened the carburator, nothing wrong(totaly clean).

I really don't know what's wrong with it. Do you think guys that it could be a voltage problem?


And thanks again for the all your help regarding the ignition box.

[echomadman]

You had to re-register because the old board went kaboom. If you have any of the old CDI swap info it'd be great if you reposted it.

Your problem sounds like what happened to me a week after i got the bike, Its a pain to have to keep it screaming in high rpms at lights to stop it from stalling
new plugs fixed it for me, but i think that only treated the symptoms not the cause.  
I think it's a coils/HT lead issue. repalcing the leads on mine made it run great for a while then it went back to poor ignition at low rpm, fine at high rpms. So I'm looking for new coils and plug caps.

it will still show a spark at low rpm, it just doesnt deliver enough power to ignite the mixture well, which leads to plug fouling if you do a lot of low rpm pottering.

Someone that knows more about ignition systems should be able to tell you how to test your coils to see if thats the problem

[lemining]

I know it has been a while since someone posted here, but yesterday i started having problem with my bike and it looks very like badidou's problem. At first I could'nt start it properly i had to push it on second gear to get it started and i would have to keep high rpm to stop it from stalling. On low rpm it sounds like it is not fairing on all cylinders. (sounds like lawn mower)
At first i checked if i get spark in all spark plugs (i replaced all of them recently maybe 2k km ago).
Then i went for carb. I gave it a nice clean (it wasn't that dirty anyway). After carb cleaning motorbike would start (not the first time but after few cranks it started but i still have problem with not all cylinders working at low rpm.
What could be wrong?

I will try and clean carbs again also i was looking at CDI as a cause of all this.

ps. Can jump starting it (on second gear) damage CDI in any way?

[Vidrazor]

>>ps. Can jump starting it (on second gear) damage CDI in any way?<<

Not that I'm aware of, but if you have enough of an incline or push, third is a better gear to start it in, at least it has been for me. I don't have the problems you guys have, mine are more cold-weather related, like trying to start the bike up in 20°F when I haven't started the bike up in a week or more. Fortunately I have a good hill a block away, so it's down I go in third and it starts right up.

I've never understood why bikes and cars won't start up in the cold. You have gas vapor, oxygen, and a spark. What's the problem?

[interfuse]

Check the charging system / voltage regulator. It's been a while, but when my R/R started frying my batteries I couldn't get the bike to run below 3,000 rpm. I could would run fine anywhere above 3,000. Changing the battery would fix the problem for a while, but eventually the R/R would fry the battery again.

[pmackie]

As interfuse says, start with the easy things first:

1. Charge the battery, and make sure it's in good shape. Check the voltage before you charge it, and after, or get it load checked at a local battery store/shop. A fully charged battery in good shape should measure 13.2-13.4 volts. Low voltage/current CAN cause starting/low rpm running issues.

2. Check your air filter - clean? new?

3. Check your fuel supply. Getting a good stream out the petcock?

4. Check all of your electrical connections. Alt to CDI, to coil, plug wires, plug caps, etc.

I've never understood why bikes and cars won't start up in the cold. You have gas vapor, oxygen, and a spark. What's the problem?

Usually related to:

A) Poor fuel atomization, especially carburated. Winter fuels DO have additional "light ends" to increase vapour pressure, but the amount needed changes drastically with temp changes. Fuel injection usually helps. Keeping fresh fuel in the tank helps, since the "light ends" vapourize away in storage.

B) Battery output is reduced considerably in cold, and since everything in the engine is colder, friction is higher, so more current is drawn by the starter, leaving less for the ignition.

C) Due to higher friction, the engine tends to turn over slower, resulting in less effective compression in the cylinders, and poorer air intake/fuel atomization.

[lemining]

I have checked the bike yesterday.
Carbs are clean. Battery is not even a year old and have been fully charged (overnight).
I took it for a spin last night to warm it up before I setup idling speed.
Just before i was going to leave the garage i decided to touch exhaust pipes that come out from each cylinders (i know there is a name for it :P) What i discovered is that all pipes but one were hot.
So basically what im going to do over the weekend is to check spark plug (#3) and connection from coil.

However what makes me wonder is why my spark plugs die so often in my bandit. Before i had bike for a month and suddenly one day none of spark plugs would work properly (they would barely spark even after clean) so i replaced them all and bike was running fine and now few (aprox. 4 months) later i have same issue. I just hope it actually is spark plug so i can quickly replace it.

ps. I know you guys relate my problems to winter etc. Well i live in southern hemisphere (New Zealand), we have very nice and hot summer here now 

[PitterB4]

I would bet on one of two things...

Most likely is a bum plug wire.  The wire-to-boot connection can go funky.  Make sure everything is good there.  (Lots of posts here about that).

Or... although clean, that carb is funky - poorly adjusted (float height, a/f screw, needle clip...), bad o-ring, torn diaphram, missing vac o-ring under the cap, or one of the other dozen or so things that can go wrong there....

[Vidrazor]

>>Usually related to:...<<

Perhaps. I notice when I bump the bike it'll start almost immediately. Sometimes I wish the hill was right next to where I park the bike, I wouldn't bother with the starter at all!

[pmackie]

Perhaps. I notice when I bump the bike it'll start almost immediately. Sometimes I wish the hill was right next to where I park the bike, I wouldn't bother with the starter at all!

Yea...but you have described ONE dead cylinder, so you need to find that. I would also look closely at the plug cap/plug boot/plug wire/wire to coil connection. The other option is to change the coils side to side and see if the dead cylinder follows the coil. If so, it is ignition related, if not, ie same cylinder with a new coil, then look at carburation.

[Vidrazor]

No, that wasn't me with the dead cylinder. That was me bumping in the cold. 

[lemining]

Problem solved! 

I took air box off and what i released was that my carb was full of fuel.
After pulling carb apart i discovered stuck float. So basicly one cylinder was full of petrol all the time thats why it wouldn't work properly. All sorted now. Also just in case i got myself fuel filter it will stop my carb from clogging... I hope...

[gsxr400 racer]