Problems with engine/transmission

[KChatham]

Ok, so for a while now my transmission would pop out of gear when shift from first to second. I'll shift into second after a stop, ride a few seconds and then the transmission will pop out of gear as throttle is applied (not necessarily as soon as throttle is applied but after throttle has already been applied). This only happened maybe once a day and I assumed it to be caused by me not shifting completely. However, today it starts popping out almost every time I shift into second and apply moderate power and I know I'm shifting completely. I was thinking about playing around with the shift linkage and see if maybe I'm running out of travel (it's gp style shifting so it might be interfering with the foot peg), but other than that I know it's something in the transmission I just wouldn't know what, nor have an idea on what could cause it. Thoughts?

The other issue is with the engine. I searched on the boards already and found 1 thread applicable (sorta) and I'm going to change out the fuel filter tomorrow and see if that fixes my problem. My problem is the engine doesn't want to idle. I'm driving to work today, after ridden my bike all day to and from school several times, and while I'm stopped at a stop light my engine stalls. I try starting it up, but it quickly died. Instead, I shift it into neutral and as I'm starting it I give it some throttle to keep the revs up and start reving it between 1-2k to keep it from dying. (When this issue started happening the bike was fully warmed up and no choke) Anyways, I get to the next light and it dies again. It does this one more time until I get to work (happened 3 times in a 1/2 mile stretch downtown). I don't know what really happened or what could cause this. It seems like a fuel delivery problem which is why I'm going to replace the fuel filter, but the problem can't be the carbs being dirty (why would they all of a sudden become dirty?). It can't be a jetting problem because I've had these jets on the bike for 2 years with absolutely no problems. Its not a choke problem (applying choke helps keeps the revs up but it still only will idle at 2k with the choke on full but it's isn't a smooth consistent idle. The bike revs fine and has good power when riding it's just at idle it wants to stall.

So within 1 day basically it seems my transmission has gone to crap and the engine decides it wants to act up.

Any ideas on a possible reason for these?

Thanks

[Skippii]

Balance your carbs.
Posted via Mobile Device

[Skippii]

Also check your spark plug gaps and clean the air filter.
Posted via Mobile Device

[KChatham]

Skippii, what would cause my carbs to unsync themselves?

[KChatham]

Ok so after another day of riding I'm beginning to think it is an ignition issue. I rode the bike for half the day with no problems until tonight. The reason I think it is an ignition problem is because when it's idling sometimes the tach will jump (rpms jump too but don't seem in-sync with the tach). The tach is read from an electrical output. I changed my fuel filter to no avail.

I also fixed my shifting issues, for now. I need to ride it a bit more just to make sure.

[423yjl]

the tach doing weird things can be a sign of a bad battery

[KChatham]

That's what I was thinking or it might be a problem with the stator. The battery was just replaced sometime last year during spring. I'll see if it needs to be refilled. If it was the stator what would most likely be the problem with it?

[Skippii]

Originally Posted by KChatham

Skippii, what would cause my carbs to unsync themselves?

just normal use. Same as valve adjustments. Actually, valve clearance changes have a big effect on carb synchonization.
Posted via Mobile Device

[Dragone]

Originally Posted by 423yjl

the tach doing weird things can be a sign of a bad battery

or a loose connection

[KChatham]

Update: So it's been a few days since I last had the problem (once on saturday) and so far it hasn't had a problem. So I don't know if it was just some debris or what. I will be taking the carbs off in the next week or so to clean them for an up coming track day.

[alex.s]

probably some crap gas.

your transmission gears' dog teeth are probably worn down from sloppy shifts. you can back-cut the dog teeth and it will eliminate slipping out like that. essentially once it goes in gear, the more pressure you put on it, the more locked into that gear it gets.

[Skippii]

Originally Posted by alex.s

probably some crap gas.

your transmission gears' dog teeth are probably worn down from sloppy shifts. you can back-cut the dog teeth and it will eliminate slipping out like that. essentially once it goes in gear, the more pressure you put on it, the more locked into that gear it gets.

by "you," I think .he means "your mechanic." Recutting transmission dogs isn't something I'd recommend the average bike rider does themselves.
Posted via Mobile Device

[alex.s]

sometimes i forget some people dont have mills in their garage

[KChatham]

I'm not having anymore problems with my transmission. The sifter was limited to travel so sometimes it wouldn't shift completely so it was an easy fix. I work in a machine shop with mills, lathes, cnc mills, cnc lathes, ect... so if anything needs to be machined it isn't a problem. I've never had a mechanic nor will I ever need one.

[alex.s]

good man. i still want a pair of "silver" valve emulators

[KChatham]

I had some new problems develop with the engine. After about a week or two of it running fine I was riding down the freeway and my engine cut out. The engine would start and idle fine but when revving it the engine would choke around 4,000rpms/midrange rpms. I took the carbs out the next day, cleaned the jets and everything and put them back on the bike. Now the bike will not start at all after going through two fully charged batteries... When took the carbs apart I found this (image) in one of the bowls. I have no idea what it is as everything in the carbs looks fine.

All this is happening just 4 weeks before my first track day...it is becoming very frustrating.

Any help would be greatly appreciated.

[Skippii]

It was just loose, in one of the bowls?
I don't recognize that. Also, to clarify:

I took the carbs out the next day, cleaned the jets and everything and put them back on the bike. Now the bike will not start at all after going through two fully charged batteries... When took the carbs apart I found this (image) in one of the bowls.

Did you find this when you took the carbs apart to clean them, or did you take them apart a second time after it wouldn't start at all, and then you found it?

If the bike won't start but cranks hard, check the fuel flow. You can unscrew the drain at the bottom of each float bowl, and check that there is fuel in each of them.

Basically, you've got 2 possible problems: Not enough fuel in the carbs, or too much. If the float bowls are dry, then there's a problem with the fuel line from the tank to the carbs, or from the vacuum line from the tank to the carbs (Or you forgot to turn petcock back on).
If it's flooded with too much gas in the carbs, drain them (both sides) with the allen screw and start again.

[KChatham]

Thanks for the reply skippii. The part was just loose in one of the bowls. I found it when I initially took the carbs apart. Once I put them back together and back on the bike it wouldn't start at all.

I know the bike is getting fuel because you can see it going through the fuel filter and, more importantly, fuel will drain out of the bowls.

Tonight I will put on my second set of carbs. These came off one of my parts bikes so I don't know if the jetting is even right but we'll see.

[Skippii]

Originally Posted by KChatham

Thanks for the reply skippii. The part was just loose in one of the bowls. I found it when I initially took the carbs apart. Once I put them back together and back on the bike it wouldn't start at all.

Well, have you tried tossing it back in there?
Posted via Mobile Device

[KChatham]

Originally Posted by Skippii

Well, have you tried tossing it back in there?
Posted via Mobile Device

Haha, seriously? I have not tossed it back in there for the sake of having a piece of metal just bouncing around in my carbs. I'd rather find out where it came from.

Little update: I put in my second set of carbs AND... nothing happened. Now I'm going to get some starter fluid and later today my new spark plugs come in. Hopefully something will work!

[FrugalNinja250]

Have you checked for spark? Pull one of the coil wires and stick a spare plug in the end, then lay it (or use jumper cables to connect it to) the cylinder head.

[Skippii]

Originally Posted by KChatham

Haha, seriously? I have not tossed it back in there for the sake of having a piece of metal just bouncing around in my carbs. I'd rather find out where it came from.

Little update: I put in my second set of carbs AND... nothing happened. Now I'm going to get some starter fluid and later today my new spark plugs come in. Hopefully something will work!

I would avoid using starter fluid. It's a mix of diethyl ether and N-heptane, which means it has an octane rating close to zero. It probably will start the engine, but it can -and does- cause engine damage like cracked pistons. It can start the engine even without any gas in the carbs at all, so really, what benefit do you get from it? It's not very useful for diagnosing problems, and the bike stops running when you stop spraying.I'd bring the bike inside and into a small room with an electric heater before using strter fluid.
Posted via Mobile Device

[Skippii]

Originally Posted by FrugalNinja250

Have you checked for spark? Pull one of the coil wires and stick a spare plug in the end, then lay it (or use jumper cables to connect it to) the cylinder head.

or just stick a finger in the plug wire. Doesn't hurt on a small bike like ours, but you can feel if there's a spark.
Posted via Mobile Device

[KChatham]

Changed out the spark plugs, checked spark and there was spark. Put some starter fluid in the carbs, and it still didn't start. Not even one combustion. I then changed out the plug wires and coil with a parts bike, sprayed some starter fluid in and after several tries it finally starts!

BUT, it still will only idle and any throttle input chokes it. Note, this is with my spare set of carbs. I took a video to show you.

http://www.youtube.com/watch?v=4kF1a...LDmZsx0qKMOcdz

[Skippii]

That bike is idling way too low. It's probably not warmed up completely. Use more choke and set the idle screw so it revs a little higher, then when it's completely warmed up try again.
Posted via Mobile Device

[KChatham]

Skippii, it's always idled that low for 2 years, I don't think it's too low... Even when choke is applied and the idle is raised to 4k any application of the throttle chokes the engine.

[alex.s]

from just watching the video it seems like its not making enough power for the CDI to keep spark up... check your battery and the output from your VRR

[KChatham]

Originally Posted by alex.s

from just watching the video it seems like its not making enough power for the CDI to keep spark up... check your battery

Alex, what's the CDI? I have some spare engine laying around, would it be worth taking the magneto and stator out and swapping? Also, if I do take the stator and magneto out, are those components sealed off from the engine oil (never taken it apart) since it's electrical? kinda a dumb question but...

[alex.s]

they are dry. but they shouldnt be your problem. the CDI is a capacitive discharge igniter. its basically a capacitor that gets triggered when the stator is in the correct position (as detected by the stator pickup coil) which then dumps that capacitors charge into the spark plug. if the VRR is not putting enough power through the system, when you rev it the capacitor wont get charged all the way back up between fires and it will die.

[alex.s]

check the VRR output into your battery and check your battery. it might be as simple as the battery needing to be refilled or something

[KChatham]

I've had the battery on a charger and it's been fully charged. I'll check the CDI, where is it located?

Thanks everyone for all your help so far!

[KChatham]

Update, I do think it is the CDI. If I let the engine idle at 4-5k for a few seconds and then apply throttle it will rev maybe 2-3k, if i left off and apply throttle again it revs a little lower, repeat and even lower... I have a CDI for a 94+ which I read is difference from the earlier ones (pin out confirms this).

So here is my question: does anyone have a CDI prior to the change (1994) or could I somehow rewire the bike to accept the new CDI?

[KChatham]

Replaced the CDI and I still have the same problem...what now? I have 2 weeks before my track day to get this thing running.

[KChatham]

Perhaps it's the regulator/rectifier? I'll check it out tonight with a multimeter (should have done this sooner...). Does anyone have one they could sell to me and get it shipped asap? Thank you.

[Skippii]

Originally Posted by KChatham

Perhaps it's the regulator/rectifier? I'll check it out tonight with a multimeter (should have done this sooner...). Does anyone have one they could sell to me and get it shipped asap? Thank you.

The R/R is really only a problem when the battery starts to drop in level. I've had a bad RR on a bike before...it's hard to diagnose because the bike will run fine until you get like an hour from home, then it will cut out and won't start again. It won't even crank the engine over.

[KChatham]

Yea, that makes sense. So the bike will start and idle and do the small revving thing and then the engine will choke. Somehow some way by holding a rev at 6-7k for about 30sec changed something because now the bike will rev freely. The problem though is when riding the bike at mid to high range rpms the bike back fires like crazy and shudders.

So I'm still lost on what the problem could be. It will start on both sets of carbs, although it runs best with the spare set. I don't know if it's ignition or fuel at this point...

I'm honestly thinking about taking it to a mechanic at this point, which I'd hate to do, but I don't have any idea.

Help someone!

[Skippii]

Originally Posted by KChatham

The problem though is when riding the bike at mid to high range rpms the bike back fires like crazy and shudders.

Jetting is too lean. Or, you have a giant hole in your headers.
How do I know? Because I have a giant hole in my headers and it backfires like crazy. On my other bike, which also has a hole in the headers (don't ask), it backfires and shudders.

Does it happen only at 2/3s to full throttle? Main jet is too small. Only happen around half throttle? Needle is too low.

[KChatham]

Sorry Skippii, I meant to say miss firing not back firing. So it could miss fire because the jetting is too loan and there is just not enough fuel to ignite, or it's not igniting because of the ignition... which one is the million dollar question.

[Skippii]

You can stick something in your exhaust to restrict it and richen up the mixture to test if it's jetting.

Also, hold it for 30 seconds or so right in the misfiring zone then immediately hit the kill switch, pull the spark plugs, take pics of them, and post them here.

[KChatham]

Skippii, it was the jetting. I swapped the main jets to 112 and it pulls strong from 7k+.

The other problem that is occuring is at idle. It doesn't want to start unless I give it gas and full choke, and once it's running it doesn't want to idle. If I turn the idle screw in and raise the idle up to 3-4k it will idle fine. Now I just need to figure out if it's the pilot jet or the idle mixture. Which do I mess with first?