Bike starts only with throttle, choke does not work.

[Guest]

Hello everyone, firstly I would like to thank everyone for the vast amount or knowledge on this site, it's been lots of help.

The bike in question is a 1986 GS400E, Canadian 8V motor. I will try and do this in point form to make it easier and shorter..

1. Purchased bike last fall with 14,000km running only on once cylinder. PO told me carbs need cleaning.

2. Over the past few months
-Adjusted valves which were in spec but put them to highest setting of 0.13mm just to be safe and installed new gasket

- Had NastyJones from this forum clean my carbs since he lives literally a 5 min drive from me using his ultrasonic method.

Which I should add that he is a genuinly cool guy as he came over and helped me remove them, and he only charged me a fraction of his normal price due to a recent layoff which I was part of. So with that said, I would highly recommend him as he's a stellar person.

- installed new boots and o-rings from motor to carb, and also from carb to airbox.

- Cleaned the super dry air filter and put soaked it in Rotella since I drive a diesel and that's all I have around. I made sure to take out all of the oil but squeezing it many times to get all the excess oil out.

- Installed new battery and plugs.

3. Spring

- Started up after first few tries..
- Initially I didn't put enough gas in it so it it would run only on prime then die, I figured this out quickly after doing a search on here and filled it up. It would start right up.

- Due to the starter slipping I believe, it takes a few tries to get it to catch and start but as soon as it does, I have to give it some gas.. after about 20 seconds of gas it starts to idle really low.. and then once warmed up a bit and driven it idles fine at around 1100 which I set to using the screw at bottom.

-It does not start on choke, even when it's -1 Celsius outside.

- I also tried to set the idle adjustment based on NastyJones recommendation but I have no way of setting up a temp gas can since I live in a highrise, after cutting a screwdriver down and making a grinding a new end to make a small slot to adjust idle fuel screw.. I realised soon that the screw driver slips and well.. I was rather ****ed off and gave up on it..

- I took off tank and set the screws to 1.5 turns out from the closed position... it seems to run great once warmed up using the holding gas method on startup and choke still does nothing. When it's warming up I've tried turning closing the choke by pushing the lever so it's parallel with the grip. and it idles up but then starts to die if I don't turn it back the other way.

BTW I really hope that position on the choke lever when it's parallel to the grip is actually correct, since I've been driving it around like that and have put about 500km on the bike in the last 2 weeks.

- I took bike in to have the tires changed and the carbs set and synced since they have the tools and can take off the gas tank and do it.. once I picked it up I noticed that the screws were in the exact same position as they were before since I made a mark with sharpie on carb so it would be easier for me to know how many turns out to set it to when I put them to 1.5... so I am not sure if they adjusted the idle using the screws or just the big knob at the end.. I didn't question this as they don't look like the type of guys I would be dealing with ever again.

- I did a temp test using a touchless at the manifold pipe right where it exits engine before and after. Before they were 8-10 degrees C appart so 164 degrees celsius on one 174 on the other...

After... 2 degrees difference at same spot so 162-164 degrees.

My questions.

1. Why does my bike run great once warmed up using throttle for 20 or so sec but never on choke... and dies right away on choke.

2. I have pulled the plugs and they don't look white or burnt at the tips.. a little carbon but mostly clean, so am I running too lean?

Bike does not pop when coming down in rpm.. accelerates great seems not to shake at all when at high speed since I drove it yesterday on a 150km round trip.


3. I am getting 47-49 mpg so is this good or bad? I am really worried about running too lean. but not sure if any of these symptoms are part of that.. like the choke thing..


Sorry for the long post but I just wanted to be detailed to give everyone a full idea..

Your replies would be appreciated

Thanks.

[A-train]

You're sure your air intake is unobstructed? Clean filter, etc?

[Maddevill]

I'm thinking like A-train. I'm not sure your air filter is supposed to have any oil on it.

[Steve]

- I took off tank and set the screws to 1.5 turns out from the closed position... it seems to run great once warmed up using the holding gas method on startup and choke still does nothing. When it's warming up I've tried turning closing the choke by pushing the lever so it's parallel with the grip. and it idles up but then starts to die if I don't turn it back the other way.

We have three bikes here that have thumb-operated "choke" levers, NONE of them is ever parallel to the grip.

When the engine is cold, PULL the lever toward the end of the handlebar.
As the engine warms up, PUSH the lever toward the center of the bike.

BTW I really hope that position on the choke lever when it's parallel to the grip is actually correct, since I've been driving it around like that and have put about 500km on the bike in the last 2 weeks.

See my comments above, as none of my levers are ever parallel to the grip.

- I took bike in to have the tires changed and the carbs set and synced since they have the tools and can take off the gas tank and do it.. once I picked it up I noticed that the screws were in the exact same position as they were before since I made a mark with sharpie on carb so it would be easier for me to know how many turns out to set it to when I put them to 1.5... so I am not sure if they adjusted the idle using the screws or just the big knob at the end.. I didn't question this as they don't look like the type of guys I would be dealing with ever again.

Those screws are for setting the idle MIXTURE, not idle SPEED. The large knob beside the float bowl is your idle SPEED control.
They also have nothing to do with carb sync, so it is not unusual that they were not moved.

How do you know that 1.5 turns is "correct"? That might have been the factory setting, but most of us are finding that over 2 turns is better, some getting up towards 2.5 or so. Try setting them at 3 full turns out. When the bike warms up, slowly turn each one in, listening for any change in idle speed. Stop when you have the highest speed (it won't be much of a change, so listen carefully), continue with the next carb. When you are done, stop the engine, turn the screws in, counting as you go. Record that number, go back to where it was, continue with the next carb.

.

[JTGS850GL]

Even the filters that you do oil don't use a lot. The K&N filters only use about an ounce of oil max. I have to admit that when I read "soaked in Rotella" it made the hair on the back of my neck rise.

Are you sure that your choke linkage is working. The enrichment linkage should slide from full open to full closed as you move the lever.

Have you asked NastyJones for a hand with this? He did, after all, do the rebuild and would have another pair of eyes to look for anything obvious.

[jsandidge]

choke lever

You may be using your choke lever incorrectly. On my bike, parallel to the grip is full choke. It should be moved perpendicular to the grip once it has warmed up.

[mrbill5491]

Not sure how you are starting the bike with just the throttle, there are no pumps on CV carbs. Another thing, with CV carbs, if the bike is on choke and you turn the throttle (goes from a rich mixture to lean), it over rides the choke system in a sense. Think you have some adjustment issues going on yet. Follow the advice that has been given you and you should be able to work it out. And with the air filter, sounds like its way over oiled.

[londongs400]

Thank you everyone for the replies and insight. Based on your answers I now know that I am using the choke correctly. To clarify it doesn't start with choke engaged.. and by using the throttle what I mean is that as soon as it catches with the starter i use the throttle for about 10-20 seconds to help it speed up then let go.. otherwise it stumbles to a slow death..

I looked online as to how I should oil a foam filter and I made sure to remove all the access oil. but applying lots what I should have said was make sure all parts are coated evenly by squeezing and working the oil around, then using paper towels and rags to remove the oil. there was 0 oil dripping from it when installed, infact none seeps out if the filter is squeezed out..

My question is why is it not starting on choke like everyone elses bike on here? as in it doesn't even burb or blip or attempt to start when the choke is engaged.. only when it's off and i use the gas to help it along once it catches. I can't get at the screws without removing the tank which I can do.. but the problem is setting up an aux tank in my apartment building parking lot. I will say the bike does run super smooth once it's running.. the idle starts off slow and once fully warmed up and on the road a while it goes to 1100 +/-100 rpm

I should have said idle mixture screws instead of speed, my apologies. I have the speed set to around 1100 using the speed knob in the middle of the carbs.

I have already bugged NastyJones enough so I would prefer to do this on my own.

[Gorminrider]

I wouldn't worry about it unless you see or smell gas, or you find yourself stalling at traffic lights,with a smoky exhaust and black plugs....
It sounds like the level in the float bowl is a bit too high when the bike sits...but there's some other richness issues it could be....check the bowl fuel levels, or get into the petcock to see what's up...you may end up tearing down the carbs or whatever. Maybe remove that airfilter sponge before you start up and see if that's it.
The thing is, you are probably going to adjust the idle mix to suit the overall condition and runability....personally, I'd BE HAPPY and RIDE ON.
In fact, my beater bike GSX400EX does exactly what yours does since temperature went up over 10C and that's what I'm doing.

[Steve]

Not sure how you are starting the bike with just the throttle, there are no pumps on CV carbs.

Actually, there is ONE little-known exception in the Suzuki GS line-up.

The GS450GA.

That little bike is FULL of anomolies.
- The BS34 carbs have accelerator pumps.
- It has Suzuki's only 'automatic' transmission.
- It is Suzuki's only shaft-drive twin.
- It is the only GS shafty with wire wheels.

Another thing, with CV carbs, if the bike is on choke and you turn the throttle (goes from a rich mixture to lean), it over rides the choke system in a sense.

That happens with the VM carbs, too. Both carbs rely on the high vacuum of a CLOSED throttle to draw air and fuel through the enrichment ("choke") circuits .

.