This bike sucks!

I have had it with this bike! I trying to figure out why it runs great until It seems to stop getting gas. This can happen when you run it and then stop for a short time and run it again or if you empty the bowls buy ridding it hard through the gears.....wide open. The thing acts like it is out of gas. I have clean and rebuilt the petcocks and vacuum diaphragm and cleaned carbs. Nothing seems to help except letting it sit for a few hours then it runs great again. Prime or reserve does not help undoing the gas cap does not help running on choke does not help. Full tank 1/4 tank no difference. Bike is not over heating.
Let the thing sit and it runs great.

I am going back to Suzuki if I cant get this fixed

 

mine did the same thing till I replaced the plugs

 

also, have you verified it is getting no gas and opened the drain screws

 

Also behind the vacuum fitting on the petcock(unscrew the fitting) there is a small disc used to stop any back firing up the vacuum line from the carb, this small disc and cause vacuum issues on the petcock when it jams or gets stuck. A lot of people just remove it.

 

Thanks I will do that and see if it helps.

 

Thanks I was in there the other day I cleaned it out but I think the disk is still there.

 

Uh. just as an aside, if you pull that disc out of the petcock diaphragm assembly, won't it always flow fuel, since they don't have an 'off' setting?

 

I have two thoughts on this.

First I woould put the petcock in the prime position and see if you have the same issue. I think that would tell you if the vacuum system is in order.

Second is that when I pulled my petcock out of the tank, the filter screens on the pickup tubes where almost totally blocked. I cleaned them in a small ultra-sonic cleaner. They look almost new now.

 

Yes it will; "redesigning" the internals of the petcock is NOT a good idea. Sounds to me like either the petcock screens or the carb needle screens are clogged up. Once everything is cleaned (again) install an inline fuel filter if you don't have one already. If you DO have one perhaps it's time to change it.

 

My petcock has not worked right sense I got the bike. It causes a huge vacuum leak. So bad it wont idle. So I remove the vacuumed line and capped the carb. Now I run it in the prime position, and switch it to run when parked.

Works like bike from back in the day!

Without the vacuum Run = Off

I’ll fix it one of these days.

 

Just a quick note the diaphragm is separate from the petcock on this model. It sits on the carbs with both petcocks going too it. One on and one prime line from each petcock. Even though the prime goes to the carbs it also goes to the diaphragm which makes no sense to me. The problem stared to show when I would take it on long rides and then shut it off. If I started to run it when hot it would do the same thing. Run like it was out of gas. I cleaned everything pick up screens in tank and rebuilt petcocks as we as the shut off diaphragm. I set the floats and cleaned the carbs. I changed the coils and wires and spark plugs. I rechecked the diaphragm when I got the thing to start acting up near home and disconnected and re connected the vac hose a few times and it seemed to help. So I took the nipple apart and got the thing so I could blow and suck air freely though it. This is the part with the disk mentioned above. I took it for a few test rides after cleaning it out and did the shut off and restart and ride thing several time and it worked good. I thought it was fixed until the next day when it worked well with shut offs but after the full open blast....no shut off... it started to act the same way. I have always tried the normal things like prime and reserve and open gas cap and It never works. I did also remove the pickup coil cover and cool them with compressed air thinking they my be getting too hot. This could be an issue as the bike did run good right after but it is also the same time that I disconnected and reconnected the vac to the diaphragm. I would think that the disk was sticking when hot. Why prime does not fix this on the spot is beyond me.

Maybe I still have bad pickup coils or a low voltage issue causing low main coil malfunction above idle. Why does the prime go to the vacuum diaphragm? Anyone know? well that's where I am with it now.

Thanks

 

I did clean all screens and I am going to replace all fuel line with clear pvc and new in line filters as soon as I get the clear line as it is in transit too me now.

 

That is a good way to fill your crankcase with fuel. I would forget to shut it off sooner or later. That said I might try it and see if it helps.
Thanks. Although if I put it on prime when it is acting up it does not seem to help any. ?
Thanks for your time.

 

If putting it on prime doesnt help, it's probably a problem in the carbs. Although, as was pointed out above, it could be that the petcock screens inside the tank are clogged up horribly.

 

I went out and started it up and it ran good. Took it for a ride and it ran good.
I went too several places and went home with no problems! This is driving me nuts! I did not do anything to it. Something must be getting hot.

 

Nope. (Or maybe.) You probably have a problem that has absolutely nothing to do with your fuel system, betcha anything you've been chasing the wrong fox.

The next time you have the problem do not make any assumptions and diagnose starting with the basics: Fuel, air, spark.

 

Is there any sediment loose in the tank? Possibly getting pulled onto the tank screens and plugging them, and then falling off when when the fuel draw stops? When it starts running poorly, try to isolate which cylinders are lean, 1&2 or 3&4, or all of them. When you turn the petcock to prime, it completely bypasses the vacuum valve and only leaves the petcocks in between the tank and the carbs. I just read your previous post about the popping carb, and it does sound like a fuel delivery problem. Hang in there, it will end up bring some goofy problem that is easily remedied, once you can find it.

 

Well when I rebuilt the petcocks the tank looked great inside I wiped my finger inside and it come out clean. The inside of the take looked so good when I bought it last year I could not get over it. The cleanest of all my bikes.
I am starting to think it is the pickup coils that are failing to send enough voltage to the cdi. But could work at low rpm. The bike idles fine when this happens. I has spark on all four cylinders when this happens but I don't know if the spark is breaking down when rpm increases. There is a report of a bike that did a similar thing it would lose power when hot and work fine when not hot. He ran the bike with the pickup coil cover off and it stop acting up. He replaced the pickups and problem fixed.
I am going to try to run it without the cover and see what happens.
I am open to any other ideas.

 

two tries for a buck?
tight valve clearance
vapor lock
i owe ya a buck

 

Yeah I thought about vapor lock, What can you do about that? As far as the valves go I don't know what they are but the bike only has about 17k on it. I do get a vibration from the motor at anything from 2k to 5k but it may be normal for the bike. It's not bad but i can feel it in the pegs. If I pull the clutch it stops. I will put it on the list.