1994 DR650 wont start

[braumannh]

:banghead:After sitting for 6 months the bike starts barely, with or without choke. When is does run it dies as soon as I try to rev it up. It back fires on and off. Once in a while I am able to very slowly rev it up to 6000 RPM for a minutes or and then again it dies. So thought this all points to varnish in the carb.

Cleaned air filter, fuel filter, carb, every jet / needle I could unscrew, float seems to be fine and blew through every hole with shop air. It does get spark and fuel gets to the float boal.

The spark plug is fine. Squirted some gas right into the combustion chamber which I expected would start the bike but did nothing, perhaps I squirted too much into it. I am at the end of my wisdom.

Can anyone please offer some advise. Thank you so much ?

[NemadjiMan]

In my mind, your suspects for now are the gas cap, the petcock and the float valve. Also, pardon me if I end up explaining something here that your already knew.

First, get something to catch gas. Then, disconnect the Petcock vacuum line from the intake boot.

Make sure that your Petcock is on "On". Because there is no vacuum with the engine off, it is really off for now.

Disconnect the fuel line from the carburetor. Get ready to catch any gas that comes out of the line. Now, turn the Petcock to "Pri" (prime). Gas should continuously flow. If it does, let it flow for a moment to see if it stops or slows down. If this happens, open the gas gap and see if it starts flowing normally again. If the gas cap has an effect, then that is your problem. If gas hasn't flowed yet, then your Petcock is plugged.

Now turn the Petcock to "On". Fuel should not flow. Now, suck on the vacuum line. Fuel should flow. Turn your Petcock to "Res" and suck again. Fuel should flow. The Petcock is messed up if fuel doesn't flow.

If the Gas Cap and Petcock are good, reconnect the gas line to the carburetor. Get ready to catch gas coming out of the carburetor bowl drain hose. With the petcock on "On", open the bowl drain. This should drain the float bowl (if there was gas in it to begin with). Now, suck on the Petcock vacuum line. Fuel should flow. If not, the float valve is stuck.

Hope this is helpful.

[braumannh]

thank you that is good input!

Did forget to mention that I also disassembled the Petcok and also cleaned it. I was able drain the tank by putting it on Prime and directing the gas to a bucket. If there would be a problem with the Petcok than there would be no gas in the float bowl, right. But the float bowl is full of fuel.

[braumannh]

hello, did check the vacuum / Petcock test and fuel does flow as it is supposed to. Could it be that the spark on the plug is simply to weak? I do see the spark but perhaps it's just not strong enough. Not even that is even possible.

[NemadjiMan]

It is possible to see spark but still have a plug that is not good enough to run the engine. It's pretty cheap and easy to replace it so, it wouldn't hurt to put in a new one and see what happens.

That said, it seems unlikely that this is your problem as the bike ran good 6 months ago and is now running poorly.

This still seems like a fuel delivery problem. I assume that you drained out all of the old gas and put fresh gas in the tank. If not, do that.

If you use the "choke" (idle enrichner) and try to start the bike for "too long", does it flood the bike?? That is, can you smell gas and when you pull the sparkplug, is it wet?? Or, does it not matter what you do and the sparkplug remains dry??

[braumannh]

Thanks for the suggestion. I did replace the gas. With the choke on it does not seem to flood the bike. When pulling the spark it is wet suggesting that it does get gas.

I also put some gas directly into the combustion chamber but it did not ignite. Perhaps is just needs the right mix. Someone suggested to spray "Thrust" into the combustion chamber to see if this ignites. At least this will allow me to rule out a bad spark plug.

[braumannh]

Could it be that although I did clean the jets and the carburator that there is a passage way I could not freely reach that might be clogged up?

[NemadjiMan]

It is possible that something is still clogged. as the symptoms seem to point that way. When starting, you should be on the enrichner circuit so that would be a good one to check. Also, I know this sounds basic but, make sure that your vacuum line is attached to the top of your carb.

One of the troubles with CV carbs like you have is that holding the throttle wide open to clear the engine doesn't work because the slide is still down on the stop until you get vacuum started. With a "normal" carb, you could just hold the throttle wide open and turn the bike over to clear a flooded engine.

If your spark plug comes out wet, then the engine is getting gas and it is becoming flooded. It won't start flooded for sure. If you get a new plug, then you will have 2 so that you can swap out the dry one for the wet one until you figure this out. So, if you suspect the plug is wet while you are trying stuff, pull it out and stick in a dry one before doing anything else.

[braumannh]

Hello, thanks again for keeping new ideas flowing. Y yes I do have the vacuum line attached to the carb. I think the next step will be to replace the spark plug, but then again this plug has only 12,000 miles on it, nevertheless it's 16 years old.

I will also try to put some carb cleaner right into the combusion chamber to see it that explodes.

[crazy_dave]

If you still have the handle bar choke assembly check to make sure the cable going into the carb isn’t stuck or broken. I had that problem with my 92 and my actuator cable was broken. Pulse its free to just take a look.

[braumannh]

Good suggestion. Did that. The cable moves freely and with it the plunger assembly moves freely.

[NemadjiMan]

If you want to spray something, get a can a starter fluid at an auto parts store. It won't cost you much.

[braumannh]

thanks for the tip. I will keep you posted if that did at least cause a combustion.

[crazy_dave]

Did ya check the valves?

[braumannh]

thanks for the feedback. Not yet, but will check compression tonight.

[braumannh]

The other thing though is that the bike ran fine before i put it in storage 7 months ago. So I can't help thinking it ought to have to do something with the carb as valves would not get out of clearance just but sitting there.

[crazy_dave]

I would agree with that. Maybe an air leak around the airbox/ carb boots.

[braumannh]

Ihink I found the issue. Two nights ago my son dropped the bike.

Tried to start it again and all of the sudden heard metal noice under crank case cover. Took of cover and found that the sproket (the one furhtest to the left - see http://www.bikebandit.com/1994-suzuki-motorcycle-dr650ser-crank-balancer-model-p-r-s/o/m5876sch239394) came of togeher with parts (6, 11, 12, 8, 9, 14, 16 as per the diagram). The key (woodruff - # 15 on diagram) sheered off. That would tell me that the sproket has been loose all the time and did not move the axil it was on. So be dropping the bike it finally fell off. Now I have a completely new problem. Is it possible that that had something to do with the bike not starting?

[NemadjiMan]

The picture you site is of the balance shafts with gears etc... It doesn't seem likely that this is the cause of your starting problem but, I wouldn't rule it out. I hope that there are some good timing marks for you to reference when you go to fix this.

[braumannh]

Tend to agree but it's just so strange that this happens around the same time when the starting problems happened. Could it be that the balancing chaince which also is running behind the magneto has somehow effected the magneto so that is does not deliver the proper juice or timing to the spark plug? I had this happen 30 years ago on a 2 stroke bike where the key (woodruff) was worn out and the spark plug lost it's punch.

More important though do you think I can replace the destroyed key with a new one jsut with the crank case cover off? By the way do you own a DR650?