'85 GS700E Won't start

[Anonymous]

I went up to my brothers place on sunday to rob a caliper off of a parts bike I just got and to get my bike set for winter. The last thing to do at the end of the day was to run the bike for a bit then top the tank off with gas/stabil and then drain the float bowls. I tried to start it and all it did was crank over. It has about a half tank of gas as we speak. I had my brother put the bat. on to charge the day before so it was good. I could get the bike to fire on starter fluid but that was it. I ran it all summer and it never once gave me a problem with starting. The last time I had my bike started was the very beginning of sept. before I came back down to school. It would seem to be a fuel supply problem...any ideas on what is wrong? I gotta fix this soon because it is really bugging me.

Trevor

...the bike I took the caliper off was almost complete so check the parts for sale listing if you need anything.

[Billy Ricks]

Two month old fuel in the bowls. Drain the carbs and tank and start off with new fuel. You would be surprised at what gets left behind when fuel is allowed to evaporate in the bowls. If it doesn't want to run right with new fuel you may need to clean the carbs. I let my bike sit way longer than I should have without draining the carbs while I did some mods. I ended up with the needles stuck in my RS flatslides and clogged jets when the fuel turned to varnish. If it runs with new fuel I would go ahead and run some carb cleaner in the gas, Chevron with Techroline is a good one.

[Anonymous]

I hope that is all there is to it. I will try to get back up there this weekend and give that a try. Any other possibilities?

Trevor

[jimcor]

You do have the petcock in the prime position, right?

[Anonymous]

Prime

I've got a question here about the petcock & prime. When is this necessary? I thought it would only be really needed when the bike sat for a very long period of time (2+ months) and/or the carbs were cleaned/drained. Is it required after as short a time as 2 weeks?

What's the "danger" of setting the petcock to prime when it doesn't need it.. just high revs as lots of fuel flows into the carb, or flooding the carbs with fuel, especially when the choke is on, its bound to be very rich.

Thanks.

-Warren

[moto_dan]

Re: Prime

I've got a question here about the petcock & prime. When is this necessary? I thought it would only be really needed when the bike sat for a very long period of time (2+ months) and/or the carbs were cleaned/drained. Is it required after as short a time as 2 weeks?

What's the "danger" of setting the petcock to prime when it doesn't need it.. just high revs as lots of fuel flows into the carb, or flooding the carbs with fuel, especially when the choke is on, its bound to be very rich.

Thanks.

-Warren

It's needed when the bowls are dry or low whether it be two days or two months. I personally use prime for a few seconds whenever one of my bikes has set for several days.
Danger? None if the needle and seat valve in the carbs functions properly. No diffenent than the old manual operated petcocks. I run my '83 on Prime since I've disconnected and plugged the vacuum line to the petcock. To turn off I place lever in either run or reserve position. The needle, seat and float height regulate the fuel level in the float bowl(if working correctly) so Prime, Run, Reserve do not directly relate to either a Lean or Rich condition. On CV type carbs the "choke" function is actually a fuel enrichening circuit inside the carbs that basically sucks pure fuel from the carb bowl into the intake tract of the carb, but again the petcock does not directly contribute to a Rich condition. Is this clear as mud?

[jimcor]

Warren, as moto dan explained the danger is if you have a float valve stick, the fuel just keeps on coming! I left mine in the prime position and rode it on an overnight camping trip and parked it on the sidestand. Yep, the far left carb is the one in which the float valve stuck. I woke the next morning to the wonderful aroma of 89 octane and a puddle of fuel. Could have been a might dangerous. His explanation of when to use prime is right on. I was lucky I didn't have a fire or fill up the crankcase with gas. To avoid a repeat performance I generally always (definitely maybe?!) use the centerstand. and after the motor fires up I immediately turn back to run.

[Anonymous]

I did put it in the prime position for about a minute after I couldn't get it to start they normal way. I hope to have this resolved soon.

[Anonymous]

In order to speed up the starting process after a prolonged downtime I found it useful to cover the air intake with one hand to artificially restrict airflow. The only problem is, you need to pull in the clutch to start, right? So I use an old rag , tie the clutch lever to the handlebar and bingo my left hand is free to enrich the fuel mixture. This works everytime after just a few revolutions, especially in the Spring...

Wolf

[Anonymous]

I have a 1983 GS750 ES, essentially the same engine as your bike. I have found it to be an awkward b*stard to start if it has sat unused for a month or two. Usually a couple of attempts with starting fluid will get it to fire and run. Once it has run for a minute or two, restarting is usually not a problem until the next prolonged dormancy (e.g. winter season). You may have to fiddle a bit with the choke on these "fluid-assisted" starting efforts but you should ultimately be successful if the battery is strong and there are no other fundamental problems.

Good luck.

Simon

[moto_dan]

Yep, starter fluid has become my friend over the years.

[Anonymous]

it started

I drained the fuel bowls and got a very nice rusty gas. I pulled the tank and rinsed it out a bit, put a little bit of "non-ferrous gas" in and it started back up and ran great. looks like I need to fix the tank in the very near future.

Thanks for the help,
Trevor