Starting Trouble

[stossboss_gaming_and_news]

Hi all,

New to bikes and im a pretty terrible mechanic, if there is a general starting issues thread I would be happy to read and work through that if someone can point me there.

Grabbed a gs750t off marketplace that ran well at the time and after bringing it home it worked well for a couple days till I tried troubleshooting some electrical problem but that was resolved (left blinker didn't work but was fixed after rewiring a crimped ground cable). After these electrical issues I had trouble starting, jumped it and had no issues after that. I noticed the oil was low and figured I should change it - everything went okay till I was putting the cover back and of course I broke a stud, ordered a new one and it arrived about a week later.

So, one week later, oil cover was put back on, filled w oil, battery connected to my car battery, bike tries to start but just can't seem to catch. I took a look at the spark plugs and it seems to be weak although I'm not a good judge. Added a new battery that I ordered when I was messing with the electricals earlier but same issue. I don't even know where to start, it has been stormy some crazy downpour the last couple days and I keep my bike outside under a tarp, could the added condensation/humidity have made my gas bad? Plan on spraying starter tomorrow to see if it will start but figured I would ask if there is a general or something to troubleshoot so I'll have something to follow in case it fails.


Thanks to all who read!!

 

[Rob S.]

Personally can't help you, but you've come to the right place. Welcome.

What year is your 750T?

Motorcycles don't belong out in the rain (see my avatar).

 

[rphillips]

Did you put the pet-cock on PRI. for a minute or so, then try it. Simplest thing first, also full choke and don't turn the throttle at all.

 

[Rich82GS750TZ]

Welcome.

When the bike sits for a while, fuel in the float bowls dries up, requiring one to turn the petcock to PRIME for 30 seconds or so, then back to On. This is to refill the bowls. Try this before the starter fluid.

If you put new gas in the tank recently and have been running the bike, no, it did not go bad in a few weeks. If you’re getting spark, and, If the bike does starts or at least sputters when you try the starter fluid, then it’s likely the carbs needing a full clean. Follow the steps in Ed Ness’s (Nessism) CV carb cleaning tutorial found on BikeCliffs website. No shortcuts in carb cleaning. Of course your petcock could also be malfunctioning.

My bike was also very hard starring until I had the carbs thoroughly cleaned, new orings. Ever since, starts very easy every time.

If you need, also on BikeCliffs Website you will find a Factory Service manual for the GS 750 16 valve bikes and a supplement specifically for the 82 750 T& E (83 T is essentially the same as the 82.

Tell us if the cabs have pod filter on them or do you still have the factory airboxes and filter.

Do you know any of the service history of the bike, particularly are the valves clearance in spec? This should be next on your list to check.

How old/worn are the tires?

How are the brakes. Check the color of the fluid in the front master cylinder. Does it look like honey, or like molasses. Does the front brake function well, or is the lever feel kind of squishy. check the front brake pads, are they near their limit? Your front brake hose is likely original, think about replacing with braided stainless when you do work on the front brake.

Rear brake is a drum, others will groan at the thought. Just part of owning a T. It should work and will lock up the rear wheel if needed. Make sure it’s adjusted properly and working well.

Lots of other things to think about, but that should get you started.

Just wait till you get into the the charging system. That’s the fun stuff.

Also, we NEED pictures. Have to know if it’s the 82 maroon/red, 82 or 83 black/gray, or the 83 black/red.

Best of luck. We’re all here to help. Well, most of us anyway.

 

[Suzukian]

Welcome to the forum. Check all the ground wires and live wires from the battery to where they terminate, it's a must as Suzuki used to rely on threads to ground their bikes, and often the ground straps terminated on painted surfaces. Oxidation built up on the threads, and this weakened the ground. All of the other advice given so far is spot on. When you get this running, you will have a very nice riding bike.

 

[Rob S.]

PS - Hard starting after sitting more than 2 weeks is not uncommon with these bikes. At least with mine. A really, fully charged battery helps.

 

[pdqford]

Did you put the pet-cock on PRI. for a minute or so, then try it. Simplest thing first, also full choke and don't turn the throttle at all.

I recall the GS Wisperer guy telling me that putting the pet-cock on prime won’t do anything unless you also apply some vacuum to the pet-cock. So if you put it on prime and crank the engine over a few revolutions that will send a few puffs of vacuum to the pet-cock to open the internal valve. Then the valve will stay open until you take it off prime.

Well, that’s the way I understood how it works.
Any one else heard it that way?

 

[rphillips]

Thinking that is for the "80" model leverless ones with no RES., but it sure couldn't hurt to give it a spin while on PRI. Hope stossboss returns to keep us informed.

 

[Rich82GS750TZ]

I think you’re right, rphillips. The lever petcock on the T needs no coaxing to flow free on Prime. At least mine doesn’t.

 

[rphillips]

Yes, I'd forgot or never knew how those awful things worked, it was explained on a thread here at GSR sometime within the past couple of months... It amazes me how much I never knew or once knew and have forgot.

 

[stossboss_gaming_and_news]

Thanks everyone for the responses and suggestions

It was as simple as petcock to prime, choke engaged, and not jamming the throttle open... Took the battery off the charger and no need for car battery connection. Retarded me thought the petcock wrote out "PRK" and assumed it meant "park" as a suzuki way of labeling "stop" as I saw on an older yamaha petcock. It's the 82' maroon/red, 18k miles not in great aesthetic shape https://files.catbox.moe/pwk38d.jpg (and thats the good side, other side has some big dents).

As for service history and the like... I recall the seller claiming the carbs were rebuilt recently, I should have brought a notebook because I forgot everything else, I'll give the guy a call he was very helpful. I'll leave the battery in overnight, tomorrow morning check the brake mechanisms, try to start it and ride to work - I imagine if it doesn't start then there must be some deeper electrical issue in addition to user error.

Uses stock airbox filter and tires have a lot of life left on them.

And again I am tremendously grateful for your help, I'm a complete noob when it comes to this stuff.

 

[rphillips]

Love it when things work out good, congrats...Remember to put the pet-cock back to the "ON" pos. leaving it on PRI. is a big NO,NO.

 

[Rich82GS750TZ]

Nice. I Love it when a plan comes together.

my bike looked much the same when I got it about 18 years ago.

with the help of the good folks here, it now looks like this and runs like a top.

When you’re ready, we can discuss how to post pics on the forum. There’s a link in my signature for that too- using Flickr/Imgur.

 

[pdqford]

Thinking that is for the "80" model leverless ones with no RES., but it sure couldn't hurt to give it a spin while on PRI.

Good catch on the ‘80. I didn’t realize that the “T” used a lever.
I learn something new every day on here. Thanks.

 

[dorkburger]

Welcome. A quick note on the tires. A lot of tread doesn't necessarily mean good / safe. As tires age the rubber hardens and available traction is reduced. They should have a date code on the sidewall. I think the consensus is that over 5 years is pushing your luck.

 

[stossboss_gaming_and_news]

Love it when things work out good, congrats...Remember to put the pet-cock back to the "ON" pos. leaving it on PRI. is a big NO,NO.

So, leaving it on PRI and running it and sitting for a couple weeks wont lead to fuel gushing out of the air filter and an inability to start right?

My cousin who is a mechanic volunteered to help get the bike to idle properly. He claims to have cleaned the carbs and got it running great, that all it needed was new ignition coils. When I got my hands on it, petcock was on PRI and wouldn't start. So I charge up the battery and try to start it fresh. Turns over for a couple seconds but then fuel comes gushing out from the air filter area about a cup's worth and it dies down.

I only blame myself for being lazy and letting someone else work on it, he is unlikely to admit to anything (when I first dropped it off, I informed him the PRI was for priming when he insisted it was "primary", but he seemed to ignore that) so I'm pretty much on my own now with the bike in a worse condition. I guess the question is where to start? Taking the carbs and rebuilding?

And if those are indeed symptoms of leaving it on PRI - is there anything else I should check to confirm and consequently fix any issues from that?

 

[rphillips]

Well, we know your cousin is not a bike mechanic. PRI is prime, if you run out of gas and carb bowls are empty, or low, turn to PRI to fill (prime) fuel bowls, then back to ON. In a perfect world and none of your needle and seats were leaking, at all, PRI may be OK, but that very rarely happens. Never an occasion to leave Suzuki GS on PRI. My opinion, get a repair manual for your bike. Tons of stuff in there you need to know or, and, look up.... most everything explained in them, well worth the $30.

 

[Rijko]

So, leaving it on PRI and running it and sitting for a couple weeks wont lead to fuel gushing out of the air filter and an inability to start right?

Not necessarily, but you are right PRI is only to prime the carbs when dry and to fill the evaporated fuel in the bowls after sitting for some time.
Like rphillips said BIG NO,NO to leave that for hours let alone for weeks on PRI.
That's asking for problems.

I guess the question is where to start? Taking the carbs and rebuilding?
And if those are indeed symptoms of leaving it on PRI - is there anything else I should check to confirm and consequently fix any issues from that?

​

Start with taking off the oil filler cap and sniff for gas, petrol could have made it into your engine oil.
Elevated oil level in the looking glass is a red flag, replace oil when there's gas in it.

I helped a buddy with a GSX600F recently, it had been standing on PRI for 10 years without leaking.
But as soon as we started the bike, crud came loose, and gas came gushing out.

With the carbs off, run the petcock line into a bottle or something.
Check that it flows well on PRI.
Check no gas comes out on ON and RES unless sucking on the vacuum line.

If your buddy cleaned the carbs properly, i'd check/clean the float needles and seats, if there's a bit of dirt there
that may be all that's needed.
Did he just spray carb cleaner through passages or did he replace o-rings and soak the carbs ?
Check the fuel and air screws while at it, settings are in below pdf.
Proper carb cleaning is a precise job, there's a nice manual here : http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf