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Do these steps sound right?

  • Thread starter Thread starter Splittie
  • Start date Start date
S

Splittie

Guest
dI have a 1981 gs750L that has been giving me problems with cold starting.
Following instructions given here, I checked the valve clearances and did find some where tight.
Upon closer inspection of the engine, I found that the air intake tubes (going from the air box to the carb) were all hard and misshaped. They won't mate up to the carbs and have a gap of @ 1/2" at the bottom of each one.
My question is does this sound like a good process of steps to get me going?
1. Adjust valves (done)
2. Replace intake tubes
3. Clean or replace petcock (If 1 and 2 don't work)
4. rebuild carbs (If 1, 2, and 3 don't work)
Also I put an inline filter going to the carbs when I first got the bike just to make sure there was nothing nasty getting through, should I take it off and rely on the petcock to do the filtering or leave it on? I think there is too long of a run going from the tank to the carb (is the fuel gravity fed?).

Thanks for any help you can give
 
Likely you'll find your intake tubes will be the culprit. How long has it sat/been since the carbs were cleaned? Try your tubes, nothing wrong with the inline filter, despite what you may hear :P then if that doesnt help move on to the carbs. Also, are you sure you are getting good spark?
 
Spark looks good .
Haven't ran a compression check but once I get the tubes on I will.
As far as I was told, the bike haden't been setting for too long before I bought it.
Fuel in the bowls looked good. Which brings me to another question. How do the bowls get filled with fuel? I noticed after I replaced the tank (After valve check) There was no fuel flowing through the inline filter?
Is there something I need to do to prime them?
 
The stock (assuming you have stock) petcock is vaccum operated. Meaning it doesnt allow fuel to flow unless there is a vaccum to pull it (engine running) OR it is in the prime (free flowing) position. Move the petcock to prime and see what happens. If you've never done this, chances are this alone may solve your problem. I dont mean to sound as if i think you are new enough to have never known that, but it happens..lol If the bike has been sitting long enough, it often takes a prime of the carbs to get them going, otherwise, a cold start without prime would take a good amount of cranking to get the vaccum to pull fuel thru the line. Give it a shot. let us know :)
 
Prime position is straight up and down, Correct??
I recently got a Clymers manual for this bike and I am sure this question is answered there, but I am at work now.
Thanks.
 
I'll show you mine

I'll show you mine

Hi Mr. Splittie,

If your petcock is pictured below, PRIme is turning the handle toward the rear of the bike. The circle on the handle is the selected position. The picture shows the "ON" position (normal running position).

petcock.jpg


Thank you for your indulgence,

BassCliff
 
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Currently still at work (system won't let me view pics in posts) but mine has no handle on it just a small hole with a plastic slot inside.
 
BassCliff said:
Hi Mr. Splittie,

If your petcock is pictured below, PRIme is turning the handle toward the rear of the bike. The circle on the handle is the selected position. The picture shows the "ON" position (normal running position).

petcock.jpg


Thank you for your indulgence,

BassCliff
Click to expand...

Bit of a late response, but this is NOTHING like my petcock.
Mine just has a small hole to insert a screwdriver into and turn.:confused:
And that just turns and turns without stopping at any point.
 
yep o.k.

yep o.k.

if its starting thats the problem then i would go with the boots not fitting snug. i had one that was off just a bit and getting it started and kms per liter was terrible..
 
Ohhh you have ONE OF THOSE...do yourself a favor and ditch that thing. Im not sure but i think you can replace it with one that looks like the one in the pic above. Toss that thing out if you can. If not, i would suggest picking up a new one from www.Z1enterprises.com for about 40ish bucks. Anyone know if he can rid himself of that crappy petcock design in favour of a normal GS petcock?
 
I ordered a set of inlet boots (I think they call them tubes) that go from the airbox to the carbs.
Hopefully it will be in today.[-o<
As for the petcock, I will see what happens after I put the boots on. I got the tank to drain yesterday via the hose, so I would assume I have it in the run position since it is flowing (If that's what you call it/More of a trickle) without assistance.
I think after I get it running, I will get a diferent one put on so I know what position it is in and don't have to use a small screwdriver to make adjustments.
Thanks for the info guys.
 
Petcock, schmetcock!

Petcock, schmetcock!

Mr. Splittle,

Check out this thread regarding "that other kind" of petcock. Is this yours? You might just have to replace it with a new one. According to Mr. Nessism, the lever-less kind is not compatible with the levered kind of petcocks (they don't fit in the same holes). I think it's a bad design not to have a lever on your petcock that you can change easily in the saddle. I guess that's why Suzuki didn't use them much. Good luck.

In the "Run" position, the petcock should allow fuel to flow only where there is a vacuum applied to the vacuum line on the petcock. The vacuum usually comes from the #2 carb via a vacuum hose. Are there two hoses connected to your petcock, one fuel and one vacuum?

Thank you for your indulgence,

BassCliff
 
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The infamous '80/'81 petcock is just a poor design. Kinda surprising, coming from the Japanese engineers.

When I need to prime my carbs I temporarily run a hose to the vacuum bib on the petcock and suck on it. Fuel then runs through the gas line to the carbs. Watch the fuel as it passes through the filter. When flow stops, the carb bowls are full.

Someday I will look to replace the petcock. Someday.

Splitte, don't forget about the Western States GS Rally in July. Bring that 750 out and join the rodeo!
 
I saw the thread you mentioned and yes that is the petcock style that I have. (Unfortunately)
It may be working fine. Took it apart and everything looked good inside.
When I could get my bike to start, it would run good, it was just a matter of getting it started cold.
I will post up once I get my parts in and installed (Intake boots)
Thanks
 
Having slotted petcock woes myself. Are you saying that if this is the kind of petcock I have that I am just stuck with it, or can i use the lever kind?
 
Now What??

Now What??

Well I installed the inlet tubes got it all back together and I STILL CAN"T GET IT TO FIRE UP WITHOUT RUNNING THE BATTERY DOWN!!
One question that I have, what should my battery be reading for output sitting with key on and then while cranking?
I can get the bike to start with the battery charger/jumper hooked up.
Battery reads (If I remember right) @ 11.7 sitting and then drops to around 9 or less when cranking.
Do I need a different or bigger battery?
What size should I be running?
I can pick one up today from Interstate Battery if I know what size to get.
Tha current one is a new one from WalleyWorld I think it was a 12--- series(Unsure cuz I'm at work now)
Thanks for any help[-o<
 
A couple more suggestions...

A couple more suggestions...

Hi Mr. Splittie,

If you're going to get an Interstate battery, I think you need this one (YB14L-A2). Other manufacturers make similar batteries. I think you can even get a compatible one at Wal-Mart. I recently got a Yuasa AGM (maintenance-free) battery for my bike and I think it's great. As for your charging system issues, have you read the Stator Papers and followed the troubleshooting guide? Other things to check (even though you mention that some of these have already been fixed/checked/adjusted):

1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.
11. Clean carburetors!

Cold starting issues are most often related to tight valve clearances. But check your charging system too. If it eventually starts while giving it a jump then you may have a combination of both issues.

Nice work replacing the intake boots. I am not looking forward to doing that on my bike. It's kind of a big job. Keep us informed.

Thank you for your indulgence,

BassCliff
 
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The link that BassCliff gave you for the Interstate battery shows that it's available for about $46.
For just a little more ($63) you can get a sealed battery from Batteries Plus.
Besides never having to check your electrolyte level again, you will get better cranking power, too. \\:D/

.
 
themess said:
Your battery isn't charged, and it might be worn out.
Click to expand...
That was my thoughts on it but I just got the thing new and charged it up,
So I may have too small of a battery?
The battery that I have is a 12____-___
I think I need a 14____-___
 
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