NOT STARTING...PLEASE ADVISE!

Could be a vacuum leak between the carb and the petcock (change that line or test by applying vacuum to the line and seeing if fuel flows freely in the normal (down) position). If you can't get fuel to flow that way, perhaps a clean/rebuild of the petcock is in order.

 

The petcock is vacuum operated. You should have a fuel line and a vacuum line to it. To teh rear is Prime and will flow fuel no matter what. Straight down is ON and will flow when engine is running only due to the vacuum operation. TO the front is reserve. Same as on in operation

 

Thank you very much for the info.

With your help I managed to find what my problem was; the vacuum tube was perished and wasn't making a good seal at all. I put a new piece on and she fired up straight away, smooth as a nut !

Ive also put some Putolene fuel treatment in to clean the fuel system and she seems to have settled down a little and the tickover is a little more smooth.

Happy days, thanks again for the help. Brilliant forum bye the way, I think I will stick around a bit...

 

Hey! I finally got one first!

Only repays the 50 or so other have given me!

 

Hi you all!

I had similar problems with my 82 750 seca.
Just renewed float jet needles and checked float levels also.
That did work perfectly.

Before that the fuelconsumption was like 3 gal per 100 miles and that sparkplug dealer nearby bought a nice sailing boat afterwards :lol: :lol: :lol:

 

Hello Gentlemens,

I unfortunately have to ask for help for the first time with similar non-starting issues as Palmer, hence I didn't start a new thread.

Here's my situation,
I've had the odd immensley loud back-fire bangs known to mankind but that's it.
Petcock is not suspect and flowing fuel, it's new
Carbs have been clean multiple times and are definitely not dirty.
In detail:
float needles replaced
needle jets cleaned and at spec
jet needles are straight and true
all circuits have been cleaned thoroughly
main and pilot jets are new as I have a four into one pipe on
126 and 41's respectively
machine was running prior to carbs being off
three turns out on a/f screws
float levels are good and I have gas in the bowls
I have excellent spark with new iridium plugs on all cylinders
Gas in new also
No holes in intake boots either side
I've even plugged air inlets to induce a false vacuum and to that I get a little fuel coming in but not nearly enough. I'm beginning to wonder if I've left a cloth in place before stuffing the carbs back on.

Despite turning over LOTS, nothing, there must be some 1/2 inch alien monsters that don't grow and live solely on vacuum and fuel living in my intake tract as each time I pull a plug, they are completely dry! If I could just get the air and fuel to take that four to six inch trip down the intake tract, I'd be in business, I think, God save me from any other unforseen crap!

Thanks for any help anyone might offer

 

Do you have a prime on your petcock?

 

Yes, and it works. however, same response with petcock in "pri" position as in "on" position.

Btw, I'm not aware of XJ1100 only the xs1100, what does the xj1100 look like?

Nevermind, did a google. learn something new everyday, I didn't know there was a Maxim 1100. Cool!

 

Hey, I am new to motorcycles and I recently got a 1985 Yamaha Maxim XJ700X. It isn't getting any spark to any cylinder. I checked coils and I got 3.8 Ohms, then I check the pickup coil and I got 238 Ohms for one and 128 for the other. I am using a Harbor Freight Multimeter so it's not the best, not sure how I much I can truck those numbers. Any suggestions what to check, or what to do. I don't know much about Motorcycles I am usually a car guy, this bike is my first attempt in the adventure.

-Craig

 

Usually means something is not right with the Safety Switches.

Try:
Removing the seat.
Looking for the RELAY beneath the Tank.
Un-Plug.
Bike in Neutral.
Try it.
Varoooom? Safety Switch (Kickstand, Clutch Lever, Neutral Switch)
Need troubleshooting.

No Varoooom? Ignition related.

 

Anyone,

Anyone, :?

Bueller?

Bueller?? :roll:

 

Sickle,
So when you pull the screw from the bottom of the bowl fuel flows out, right?
My first guess would have been floats set to low cutting off the fuel prematurely.

Which air inlets are you talking about?
There should be caps on three of the vacume nipples on the motor side top of the carbs.
The fourth is connected to the petcock.
Is this an 1100, with the dual petcocks?

 

No Varooom so far. I'm thinking of replacing the Pick-up coil assemble because the resistance was so far out of Spec ?

 

Look behind the "Safety Cover" that keeps the Pick-up Coil Pigtail from flopping around.
It's the little metal cover at around "10 O'Clock" on the Shifter Case.

Check to see that the Pick-up Coil Pigtail IS NOT pinched in there.
If somebody had the Shift Case off ... and pinched the wire in there ... the Bike don't GO.

Also, take the two Screws out of the Side-stand Switch and see that the Switch isn't stuck OPEN.
The Actuating Rod on that Switch is prone to getting "Gummed-Up" and NOT traveling far enough to let the Switch actually Close.

The Bushing where the Rod passes through the Top of the Sidestand "Binds" when it isn't both Clean and Lubed ... causing No Starts because the Switch sends a "DOWN" Signal all the time.

(But if the Bike was in Neutral ... it shouldnt matter)

Get inside the Headlight Bucket and UnPlug the Kill Switch.
That's another thing that takes all week to figure-out.

 

But if it were any of those things, he wouldn't get the back-fire. He should get nothing, cuz the bike shouldn't even turn over....if I'm reading things correctly above. Since he's getting a back-fire situation, the safety switches should be good to go because the switches all say it's ok to try and start.

I would suggest that since there is a backfire, double-check that the spark coil leads are going to the correct plugs, and make sure that the coils are connected into the correct plugs on the harness....and now check fuel levels, etc....

You said you turned the mix screws out three turns.... is that three full revolutions or three half turns? Three full-circle turns will give you a just slightly rich from factory settings, but three half-circle turn will keep you reeeeaaaaaally lean, which could also give you a pretty good backfire.

Keep us posted,

Dave Fox

 

I checked all those, still No spark. Any other idea's ?

 

I believe I've remedied my situation. Yeah!!!

Butterflies were completely closed right off and my float levels were completely out to lunch.

Thanks to those folks who were helping.

Mindgame,

What you can do to by pass all the relays and crap is this. Pull all of your relay's having to do with ignition, headlight relay, sidestand switch relay, and starting circuit relay. (As you're holding the female molex plug of the starting circuit relay with the relay unplugged)Probe with a test meter just to make sure but the very bottom right hand spade connection should register positive while the key is in the on position. The connection right above it goes to the starter. When the relays are all working jimdandy that positive 12V's you checked for in the bottom right hand corner is routed up towards the top right hand connection. So all you need to do is just jump that connection and all the safety switch stuff is defeated and you should get spark now if the relays are an issue. Obviously you'll need to make sure your machine is in neutral and all that stuff now because by doing this, it will start in gear. If this doesn't give you anything, you don't have a relay problem with spark and it may be your ignitor, a switch, coils or some electrical demon within your wiring harness. Also, make sure you check the condition of your brushes in your alternator and your pickup coil, these can contribute to a very weak spark also.

Hope this helps some.

 

That works-out for testing purposes, ...

Doing that will allow the STARTER to engage in any configuration.
The will lurch.
If its tuned ... it will start.
Loaded gun. No safety.

 

Awesome! I got the bike started !!! Now just have to clean out the tank

-Craig

 

I hope someone can help...

I'm having a similar problem. My '82 xj1100 that I have been working on isn't starting, well it is, but just not for long. If I have the choke all the way on, it will start for 1-2 seconds. It runs great on starting fluid, and just because I read it in this thread, I used a spray bottle of gas and it runs and revs great on that too. A little background on the bike:

It was not running when we got it, but had just been serviced before it was put in storage for 4 years (rebuilt carbs, amongst other things as well at the dealer). It started on starting fluid (left the petcocks on off), has good compression, good spark, etc.

Got it home, put in new plugs, removed and cleaned the carbs ( 2 slightly sticky floats, very little varnish buildup, though), cleaned the tank (rust, gunk, & kreem), new petcock filters, new petcock rebuild kit (both sides and the vacuum manifold), new manifold boots, new fuel sending unit gasket, new vacuum lines, etc.

I've tested all the relays for the starting and safety circuts, checked to see if the vacuum manifold is working correctly (when I suck on the vacuum hose, the fuel flows out of the lines to the carb bank), I have good flow on pri, checked all of the fuel lines for kinks, no inline filters, carbs looked spotless inside, cables hooked up correctly, float bowls have fuel in them, and anything else I could think of.

I'm not new to bikes, just to yamahas. This just has me a little stumped. I'm not sure where to go next, so any guidance would be greatly helpful. Thanks in advance, Matt.