firing problem ?

hi fellows my bike wont fire at all it 750 seca the first problem was it wouldn't take gas into the carbs i thought is was the petcock rebuilt that it works fine but i didn't realize how the float needle worked and when i put it back together i thought i still had the petcock problem finealy just pulled off the carb's and cleaned the bowls and float needles everything in the bottom put them back on and it would fire for about 30 second's then die.
someone on here told me in private message he thought i hadn't went far enough into the carb's so i took them off and claened them completly a jet needle had pulled out of its plastic retainer and frozen in place in top of the pick up/emulsion tube i luckily found 2 replacments(one for now and a spare) for ten bucks for both at a local scrap yard(i was leary they wouldn't be the same part number but their y-13's same as came out) well anyway now it wont fire at all. diaphrams are perfect.its kind of weird it would fire with that kind of problem but wont fire now ?maybe start from scratch on the sync settings ? im not sure any help is apreaciated.do you think it could be a firing problem ?

thanks james

 

James, once you break apart the carbs and tear them down you will need to resync those carbs.

Are you getting good spark on all 4 cylinders?

Did you test the petcock by running it into a container and check to see that the diaphram holds when there is no vacuum and that it does indeed open up to allow sufficent fuel flow?

Does the petcock bypass the diaphram and run freely when you put it in PRI position?

Did you prime the carbs after putting them back on when you took them apart?

Did you remove the emulsion tube and clean it too?

How full is the crankcase (be sure it isn't over filled)
Petcock could have dumped a bunch of gas into the crankcase,




Ok that should give us a start at trouble shooting this problem

Good Luck

 

If you has stuck needles and clogged emussions and it was running a bit ... now ... with it being un-stuck and cleaned-out you need to dial-in the mixtures again.

Start the Pilot Screws at three turns out and see if it will pop.

Every time you leave the bench and head back to install that rack ... you do a fast bench sync to be sure to have everything opening and closing together.

Now, that you are getting closer to having the rack close to being right ... you're going to need the fine-tuning aspects all coming together; too.
Float height.
Clunk test.
Fuel supply and inline filter.

 

ok Ill answer let me go down the list.

1. i didnt take them apart just off the bike -will i still have have to resync ?

2.sure if im getting good sprak can i test it like a car ? if i can i can do that.im not sure with this thing tho i dont want to fry somthing.

3.i did not test it like you said. it does have fuel flowing on prime and fuel flows in pulse's when there is suction on the vacuum tube.i didn't know about this test

4.i did prime the carbs when i put them back on

5 I didnt intialy remove the emulsion tube just float valves and flaots and bowl but after rickcomatic told me i needed to do that i did take them back off everything is perfectly clean shined up with steal wool all the little holes cleaned out everything.
the weird thing is after i cleaned the bowl and float needles it would start and run about 30 seconds maybe and the needles were stuck in 2 of the carb's one pulled completly out of the plastic holder and now with them all cleaned and the bad one replaced it act's like it want's to attempt to fire but then wont.

6 crankcase has brand new oil in it and is the right level.though im going to change is again after i get it running i used 10w 40 because i planed on just flushing is right back out after it does run.i dont know when that's going to be be i know im not going to rest until it happens its making me very mad now.

i did the clunck test rick all fall freely
i have an inline filter havent put it in yet because it doesn't run .

no i dont fast bench test and the reason is -
i dont know what that is lol
all the carbs open and close together if thats what you mean ?

so take the sync screws all the way in then come out 3 whole turns right ?

ok thanks for the info ill try this stuff rick and see if it helps.

thanks guys

james

 

It will not hurt. Re sync once a season seems to be the way to go.

Yes. Make sure the plug is grounded. Be careful about touching the plug or lead while the motor is running risk of shock.
I leave the plugs in and test each lead with a spare plug. The bike will run on 3 cylinders.

Yes, check everything works as it should and do the clunk test. You can bench sync the linkages between the carbs to get them close at this point too.

NO, the mixture screws at the top front of the carb bodys are set this way.

 

DONT set the sync screws to 3 turns!!!

That's the mixture screws located on the top front of each carb.
You may have to remove a seal cap, becareful because the screw is right under it.

 

I should have mentioned....dont freak out!

Sometimes it just takes persistance and a process of elimination.

Yes, you should be sure all the throttle butterflys are open the exact same amount on the bench so you dont have to pull them again.

Check with a piece of mechanics wire or something like that that has no give, use it like a feeler gage.
If you have to use the throttle adjustment screw to set the 1st one then match the others to the 1st by adjusting the sync screws between them.

Move the throttle plates and be sure they all stay the same.
if so
Adjust the idle screw back to normal.

Good Luck

 

lmao i set the sync screws already to 3 turns each and it actualy tries to fire now. but i screwed myself doing that huh ? oh well its par for the course lol wish I had known about the bench test before I put them back on.im getting lot's of practice taking them off and on though lol unwanted pratice.
alright now I've screwed up the sync screws I should just start from srcatch huh with one of those articles on how to sync the carbs ? Im going to make a yic's tool but it will have to wait for just a bit, Ill be able to get on a computer but ill be away from the bike for a bit so that's that until i can get back.

yea let me know what i have to do to fix the screwed up sync screws though is that right just start from scratch ? and then set these mix screws to 3 turns out now too ?

thanks

james

 

Yeah, you get fast at removing carbs, believe me! 8O

To bench sync.

Carbs off the bike.

Looking from the engine side into the carbs you will see the shafts with there butterflys attached.

The sync screws are on the shafts that connect to the shaft on the next carb.

Number 3 carb sync is fixed and is what you match the other 3 carbs to.

I use feeler gauges. With the idle speed screw lowered to close up the butterflys, measure the space at the bottom of the butterfly to the carb body on number 3. It was 0.0015 of an inch on mine.

If you can't get number 3 closed down enough, one of the other butterflys might be closed down too much, open the others up and try again.

It is a good idea to make sure the sync srews are clean, also to turn them each way (2 or 3 turns) a couple of times to make sure they do not bind. This also makes them easyer to adjust when fine tuning with the motor running.

Set the other 3 carbs to 0.0015 inch.

I found that at 0.0015 inch the feeler gauge was flexible enough to use by opening the butterfly, placing the feeler gauge on the bottom of the carbs venturi and gently closing the butterfly. You then loosen or tighten the sync screw until you can just with gentle force pull the gauge out without it grabbing or coming out with no force. I got mine spot on 0.0015. Open and close the butterflys every now and then while you set each one as well to make sure everything is in place.

You have now bench synced the carbs "pretty close".

Make sure float levels are good before putting the carbs back on the bike.

Turn the idle speed up a bit (1 turn clockwise), so the bike will idle.

Set the mixture screws to 3 turns from closed.

Start bike (prime and choke). Should start and run ok.
If so go for a ride to warm her up. 15 minutes down the road stop and set idle. Note how bike is running. Go home and (if you have the gear ready, fine tune the sync of the carbs using the guides (have a look at my FAQ write up). Go for another ride to make sure all is well.

Colour tune or get the mixtures set on a co2 meter (some states in the US might have requirements for the bike to meet emission standards).

If you need a YICS tool look at Rick's thread "Free YICS Tool For All".

You can use other things like a pice of wire, paper or tube to measure the sync gap, but a good set of feeler gauges come in handy for other work.

Good luck, I hope this helped?

 

YEP youre goning to be needing a bench sysc at the very least!

I like Kiwi's writeup!

One thing I might add,
When those carbs are inverted (upside down) the float valves may become stuck in the closed position.
Simply tap on the float bodies a bit in the upright position before or after the carbs are reinstalled..
Good Luck

 

There's something we often miss when discussing bench syncing.

If you're way out of wack that #3 butterfly may not close down because one of the others may be holding the rack open.

I suggest you open 1,2 and 4 up a bit extra, then set #2 to your gauge. Then, open 1 some extra so it is wider than 2. Bring 2 into line, then 1. Last bring 4 down.

 

ok thanks guys but not looking at the bike right now if i remember correctly it has the 3 brass screws thats operate the buterflys right ? number 3 is set already to screw to the right o of 3 controls the opening and closing of carb 4 correct ? then the one next to carb 1 controls carb one right ? doesnt the missle one control all of them for idle ? and if thats the case then how do you set number 2 ? i remember looking at it and thinking thats the way it operated but now im not sure after reading this.the way your saying it each one of those screws control either carbs 1 2 or 4 ?

thanks

james

 

OK, I scanned a picture from my manual, hope this is OK with site terms.

Adjuster between NO. 1 and NO. 2 matches carb 1 and 2 together.

Adjuster between NO. 3 and NO. 4 matches carb 3 and 4 together.

Then adjuster between NO. 2 and NO. 3 matches carbs 1 and 2 to 3 and 4.

The other marked screw is the idle speed adjuster.

You see how 1 and 2 are matched, then 3 and 4 are matched, then the adjuster between 2 and 3 makes them all the same.

Number 3 cannot be adjusted as it is fixed.

The Idle speed adjuster will open or close all carbs together for idle speed fine adjustment. This will move the number 3 as well.

 

The Rack has 3 Sync Screws.
#-1, #-2 and #-4 are adjustable.

#-3 is THE MAIN Butterfly. #-3 is Adjusted with the IDLE ROD.

For "Bench Sync"

Open 3 to tolerance of feeler gauge using Idle Adjust Rod.

Match #-4 .. to .. #-3

Match #-1 .. to .. #-2 by adjusting the #-1 Sync screw.

Finally ...

Match #-2 .. to .. #-3 by adjusting the #-2 Sync screw.
Since #-1 is connected to #-2 ... #-1 goes along with the adjustment and the rack's butterfly valves are Mechanically synced for preliminary running of the engine after a Carb Overhaul.

 

Yeah....what Rick & Kiwi said.

Do like they say & you'll be OK (syncing at least)


Dont forget that you should still sync them with gages or sticks too.

&
You still need to run a color tune to fine tune ea carb

 

Thank you kiwi thats a big help. and its mixture screws that each carb has on top that needs to be 3 turns out(thats 3-360 degree turns after i screw them all the way in right ? ).
and thanks rick i do remember now seeing this in one of your posts before now that i see it again.

thank you guys will do it as soon as i get back to the bike.


james

 

Hey ...

YOU better be taking it easy for a little bit.
I've asked around about how long it takes to recover from a Triple Bypass.
Don't be trying to do anything for awhile.
First ... you heal.
All that surgery needs time to take and heal.
Then, you recover.
Get some strength back and do what your health care providers insist you do to rehabilitate.

You don't need to be working on the bike.
Spend the time READING a comprehensive manual.

Better yet ...

Spend the time reading an enjoyable Novel or some magazines.
Just take it easy ... for cryin' out loud.
We don't want you to do anything that might be detrimental to your complete recovery and rehabilitation.
Our focus is going to be right ON YOU ... for a little while. NOT on your motorcycle until you've had some recovery time.

Get well; soon. You must take it easy.
Rick Massey

 

thanks for your concern rick but lets get real .This isnt exactly like real work! rofl im standing there in front of it ! the hardest thing ill be doing is pulling off carbs realy now rofl i told you before thats not what these doctors are concerned about their concerned about blood preasure and every ones is going to go up no mater who you are when you keep doing things and the problem gets worse instead of better lmao my blood preasure goes up 40 pts everytime i think of this thing sitting im my garage not running lol and it will until the problem is taken care of.
ill be messing with it soon as i feel up to it maybe next week if my stitchs and chest feel up to it these doctors act like its an everday thing here lol so it must be if thats what they think lol im with em !!!!!!!i realy didnt want to broadcast my problems across the forum my problems are mine and it only takes away from what were here for you know ?


cya

 

"Desperate times call for desperate measures."

I'd rather have everyone know what's going on ... than have somebody suggest you to do something to exert yourself beyond the limitations usually imposed on those who ...

ain't in this weeks starting line-up ...

because they're a** belongs on the 15-Day disabled list.

Edited, please keep it clean. Thanks, Robert

 

I worked in Taylor until last week. Woulda been easy to shoot over for any lifting or prying.

I'll come over anyhow

Shoot me a message if anything heavy comes up.

 

You are welcome, happy to help

Be careful bottoming the mixture screws that you do not over tighten them. A gentle tough is required to avoid damaging the tip. A correctly fitting screw driver is required too.

 

James, we're here to help each other out, right!?!
If I'm not mistaken, Thats What We're Here For!

Take care of yourself, we are all hoping to hear good reports.

If you werent on the other side of the continent I'd come over and give you a hand myself.

 

thanks rick again for your unbridled concern lol but wheter my a** belongs on the disabled list isn't realy for you to say is it ? lmao i can't even beleive that you would go so far as think you can diagnose my heatlh problems rofl do you realy think if YOU dont give me information that when the time comes that i can work on my bike that i wont get it ? lol
do you know how many not just xj sites are on here theres about 10 of em
and theres 100's more for yamaha's in general not to mention hopefully not everyone here shares your passhion for pronoucing people you dont even know their a** ready for disabled list ilmao so when my DOCTOR says im able and my a** is of the disabled list ill be back out there.man i come here for info on my bike and its one weird thing after another
i dont know about anyone else here but i would never presume to try and tell somone that comes to an xj motorcycle site their a** belongs on a 15 day disabled list im starting to think you belong on the permenent disabled list in the nut house dude lol
all for my good huh ? your going to protect me from myself ! rofl wow unfrickingbeleivable.i have a wife been married 26 years 4 kids 5 grandchildren 2 houses to support and you think i dont want to live ! omg.i dont need saving but thank you for your consideration.

sorry to everyone else this is completely out of line.

thanks hvnbnd yes we are here to help each other out and thanks i beleive you would come help me out i beleive rick would to if he werent so far away but i think his heads up a** right now trying to be do gooder hero and then he doesnt just say what he had to say he adds some stupid comment about my a** on the 15 day disabled list.


thank you again kiwi sorry it got lost way down here where it doesn't belong ill try these things when my a** gets off the 15 day disabled list.
lol ill be sure and come back to the xjsite first and get clearance rofl i may get out of the hospital today if the bloodpreasure machine doesnt explode when they come to take it.
but hey!! if that dude still needs some mercury for his manomter ill be sure to catch it in a cup for him lo

cya guysl

**Edited by Robert, keep it clean please**

 

You're right, it is completely out of line.

Can we please delete all this non-XJ stuff ? There is some good info here stuck in the middle of a pile of stuff that could and should have been PM.

 

That's OK James.

The carbs on these bikes work well when setup right though I'm lucky I just have to sync mine, EFI is great (until something goes wrong, parts cannot be found :cry: ).

 

I will agree that some things should have been PMd. Let's knock it off fellas.