Carb help needed.

sporty982000

sporty982000

New Member
Jul 10, 2012
762
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Illinois
Info,


carb, does not have tors, does have a idle screw in it.

I put that 280 jet in.



2nd kick, started right up, however, then it died, did not matter if I gave it throttle.

then it will pop and almost start, real close.


issue, no with the tors and oil injection off. do i need to block or plug the oil coupling coming out of the carb ?



This is first time with no tors and no oil injection for me and first time with fmf fatty and power core 2.

This is the white blaster,. I got a few weeks ago. it came with no tors/. with block off. but did not have the cabr coupling where the oil line would go to the oil pump.

Does it need plugged ?

tid bits, that may help

choke or no choke, no help start.

seems like if I open throttle wide open, it will pop and almost start.

(pop) not back fire.


Sporty
 
yes you need to plug the oil line. the carb will pull air through there if it is open. make it too lean to start. get that plugged then let's see what happens
 
K. UPDATE.
plugged that oil line outlet.


fresh fuel, 32-1 mix, new plug. went to 260 main jet.

No luck. pops,

and kills my foot. the kick starter is kicking back at me.

I tried screw anywhere from 3/4 to 1 1/2.

this carb they installed a idle screw, it is a stock blaster carb.

I tried adjusting that from one end to the other.

If I try and choke it, i can tell that makes it worse.

Sporty
 
Update,

yes plug getting wet.

tried the 260 jet, tried the stock jet, double checked carb, took apart 3 times, checked float level. ect, ect.

Guess what, I got spark, but its week. I have week spark !

Sporty
 
The very first thing you should when aquiring any 2 stroke is a leak down test.

If the kicker is pushing back it could be caused by either flooding of the motor or by a broken flywheel key.

Changing the main jet should have no relation to the starting problem.

Try draining the carb, take the plug out and kick the crap out of it to try to dry the motor out.

Fit a new plug, and if no luck try the flywheel.
 
Blaaster said:
The very first thing you should when aquiring any 2 stroke is a leak down test.

If the kicker is pushing back it could be caused by either flooding of the motor or by a broken flywheel key.

Changing the main jet should have no relation to the starting problem.

Try draining the carb, take the plug out and kick the crap out of it to try to dry the motor out.

Fit a new plug, and if no luck try the flywheel.
Click to expand...
That's exactly what I was thinking as the flywheel has a lot to do with the ignition. The blaster engine shouldn't be able to kick back on you hard at all unless it was firing at the wrong time.
 
I have not checked the reeds, when I put them in last night, they looked okay. what do I lok for on reeds ?

I did a leak down test, I build this motor lastnight.

I did check the fly wheel also, and the key was fine and fly wheel was turning with the crank.

Replaced the coil. spark was stronger, but did not resolve issue.

the kick back was caused by flooding, I found that out, and i adjusted the float and that seemed to resolve or is better. not getting kick back as much or as often.

Yes I did try new plug, I had 3 plugs that I used.

Been at this since 11 am, im beat and my foot is killing me.


All it will do is pop or if im lucky run for maybe 10 seconds, but low idle, would not speed up and then just died.

Sporty
 
rockymountainatv.com has them. shipping will suck though. make sure you get those mating surfaces on the crank and flywheel cleaned up really well before you put a new key in
 
I want to say thank you.

We found one at local hardware store for 50 cents.

Fix and 2nd kick up and running.

Son got to ride it, woohoo, he was happy.

So thanks. What eludes me, is I checked it 2 times, i had marked the crank with amarked on the same line up for the wood ruff key. Thats how I double checked it.

But next time, i need to just pull off, would have saved me allot of waisted time.


.

Now, from idle to 1/2 throttle runs real good. from 1/2 throttle to full throttle, not so well.

What adjustments should I look to do ?

260 main, 1 1/4 for the carb adjustment. ( i tried from 3/4 to 1 3/4. Didnt seem t resolve the issue I mention.

needle in 3rd position.

Im new at this pipe and bigger jet. So better for me to ask, where I need to adjust or try.

Sporty
 
If you have spun the flywheel it would pay to lap it to stop it happening again.

Lapping the flywheel consists of putting some fine valve grinding paste on the taper of the crankshaft, placing the flywheel on, ( without the key), and revolving the flywheel back and forth.

When the flywheel turns more freely as the paste gets broken up, take off the flywheel, wipe out the used paste and inspect.

The grooves should now be flattened out.

If there are still grooves, repeat the operation until good mating surfaces are made.

Be sure to wash off all, and I mean all of the grinding paste.

I like to finalise by using a Duco cutting compound No 3 for the final lap.

Tension the nut to 53 ft lbs, some use Loctite but I never do, it is not the nut that holds it on, it is the pressure applied to the tapers.

Make sure that you have the spacer under the nut.

...................................................................................................

That #260 main could be too small if you are having problems from 1/2 to full throttle.

If you run 32:1 you should be at least #270 main.

After doing a leak down test, set the idle correctly and proceed with a plug chop.



14mqc1y.jpg


.......................................................................................................

Idle adjusting.

Start with air screw 1.5 turns out.

Set idle screw so that it has some sort of idle.

Warm up motor and then set idle screw for a fast idle.

Adjust air screw either way to get the fastest idle.

Adjust air screw a little at a time leaving 10 secs to allow the motor to respond.

Re adjust idle screw for desired idle .

.....................................................................................................

Plug chop.

Warm up motor to operating temp.

Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.

Switch off the motor and pull in the clutch, roll to a stop.

Take the plug out and replace the old one for the ride home.

Carefully cut the threaded end off the plug to expose the insulator.

There should be a smoke ring of a cardboard or biscuit colour around the insulator.

If it is non existant or a very light colour, you are lean and require a larger main jet.

If it is a lot darker you are rich and may go down a size in main.

I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.

http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/

http://www.blasterforum.com/engine-13/plug-chop-how-vid-48226/

This is a good to go plug.

2wr2fwo.jpg



This one is a little rich, but I would run it, I like to be on the safe side.

plug152mainmediumoi2.jpg
 
Last edited by a moderator:
Thanks for the tip with the lapping compound.

I dont want to pull the flywheel, since it's working good now But if it happens again I will.

I do have a 280 main, I will put that in and see how it goes.

Im pretty good with carbs, but not use to modded pipes.

When I pulled the plug it was wet, so it might still be running rich.

I will do a plug chop, its on my list, But needs to be running a little closer to good, before I do it.

You might have missed, I did do a leak down test on it. I built one and posted it a few weeks ago.

I have a idea on possible issue with the carb.

The float is set right, did that yesterday, when I had it apart a 1/2 dozen times. lol

But I did notice that the needle housing. Which is called the valve seat in the manual, that has a rubber o ring on it. and I see some of the rubbe protruding out of the valve seat.

So I need to get a new seal there and replace. this may be some of my problem.

Thanks again,

Sporty
 
My old 70 yr old memory is not so good in the short term region, so I would have had trouble remembering about the leak test.

If that "O" ring is protruding it could be letting unwanted fuel into the bowl.

A wet plug is not a true indication of rich running.

Even a perfectly jetted motor after idling for a few moments can return a wet plug, especially if the idle is set a tad rich.

It is the plug chop that tells the true story.

Set the float level, idle, clip on centre slot and plug chop the #280 main.
 
Wanted to provide a update.

2 issues found.

1, the slide on the carb was not going all theway down like it should, the throttle cable adjustment was causing it not to lower all the way.

I did not catch this the 1/2 dozen times I had it apart, my fault there.

2, I did take the reeds off and looks like someone before me, had flipped them. the screw heads were messed up some.

However, 1 of the reeds is not sealing, has a gap, mean 1 out of 4. but I will get new reeds, since they dont sell in halfs. lol.

Even the the gap was not bad, it was not sealing.

Hurry up pay-day.

Called local yamaha dealership, $12.80 per side, 2 pieces, they have to order.

Sporty
 
Last edited:
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