Idles to fast

[JoeBlaster64]

96 Blaster, I am assuming engine has been rebuilt but not sure how much, has FMF core pipe, K&N Air Filter. Never has started or run really great. I decided to start with rebulding carb and installed all stock jets with needle clip in center. Air screw 1-1/2 turns out. Installed new plug. It fired right up but at very high RPM'S. I turned the idle screw all the way back but no difference. I went upward and the RPM's increased. If I put my hand over the airbox openning to restrict air I can bring the RPM'S down. I turned the Air screw in it did not slow RPM'S but just died. I turned it outward, same. What can I do next ?

 

[blasterdemon7]

Make sure the slide is installed correctly. Not backwards.

 

[scotj77]

you don't want stock jets in that thing with an fmf pipe. you need a 270-290 probably. stock is 230. you will be running lean. as for the high idle it sounds like you've got something wrong in there. getting too much air. so I would also suggest checking the slide

 

[Blaaster]

Leak down test!

 

[JoeBlaster64]

The slide has a notch in it so it only goes in one way. The main jet shouldnt effect the idle, but was planning on jets next after getting this idle problem fixed. Whats a leak down test ?

 

[JoeBlaster64]

Googled Leak down test. I will check it out.

 

[Braaaptor]

Good decision. Do the leakdown test and get back with us. If you find and fix an air leak, you should have the idle problem solved.

Also, be sure that the carb is clamped firmly in the boot, and that the carb's cap is tightened securely. Neither of these problems will show up in a leakdown test because you have to remove the carb to do the test. Just FYI.

 

[Blaaster]

http://www.blasterforum.com/engine-parts-151/leak-down-tester-43284/index2.html

 

[EvilElvis]

plug the ignition coil into some c4 no more problem j/k LOL

 

[Blaaster]

detonation .

 

[Blaaster]

plug the ignition coil into some c4 no more problem j/k LOL

Or should it be,,

DETONATION

 

[96MXBlaster]

Just to be safe check your reeds to. mine wouldnt run right either and it ended up being that my reed pedal was stuck open. just a suggestion.

 

[JoeBlaster64]

No leak found. Took carb back apart and re assembled. I did check the old pilot jet size and it was a 300 so I re-installed it. Double checked slide, goes all the way down and in correct direction. Could the Jet needle be to high ? change clip position ? I turned the pilot screw in slowly and it did decrease the RPMS down but never to a calm idle. Tomorrow I will re-installing old pilot screw to see if that's it and then old Jet needle.
It does run like a bat out of hell now though. Front wheels didn’t stay on the ground to often running through the gears.

 

[JoeBlaster64]

Made all changes no difference. Confused what to do next. Until I rebuilt carb it ran ok, leaked gas out overflow sometimes, bogged after jumping or heavy woops sometimes but idling high was never a issue. What does that mechanisim on top of carb do ? It has wires hooked to it and which looks like a idle screw ? I turned that all the way down, no difference.

 

[quadsrus1]

Are you sure you performed a leak down test right, and have you checked the reeds?

 

[EvilElvis]

Made all changes no difference. Confused what to do next. Until I rebuilt carb it ran ok, leaked gas out overflow sometimes, bogged after jumping or heavy woops sometimes but idling high was never a issue. What does that mechanisim on top of carb do ? It has wires hooked to it and which looks like a idle screw ? I turned that all the way down, no difference.

that is your idle control screw and may be stripped, take apart the box on top of the carb and see if its stripped ...also make sure those wires to the top of the carb are un-plugged and the same color wires under the hood are unplugged where it plugs into the square metal box ....thats TORS "throttle over ride system" make sure its disabled

 

[EvilElvis]

And as far as the overflow leakiing you need to take the bowl off and the float mechanism theres a little rubber stopper that goes up in a hole that hole needs to be cleaned.....qtip and toothpaste then clean it up with carb cleaner and re-assemble

 

[Blaaster]

Made all changes no difference. Confused what to do next. Until I rebuilt carb it ran ok, leaked gas out overflow sometimes, bogged after jumping or heavy woops sometimes but idling high was never a issue. What does that mechanisim on top of carb do ? It has wires hooked to it and which looks like a idle screw ? I turned that all the way down, no difference.

What were the results of the leak down test? Did it hold 7psi for 5 mins?

I have known carb boots to produce the same bogging symptoms when jumping, as you posted.

They have passed the leak down test with flying colours with the bike at a standstill, but the boot has had a small split on its underside, and the weight of the carb has masked its leaking.

Do the leak down test again and flex the rubber boot and spray around it with soapy water.

As to the TORS get rid of it, it is a useless bit of junk and will always give you greif in the future.

 

[JoeBlaster64]

How do I get rid of the TORS ? Can I totally remove it and run the cable directly to the carb ? I never seen anything like this before. I have had motorcycles all my life and the throttle cables have always run directly to the carb not through something like this. I will check the boot. If no luck I plan to borrow my buddies carb of his blaster to see if I get the same results.

 

[Blaaster]

If you borrow a carb, make sure it is jetted for your motor.

You are able to buy a TORS removal kit on Fleabay, instructions come with it and there are pics on the forum if you do a search.

TORS was Yamahas attempt at stopping over rev, but it has caused so many problems..

The kit should include carb cap, therottle cable, idle screw , drill and tap.

If you have no access to tools to do the carb mod, the idle can be controlled by the throttle cable alone, but I do not recomenned it because the revs will increase with handle bar turning.