Never Seen This---Engine Went Out of Control

[gottaroost]

First off Howdy from Texas!! I am new here, but not new to forums but I was driven here out of shock.

This afternoon I brought home a 1999 Blaster for my son's birthday present. I wanted to give it a thorough going over before I put him on it. Pretty much everything works...lots of compression, just no back brakes---the parts are there but no stoppy.

When I tested it out, it ran fine but would not idle. I figured this would be as simple as an idle screw. So I tried the screw on the TORS and it had no effect. I removed the carb and hand tested the idle screw and could see that it does change the slide position so it is working in that regard.

I reassembled it and started the bike, no idle again. With it running I started to adjust the cable where it exits the thumb throttle. It did not make any difference...Then suddenly it surged into 100% full rev and I quickly tried to adjust the cable back where it was---nothing. I hit the kill switch---nothing. Then I turned off the ignition key---still nothing. So I jumped on it, pulled the clutch and put in 1st gear and let out clutch to stop it. WTF was that about???

So now I am thinking this thing is potentially a death trap for my son...for me too for that matter. I fully adjusted the thumb throttle cable back where it was and started it up...back just like it was when I bought it where it starts right up, runs great but won't idle.

But wait there's more. I have an idea where it could possibly be adjusted but I do not yet know how. If I apply slight pressure to the thumb throttle it sort of hits a spot where it has a slight bit of resistance before you start to get into the meat of the throttle. It will idle right there if I hold it, and while holding it there I can adjust the idle just fine from the idle screw...but as soon as I let off that bit of pressure, it dies.

Well if anyone survived my story, I am very hopeful this has an easy solution. Oh, the bike is 100% stock through and through...carb cleaned, air filter brand new, fresh fuel, the oil mixes perfectly, TORS appears to be completely intact.

Thanks!!!

 

[blasterdemon7]

First thing it to take the carb apart and clean it real good. Make sure you air filter is clean. You have to be carful with the threads on top of the carb because they tend to strip. I would read up on here for the basics. Plug chops for jetting and leak down test. The two main things to help your Blaster live long.

 

[blasterdemon7]

Oh. Welcome to the forum.lol

 

[96MXBlaster]

hope you get it figured out welcome to the forum

 

[dbowhntr]

Yes.clean out the pilot jet. That is your main idle circuit. Lean will make the idle go really high.

 

[gottaroost]

Yes.clean out the pilot jet. That is your main idle circuit. Lean will make the idle go really high.

Well I think my explanation was too long. The bike launched into full throttle and the throttle was not even turned...I had simply adjusted the throttle thumb cable in small increments hoping it would lock in some idle...It absolutely went wild---and it overrode both kill switches at the same time...what kind of circuitry does that?

To address::: I appreciate the mention of the jets etc, but this was completely different (do not want to imply I am a know it all but I have worked on countless bikes since my teens and this is a first). The carb was completely cleaned out today and it was surprisingly clean already before I cleaned it. It did not exhibit any of the classic lean symptoms, just this insane overrev trying to adjust for a missing idle.

I do not know a lot about the TORS system, but it almost felt as if its sensories were inverted and CAUSED it to NOT be able to be cut off. I understand that part of its function is TO CUT OFF the bike in dire situations.

Anyway, I am hoping someone has crossed this bridge before and gotten to the other side safely.

Thanks.

 

[gottaroost]

Oh also, all the carb parts are doing what they should be doing..all smooth moving and clean inside and outside. Ummm what else...no cable binding. Truly this was not a twist of the throttle, stuck or dirty part. It just started to scream out of the blue at the time I was making slight adjustments to the cable and then testing it with a little blip of the throttle to see if it would settle down to a proper idle.

 

[cole454]

If it continued to run after the kill switch was flipped then it was running very lean. Most likely cause is an airleak. Look in my sig for a howto on making and using a leak-down tester

 

[DirtDiggler]

Welcome! There are several diagnostic steps that you should do .
Compression Test
Leak Down Test
Clean the carb
Get rid of the tors system by getting a tors elimination kit .
Delete the faulty oil injection system and premix your fuel at 32:1 ratio and use 2 stroke oil , not yamalube injection oil . They are different .
Get rid of the mechanical rear brake , buy a awk ( he's a member here ) hydro rear brake
Kit . Sky's the limit , let the boy go nuts

 

[Prime]

Clean the carb, do a leak down test, and if there is still no idle try finding an intake leak somewhere. (Most commonly a broken bolt on the reed cage) Oh and get those rear brakes fixed

 

[gottaroost]

Well I found the Idle Stall Problem

Ok, here is one and it is clear that I was telling my story without some of the facts.

I popped the cover off the thumb throttle and voila, there is the no-idle problem...There is a very small toggle switch in there that is engaged when you let off the throttle. I do not know the terms for this, but the inner throttle cable actuator is actually two metal pieces one bolted on top of the other. The part on top controls the actual throttle cable action. The metal part just below follows the same line as the cable actuator, but when you let off the throttle the bottom metal part comes back just a little farther than the cable actuator and hits the tiny switch button and that cuts off the motor.

Soooooo, my non technical idea is to add a small gizmo that disallows this bottom part to actually touch that switch. This feels like part of the TORS system since it has an electrical connection. It just seems like it is working in reverse. My understanding is the TORS should cut off the motor if the throttle is stuck open, not when you let off the idle.

Anyway, curious if this info helps. It is not running lean just one random time that went spastic. Carb is very clean. I really do not want to bypass anything or buy a kit for it. I believe/hope there a "nearly stock" fix looming on the horizon.

 

[EvilElvis]

Its your TORS setup heres all you need http://www.blasterforum.com/do-yourself-20/how-remove-your-tors-655/

 

[98blaster+4]

yup that button the throttle part is touching at rest is the tors sensor. if your not on the gas and it surges while that button is depressed it should die out.

but they malfunction all the time leaving you stranded in the woods.
delete the tors system by first unplugging the connection at the top of the carb then out under the hood there is a little box. it is located right next to the cdi box so dont unpluig the wrong one.

 

[Blaner]

are the kill switch and the key functional the rest of the time?...welcome...nice intro to blasters for you!

 

[scotj77]

sometimes you get a runaway motor when it over revs like that and it won't shut off any other way than killing it manually witht he clutch. I would say tors is your problem. and it is attached to that little switch in the thrumb throttle

 

[Paulie B]

I vote an air leak. TORS problems often result in the motor NOT reving up.

 

[gottaroost]

Idle Cutoff Problem Solved

Ok, wanted to post back that I fixed the idle issue...did not have to disconnect the TORS (well at least not for now) and it was not an air leak. And the kill switch and key are fully functional now and were after I shut it down after that big surge and readjusted the cable. Have been functional ever since that time.

Idle history:::When the bottom piece inside the throttle assy was coming to rest on that tiny TORS button, it caused the engine to die (not sure the purpose of this but...). I fashioned a very thin piece of metal into a "U" so that it would fit around the front and sides of the TORS sensor but not touch the TORS button. I took out the TORS sensor screw that holds the sensor in place, pulled up the sensor, put my piece around it, wedged it back in, and put the sensor holding screw back in. Now the bottom plate of the throttle assy cannot ever reach the cutoff button.

I may post my back brake issue separately, what a POS system that is---and I have something odd that occurred when I took it apart to investigate. Oh, I think I posted it was a 1999 Blaster...the P/O said it was a 1999 but the VIN search said 2001...ooh, a little added value.

 

[Larry's Shee]

Welcome I:I First thing you should do is get or download a manual. Next, don't add any "gizzmo" to the throttle housing . Lube the throttle housing (maybe dissasemble and clean first) , spray some brake or carb cleaner down throttle cable then lube it. Pull both sides off TORS "brick" on top of carb clean and lube this area. Re-clean carb, pull pilot jet , be sure you can see thru it. Be sure there is a rubber gasket where the slide cap is , be sure clamp is tight for carb to boot. Be sure to re-install oil tube on carb. For all stock Blaster injection will be fine for now. Be sure cap is on tight for slide.

Your run-away might have been a lean condition, but should have still been there when you re-started it. I susspect that it was a hot engine from sitting there adjusting on it, the throttle hung slightly, then it started into the auto-ignition, also known as deiseling, either the piston or a little chunk of carbon was hot enough to cause ignition of fuel charge WITHOUT spark. X(

Might as well drain tank and clean it and the petcock while you're working on it. You're a good father for doing this for you son.

My son has gone from a RM50 to a CBR600, along with a Warrior,Blasturd, and Banshee in his stable. Just wish he either paid closer attention or gotten more "mechanical" genes , instead of Dad ......................

 

[davenichole]

sounds to me like the tors was disconnected at the carb while nothing was changed at the throttle. all you should need to do is disconnect it at the throttle and splice the wires together. i removed my tors and had the exact same idle problem before i spliced the wires. so just to make it clear, if you disconnect tors at carb, disconnect at throttle also but splice those 2 wires at throttle together.

 

[gottaroost]

Welcome I:I First thing you should do is get or download a manual. Next, don't add any "gizzmo" to the throttle housing . Lube the throttle housing (maybe dissasemble and clean first) , spray some brake or carb cleaner down throttle cable then lube it. Pull both sides off TORS "brick" on top of carb clean and lube this area. Re-clean carb, pull pilot jet , be sure you can see thru it. Be sure there is a rubber gasket where the slide cap is , be sure clamp is tight for carb to boot. Be sure to re-install oil tube on carb. For all stock Blaster injection will be fine for now. Be sure cap is on tight for slide.

Your run-away might have been a lean condition, but should have still been there when you re-started it. I susspect that it was a hot engine from sitting there adjusting on it, the throttle hung slightly, then it started into the auto-ignition, also known as deiseling, either the piston or a little chunk of carbon was hot enough to cause ignition of fuel charge WITHOUT spark. X(

Might as well drain tank and clean it and the petcock while you're working on it. You're a good father for doing this for you son.

My son has gone from a RM50 to a CBR600, along with a Warrior,Blasturd, and Banshee in his stable. Just wish he either paid closer attention or gotten more "mechanical" genes , instead of Dad ......................

I hear ya...I do not like adding gizmos either, it makes no sense why engaging this button at idle cuts off the engine. I am certain it is confined to our Blaster wiring or all Blasters would do this.

Maybe I should snap a pic of what I did...it is not a piece that could ever come loose or rattle around, basically permanent and we rode it all day yesterday without any issues. I have instructed my son to simply pull in the clutch if anything happens and he has been clutch riding for awhile now. Honestly I feel better about this rig than cutting/splicing wires. Also, the throttle is clean, lubed, and functions smoother than some of our other bikes---no binding whatsoever.

Funny you mention...I got into playing on used bikes to show my son a few things...I end up being the primary guy out there sweating in the garage and never notice him disappearing from view when "we" are working together.