Back Firing - 2002 Blaster

[coloradoblaster]

Hello guys.

I have a 2002 blaster. not in the best shape but it runs great... well.... it did.

I took the carb off of it to clean it, but it turns out it was already pretty clean and all the parts you can replace seemed brand new so i'm guessing someone did it recently since I purchased it.

I also replaced the rear plastics, which also means the air filter. It used to be a foam one wrapped around the black plastic cage, but now its what appears to be a K & N filter.

I did nothing else to the bike.

I put it back together, and BAM! it fired right up on like the 5th kick. I was so excited. I drove it around for about 10 minutes that day, and put it away, thinking how great it was.

Pulled it out the next day, it took more than 5 kicks, but no worries, it did fire up. Ran it for about 5 minutes, then the stuttering started... then the backfires, BAD LOUD backfires multiple times. it was rough. people were probably mad in the neighborhood. I managed to drive it back to the house, despite the backfiring and it shutting off 3 times, but the next time I tried to start it, it wouldn't start anymore.

I know it has to do with the carb or air filter? but what could this be. how could it work for say, 15 minutes, then all of a sudden fail?

Is it the TORS? I want to remove that, are those 39.99 kits you can buy on Ebay worth it? are there other options? Is it the air filter? did I break the carb somehow? I only opened the carb, looked at it, then put it back together, really no reason to believe something didnt' go back together right.

could this haver fouled my plug? I do know how to test a spark plug though, so I suppose that isn't a big deal.

the bad part is, I threw away the old plastics (they were finished) and dont even have the old air filter anymore to test it.

Any help on what I can do to try to fix this problem, or what the problem even is with backfiring and now, not even starting up.

THANK YOU SO MUCH!!!

Derek of Colorado

 

[Painthehouse]

You need to check your jetting, switching from a foam to a K&N means more airflow, which means a leaner mix.

 

[Larry's Shee]

Did this filter come with the plastic? Do you have a lid for box? As to TORS, you can just diconnect the box in front. You'll have to search, don't remember which box it is. What does your plug look like?

 

[roadkill]

check your flywheel key to see if it sheared

 

[coloradoblaster]

I was thinking it was the jetting also. I might by some different jets and try that out.

The air filter "box" does not appear to have a spot for a lid or top. Both of the rear plastics i've had, neither had a top to the air filter box.

I dont know what you mean "did it come with plastic". when I bought the rear fenders, the air filter was already connected to it.

I'm not just going to disconnect the electrical box for TORS and leave the giant thing on top of the carb. as far as I can tell, that TORS thing on top of the carb can significantly alter how the bike reacts, plus, my bike "peaks" out at like half way through 4th gear with some kind of "limiter" on it, and i'm 99% sure its that TORS crap causing this becasue it thinks the throttle is stuck open, when really i'm just hold it open because the bike is still going to slow.

so, again I ask, does the 39.99 kits you can buy on ebay for TORS removal work? anyone ever used one?

Back to my original problem though. do you guys think if I took say, a old t-shirt or something of the sort and "wrapped" it around the air filter, i could trick the system to work?

really what it come down to is, i need to figure out what the issue is, before I go buying new parts. i dont want to spend 20.00 in jets only to find out it was an air leak or a broken k and n or <insert random problem>

do you guys have any suggestions as to what I can test w/out buying new jets ?

thanks again.
Derek of Colorado

p.s. i dont know what a flywheel key is, but if it "sheared" the bike is going in the garbage, because i have other bikes i'd rather spend time/money on especially if this one is "shearing" parts, however, i'm almost certain its a carb/tors problem because that is all i've messed with.

 

[roadkill]

its very simple to replace a key if it is sheared its like a 5 dollar part and maybe 20 min of labor, definatley not worth throwing it away if it is sheared

 

[davenichole]

the backfires could be from a tors malfunction. i remember this from when i disconnected mine. i did not buy a tors kit. i just removed all wires and switches from mine. problem at the time was, i did not realize that the wires that go to the throttle switch need spliced together. the wires that go to carb need to be taped off separately. i think at the time i still had the throttle switch connected and what was happening was, when you let off the throttle, it was killing the ignition and flooding the cylinder. as soon as you hit the throttle again, ignition would work and cause the backfire. also, the throttle had to be pushed some before it would start because of the switch killing the ignition. i still have the tors box on top of my carb because i did not want to drill and tap my carb and then have to adjust idle with a wrench every time. i can just pull off the seat and turn the stock idle knob. so the aftermarket tors removal kits are not necessarily needed. i agree though that the carb without the box on top certainly looks better and there is a weight savings.

 

[davenichole]

"as far as I can tell, that TORS thing on top of the carb can significantly alter how the bike reacts,"

there's a lot less to that tors box on the carb than you may think. in fact, the only thing tors about it is a very small switch inside it. the rest of its whole big size and design is for the way the idle adjustment works.

the only thing tors does is kill the ignition if it thinks your throttle is stuck open. it does not make any changes or adjustments to your carb as you ride.

also, if you are holding it wide open and the quad is still going slow, maybe you have a fuel starvation problem. maybe you have a fouled plug. idk.

 

[jlsparky7]

Ill do a how to vid on the TORS removal as well as a idle jet guide. Check back in a week.

Sounds like either a wet air filter (this week definitely do it). Bad tank of fuel (water in it). Or your idle jetting is a little off. (more than likely a little lean). Try turning you idle jet screw 1/2 a turn in and go for a ride. This also could be caused by a severe exhaust leak. The exhaust on a 2-stroke is a lot different than on a 4-stroke. It doesnt just provide back pressure. The engine actually sucks some of the combusted air in the exhaust back into the engine. If fresh O2 is introduced into the exhaust then it will cause a leaner mixture and itll backfire.

How to cleaning vid here.

 

[Larry's Shee]

T.O.R.S Removal. Idle Screws Install. - Banshee HQ Forums

Actually is a thred on here that is same but didn't feel like searching

 

[coloradoblaster]

this is some GREAT information guys.

thanks alot!

i'll update with any new information after I try a few things.

I'm really hoping I just "turned" the idle screw on top of the tors (I assume its the GIANT turnable screw thing that is the idle screw) and see if its something that simple.

with the new k and n i might still need new jets, but dangit, it ran for 15 minutes AFTER my messing with it, so i just cant get off the idea that its something simple. and knowing me, i'll do 10 hard things that were completely unnecessary before I find the 1 simple fix.

thanks again guys!!

derek of colorado

 

[coloradoblaster]

Re: Back Firing - 2002 Blaster UPDATE

I have finally gotten back around to testing different things to figure out what it could be.

So far, i've replaced the carb (got a good deal from someone on here) so now the cap and carb screw together nicely.

I also had a carb rebuild kit with a 230 Jet in it, so I tried that.

I couldn't even get the bike to start with the 230 jet in it. I tried and tried, but nothing. tried lots of different combo's with the air screw, the choke and the TORS screw. nothing.

I put the 200 MJ back in it and it fired up (for the first time with the new carb) but it was still backfiring. (and wouldn't run longer than a few seconds) this leads me to believe it has nothing to do with the carb (except maybe jetting).

I still have the KN air filter on it.

Based on the fact that the bike backfires with a 200 MJ and wont even start with a 230 MJ, where do you guys think I should try next? I'm going to buy some jets just want to know which ones I should get. I'm assumin 210 and 220 but wanted some expert opinions.

with those symptoms, do you think it still might be a jetting issue?

I've checked the whole air system up and down more than twice and i cant find anything that suggests it might be a leak. i'm still assuming putting the KN air filter on screwed up the ratio, but before I buy 210 and 220 i'm seeing if that is the right next step.

thanks again guys

derek of colorado

 

[Larry's Shee]

WTF?? took nine months to get back ?? Hopefully you've done a little reading on here to learn something 8-|. Bone stock the Blaster comes with a 220 or 230 main jet. Remove air lid= increase main jet. Add uni filter=increase more, K&N=even more. Do you have stock pipe?
When you work on jetting/carbs ONLY change one thing at a time.
When you cleaned the carb did you check/set float? Did you check flywheel key? Five dollar part 1990 Yamaha YFS200A BLASTER Parts, 1990 Yamaha YFS200A BLASTER OEM Parts - BikeBandit.com, need Blaster flywheel puller X( or you WILL fubar the wheel. Have you done a leakdown test? What does the plug look like? Have you pulled the reed cage to inspect the reeds that they are sealing, have no chips, cracks, frays?

BTW, if you decide to toss it in the garbage (as you said) give me a call and Junk Yard Johnny will take the trash out I:I

 

[heyketz]

I had a bad plug that was causing the same problem. Cleaned the plug and put it back in and still backfired. Replaced with a brand new plug and backfiring went away.

 

[coloradoblaster]

I'll try a new plug.

As far as all your suggestions Johnny, they are good ones. The reason I have not done most of those is because the bike worked great, I took the carb off to clean it. While I did that, I also replaced the rear plastics, which CAME WITH an old K&N Filter (which i'm still trying to use). When i put the carb back on, it started the back firing problem.

I could go through and do all that stuff your talking about, but it would be awfully crazy to me for any of that to happen because I removed the carb and replaced the rear plastics.

I believe the problem to be either A) the "new" rear plastics have a air leak problem or B) the 200 jet that is in it now (which used to work great) is now to small because of the switch from a OLD ROTTING air filter to the K&N filter and I suppose C) a bad sparkplug

Since I had a carb rebuild kit, I Tried the 230 Main Jet and the bike wouldn't even start (why do I feel like i'm repeating myself here) and when I put the 200 back in, it would still backfire.

The next thing i'm going to try is a 210 Main Jet, and then a 220 if the 210 still backfires.

However, i'll probably try a new spark plug first just to see. wouldn't that be awesome if it just fouled a plug LOL. how much would I feel like a noob? i mean, i am a noob but you know, noone likes feeling the truth i always thought bad plugs meant the bike wouldn't start, not that it would start then backfire.

Lots of people seem to think that when I went from a foam air filter to a k&n that it would ruin my jetting which is why i'm TRYING to confirm that if i'm running a 200 (with backfiring) and switch to a 230 (will not start) if a 210 is a good next jet to try or if I should be going the other way with say a 190.

I know there is lots of information about this and i've read alot of it, but unfortunately nothing out there says "if your using a 200 with backfiring and then try a 230 and it doesn't start, then use _____ jet." it also doesn't mention specific jetting for specific types of air filters, which again, is why i'm asking here.

I'd also like to mention that I think its crazy strange that my "stock" blaster had a 200 mainjet in it while the rest of the bike was stock. now when I put the "stock" jet in it, it wont even try to start. any suggestions as to what could be causing that? meh!!

Thanks!!

derek of colorado

oh, and as far as taking 9 months to get back, sorry... i'm not on a time schedule with my hobbies, i do them as I want hehe (and I have alot of them) ;P

 

[Larry's Shee]

Just funnin withe time schedule

 

[2-Stroker]

How do i start a thread? IM a new member