My Sled Backfires Then Won't Start - Snowmobile World : Your #1 Snowmobile Forum

Reply
 
LinkBack Thread Tools
post #1 of 19 (permalink) Old 01-17-2004, 09:21 PM Thread Starter
Senior Member
 
FreezerBurnt's Avatar
 
Join Date: Mar 2001
Location: Sudbury,Northern Ont
Posts: 4,869
Arrow

I Went to go sledding today

My bros has tried to start the sled the past 3 days

it starts then backfires after acouple of minutes

So today I went to start it

It started allright

Then backfired the filter on top of the airbox flew about 8 feet in the air :dazed:

would not start after that

So I took the carbs off to clean them,the back of the airbox was split open,I guess from the back fire

Cleaned the carbs

Put them back on and started the sled again and it back fired again then would not start

So I call the Doo dealer the service guy says it might be the coil

What do you think? SWRules

I am baffled

Current sled 01 ZR 700 X
3.5 Oles Machine riser,1.25 ripsaw,388/389 rear springs,45deg hooks,Shell Utra Oil

Previous sleds
-69 Dauphin--71 SW 396--75 GPX338--85 Safari 447--87 Safari 377
89 Safari Scout E--84 SRV 540--86 SRV 540--91 Indy 500--87 Indy 400
2nd 91 Indy 500
--95 STX 583-- 01 ZR 600 VEV
Current weather in Chelmsford
FreezerBurnt is offline  
Sponsored Links
Advertisement
 
post #2 of 19 (permalink) Old 01-18-2004, 05:40 PM
Member
 
Join Date: Oct 2003
Posts: 78
thats a good one! i can picture that foam sponge popping into the air. as for a fix..dunno. backfiring that bad out the carb is usually lean on fuel or timing way off. i know neither of those you probably fiddled with though. bad coil usually causes intermittent loss of spark after warm up...but that is not a rule set in stone. i guess try a coil from another sled and epoxy your airbox back together. is that sled reed or rotary valve induction? broken rotary valve or valve timing off?
sfrgnmaguire is offline  
post #3 of 19 (permalink) Old 01-18-2004, 09:05 PM Thread Starter
Senior Member
 
FreezerBurnt's Avatar
 
Join Date: Mar 2001
Location: Sudbury,Northern Ont
Posts: 4,869
Unhappy

How would I check the timing?

Its a rotary valve 583

Could it be sucking air?(carb boot)

It ran good on the monday I put about 40miles that day

Bros put another 15

But on tuesday he said the sled started he let it wamr then went to leave it backfired

Tryed wednesday and thursday and all it did is start then backfire

So I clean the carbs saturday

It has stock jets

Will check compression tomorow and try another coil before buying a new coil

thanx SWRules

Current sled 01 ZR 700 X
3.5 Oles Machine riser,1.25 ripsaw,388/389 rear springs,45deg hooks,Shell Utra Oil

Previous sleds
-69 Dauphin--71 SW 396--75 GPX338--85 Safari 447--87 Safari 377
89 Safari Scout E--84 SRV 540--86 SRV 540--91 Indy 500--87 Indy 400
2nd 91 Indy 500
--95 STX 583-- 01 ZR 600 VEV
Current weather in Chelmsford
FreezerBurnt is offline  
post #4 of 19 (permalink) Old 01-19-2004, 11:21 AM Thread Starter
Senior Member
 
FreezerBurnt's Avatar
 
Join Date: Mar 2001
Location: Sudbury,Northern Ont
Posts: 4,869
TTT

Current sled 01 ZR 700 X
3.5 Oles Machine riser,1.25 ripsaw,388/389 rear springs,45deg hooks,Shell Utra Oil

Previous sleds
-69 Dauphin--71 SW 396--75 GPX338--85 Safari 447--87 Safari 377
89 Safari Scout E--84 SRV 540--86 SRV 540--91 Indy 500--87 Indy 400
2nd 91 Indy 500
--95 STX 583-- 01 ZR 600 VEV
Current weather in Chelmsford
FreezerBurnt is offline  
post #5 of 19 (permalink) Old 01-19-2004, 01:27 PM
Junior Member
 
Join Date: Sep 2003
Location: Mountain View , Wyoming
Posts: 24
It could possibly be the cdi box.
summit33 is offline  
post #6 of 19 (permalink) Old 01-19-2004, 06:00 PM
Member
 
Join Date: Oct 2003
Posts: 78
bad cdi will usually mean no starts. you will have to go to the manual for motor timing or rotary valve timing...complicated. try the simple stuff first. my bet is still bad high tension coil.
sfrgnmaguire is offline  
post #7 of 19 (permalink) Old 01-19-2004, 06:59 PM
Administrator_X
 
idooski's Avatar
 
Join Date: Mar 2001
Location: SW Michigan!!
Posts: 5,122
That is a good one!

I have a hard time thinking it may be the coil. It can cause problems, but it certainly won't make a cylinder fire early and it has to fire to early to blow thru the carbs. Have you checked the plugs? I assuming you did, but I don't see where you say whether you did or not. I would check compression first and look for a broken ring or a hole in the piston. No dents or obstructions in the pipe? It could be the CDI, but I doubt it. You might also want to check to be sure that when one piston is at the top, the other is at the bottom where it is supposed to be. Rotary valve timing won't make it backfire.

Give us all the details - year, model, miles, work done, etc. I'll look into it a bit more when I have all the details.
idooski is offline  
post #8 of 19 (permalink) Old 01-19-2004, 10:46 PM Thread Starter
Senior Member
 
FreezerBurnt's Avatar
 
Join Date: Mar 2001
Location: Sudbury,Northern Ont
Posts: 4,869
Lightbulb

Stock 1995 STX 583

14,000kms

365km this year so far

no rebuilds,cleaned RAVE valves(clean btw) 125psi both sides in Nov,but will check compression this week

Stock jetting

I have the 1995 Skidoo manual

Cleaned the TRA last week,clutch bolt used to get loose(previous post in tech btw)

Bros has been fouling plugs right and left before this situation,he says both sides one day PTO another day Mag

BTW like I said before I have never fouled plugs on it I have had it for 3 yrs

Once he put new plugs it would run fine

But not this time,tryed all the old plugs still no go

Prime it it starts then goes to die out and then backfires :dazed:

The sled is stored outside ,tarped of course

Temps have been -28-36c at night and -17-26 daytime,maybe ice in fuel

I just brought the sled to my bros inlaw into the heated garage to thaw out tonight,will drain gas from tank and put some fresh gas

No dent in pipe/muffler

Have recoil from older 503(doo recoil are POS),3rd recoil in 3yrs

Clean carbs Saturday and still no go

Current sled 01 ZR 700 X
3.5 Oles Machine riser,1.25 ripsaw,388/389 rear springs,45deg hooks,Shell Utra Oil

Previous sleds
-69 Dauphin--71 SW 396--75 GPX338--85 Safari 447--87 Safari 377
89 Safari Scout E--84 SRV 540--86 SRV 540--91 Indy 500--87 Indy 400
2nd 91 Indy 500
--95 STX 583-- 01 ZR 600 VEV
Current weather in Chelmsford
FreezerBurnt is offline  
post #9 of 19 (permalink) Old 01-19-2004, 10:50 PM
Administrator_X
 
idooski's Avatar
 
Join Date: Mar 2001
Location: SW Michigan!!
Posts: 5,122
idooski is offline  
post #10 of 19 (permalink) Old 01-20-2004, 04:32 AM
Member
 
Join Date: Dec 2003
Location: Wasilla, AK
Posts: 90
Send a message via MSN to MXZ_AK_Adam Send a message via Yahoo to MXZ_AK_Adam
ive never been ito these motors a wole lot, but how does the ignition trigger work?...magnet style crank snesor trigger?...ive seen those come loose and move around, causing the ignition timing to be off...but im not sure..i havent been inside yet. Check the primary windings?...see that everything is sound under the recoil magneto. If its firesoming out of the intake, its gota be firing before the piston closes the intake port off. Unless there is a way for one firing cylinder to backfire thorugh the other cylinders intake due to a broken rotary valve?...since there is only one valve for two Cylinders?....ideas, but i havnt been inside yet...

97 MXZ 670 outfitted with a 136", 2" track, 8 tooth finals, and aluminum tunnel extension.
MXZ_AK_Adam is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Snowmobile World : Your #1 Snowmobile Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome