RX1, backfires at low rpms??

[freelheeler]

03 rx1 with under the tunnel exhaust running at around 6-9000'
at just above idle the sled pops and backfires but at higher rpms it's running great? seemed to come on after adjusting the secondary and gearing down, plus there may have been some bad gas?? i've read alot about folks with this problem but no one seems to write back about what actually worked?? here's what i've tried

disambled TORS
used gas treatment

next steps...
new plugs
new fuel filter
clean the carbs

question...
should try adjusting the main jet i'm at 135 and the sled runs well at high rpms?
adjusting the needle?

spoke to the dealer and he thought maybe valve adjustment?? at 2000 miles???

 

[RXMax]

At idle your running off the pilot circuit you might try 20 pilots instead of the stock 17.5, also from reading your adventures, when is the last time you have sync'd your carbs since you have had your carbs off and on a few trimes. That will help as well.

 

[colorado yamaha]

At idle your running off the pilot circuit you might try 20 pilots instead of the stock 17.5, also from reading your adventures, when is the last time you have sync'd your carbs since you have had your carbs off and on a few trimes. That will help as well.

I'd look at the above also - we have a problem with water in our gas due to the extreme temp changes; and water will give an occasional "pop" just off idle or when cruising down the trail.

 

[freelheeler]

the sled seems to idle fine however the new lefty throttle will sometimes pull on the flipper, and it'll idle a bit high (200-300 above normal) till i flip the flipper and it settles back to normal. the local dealer claims they've never fooled with the pilots and seems to think i need to buy an APEX. so they don't have the 120 pilots in stock i quess i can call outlaws??

does adjusting the needle height affect the pilot and the main?
thansk

 

[BigFish BC]

make sure the lefty is not setting off your tps

 

[RXMax]

the sled seems to idle fine however the new lefty throttle will sometimes pull on the flipper, and it'll idle a bit high (200-300 above normal) till i flip the flipper and it settles back to normal. the local dealer claims they've never fooled with the pilots and seems to think i need to buy an APEX. so they don't have the 120 pilots in stock i quess i can call outlaws??

does adjusting the needle height affect the pilot and the main?
thansk

I wouldn't say that it will affect the pilot and the main but it will help a little. I would say you should sync your carbs and get your lefty working correctly before changing anything else. If that does not fix I would order 20 pilots and try as a band-aid raising your needles one clip.

 

[freelheeler]

take a look...??

 

[RXMax]

Plugs look fouled or from a lot of idle or slow speed running. Might be time for a new set.

 

[freelheeler]

i've disconnected the TORS and it didn't seem to make a difference the last time out, the lefty has been on for about 800 miles now i don't think it's the problem. what's the TPS?

on TY they mentioned coils? how do i tell if they're updated? i checked last night and i don't see sparks across the head.

the plugs look fouled to me as well could this mean the sleds running rich and i've got a loading backfire rather than a lean backfire??
thanks

 

[RXMax]

Improper starting like not letting the sled come up to temperature before shutting it down can cause the plugs to look like that or too much choke even when a sled is properly tuned. A fouled plug will cause a rich condition as the plug is not firing correctly for the amount of fuel present. Take the coils, clean them up good with brake clean, get some de-electric grease and lube up the insides and put them back on with some new plugs.

The TPS is the throttle position sensor.

 

[freelheeler]

could this have something to do with it??? went thru the carbs last night and while inspecting all the connections i noticed this little issue, looks like a mouse to me! i'd noticed a little crew mark on the gauge pod when i'd purchased the sled, and figured since i'd gone thru most everything else that was the extent of the damage?? i was wrong! both fuel lines from the tank to the pump have rather extensive damage which actually leak and look like he or she was eating a cob of sweat corn. i'm looking for new fuel line today!

so this could cause air in the line correct which could be part of the problem? the other issue i'm having is the o-rings on the main jets are torn up pretty good i reinstalled the pieces and parts and will order new ones today. plus i cleaned all the jets figured it couldn't hurt. the air box is always a pain to seal correctly so it was good to reset it.

When i went to start the sled it wouldn't start?? so i popped the hood again and moved the fuel around a bit and tryed again and it started right up. seems in certian positions fuel can move thru it??

 

[ski-bum]

what's the TPS?

TPS is the throttle position sensor on the fuel injected engines. Makes the Apex's run like crud at low rpm when they go bad, but doesn't apply to the RX1. Fix the fuel lines, change the plugs, and clean the coils. Coils do not hold up well on the '03's and you may want to upgrade to '05's if you continue to have trouble.

 

[x-ray]

had same problem turn idle screw up or disconect lefty throttle

 

[freelheeler]

update-

new plugs
cleaned coils
new gas lines
new o-rings on the main
cleaned carbs
reset airbox
gas treatment

backfiring has gone away, however i still have a bit of the burbles at low rpms but nothing like before.

here's something to think about. o-rings on the main were all but hanging on. my local auto mechanic had o-rings andwe ended up discussing the problem, he thought the lack of o-ring could be the cause of the sled running rich? allowing excess fuel to get around the jet?

overall the sled seems to be running really strong. even had an oppurtunity to ride a stock APEX. just not sure if i like them. got the apex stuck (engine break) and it felt real freak'n heavy and real stuck! when i get the rx1 stuck it just seems to work it's way up on top, the apex just sort of trenchs along.

thanks for all the help

 

[ski-bum]

Try installing a shut off valve on your carb heaters. I'm guessing you were high altitude in warmer temps.