95 hx 717 race motor backfires but wont

[2strokesmoke]

Recently purchased 95 hx that was raced yrs ago. When cranking it just backfires out carbs and exhaust but more from carbs. Ski has FPP and a micro touch wired into gray box. Also has 180 185 compression and west coast head. I took the 46mm buck shots off and high output fuel pump and installed ones from a 95 xp thinking that was my problem. Also checked rotary and set it to 147 dg.new plugs gapped corfectly.new clamps on hoses.iliminated primer and installed fuel selector and choke. Still just backfires...plzz help

 

[gazzaskirepair]

If you have contact with the previous owner ask what he set the rotary valve too
Back firing through carb is wrong timing , blocked exhaust and possible too much fuel ️

 

[NickCawks]

Sounds like your timing is off.

Since you said your RV timing was just set I would check the stator and make sure it has not come loose and is in the correct position.

This could also have been caused by the key on the flywheel shearing so be sure to check that while your in there

 

[2strokesmoke]

If you have contact with the previous owner ask what he set the rotary valve too
Back firing through carb is wrong timing , blocked exhaust and possible too much fuel ️

The cases have the little notch where to set it but in my book i thought it says 91 and later use degree wheel. Thanks for reply

 

[2strokesmoke]

I also tried notch had same result. Thsnks

 

[2strokesmoke]

Sounds like your timing is off.

Since you said your RV timing was just set I would check the stator and make sure it has not come loose and is in the correct position.

This could also have been caused by the key on the flywheel shearing so be sure to check that while your in there

Thanks i will!!

 

[2strokesmoke]

Ive seen multiple forums saying these Factory Performance Pipes can be tricky as well. Not sure if i should abandon this and go to stock pipe or something else?

 

[2strokesmoke]

If you have contact with the previous owner ask what he set the rotary valve too
Back firing through carb is wrong timing , blocked exhaust and possible too much fuel ️

Should i try going forward a tooth and or back a tooth?
Thanks

 

[mikidymac]

Do not use the notch or any marks on the cases or your timing will be wrong.

You have to use a degree wheel and set it off the top and bottom of the front intake port with the front piston at TDC per the manual. This is the only way to set the timing correctly.

The issue with the factory pipes was the first ones had the outlet stinger too small and would melt pistons no matter what you did.

Also you should not be using carbs off a 1995 XP, you should be using 787 carbs off a 1996 or newer XP.

I also see a gray fuel hose which is bad news.

What intake are you running? The carbs look like they are on their side instead of vertical as a 720 should be.

 

[2strokesmoke]

Do not use the notch or any marks on the cases or your timing will be wrong.

You have to use a degree wheel and set it off the top and bottom of the front intake port with the front piston at TDC per the manual. This is the only way to set the timing correctly.

The issue with the factory pipes was the first ones had the outlet stinger too small and would melt pistons no matter what you did.

Also you should not be using carbs off a 1995 XP, you should be using 787 carbs off a 1996 or newer XP.

I also see a gray fuel hose which is bad news.

What intake are you running? The carbs look like they are on their side instead of vertical as a 720 should be.

 

[2strokesmoke]

I shoukda joined this forum yrs ago. Thanks for reply. Setup on left is what i switched to from the rossier intake with buckshot carbs. The carbs on the right are different than ones i just now pulled out. Right side look like whats in my gsx. I should use those?

 

[2strokesmoke]

I shoukda joined this forum yrs ago. Thanks for reply. Setup on left is what i switched to from the rossier intake with buckshot carbs. The carbs on the right are different than ones i just now pulled out. Right side look like whats in my gsx. I should use those?

 

[Mekanix]

Stripped key on the mag flywheel.

 

[2strokesmoke]

Stripped key on the mag flywheel.

Took flywheel off and there was no key. The flywheel has 2 grooves and the shaft had 1 but there was no key . its a yellow flywheel says RAD on it. Which groove should i use to line up on the shaft when i get a new key?
Thanks

 

[mikidymac]

Since you are way into the performance parts on this one Matt Braley is your new best friend. He knows most of the parts you have.

 

[2strokesmoke]

Since you are way into the performance parts on this one Matt Braley is your new best friend. He knows most of the parts you have.

Thanks and id be completely lost right now if not fr u dudes.

 

[mikidymac]

Now where is @Matt Braley?

I am sure he can tell you which keyway to use on your flywheel.

 

[gazzaskirepair]

The link below has a bit of info on timing on RAD flywheels but if your not going to race I would get a stock flywheel
You need to adjust timing etc using those flywheels

Jetinetics Charging Flywheel and timing

 

[2strokesmoke]

Stripped key on the mag flywheel.

Shes a runner!

The link below has a bit of info on timing on RAD flywheels but if your not going to race I would get a stock flywheel
You need to adjust timing etc using those flywheels

Jetinetics Charging Flywheel and timing

Thanks!

 

[2strokesmoke]

I cant believe this thing runs. Was on fire 2 different times and days/weeks of labor and research. Its def hard starting. Have to keep hitting throttle but once it finally pops its really crisp. No power in water and when i pulled up off boat ramp and started it puked out some nasty lookin lard stuff from exhaust. I believe its sat through multiple owners since 2000.
I drilled jets out 075 and 1.4 on stock carbs. Seems like at first its not getting enough fuel.

 

[2strokesmoke]

If you have contact with the previous owner ask what he set the rotary valve too
Back firing through carb is wrong timing , blocked exhaust and possible too much fuel ️

Safe to say with flywheel key sheared and the crazy amount of not sure exactly that came out exhaust on boat ramp that u hit nail on the head!! Thanks im blown away right now. My neighbors im sure think i have terrets or sumthin from the amount of random F bombs and muthr Fers they heard this month

 

[2strokesmoke]

The link below has a bit of info on timing on RAD flywheels but if your not going to race I would get a stock flywheel
You need to adjust timing etc using those flywheels

Jetinetics Charging Flywheel and timing

Not sure if i should just part this thing out or sell outright. Its def more than what i would use it for or anyone around my area would. To make a fun fast ski thats not needing work all time what all parts would u take off. Factory performance header and pipe? Micro touch rev limiter? West coast head? Def the rad flywheel tho?

 

[mikidymac]

To make it fun and reliable I would go with stock carbs and pipe.

The head will be fine just running 91 octane and the flywheel will be fine also.

 

[2strokesmoke]

Then thats what il do. Some where i seen these pipes will burn up rear pistons. My rear piston is black on top and front one is still clean. Guessing from this pipe then.. What about the micro touch??
Thanks

 

[mikidymac]

You don’t need to the micro touch if you aren’t using the pipe.