Ski-Doo Snowmobiles Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
889 Posts
Discussion Starter · #1 ·
lost a piston a couple weeks ago, so for precautionary measures put 400 main jets in it to make sure it would not run lean. i had it back for about a week with the new piston running it with the 380 main jets, (because the 400 main jets were on order) and it was running perfect. took it to the shop and got the 400's installed a couple days ago and ever since it was running like crap, once it got up over 6000 rpm it was fine but when i let off the throttle when the rpms drop between 6000 and 4000 the rpms would jump back and fourth like it didnt want to rev down and sometimes when at low rpms it would bog and feel like it was cutting out on one cylinder. i took it back yesterday and got the fuel screw adjusted, but that didn't make any difference. its at the shop today and the 380's are going back in it. im sure the jetting is the problem because before the jets were changed it ran perfect. i am running v force 3 reeds, an aaen pipe , and an mbrp silencer, are 380 main jets rich enough for this?
 

·
Registered
Joined
·
889 Posts
Discussion Starter · #4 ·
Shaneo13 said:
I would say yeah. But I'm not too sure when you throw in all the pipes and reeds and stuff. What alt. are you at???

[snapback]710301[/snapback]​
from 0 - 1500 ft
 

·
Registered
Joined
·
889 Posts
Discussion Starter · #6 ·
i think when i get the 380's in i will shut it down at full throttle and look at the plugs, i think it should be ok. any explaniation on why it was reving weird and working like crap on low rpms with the 400 jets?
 

·
Registered
Joined
·
889 Posts
Discussion Starter · #8 ·
Sports Motorsports said:
Likley because it was too rich.
You need to find the balance between lean and rich.
Lean=expensive, rich=runs like crap.
Loose the can for starters. You will likley be loosing power and consistency with that can.
[snapback]710383[/snapback]​
i was running the can for the last 2 and a half years and it was always constient, it was performing well all year , and it was since the motor was replaced, until the jets were changed, and today the jets were changed back to 380's and it is a little better but it is still not running good. any explaniation why this is happening even when the stock jets are now back in it?
 

·
G MAN
Joined
·
5,381 Posts
mike157 said:
Sports Motorsports said:
Likley because it was too rich.
You need to find the balance between lean and rich.
Lean=expensive, rich=runs like crap.
Loose the can for starters. You will likley be loosing power and consistency with that can.
[snapback]710383[/snapback]​
i was running the can for the last 2 and a half years and it was always constient, it was performing well all year , and it was since the motor was replaced, until the jets were changed, and today the jets were changed back to 380's and it is a little better but it is still not running good. any explaniation why this is happening even when the stock jets are now back in it?
[snapback]710517[/snapback]​
Try different plugs. Check your reeds too!
 

·
Registered
Joined
·
889 Posts
gman086 said:
mike157 said:
Sports Motorsports said:
Likley because it was too rich.
You need to find the balance between lean and rich.
Lean=expensive, rich=runs like crap.
Loose the can for starters. You will likley be loosing power and consistency with that can.
[snapback]710383[/snapback]​
i was running the can for the last 2 and a half years and it was always constient, it was performing well all year , and it was since the motor was replaced, until the jets were changed, and today the jets were changed back to 380's and it is a little better but it is still not running good. any explaniation why this is happening even when the stock jets are now back in it?
[snapback]710517[/snapback]​
Try different plugs. Check your reeds too!
[snapback]710567[/snapback]​
there should be no problems with the reeds there are less than 500 km on them, im guessing it has to be something with the carbs, probably something not put back right, because it worked perfect the day i brought it to the shop, but since the jets were changed it didnt work right , and even after they were changed back to the same as they were before it still doesnt work right. it is fine when accelerating and on the top end, but if i drive around 4500-5500 rpms at a consistent speed the rpms jump back and fourth by a few hundred. and when letting off the throttle it jumps around a bit in the low rpm range, like it doesnt want to idle back down.what kind of problems associated with the carbs could cause this??
 

·
Registered
Joined
·
1,032 Posts
mike157 said:
gman086 said:
mike157 said:
Sports Motorsports said:
Likley because it was too rich.
You need to find the balance between lean and rich.
Lean=expensive, rich=runs like crap.
Loose the can for starters. You will likley be loosing power and consistency with that can.
[snapback]710383[/snapback]​
i was running the can for the last 2 and a half years and it was always constient, it was performing well all year , and it was since the motor was replaced, until the jets were changed, and today the jets were changed back to 380's and it is a little better but it is still not running good. any explaniation why this is happening even when the stock jets are now back in it?
[snapback]710517[/snapback]​
Try different plugs. Check your reeds too!
[snapback]710567[/snapback]​
there should be no problems with the reeds there are less than 500 km on them, im guessing it has to be something with the carbs, probably something not put back right, because it worked perfect the day i brought it to the shop, but since the jets were changed it didnt work right , and even after they were changed back to the same as they were before it still doesnt work right. it is fine when accelerating and on the top end, but if i drive around 4500-5500 rpms at a consistent speed the rpms jump back and fourth by a few hundred. and when letting off the throttle it jumps around a bit in the low rpm range, like it doesnt want to idle back down.what kind of problems associated with the carbs could cause this??
[snapback]710588[/snapback]​
DPM hose not connected? Bad gas? choke adjustment correct? These are just some thoughts. Maybe the shop premixed so oil in with your gas to be safe and it if finally working its way through the system.
 
1 - 11 of 11 Posts
Top