Pverra
New member
Jetting Newbie: project sled, came with exhaust can installed. I have gotten rid of can and gone back to stock exhaust ( too loud). I’ve made a few posts about lean condition, and exhaust very hot! In addition I feel running at WOT the engine RPM are way too high.
Pulled carbs off tonight, again, and checked the jets that are currently in it. The main jet has a marking of 131.3, and pilot is 40.
These seem to differ from stock numbers found in tech pages.
Question: if running stock exhaust, and experiencing symptoms noted above, should I be ordering the stock jets as listed in tech pages? Will this be causing my “lean” condition?
My gut is telling me go back to stock, with fuel / air screw at 2 turns out, as listed in specs.
Can anyone “in the know” please advise.
Thanks again.
Pulled carbs off tonight, again, and checked the jets that are currently in it. The main jet has a marking of 131.3, and pilot is 40.
These seem to differ from stock numbers found in tech pages.
Question: if running stock exhaust, and experiencing symptoms noted above, should I be ordering the stock jets as listed in tech pages? Will this be causing my “lean” condition?
My gut is telling me go back to stock, with fuel / air screw at 2 turns out, as listed in specs.
Can anyone “in the know” please advise.
Thanks again.
Pverra
New member
BTW , I am not looking for “performance” , just want it running right, and reliable.
74Nitro
VIP Member
Yes, I think what is happening here is the the previous owner was looking for better fuel mileage. Pilots should be 42.5 and mains should be 136.3, 133.8 and 133.8
Most likely the main nozzles are wore out so if you can get new ones still change them too. #24 in the picture.
https://www.cyclepartsnation.com/oemparts/a/yam/5003be67f8700212fc84098a/carburetor
Most likely the main nozzles are wore out so if you can get new ones still change them too. #24 in the picture.
https://www.cyclepartsnation.com/oemparts/a/yam/5003be67f8700212fc84098a/carburetor
74Nitro
VIP Member
I would think the mains could be left one size down from stock, so 135, 132.5 and 132.5
Pverra
New member
Again, this is new to me, so sorry if this is a dumb question. I only opened one carb last night ,a saw the jets were different, but when I see you guys list three different numbers, does that represent one carb would have a different size than the other two. If so, which side receives the larger? (For the main jet sizing)
Pverra
New member
It is very hard to see on the exploded version, but are referring to the brass collar that comes off once you remove the main jet, or the brass threaded part that the main threads into? If the latter, how is this removed\ changed. I have never had these out, and don’t see anything about removal in the tech pages.
sideshowBob
VIP Member
Again, this is new to me, so sorry if this is a dumb question. I only opened one carb last night ,a saw the jets were different, but when I see you guys list three different numbers, does that represent one carb would have a different size than the other two. If so, which side receives the larger? (For the main jet sizing)
On the Yamaha tripples the cylinders are numbered starting from the clutch side to the recoil side or mag side so the number one cylinder is on the clutch side and number 3 is on the mag side.
On the Red Head tripples the larger jet goes in the number one cylinder and number two and three cylinders use the same slightly smaller jet size.
You can find all the factory stock jetting specs if you go to the home page, technical and look at snowmobile specs and select your model year.
sideshowBob
VIP Member
When you clean your carbs make sure you also remove the floats, then the brass needle and seat and check the hidden "top hat filters" as they can cause real problems if they get plugged. I actually always remove those filters and discard them.
Pverra
New member
Awesome, thanks, I now understand, learning as I go!��
Pverra
New member
So, knowing what I have just learned, I went out to the shop and opened all three. Here are my findings: PTO sd- 133.8, Ctr & Chaincase-131.3
Pilots - 40 across all three.
My plan is to restore all to stock- 136.8/133.8,133.8 mains, 42.5 pilots / fuel screw- 2 turns from seated
My question, is this my “smoking gun” causing “lean” symptoms, once I switched back to stock exhaust?
Next question, are these a dealer item, or something I could get from Royal Distributing?
Pilots - 40 across all three.
My plan is to restore all to stock- 136.8/133.8,133.8 mains, 42.5 pilots / fuel screw- 2 turns from seated
My question, is this my “smoking gun” causing “lean” symptoms, once I switched back to stock exhaust?
Next question, are these a dealer item, or something I could get from Royal Distributing?
sideshowBob
VIP Member
So, knowing what I have just learned, I went out to the shop and opened all three. Here are my findings: PTO sd- 133.8, Ctr & Chaincase-131.3
Pilots - 40 across all three.
My plan is to restore all to stock- 136.8/133.8,133.8 mains, 42.5 pilots / fuel screw- 2 turn
Next question, are these a dealer item, or something I could get from Royal Distributing?
The pilots are only available from Yamaha so I would just go to the Yamaha parts micro fiche for your model and year and order all the parts that way.
sideshowBob
VIP Member
Has the P O modified the airbox? Make sure the shelf is still in the Airbox.
Pverra
New member
Has the P O modified the airbox? Make sure the shelf is still in the Airbox.
Yes, when I spli the air box, it does have a divider still, if that is what you are referring to. I did patch a hole I’m guessing was chewed by rodents at some point, about the size of a quarter, but definitely out of round, and didn’t appear “man made” with a drill bit or such. I used a black automotive goop from a tube and sealed it up.
74Nitro
VIP Member
I would probably have all those jets on hand, I live about 1.5 hours south of you.
Again, I would highly recomend changing the nozzles if the sled has lots of miles.
Again, I would highly recomend changing the nozzles if the sled has lots of miles.
74Nitro
VIP Member
See this thread, the picture on post #35
https://totallyamaha.net/showthread...00-XT-Mid-range-rough-using-lots-of-gas/page4
https://totallyamaha.net/showthread...00-XT-Mid-range-rough-using-lots-of-gas/page4
Pverra
New member
See this thread, the picture on post #35
https://totallyamaha.net/showthread...00-XT-Mid-range-rough-using-lots-of-gas/page4
Wow, those really are worn! This sled has about 14k on it so probably due. I can’t seem to find a step by step(with pictures ���� on changing those.
Where about s are you? I have a local guy I’m waiting to hear back from if he can source them, but good to know.
*sorry, I see it now, you are in Dublin
Pverra
New member
Looking for more advice. While I am waiting for my set of stock jets from the dealership, I have a few more quick questions. If the jets have been changed, it is possible they also adjusted the needle height. I see stock setting is “clip 3”. I can find no info on how to check, or change back to stock.
Secondly, stock main jet for PTO side is listed as 136.8. Dealer says they are “currently unavailable “. He says go with a 137.5 for main on PTO side. As I am unsure, is this good advice? Will this effect anything. All the rest of stock jets are available.
Thanks again.
Secondly, stock main jet for PTO side is listed as 136.8. Dealer says they are “currently unavailable “. He says go with a 137.5 for main on PTO side. As I am unsure, is this good advice? Will this effect anything. All the rest of stock jets are available.
Thanks again.