Exciter knowledge 101

For one, if you have the stock pipe on it your over revving by 500 rpm. The SX should run at or very near 7500 rpm. After peak RPM you are loosing 15-20 hp per 250 rpm. So you could be loosing as much as 40hp by running at 8,000 RPM. Also if you could post a pic of the piston damage I could tell you with more certainty what is wrong.
For starters, are you running the stock air box?? Stock pipe?? Im doubting you have an oil related problem and I would bet your burning up the mag side piston or both with the mag side showing more damage. Im guessing the crank seals are shot judging from my experience with the 570's. Another question is, what brand of piston and rings are you using?? Are you using 91 octane fuel??
 
Ok, I just re-read your original post. You basically run the throttle wide open, then your blowing the motor?? You say your running 142.5 main jets??? That would explain your issue. That is rediculously lean unless your at 10,000' elevation and running in 90 degree weather. lol. The stock jetting is 155. Now with your Decker pipe, I wouldnt be surprised if it would have to be increased at least one size to say, 157.5?? I dont have the specs on that pipe but I am just speculating with the knowlage of other pipes I have run.
Where are you located and whats your elevation?? If you are under 3,000 feet I would try 157.5 mains and check the plugs often. Now that the season is almost over and the temps are a bit warmer you may have to test next year in cooler temps to get your jetting spot on.
Im guessing that you are still over revving a little at 8,000 rpm. Most single pipes for the SX peak at 7500 RPM. A few peak as high as 7750 so you still should do some clutch tuning.
 
The sled came from Idaho an its clutched for the mountains, just to get going have to get her to 3k rpm then no power to 6k then after 6 its hold on. I don'tknow much about exciters have always had Polaris, main clutch has a purple spring? I'm in Roseau mn, brought the carbs to a shop an they said jets were right, its a reputable shop so I took his word, another thing is my throttle is loose. I can give it half throttle an don't move, I've bought 3 new cables all different lengths an all are the same, ive took my bar riser off worse yet, I have a 3 inch rise 5 inch, an a 8 inch. With the 8 its still an 1\4 inch of play, I don't hold the throttle wide open I slowly feather my way up
 
Last edited:
Like I said, stock mains are 155. I would run 157.5 main jets. Check your plugs often. You can always lean it down if your overly rich. Check to see that the needles are in the middle position as well. As for clutching, I would shoot for a 4,000 to 4500 engagement. If your running a Polaris primary, 52-54g weights and red Polaris spring should do the trick. The purple spring may be a comet?? 52g weights work pretty good with that spring. Do you know what weights are in your primary?? Are you running a yamaha secondary or Polaris??
 
No clue on the clutches, I have never messed with one. Don't wanna f*** something up. Heard they are a bitch, I've got a long track an I wanna try to keep the launch as I ride in powder. Will that set up still work? Decker pipe "says" 12-20 HP increase, also what's a good gas pre-mix I can run or can I trust the oil pump?
 
Last edited:
gman95 said:
What's a good gas pre-mix I can run or can I trust the oil pump ?
Click to expand...
Ditch the whole oil injection system completly and run only pre-mix.

1/40 will give you a pre mix combination with 2,5 % two-stroke oil and the Exciter engine will run lika a champ.
 
Lasse said:
Ditch the whole oil injection system completly and run only pre-mix.

1/40 will give you a pre mix combination with 2,5 % two-stroke oil and the Exciter engine will run lika a champ.
Click to expand...

Dude,,

What is your problem with Yamaha oil injection???

Seems like when ever there is a question about it you recommend tearing it all off, tossing it in the trash and pre-mixing.

Don't know how it works in Sweden but here in the states you can easily ride for 100's of miles (many 100's of KM's) in a day and never see the same trail twice. Having to refuel multiple times in a day a long distance from home is not uncommon. Premixing at a gas station is just a complete pain in the a$$. That is why Yamaha invented oil injection and it works just fine.

???

opsled
 
With Polaris if you adjusted the oil pump too much the screw set an then blow your sled, happened to me twice on my super sport. With premix you know exactly what mix it is running, only hard part for me is getting the right mix
 
You still havent found an RPC single Lasse?? I'll keep an eye out for ya.
Im in total agreement with Opsled on the oil injection. Keep the injection!! The oil injection on Yamahas are very reliable. I've only seen one pump fail on an Exciter and I would believe it was because someone ran the sled out of oil a few times. There was also over 17,000mi on the odometer.
As for clutches, primarys are a piece of cake to change springs and weights. If you know how to use a wrench, you can change the tuning parts. The secondarys are easy to take apart, but require a bit of coordination to re-assemble. You develop a knack after you send a few retaining clips across the shop. LOL
To really get your set up going it is very important to know what you have for clutch components.
 
gman95 said:
With Polaris if you adjusted the oil pump too much the screw set an then blow your sled, happened to me twice on my super sport. With premix you know exactly what mix it is running, only hard part for me is getting the right mix
Click to expand...
Im not sure what your talking about exactly. Any motor will blow if you adjust the oil pump too lean. I believe when the polaris style pumps go bad they will over oil. Basically running the oil pump wide open. Do what you want, but Yamaha was the pioneer with oil injection and has had it on their sleds for over 40 years. I believe they started it on their bikes in the early/mid 60's. If it is such a crap design they would have scrapped the idea way before your Exciter was built.
 
opsled said:
Don't know how it works in Sweden but here in the states you can easily ride for 100's of miles (many 100's of KM's) in a day and never see the same trail twice. Having to refuel multiple times in a day a long distance from home is not uncommon. Premixing at a gas station is just a complete pain in the a$$. That is why Yamaha invented oil injection and it works just fine.
???
opsled
Click to expand...

;)! ;)!
 
I thought I would bring this thread back to the top with some info. For years I have heard guys talk about using Exciter Sx pistons in std Exciters because of some performance gain. I happen to be extremely bored today (too dang cold to do much) so I sat down with a caliper and compared an Exciter Sx piston to a std 88R piston. There is absolutely NO measurable difference between the two pistons at any point or angle. I measured every possible start and stop point. So why does it have a different part number????..... The ONLY difference is........... the locating pins for the rings are 2.5mm closer together on the Sx piston vs. the 88R. Its been a while since I looked at an SX cylinder but I do remember there is no bridge on the intake port, and Im going to make a safe guess that the upper portion of the intake port has to do with where the locating pins need to be. I thought this would be some good info to add.;)!
 
I've got an 88 exciter that bogs down was wondering if anyone has ever experienced this and what would be the problem ? Carbs cleaned new plugs. sometimes I have to feather the trotted to even get going and other times it goes but won't stay at top end. Any help would be appreciated.
 
Shaun said:
I've got an 88 exciter that bogs down was wondering if anyone has ever experienced this and what would be the problem ? Carbs cleaned new plugs. sometimes I have to feather the trotted to even get going and other times it goes but won't stay at top end. Any help would be appreciated.
Click to expand...

Shaun,
I have a 90 exciter that's doing the same; however, mine tops out initially. I've tried a lot of things but I'm now replacing jets, I am putting new vent lines on. I've inspected my floats, reset my air screws, ran bottles of cleaner and soaked parts then flushed with compressed air. I think I'll clean my airbox and inspect boots to carb for rips in rubber, members have mentioned stator but I hope it's carb related. I've purchased sets of main jets a size up and down from factory for my elev. and temps just in case. Choke cables seem to function well and opening my fuel tank doesn't fix the issue. My post "Understanding my new/used 93 Exciter" ends up being plenty of discussion and advice from some senior guys on my 90 bog issue.

Good luck!
 
Choke cables are prone too sticking from water dripping into the flipper over the years,If it was me I would remove the cables right out of the carbs when it bogs and see if you can pull the barrels down.Plugs should be black when it bogs if it is over fueling.Too mutch oil and rich jetting on a warm day will cause a bog at least on my old 90.I added a hole in the air box to grab more air on warm days.
 
Bluewho,

Are you saying even if the machine, from a cold start responds to being full, half, then no choked is driven till a bog condition arises, pull the brass and cables to see if either can be extended out to a "no-choke" position?

My 90 Exciter has a hole approx. 1/2" round above the carb intakes as well as the factory cut back in the corner. Are the more areas that can be cut out safely?

At 1200-1300 ft. Above sea level and northern MN winter temps would you try sizing down one on mains and going to 310 jets and trying 2nd from top needle clip position to resolve a persistent mid range bog experienced usually while coming down for a corner or trying to get back on it from mid range/half throttle?

I always experience excessive rich smelling smoke...?
 
You must log in or register to reply here.


Back
Top