I have a buddy with a late eighties/early 90's exciter 570 (do not know right now). It has been sitting for two years, so I went over and tore his carbs down last night, and the sled now runs great to half throttle. Much over that, and it bogs. If you squeeze full throttle, it bogs no matter what RPM you are at. I pulled the belt to eliminate the clutches, same thing. The carbs were very dirty, so I will be pulling them again to re-clean. I also thought maybe coil? Weak spark? Also, these are round slides, but are kind of different. There is a sensor or something across from the idle adjustment screw. Looks like at one time it had wires hooked to it, and it extends into the mouth of the carb. What is that? It also has a fuel line from the base of the fuel bowl to the rear of the carb. ??? any help with this carb (and problem at hand) would be greatly appreciated. Also, it has a choke cables, and what looks like a compression release, and another toggle that may be a fuel cutoff?? Is that correct, and is there anything I should be looking at with these? The thing just refuses to go over about 5000 RPM.

Thanks!

Jimbo

Ok as a former Exciter owner here is some info.

First. Never run the engine without the belt. Idle might be ok but testing WFO without it can result in motor being scattered all over the garage.

The sensor thing with the wires off both carbs is the TORS. I would recommend disabling the TORS system these switches are not to reliable. This is the thing I would do first. TORS will keep the motor from spinning much higher than 4500.

WFO bog. How many miles are on the motor? Since you looked at the carbs maybe there is a problem with the reeds or something stuck in the exhaust pipe. Also was the decompression valves removed and plugged? That was on some of the earlier motors like my '88. The decompression lever on the right side allows easier starting but really is not an issue and should be plugged. The lever on the left side is a remote fuel shut off. There is a valve near the gauges on the right side of the machine that cuts off the fuel.

I have a picture of the left carb at http://www.mykeeshond.com/snowmobile/exciter%20carb.jpg hopefully it will be just like yours.

FuzzButt has some solid advice on the TORS Throttle override system.
On the newer Excites there is a TOR sytem light on the dash, older ones just mention the system in the manual. Anycase, Disconect the system and I bet that will sovle the bog.

Certainly sounds like this TORS. How does a person go about disabling it? There are no wiresa hooked up to the sensors on the carbs. Do I need to find the wires that were hooked up and short them across?

I only pulled the belt off for a quick rap on the throttle and killed it, just to rule out the clutches. I know, not real smart, but in a pinch...

Thanks for the replies, I am sure you just saved me a bunch of troubleshooting time!!

Jimbo

any chance you have a main plugged and not letting the additional fuel in???

OK. I was off on the year, it is an 86. I looked at the TORS thing, could not find the wires, so I am assuming it did not come on the 86. So I pulled the carbs and fuel pump. Pump looked good, as did the carbs, but I tore them down and cleaned them again anyway. Left the airbox off to make sure carbs were close to synched, ran better, but still high end bog. I am having my buddy pick up a pump kit today and we will try that tonight, even though the pump looked fine. I also pulled the pickup/filter out of the tank and it flowed perfect. I can get it to 7000 on the stand with a little work on and off the throttle, but get that cool bog once on the ground. If I feather the throttle I can get 35-40 mph, but anything much over 2/3 throttle and it bogs. Is there something else I might be missing???

Thanks!!

Jimbo

i think that it might be the carbs. even though you cleaned them already are all the ports free? when u run it try putting it on half choke and see if that works out.
maybe you just dont have the needle and seat adjusted correctly

I will try that tonight and see what happens if the pump does not fix it. It would not surprise me, the carbs were filthy. I did use good cleaner and an air compressor to clean, though.

Jimbo

Well, I have to switch gears now. before I got overr to look at it, he took it across the yard a couple of times to see if he could get the machine to magically come out of it. Well, after cruising up the yard and back a few times, it quit. Now we have no spark at all, wich leads me to believe maybe I have been following the wrong path here. I have not looked at it yet, he was so frustrated after dragging it back to the garage that he just went inside and did not want to look at it. (can't say I blame him, long drag). Any ideas? Things I should look for specifically?? Thanks in advance!

Jimbo

i have the same problem with my 92 exciter. the carbs are soaked and clean. it did run great earlier in season on the grass but know it will run to about 6500 ok after that it has a rich bog and falls flat on its face. please help

jim i hope you see this. im having the same exact problem and i cant figure it out. :bash:

it seems almost as if the timing is messed up. like the pulser is bad or the cdi. do any of you have a yamaha manual that can tell me the resistance reading of the pulser coil?

could it be the stator? or the cdi or the pulser? i already changed the coil and thats didnt make it any better.


thanks Bill

Jim,

Well, I will try and take a stab at this problem, since I own two Exciters. First the carbs are Mukuni, 38MM, but they made a couple of different styles, and it sounds like you have the ones with the power jet. Reason I say this is because you made a reference to a hose coming from the float bowl, which goes back to an inlet on the carb inlet side. In the carb you have two sets of jets, one is the main jet (stock is a 320) and the other is the power jet (stock is 160). The power jet functions like a power valve in a Holley Carb. In essence when you give it a quick snap of the throttle (like when you take off) it will allow extra fuel to flow to take care of any low speed lean condition. Are you sure the jets are in there correct location?

I guess the next thing I was wondering is at what altitude do you generally run your machine and what are temperatures you normally have. I generally ride at 6000-8000 feet and our temps are generally in the low to mid 20's. On my machines (1-1990 the other is a 1991 Exciter II) I have them jetted with 290 mains and the powerjet is left unchanged at 160s. If I wanted to play with them I could also lean the powerjets down a hair, but they both run fine and my plugs look wonderful!

I have also bypassed the TORS system, which on my 1991 was giving me intermittent problems, but after bypassing it I have had zero problems. I have probably not told you anything that you don't already know and have checked but I'm just trying to be helpful. If you need anything else holler and look up the spec's in my manual.

Good Luck........Dave

I am also having a problem with my Exciter. When I first bought the sled you had to have the choke half open to drive it around. It would only hit about 50-60. I took apart the carbs and cleaned the jets out with torch tip cleaners. I started the sled up and the sled idled and ran without the choke being on. I though I fixed it but when I took it out for the test run it bogged down bad, when I tried to open it up. Now it will only go about 30-40. If you hold the throttle wide open it bogs right down and doesn't move at all, and when you let of the throttle it stalls out. The tors system has already been disconnected, the carbs were cleaned, new fuel lines were put in and I put another fuel filter on it before the pump. I checked to see if it was running on both cylinders and it is. When you run the sled and pull the choke open it starts to stall out, it doesn't make it run better.
My second problem is when I am running my sled very slow, barely moving it feels like you are in a tank. You can feel the sled edge forward and let go over and over. When you give it gas and bring up the rpms to go faster you can't feel it anymore. I was wondering if the track is loose or if my clutch is messed up.
If anyone can help out this first time sled owner I would be grateful.

Scott,

You stated you clean the jets, did you pull the pilot jets and clean them also? Next, you said you put a new fuel filter on just before the pump, did you take out the inline fuel filter which is in the tank? I take it your fuel pump is in good working order?

What is your engagement RPM, factory states this should be around 3700 - 3800 RPM depending on what elevation your at. If your engaging to low, say around 3000 RPM, this will labor the motor and cause a bog also.

As far as the sled inching forward, have you check your clutches and belt. Sometimes a worn belt will sit to far down in the secondary and your gear ratio changes which will cause a bog and the secondary will also hang on the belt, not releasing or shifting all the way back. Also check your center to center distance between the primary and secondary clutches. (should be around 10.5 inches) There is a multitude of things which could be causing your problem, I have just given you a couple to check. But, by far, the first I would be checking is the fuel system, boiling the carbs and checking every orifice for obstructions (had this problem on one of mind).

Good Luck..........Need any specs, give me a holler............Dave

I checked my air settings and they were out way to far. I put them in to the factory specs, actually I went 3/4 the way out instead of 5/8 out. The sled about put me off the back. It now runs the way it should. I was checking out the fuel line that goes from the carb down to the float tank, and noticed that there is a little silver ball about the size of a BB. Is that supposed to be there? Thanks for your time and your knowledge.

Originally posted by jims1969bt@Feb 18 2004, 07:40 PM
I will try that tonight and see what happens if the pump does not fix it.* It would not surprise me, the carbs were filthy.* I did use good cleaner and an air compressor to clean, though.

Jimbo
271441

carbs for sure..make sure they are level..there should be something on the airbox to line it up...i had the same problem

well if your getting rpm's and can hear it rev it probably has something to do with the track or clutch......if no rpm's check fuel pump and if the carb is on correct...maybe a gasket issue as well, but probably not...make sure you are using correct jets and they are not in bad shape or that the floats are letting correct amount of gas..float arm might need to be adjusted