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Discussion Starter · #1 · (Edited)
My 1990 Exciter runs great for 10 minutes or so and then boggs down at lower RPM's or climbing hills after warm up. Runs great at high RPM's. Shut it down for 20 minutes to cool and it runs great again for several minutes. Sometimes when bogging down, if you go easy on the accelorator, you can crawl it into higher RPM's. Once higher RPM's are reached it runs smooth until you slow down and try to start again or try to climb a hill. If you don't let off the accelorator it stalls out. I'm new to the sport so I have been reading all the threads I can for info. Seems like several owners of older Yamaha's have similar problems after warm up. I plan to clean the carbs but I'm not sure why, if dirty, they would only fail after it warms up. Anyone have any suggestions?
 

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Discussion Starter · #3 · (Edited)
Thanks for the help. That sounds like a large job. I read a thread about an 88 Exciter doing the same thing. He said the coils tested fine cold but dropped under specs after warm up. Does that sound right to you? The guy I bought the sled off of swears it never happened to him. The only electrical items I replaced were the plugs, which the prior owner bought so I can't say for certain they were the correct ones. Could that cause this kind of a problem? The plugs look black, not brown, but they don't look fouled. Sorry about all the newbie questions. Thanks again for the help.
 

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Discussion Starter · #4 ·
Cleaned the carbs and replaced the plugs. Runs better but still bogs down after it idles when warm. Seems like it's loading up with oil. I replaced the plugs with a hotter plug. (Went from a 9 to an 8) This made it run better but will it cause damage down the road? What's the best way to ajust the oil injection? Don't want to go to lean and toast anything. The cable from the throttle lever has looks like it can be adjusted in the middle. When removing the carbs I inadvertently tugged the cable and the outer casing seperated at the hex adjustment area. Is it normal to have enough slack in the cable to easily pull this apart? Any help would be appreciated.
 

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Candlman,

Well, I quess I will wade in on this, considering I have two Exciters and have suffered a multitude of problems myself.

First, clean the carbs good, I don't mean take them apart and spray carb cleaner in around the pieces, but buy a gallon container of carb cleaner and soke both carbs real good, then after washing them off, use a compressor and blow them out!

Second, make sure your chokes are adjusted properly when you re-install the carbs. Check that your jetting is correct for your altitude where you generall ride and the needle is correctly set in the proper groove. Pull the seat of your machine and replace the in-the-tank fuel filter and check that all your fuel lines are not kinked or bent in places that would obstruct flow.

You didn't state at what RPM the engine seems to bog? I had a problem with one of my machines, it appeared it was bogging down in the lower RPM range but would run okay, not great, just okay in the upper range, so I though fuel was the problem. Come to find out my primary clutch needed a rebuild with new rollers, spring, bolts , etc, then I put on a new belt and away I went, it wasn't a fuel problem at all!

I am sure you have probably check all this and then some, but sometimes we get sidetracked and lose sight of some of the more obvious things that we should be checking!

If you need anymore help, send an email to me and I'll see if I can help! Good Luck!

Dave
 

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Discussion Starter · #6 ·
Thanks fo the help

Do your Exciters tend to run rich? Mine smokes pretty good, even more when it's bogging down. What's the best way to check and adjust the choke on these? It bogs less with the one step hotter set of plugs but that seems like a bandaid fix to me. Thanks again for the help.
 

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Candlman,

In regard to the choke cable adjustment. First, make sure you have no kinks in the cable and they are free of any obstructions. With the choke lever in the off position, you should be able to reach down to the cables where they screw into the carbs and pull up on them, release them, and there should be some slack. If not, then an adjustment is in order, which can be done on the cables. If you had the carbs off, you should have been able to pull the choke lever and watch the cables move back and forth freely. I have seen the choke cables get moisture and rust in them after a period of time and will seize up, sometimes you can free them, others require that you replace the cables altogether.

As far as your oil injection, I could attempt to give you this information, but without a manual right in front of you, it would be difficult to understand how to check it.

Finally, you did not state what altitude and temperture you ride at. If your running that rich, where it smokes excessively as you state, then you've got a needle and seat that are not properly working, which is causing an excess amount of fuel into the motor, chokes not set properly or obstruction in the airbox. If your running close to sea level, say within a couple of thousand feet and your jetting is incorrect, say on the rich side, and your also running in warm temps outside, this will only magnify the problem. Also make sure you do not have any obstructions in the exhaust, this could cause additional problems as well.

Both my Exciters smoke when cold, which is to be expected, but after a lengthy warm up period the smoking is reduced considerably.

Dave
 

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Discussion Starter · #8 ·
Dave,
Thanks again for the advice. I'm going to check the choke adjustment and see if that helps. I'll let you know how it turns out.
Jeff
 

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Jeff,

I can't quit thinking about your problem with the Exciter. I got to wondering about the carbs, and do you know for sure if it is a power jet carb? If it is, when you had the carbs apart, how was the o-ring on the bottom of the center nut which holds fuel channel in place? Was it worn at all? The o-ring seals the port in the bottom of the float bowl in which the fuel must travel through the main jet, then up through the center of the metering tube and out past the metering rod to the engine. (Hope you can understand what I'm attempting to explain)

Anyway, if this o-ring is not sealing properly the vacuum of the motor, wether at idle or under full power, would draw an excess amount of fuel and cause a extreem rich condition, hence alot of extra smoke!

Just another thought!

Dave
 

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my sled had the same problem. my fix was the three into one throttle/oil injector cable. the sled would run good in the upper rpms becuase it could use all the extra oil that it was getting from the frayed injector cable which wouldnt shut off the injector becuase it was stuck in the casing. then u would stop and it would load up. i would deffinately check your cable and make sure it has some slack and is not frayed
 

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Candlman,

Well, I quess I will wade in on this, considering I have two Exciters and have suffered a multitude of problems myself.

First, clean the carbs good, I don't mean take them apart and spray carb cleaner in around the pieces, but buy a gallon container of carb cleaner and soke both carbs real good, then after washing them off, use a compressor and blow them out!

Second, make sure your chokes are adjusted properly when you re-install the carbs. Check that your jetting is correct for your altitude where you generall ride and the needle is correctly set in the proper groove. Pull the seat of your machine and replace the in-the-tank fuel filter and check that all your fuel lines are not kinked or bent in places that would obstruct flow.

You didn't state at what RPM the engine seems to bog? I had a problem with one of my machines, it appeared it was bogging down in the lower RPM range but would run okay, not great, just okay in the upper range, so I though fuel was the problem. Come to find out my primary clutch needed a rebuild with new rollers, spring, bolts , etc, then I put on a new belt and away I went, it wasn't a fuel problem at all!

I am sure you have probably check all this and then some, but sometimes we get sidetracked and lose sight of some of the more obvious things that we should be checking!

If you need anymore help, send an email to me and I'll see if I can help! Good Luck!

Dave
Lou?
 
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