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I just bought a 1988 Yamaha Exciter 570 twin for my son's,(14 Yrs. old) 1st. sled. The seller was able to get it started with difficulty. It ran, but roughly. The track runs freely and overall the machine is in very good shape and seemed to have ample power. It had not run for 2 -3 years.
I have moderate mechanical ability and have been sledding off & on for 20 years.
This sled has a manual primer, a manual decompression release and a choke. I'm not familair with the throttle switch used in the Mikuni carbs but I assume it functioned OK wnen the seller started it. Now, at home, I can't get it started.
First, I do not have an owners manual and really don't know the correct starting procedure and sequence with this sled using the choke decompression, etc. If it doesn't start initally when choked, can I hold open the throttle the way I do with my Polaris and have done with numerous Cats? I'm not sure with the carb throttle switch. (I've tried it but, still no start)
I noticed the primer line was cracked and a pinhole sprayed gas so I replaced the primer lines. New plugs and a squirt of oiled starter fluid & no luck. (I do have spark to the plug electrodes when pull started.)
I don't really want to start troubleshooting blindly.
My first thought was replace the fuel filter (any idea if it's in the tank or where on this sled?) How do I check the fuel pump? I'm hoping I don't have to rebuid the carbs.....
Any quirks or anything peculiar with this particular sled you know about?
Anyone with any knowledge of this model or maybe an old owner's manual would be very helpful.
Any help ideas or suggestions would be greatly appreciated.
PLEASE HELP Me get this Yamaha EXCITED again..........
Thank you so much for your thought and time.
Tom D.
ARTICMAN advised me very well on getting my 1987 Yamaha Exciter 570 L/C started and running. I bought it used and don't know it's history other than this sled had not run for a couple of years. I changed the needle and seat and cleaned both carburators. If he is still available, please ask him or other experts, the following question..............
My 1987 Exciter 570 L/C bogs down and loads up at low speed. ARTICMAN suggested using the next hotter NGK plug (BR8ES) which I intend to do. This sled is oil injected and I have been using Regular 87 octane gasoline.
My question is can I SAFELY USE A HIGHER PREMIUM OCTANE? 89 or even 92 Premium octane without fear of burning a piston or blowing a head gasket? There is almost 6K miles on the odometer? Your advise and expertise is greatly appreciated.
Thank You,
Tom D.
Answer -
Hello Tom,
First off I want to say that I am very sorry for not getting back to you the same day you sent me your question. I've been so busy at work I haven't been able to check my emails. As far as starting the engine, I would leave the decompression lever off, so that it's not in use. The choke should be a black plastic lever on those sleds. Pull/turn the lever all the way in the up position. Holding the throttle open will usually just flood the engine. Attempt to start it. If the plugs are soaked in gas, you don't need to use the primer. If the plugs are dry, push the primer 3 times and try to start it again. If the plugs are dry the filter could be an issue, and is generally located inline with the fuel lines about 6 inches down off the tank. It has been my experience with sleds that have set around, to have the inlet needle inside the float bowl stick and cause the engine to run ruff or not at all. My suggestion is to buy a carburetor rebuild kit and install it. Dennis Kirk has very good prices on their carb kits, at www.denniskirk.com. Generally you will get the best results that way. The best way to check the fuel pump is to just install a repair kit, as the pumps get old they don't deliver the fuel at their original pressure. Here is the Mikuni website: http://www.mikuni.com/fs-carburetor.html that fully explains the carb on this sled.
Here is the basic FAILURE TO START guide lines, I hope you find them helpful.
Remove and examine spark plugs. If fuel is reaching the cylinder in the proper amount, there should be an odor of gasoline on the plugs if they are cold. Too much fuel or oil can foul the plugs causing the engine not to start. Fouled plugs are wet in appearance and easily detected. The presence of fouled plugs is not a sure indication that the trouble has been located, however, the engine might have started before fouling occurred if the ignition system had been in good working order. With spark plugs removed, hold wire about 1/8 inch away from an unpainted part of engine and crank sharply. Be sure to check both plugs and wires, and also ground the other wire while check for spark. the resulting spark may not be visible in broad daylight but a distinct snap should be heard as the spark jumps the gap. If carburetor and ignition were both in apparently good condition when checked, examinee other elements of the engine such as crossed plug wires, or a fuel delivery problem.
DIAGNOSIS:
If the presence of fuel was not apparent on the plugs and the spark is good, systematically check the fuel system for the cause of trouble. Possible causes of lack of fuel could be: No fuel in tank, Frozen or clogged fuel lines or filter, fuel pump impulse line disconnected, Damaged or frozen fuel pump diaphragm, Carburetor dirty or improperly adjusted, including a sticking inlet needle. Also try removing the muffler and checking for clogged ports. The proper plug to this sled is: NGK BR9ES, gapped at 0.028in. but if you have trouble with fouled plugs you may want to use the NGK BR8ES. I hope this helps you, and let me know if I can answer any other question you might have. Good luck to you and your son with his first sled! Arcticatman
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Hello Tom,
Have you tried to contact me recently? I am very sorry if you have had a hard time trying to get in contact with me. It appears we have had a little trouble with the Allexperts server. Glad you were able to get the sled running. I have not studied the aspects of running lower or higher octane gas in snowmobiles. So, to answer your question I have taken the advice from the expert team over at Snowgoer. As a side note, I have run high, medium and low octane gas in my Yamaha, Arctic Cat, and Ski Doo, with not so much as a small problem. Here is the advice from the team:
" There is no danger in using higher-octane gasoline in your snowmobile than it requires-but there's also no point in using it. The octane number of gasoline is an indication of that particular fuel's resistance to detonation. High performance engines with higher cylinder pressure require high-octane fuel to keep them from detonating. The high octane gasoline doesn't provide more power, but it allows a high performance engine to make the most power it can without detonating. There are some high-octane race fuels that are "tuned up" with a few non-gasoline additives that could be damaging to your engine if it is not jetted for their use. If the fuel you want to use is good old 92 at the pump gas, you will have no problems.
Hope their help answers your question properly. As far as the bog down problem, I have a few ideas that may help you. Basically, I have these recommendations to take a look at.
1. Float height.
2. Coil.
3. Spark plugs
4 Oil.
Starting with the float height, with a new needle and seat, nearly all new needles and seats are a bit different in length than your OEM ones. When this happens, it causes your float to be set at a different height. What I recommend is to remove the carb(s) and take the float bowl off. Then, lay the carb on it's side. Take the float arm and pull it all the way down. Now, begin pushing the arm back up. Right at the point where the arm's tab contacts the inlet needle, stop. The arm should be parallel with the carbs body, horizontally straight. Make sure that the inlet needle is pushed up, but no pressure is on it, especially if it has the spring loaded pin that the float arm tab contacts. If the arm is not straight, bend it with needle nose pliers until it is just right.
Next, the coil. They weaken over time, and begin to not put out the amount of voltage they should. In this case, over time they cause plug fouling. You may want to have it tested, or replace it, you can get a new one here: http://216.37.204.202/yamaha_oem/YamahaSnow.asp?Type=13&A=4&B=33
It seems to be the evil of snowmobiles, spark plugs. Sometimes I see guys with pre 1990's snowmobiles carrying 10 packs of NGK in the back of their sleds. Some sleds just foul and foul. The best solution here would be changing the spark plugs you are using. I have made the change to using Champion Powersport plugs not too long ago. They last nearly all year, and work very well. they cost about 3 a plug, and are available at Wal-Mart. I would recommend using the BR8ES equivalent. This will really make a difference. Unless you have a newer sled, NGK BR9ES are going to make your sled smoke and bog, and sooner or later you will be running beside it trying to get it home, because it won't have the power to carry you.
Oil. Any cheap oil will speed along the fouling process on your plugs. The most ideal oil is Amsoil of any type. It is made for snowmobiles, and can't be beat. Other than that, any oil manufactured for snowmobiles, ideally JASO or JASCO certified oil is best. Synthetics work great. Oil's that are NMMA or TCW3 are not good oils for your sled. They work good in the boats, but will wreck havoc with sleds.
I hope this helps you out. Let me know how you make out. If you need any help at all, let me know! Good luck with the sled! --Arcticatman
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