Mach 1 Engine noise, 1998 Mach 1 "pops" Options

[Yamdoo]

I am new to snowmobiling and bought a 1998 Mach 1 for my wife. Starts first pull, runs smooth but yesterday when I started it there was some distinctive knocking in motor at random times while it was warming up. It didn't do it when I gave it some throttle but did it when running at 2000 rpms...thoughts?

[djuseless]

I am new to snowmobiling and bought a 1998 Mach 1 for my wife. Starts first pull, runs smooth but yesterday when I started it there was some distinctive knocking in motor at random times while it was warming up. It didn't do it when I gave it some throttle but did it when running at 2000 rpms...thoughts?

Start will the simple obvious stuff, check the plugs, put brand new ones in, and be sure they are the correct ones. Sometimes on a used sled, some yahoo will but the wrong plugs in.

While changing the plugs, make note to look down the plub hole with a flashlight, and make sure that there is no garbage or metal flakes from a bad piston or ring.

Are you getting proper oil lubrication. If you dont know alot about sleds, just check your oil reservoir, you should be using roughly a 1/2- 3/4 quart of oil to a full tank.

If its carburated, which is probably is, clean the carbs. If you dont know how to do it, at least buy some K100 and some fresh fuel and just run the thing. Sometimes water or gum can build up giving you a rough idle and poor performance.

Lastly, check you airbox, make sure its clean and free of mouse droppings or nests. Lack of air will cause the engine to load up and stall out, pop and run like crap. Used sleds sometimes are stored in poor conditons and Junk gets in the air box

[djuseless]

air box is suspect to me from your symptoms. Its easy to fully remove it, clean it out and re-install. Where the airbox attaches to the carburator, check the rubber boots and make sure there are no cracks. Sometimes that can cause issues too. Simple setup, you need Air, fuel and spark for an engine to run..... start with the simple stuff, clean airbox for air, new plugs for spark, and new fresh fuel with K100 in it. I would bet one of these things are the problem.

[grasshead]

DJ he says the motor runs just makes a knocking sound a few time at low rpm so the motor is running and runs fine at higher rpm. A knocking sound at lower rpm could be in the primary clutch before it starts to engage? or something is loose. If it was bad spark,fuel or air it would bogg or stall your hearing a knock.

[Yamdoo]

air box is suspect to me from your symptoms. Its easy to fully remove it, clean it out and re-install. Where the airbox attaches to the carburator, check the rubber boots and make sure there are no cracks. Sometimes that can cause issues too. Simple setup, you need Air, fuel and spark for an engine to run..... start with the simple stuff, clean airbox for air, new plugs for spark, and new fresh fuel with K100 in it. I would bet one of these things are the problem.

Thank you. I will start with these suggestions. On another note, the sled has the low winshield on it and I was given the tall one as well. In order to remove the windshield I see what appears to be black caps over some screws. Am I correct or are the caps/screws really one time snap in plugs?
How do I remove them? Do I need to drill them out or are they truly caps that I can pop off with a small screwdriver to gain access to what I am hoping is a screw head.

[MASSMACHZ]

Thank you. I will start with these suggestions. On another note, the sled has the low winshield on it and I was given the tall one as well. In order to remove the windshield I see what appears to be black caps over some screws. Am I correct or are the caps/screws really one time snap in plugs?
How do I remove them? Do I need to drill them out or are they truly caps that I can pop off with a small screwdriver to gain access to what I am hoping is a screw head.

I don't think you want to drill them out. They are probably plastic "darts" that pop in and out. Try gently prying with a screwdriver and see if they come out.

[djuseless]

DJ he says the motor runs just makes a knocking sound a few time at low rpm so the motor is running and runs fine at higher rpm. A knocking sound at lower rpm could be in the primary clutch before it starts to engage? or something is loose. If it was bad spark,fuel or air it would bogg or stall your hearing a knock.

My polaris did the exact same thing, the old one I sold. It ran ok with full throttle, but at idle popped and sputtered. I found a mouse nest. Maybe its something different.

Yamdoo, the windshield, yes those are made to pop out with a bit of prying with a small screwdriver. Most of the time, if you pop the center of the plastic rivet, the rest will follow. I personally would just buy a few new ones, sometimes they get brittle with age. They are cheap, you can get them at a hardware store.

[grasshead]

My polaris did the exact same thing, the old one I sold. It ran ok with full throttle, but at idle popped and sputtered. I found a mouse nest. Maybe its something different.

Yamdoo, the windshield, yes those are made to pop out with a bit of prying with a small screwdriver. Most of the time, if you pop the center of the plastic rivet, the rest will follow. I personally would just buy a few new ones, sometimes they get brittle with age. They are cheap, you can get them at a hardware store.

Well that's what we need to now? Is it a pop like a backfire or a knocking clucking sound like metal on metal.

[djuseless]

Well that's what we need to now? Is it a pop like a backfire or a knocking clucking sound like metal on metal.

The sled I just traded in, I thought the engine puked one day, I was coming down a hill, and heard a loud rattling, like metal on metal. What I found was the exhaust heat sheild straps broke making the heat sheild rattle like crazy on the pipe, but the wierd part was that it only happened at certain RPM"S. I clamped the sheild, and back in action.

[Yamdoo]

My engine was knocking, like it was a timing issue or that low octane gas was in the tank and you gave it heavy throttle. I filled my portable gas tank with Premium and put the same gas into my Yamaha as I did in the Ski Doo. Both need premium gas, only the Ski Doo is knocking.

[Yamdoo]

My engine was knocking, like it was a timing issue or that low octane gas was in the tank and you gave it heavy throttle. I filled my portable gas tank with Premium and put the same gas into my Yamaha as I did in the Ski Doo. Both need premium gas, only the Ski Doo is knocking.

I bought them both used this year as an entry into snowmobiling. The Yam is a 1998 SRX700.

[MASSMACHZ]

My engine was knocking, like it was a timing issue or that low octane gas was in the tank and you gave it heavy throttle. I filled my portable gas tank with Premium and put the same gas into my Yamaha as I did in the Ski Doo. Both need premium gas, only the Ski Doo is knocking.

Sounds like you need to drain the tank and start from scratch with new fuel. Bad gas WILL toast your motor.

[grasshead]

My engine was knocking, like it was a timing issue or that low octane gas was in the tank and you gave it heavy throttle. I filled my portable gas tank with Premium and put the same gas into my Yamaha as I did in the Ski Doo. Both need premium gas, only the Ski Doo is knocking.

These are 2 stroke and don't knock like a car. also running higher octane in the sled will do nothing unless you have the compression to run it. I run 87 in my new 1000.

[Yamdoo]

Sounds like you need to drain the tank and start from scratch with new fuel. Bad gas WILL toast your motor.

Interesting. The only thing is the SRX700 has the same gas in it's tank and it's not knocking.

[djuseless]

These are 2 stroke and don't knock like a car. also running higher octane in the sled will do nothing unless you have the compression to run it. I run 87 in my new 1000.

agreed, I run 87 octane in my new 800R too. The manual states "use 87 octane unleaded fuel only" "use of fuel with an octane rating higher than 87 can cause engine damage".
But the new 800HO motor requires 91 octane or higher.

[djuseless]

Yamdoo, do you know how to clean the carbs? If you do, and you already tried new gas with gas treatment and new plugs, it cannot hurt to try it.

[MASSMACHZ]

agreed, I run 87 octane in my new 800R too. The manual states "use 87 octane unleaded fuel only" "use of fuel with an octane rating higher than 87 can cause engine damage".
But the new 800HO motor requires 91 octane or higher.

Mine says to run 91 or higher, but has a detonation sensor to adjust for lower octane fuels.

[BANDIT]

Yamadoo, Where are you located ?

[djuseless]

Mine says to run 91 or higher, but has a detonation sensor to adjust for lower octane fuels.

My old polaris touring sled had that too. Two clicks on the key, 93 octane, one click for 87.

[Yamdoo]

Yamadoo, Where are you located ?

East Brookfield. I joined both the Spencer SnowBirds and Colbrook clubs. I joined Spencer since those trails are close but I rode on the Colbrook trails and enjoyed SR71 so I joined Colbrook as well to directly support the club that manages those trails. Just got the sleds this season, haven't done any club events.

Yamdoo, do you know how to clean the carbs? If you do, and you already tried new gas with gas treatment and new plugs, it cannot hurt to try it. - Don't know how to clean the carbs. I'll take a look at the plugs. I can order some from the local auto parts store or Motorsports Intl in Auburn. Suffice it to say I am no longer mechanically savvy though I suspect I will become so again.

[BANDIT]

OK somebody from that area step up and give the newbie a hand..At least somebody who knows a little bit. These are the things that make a good club a great club..After all it is his wifes sled. I noticed that pictures really get em going YAMADOO

[djuseless]

East Brookfield. I joined both the Spencer SnowBirds and Colbrook clubs. I joined Spencer since those trails are close but I rode on the Colbrook trails and enjoyed SR71 so I joined Colbrook as well to directly support the club that manages those trails. Just got the sleds this season, haven't done any club events.

Yamdoo, do you know how to clean the carbs? If you do, and you already tried new gas with gas treatment and new plugs, it cannot hurt to try it. - Don't know how to clean the carbs. I'll take a look at the plugs. I can order some from the local auto parts store or Motorsports Intl in Auburn. Suffice it to say I am no longer mechanically savvy though I suspect I will become so again.

I am from Wales, did you ever ride the Mill Valley system out of Belchertown. Its actually a pretty good trail system, but snow this winter has not been in the clubs favor. I really want to ride Belchertown this year, they buldozed the rail bed and really cleaned up this year.

[pj600]

Its a Ski doo. If you want some answers try and get the King to answer you. He's the master of ski-doo's.

[Forwhldrv]

Its a Ski doo. If you want some answers try and get the King to answer you. He's the master of ski-doo's.

Agreed

[BANDIT]

I agree about the KING. At this time we have gone from being a clutch problem to cracked boots to carbs. Somebody with experience needs to look at it.

[djuseless]

I agree about the KING. At this time we have gone from being a clutch problem to cracked boots to carbs. Somebody with experience needs to look at it.

Take it easy stimpy, folks are just giving suggestions to help the poor guy out. I gave basic suggestions becuase most of the time, its a simple solution to a minor engine issue. Remember too, that Yamdoo admitted he is not mechanically inclined, so it wont hurt for him to learn how to do some of this things recommended just to get familiar with the sled and general maintance. I am no mechanic, but have learned alot from tinkering around, listening to folks, getting advise, and actually making friends that have some expirience and watching what they do.

[Yamdoo]

Take it easy stimpy, folks are just giving suggestions to help the poor guy out. I gave basic suggestions becuase most of the time, its a simple solution to a minor engine issue. Remember too, that Yamdoo admitted he is not mechanically inclined, so it wont hurt for him to learn how to do some of this things recommended just to get familiar with the sled and general maintance. I am no mechanic, but have learned alot from tinkering around, listening to folks, getting advise, and actually making friends that have some expirience and watching what they do.

Thank you everyone for their help with providing some possible answers. I picked up a set of NGKBR9ES's at lunch today. Hopefully I can try to put them in tonight but I may run out of time with some house stuff I've got to get done before the w/e. I'm hoping to get the plugs replaced and gas drained first as that seems to be the best place to start. If I can get these done this week my wife can try out the sled on Lake Lashaway this w/e to make sure evrything is good to go.
If anyone is local to East Brookfield I'd always appreciate the hands on insight and tips. It would be great if at some point I had another set of eyes looking at the sleds to tell me what needs to be done to them.

I attached a bad cell phone pic of the two toys. I'll have to get some better pic to put on the profile

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[96formula600]

I am new to snowmobiling and bought a 1998 Mach 1 for my wife. Starts first pull, runs smooth but yesterday when I started it there was some distinctive knocking in motor at random times while it was warming up. It didn't do it when I gave it some throttle but did it when running at 2000 rpms...thoughts?

Skidoos have a bad crank bearing design. They have plastic "cages" (plastic rings with pockets for each ball bearing)... It's not uncommon for these plastic cages to fall apart over time. The result is bearings inside the engine rotate as the crank rotates, but the balls bang into each other.

To check if this is the case on your sled:
quiet location needed...
hood open, engine off... Rotate the engine by hand turning the clutch... listen closely for the tell tale sound "clink, clink" as the ball bearings roll into each other. If you hear this, you need to split the engine & replace the crank bearings & seals. Do it before the sled blows up.

Don't confuse the "clink, clink" sound your going to hear from rotating the clutch... There are weights in the clutch that will make that sound even though the clutch is good. (note: 3 clutch weights, equally spaced @ 120 degrees = 3 notable "clink" sounds per full revoloution of the clutch)

If infact your crankshaft bearings cages are bad, the "clink, clink" sounds are notably different than those you'll hear from the clutch.

Does the motor make the noise after it's warmed up, or just when it's cold?

[Yamdoo]

I am from Wales, did you ever ride the Mill Valley system out of Belchertown. Its actually a pretty good trail system, but snow this winter has not been in the clubs favor. I really want to ride Belchertown this year, they buldozed the rail bed and really cleaned up this year.

The extent of my snowmobile riding has consisted of 1 day on the Spencer area trails last year, 1 day on SR71 from Oakham to NH, maybe 6-8 days of riding on Lake Lashaway (my home) to get used to the Yamaha and one day each in VT and NH over the past few years. I am truly a newbie, but a very excited one, eager to ride and learn..but I'm also a middle age newbie which brings it's own set of time challenges. I am really looking to get into snowmobiling and hope to get my wife into it also. That's why I want to get the Mach 1 running flawlessly for her.

[BANDIT]

The extent of my snowmobile riding has consisted of 1 day on the Spencer area trails last year, 1 day on SR71 from Oakham to NH, maybe 6-8 days of riding on Lake Lashaway (my home) to get used to the Yamaha and one day each in VT and NH over the past few years. I am truly a newbie, but a very excited one, eager to ride and learn..but I'm also a middle age newbie which brings it's own set of time challenges. I am really looking to get into snowmobiling and hope to get my wife into it also. That's why I want to get the Mach 1 running flawlessly for her.

I totally agree..It sucks for a gal on a sled that's not running properly. If it's not fun they don't want to go. The best advise that I can give you is,.... GO BUY A BRAND NEW YAMAHA. She will love the sport and want to go every day