Hey everyone...new here, and I have a few questions about my new to me sled. I may have made a bit of an impulse buy, and now in over my head. I purchased a 98 or 99 Mountain Max 700. I have conflicting paperwork. I bought off a fellow who said it was a 98. The paperwork I got that tranfered ownership to him from previous owner indicates it's a 99. Are the two sleds the same? What other motors are the same? SXR or SRX? Viper? I have done lots of reading on here, and it seems they changed in 2000?
I am having a plug fouling issue. Done lots of reading and found lots of good advice. First thing I have to do is clean the carbs. I've already replaced the caps with NGK LB05EP. I took off TB05EM. I checked the old ones and were at 4.80 K ohms, 4.85, and 5.00. Are those two within spec? I fouled plugs tonight after changing caps. Aaargh! I
am letting the sled warm up before touching the throttle. It will run for about 5 mins and die, but it resarts just fine. Cold compression check was also good. within 5psi on all three. This sled is not stock, but has many miles on it, so I'm sure it ran fine at some point. The previous owner claims the sled ran awesome for him. Might be bs, I don't know. He rode it for a year and a half. Engine was rebuilt just before he got it, and he didn't put many miles on it I don't think. He got it from a frind of his, and claims the motor is stock. The sled has Decker pipes on it. Sounds awesome! Most of my riding will be at aroud 2000ft. Does anyone have jetting recomentations? It is a 151 with an Ekholm tunnel, dropped and rolled, Boysen reeds. New primary. About an 8 inch bar riser. This sled should haul butt, if I can get itnto run right. Seems to me, it has all the right mods done to it. But, a few things are in rough shape. There is no speedo as the cable won't clear the secondary. That is another post and I am working on that. The right grip and thumb warmer have only worked once. Left grip never has worked. The temp sensor has a broken wire on the harness side. I think I can fix that. Should the oil light come on when it is started? My sons Exciter does, but mine doesn't. The TORS is bypassed, and I can't find the other side of the harness to reattach. The cable seems tight now, so thats probably why. Need to check the oiler cable too. I want to play with the clutching too. I would like to get it a bit more trail friendly. Right now, it seems to like being wot, not midrange. Is that partly the reeds?
So....am I in over my head? I am capable of wrenching on this stuff, just not too knowledgeable.
Sorry for the long post and the many questions.....
I am having a plug fouling issue. Done lots of reading and found lots of good advice. First thing I have to do is clean the carbs. I've already replaced the caps with NGK LB05EP. I took off TB05EM. I checked the old ones and were at 4.80 K ohms, 4.85, and 5.00. Are those two within spec? I fouled plugs tonight after changing caps. Aaargh! I
am letting the sled warm up before touching the throttle. It will run for about 5 mins and die, but it resarts just fine. Cold compression check was also good. within 5psi on all three. This sled is not stock, but has many miles on it, so I'm sure it ran fine at some point. The previous owner claims the sled ran awesome for him. Might be bs, I don't know. He rode it for a year and a half. Engine was rebuilt just before he got it, and he didn't put many miles on it I don't think. He got it from a frind of his, and claims the motor is stock. The sled has Decker pipes on it. Sounds awesome! Most of my riding will be at aroud 2000ft. Does anyone have jetting recomentations? It is a 151 with an Ekholm tunnel, dropped and rolled, Boysen reeds. New primary. About an 8 inch bar riser. This sled should haul butt, if I can get itnto run right. Seems to me, it has all the right mods done to it. But, a few things are in rough shape. There is no speedo as the cable won't clear the secondary. That is another post and I am working on that. The right grip and thumb warmer have only worked once. Left grip never has worked. The temp sensor has a broken wire on the harness side. I think I can fix that. Should the oil light come on when it is started? My sons Exciter does, but mine doesn't. The TORS is bypassed, and I can't find the other side of the harness to reattach. The cable seems tight now, so thats probably why. Need to check the oiler cable too. I want to play with the clutching too. I would like to get it a bit more trail friendly. Right now, it seems to like being wot, not midrange. Is that partly the reeds?
So....am I in over my head? I am capable of wrenching on this stuff, just not too knowledgeable.
Sorry for the long post and the many questions.....
the only way to verify what year your sled might possibly be will be the engine serial number. its located on the engine case just behind the recoil. post up the entire number and go from there. this assuming the engine is original to the chassis. obviously you lost the tunnel vin with the aftermarket tunnel. parts wise, they are all the same for the redheads 98 and up except the ignitions 2000 and up, for the most part. 98 and 99 are the same.
re-think your starting procedure. typical would be full choke until it lights, down to half after about 5-10 seconds, and then off once it can take it. where is the idle set at? too low idle can cause your issue. dont be afraid to set it a couple 100 more than spec. i never leave my sleds idling unattended. some sleds just need a bit of throttle to keep them clean. piped sleds are even more finicky.
best thing you can do is go through the carbs to verify cleanliness and map out the tuning parts to know what you have and where your at. you will want to know and write down the main jet sizing, pilot jets, fuel screw setting along with needle placement. your chasing your tail until you know whats what. pay close attention as those carbs may have staggered jetting. one at a time going through them.
if a sub-par install was done on the risers to the point of disconnecting the tors, you will want to correct that as turning the bars may be pulling the throttle as well as activating the oil pump. as you mentioned, confirm the free-play setting for the oil cable. oil light shouldnt come on, but you should see a 3 blink of the tors light on initial startup.
temp plug can be "presidentially engineered" with some small female spade connectors or if you have access to weatherpak connections thats what yamaha uses. you will need to troubleshoot the grips and wiring with an electrical multi-meter to figure that out.
over your head? i dont think, yet. you just need to spend some time with the machine to learn its quirks as with any used machine. do not start tossing money at it until you know where your at. for the most part, your in for some sweat equity first and then take it from there.
re-think your starting procedure. typical would be full choke until it lights, down to half after about 5-10 seconds, and then off once it can take it. where is the idle set at? too low idle can cause your issue. dont be afraid to set it a couple 100 more than spec. i never leave my sleds idling unattended. some sleds just need a bit of throttle to keep them clean. piped sleds are even more finicky.
best thing you can do is go through the carbs to verify cleanliness and map out the tuning parts to know what you have and where your at. you will want to know and write down the main jet sizing, pilot jets, fuel screw setting along with needle placement. your chasing your tail until you know whats what. pay close attention as those carbs may have staggered jetting. one at a time going through them.
if a sub-par install was done on the risers to the point of disconnecting the tors, you will want to correct that as turning the bars may be pulling the throttle as well as activating the oil pump. as you mentioned, confirm the free-play setting for the oil cable. oil light shouldnt come on, but you should see a 3 blink of the tors light on initial startup.
temp plug can be "presidentially engineered" with some small female spade connectors or if you have access to weatherpak connections thats what yamaha uses. you will need to troubleshoot the grips and wiring with an electrical multi-meter to figure that out.
over your head? i dont think, yet. you just need to spend some time with the machine to learn its quirks as with any used machine. do not start tossing money at it until you know where your at. for the most part, your in for some sweat equity first and then take it from there.
Thanks for the info. What other sleds run the redheads? Just so I know what I can look for for parts. There seems to me many more SRX's and Vipers than Mountain Max's. I realize a piped and modded sled is more finicky. I can live with that for the added performance.
My startup procedure is full choke until it fires, half choke for 10-15 seconds and then no choke. I have left the sled unattended, but within earshot so to speak. It will usually run for several minutes. If it dies, i'll restart with no choke and try not to touch the thottle until I feel heat in the heat exchanger under the tunnel.
Changed plug caps last night and still fouled a plug. I can't snip the wire back any more as they will be too short. Can I replace the wire out of the coil, or is it part of the coil. I pulled the boot off at the coil end, and it appeared to be siliconed in. I didn't want to disturb it.
What about the values I found on the old boots? Are they withing spec, or could that be part of the problem?
I am playing with the idle. I think it was too low at first. What is a hanging idle? When I come to a stop, the rpms stay up for about 10-15 seconds before they drop down and it idles normally. Just wondering if this is normal?
I'll probably have more questions....thanks for putting up with me.
My startup procedure is full choke until it fires, half choke for 10-15 seconds and then no choke. I have left the sled unattended, but within earshot so to speak. It will usually run for several minutes. If it dies, i'll restart with no choke and try not to touch the thottle until I feel heat in the heat exchanger under the tunnel.
Changed plug caps last night and still fouled a plug. I can't snip the wire back any more as they will be too short. Can I replace the wire out of the coil, or is it part of the coil. I pulled the boot off at the coil end, and it appeared to be siliconed in. I didn't want to disturb it.
What about the values I found on the old boots? Are they withing spec, or could that be part of the problem?
I am playing with the idle. I think it was too low at first. What is a hanging idle? When I come to a stop, the rpms stay up for about 10-15 seconds before they drop down and it idles normally. Just wondering if this is normal?
I'll probably have more questions....thanks for putting up with me.
spec on the caps is 5 ohms. i wouldnt sell the 4.8's down the road unless you have quality equipment for testing and the temps were correct. your call. the only reason you would want to clip back the wires would be if they were overly corroded, green inside, etc. you can just as easily refresh the inside wire with a needle brush vs clipping. too many folks simply short cut to clipping. personally i have never tried to remove the wires from the coil end as i was lead to believe you couldnt. i have used wire sleeves in the past. basically a product specifically designed for epoxied in wires. not sure if they are still available. it was either a western power sports item or a parts unlimited item. been awhile since i had to rely on those.
as mentioned, re-think your starting procedure. i am thinking your unattended idling along with some underlying issues is causing your fouling of the plugs. check the ones that are dropping for signs of oil or fuel and that will lead you as to whats next. dont toss them, clean them up and hit them with a propane torch, save them for testing.
what your describing is an idle hang. usually a fuel screw setting or too small of pilot. back to that mapping out whats in there as mentioned earlier. need to know what your dealing to make decisions. check your airbox. one that has been altered can contribute to a hanging idle.
still cant grasp your cable issue. if the speedo housing is oem, the cable will come in straight next to the bulkhead. i dont think i have ever seen a cable come in any other way but 90 degrees to the shaft. i understand not posting pictures, i cant. if its easier to email or text a shot or two, let me know.
i have no idea where your located, but out here the mtn max is the norm along with the mtn viper. what you have is referred to as a redhead triple. any sx, sxr, or mtn max
is compatible parts wise. there should be days of reading about redheads here on this site. the srx and viper are completely different from your engine. search a bit and you will figure it out.
on a side note, i go more for the exhaust heat than the exchanger heat. simply put your hand under the outlet for the exhaust, and when the exhaust feel warm, your good to go. exchanger heat may me a bit much.
as mentioned, re-think your starting procedure. i am thinking your unattended idling along with some underlying issues is causing your fouling of the plugs. check the ones that are dropping for signs of oil or fuel and that will lead you as to whats next. dont toss them, clean them up and hit them with a propane torch, save them for testing.
what your describing is an idle hang. usually a fuel screw setting or too small of pilot. back to that mapping out whats in there as mentioned earlier. need to know what your dealing to make decisions. check your airbox. one that has been altered can contribute to a hanging idle.
still cant grasp your cable issue. if the speedo housing is oem, the cable will come in straight next to the bulkhead. i dont think i have ever seen a cable come in any other way but 90 degrees to the shaft. i understand not posting pictures, i cant. if its easier to email or text a shot or two, let me know.
i have no idea where your located, but out here the mtn max is the norm along with the mtn viper. what you have is referred to as a redhead triple. any sx, sxr, or mtn max
is compatible parts wise. there should be days of reading about redheads here on this site. the srx and viper are completely different from your engine. search a bit and you will figure it out.
on a side note, i go more for the exhaust heat than the exchanger heat. simply put your hand under the outlet for the exhaust, and when the exhaust feel warm, your good to go. exchanger heat may me a bit much.
Thanks again for the great info.
The wires were not corroded. No green at all. The inside of the caps looked good too. I tested them with a good quality multi meter at room temp.
How do you tell the difference between an oil fouled plug and a fuel fouled? The are black and wet when I take them out. I am goig to iridium plugs and see if that helps.
I have looked at my airbox and I believe it has been gutted. It appears to be an open box with no baffles or anything inside. I just discovered my neighbor has a MM, so I am going to look at his, as it is supposed to be stock everything.
The speedo cable does comes in parallel to the bulkhead, and the speed drive does a 90 like it should. I think when the d & r was done, they trimmed the flange incorrectly. The drive points forward and up towards the secondary, leaving no room for the cable. The drive should point forward and down slightly. I am going to pick up a used drive and trim it different than the one I have.
I was refering to this site when I said there were not as many MM. I am in central BC, and there are probably more MM here than the others.
The wires were not corroded. No green at all. The inside of the caps looked good too. I tested them with a good quality multi meter at room temp.
How do you tell the difference between an oil fouled plug and a fuel fouled? The are black and wet when I take them out. I am goig to iridium plugs and see if that helps.
I have looked at my airbox and I believe it has been gutted. It appears to be an open box with no baffles or anything inside. I just discovered my neighbor has a MM, so I am going to look at his, as it is supposed to be stock everything.
The speedo cable does comes in parallel to the bulkhead, and the speed drive does a 90 like it should. I think when the d & r was done, they trimmed the flange incorrectly. The drive points forward and up towards the secondary, leaving no room for the cable. The drive should point forward and down slightly. I am going to pick up a used drive and trim it different than the one I have.
I was refering to this site when I said there were not as many MM. I am in central BC, and there are probably more MM here than the others.
Last edited:
So....We had a cold snap a couple weeks ago and I didn't feel like working on the sled. No shop. Now I am into a constuction project that is taking most of my time. But, I decided to go for a little rip on the weekend anyway. Did about 5 laps around our 5 acre property with no problem, and then about 1 km down the road. Fouled a plug....Got it back home an was checking to see which one it was this time. I pulled the left boot off an there was no change. As I put the boot back on, that cylinder picked up and it idled fine. If I snapped the boot onto the plug, it would not fire. Unsnapped it from the plug, and it fired. Snapped it on and it dropped off again. Wiggled the wire and no change. These are new boots and newer plugs. It has been different plugs that foul on me, center and left for sure. I can't remember if the right plug has ever fouled. So now I'm thinking there is an electical issue, not fuel or oil......Any ideas?
A couple of bucks
VIP Member
If your sure the plugs are good, move a coil from a problem cylinder over to #2. The one that hasn't had any issues. See if problem follows.
A couple of bucks
VIP Member
Oh! Lightbulb! Didn't think of that. Thanks! Construction going to take most of my time now, but will let you know what happens.
mod-it
Member
I've had dirty carbs cause fouled plugs before, I don't think you said you've cleaned them yet? That would definitely be my first step. Partially blocked pilots can be causing the idle hang, or the fuel screws need opened up a bit more. Any more turns than 3, and you'll want to go up a pilot size because the spring tension on the fuel screws gets so light that they will start vibrating out. I'd set yours back where you find them after cleaning and see how it does. PIA, but if there is still an idle hang after cleaning then start adjusting them out a 1/2 turn at a time.
Also, one time I was having trouble with my viper fouling random plugs. Half way through the ride I finally realized that my oil cable wasn't seated all the way in at the adjustment joint, so at low rpm it was over oiling and causing the fouling. Since your sled has risers, I'd make sure it is seated correctly. I'd also check what the gap setting is at the adjustment joint. Over oiling will definitely cause random plug fouling.
Also, one time I was having trouble with my viper fouling random plugs. Half way through the ride I finally realized that my oil cable wasn't seated all the way in at the adjustment joint, so at low rpm it was over oiling and causing the fouling. Since your sled has risers, I'd make sure it is seated correctly. I'd also check what the gap setting is at the adjustment joint. Over oiling will definitely cause random plug fouling.
mod-it
Member
I also just thought of your previous comment that the plug wires are getting short...could that be causing a poor connection at the boot when you snap it all the way on? That might explain why it would fire when set on the plug but not when it was snapped all the way on, as it may pull tight and cause the wire and cap to not have connection...?
Thanks for the suggestions. I parked it 3 weeks ago with a fouled plug. Haven't had time to ride since. I'm curious if that plug is still not firing. If it does fire, then I'm looking at an electrical issue. I'm hoping it doesn't fire, and I can switch the coil wires and see if a different cylinder cuts out.
I haven't cleaned the carbs yet, and it's something that should be done. More than anything to rule it out. When the last plug cut out, it was under hard acceleration, not just sitting there idling. I don't think I have an over oiling issue, but another thing to check to rule it out.
I'm wondering if fuel could be an issue? My son's 99 Exciter is doing the same thing. Fouling plugs randomly. I've always used 91 octane boat gas in everything and never had an issue. Lawnmowers, weed wackers, lawn tractor, quads, snowblower, chainsaw etc. I've never had fuel go bad on me. And these things are running now on the same fuel as the sleds. So, again, I don't think it's a fuel issue..... Thinking about trying a couple of jerry cans of Cheveron 94 octane. Still doing my construction project, so I'll have to find time to work on this soon.
I haven't cleaned the carbs yet, and it's something that should be done. More than anything to rule it out. When the last plug cut out, it was under hard acceleration, not just sitting there idling. I don't think I have an over oiling issue, but another thing to check to rule it out.
I'm wondering if fuel could be an issue? My son's 99 Exciter is doing the same thing. Fouling plugs randomly. I've always used 91 octane boat gas in everything and never had an issue. Lawnmowers, weed wackers, lawn tractor, quads, snowblower, chainsaw etc. I've never had fuel go bad on me. And these things are running now on the same fuel as the sleds. So, again, I don't think it's a fuel issue..... Thinking about trying a couple of jerry cans of Cheveron 94 octane. Still doing my construction project, so I'll have to find time to work on this soon.