Yamaha Vmax700 sx 98' mountain mods

[J@ckrabbit]

Hello everyone from Greece! We're snowboarding with this sled for the last years(previous owner pulling us uphill). I'm a newbie in snowmobiling and i need your help. Read a lot of good posts and answers in here, you guys are scientists. I'm not sure if i have to go the extra mile or leave the yammie "as is", and stop throwing money in a big hole, like my friends tell me. Cant find parts in europe easily, and everything is so expensive.

Got a hard-used 98 vmax700 sx 121 track(1inch with studs)-no pipes from my friend, and decided to keep it and make it more mountain friendly. The machine has 4800miles and starts with 2nd-3rd pull but everything else needed a refresh. Don't want to jump or boondocking, but i would appreciate some climbing skill in extreme conditions(my definition of extreme)- deep powder(2 feet) with max 40% slopes - if its feasible. Will be running at 5000ft to 8600 max altitude(never tuned for altitude) as well.

So, what i've done so far: replaced arm trails(old ones where fixed and super heavy), straightened out the rod ties and replaced rose joints, 4 new bogies, all bearings, new front suspension(olds where frozen - larger travel by 2 inches and used the old springs),new rear suspension(short one-also frozen), replaced some cut rivets with inox screws, fixed and painted plastic parts, new sliders and got myself a holeshot and a pair of slydog 7inch skis.



I think this track, still has some juice, but besides some torn lugs(mostly in the outer), i see this cut/line between studs. The placement of studding, obviously was trimming down bogies as well.

Do you think that is should keep this track, just for a season in order to learn how to ride or change immediately?




Also, my main concern. Thinking of extending to 136 or 144(mountain usa kit-650$ delivery and customs!) and replacing with 1.22(factory studded track) or higher lug like 1.6 ice cobra. Don't want to remove heat exchanger, and have to be studded.

Is it possible with 8tooth driver(extros) change to fit 1.6 ice cobra or only the 1.22? Based on what i read so far regarding gearing i will be ok, since top speed is not really what i'm after and accelerating is what i need, but will it need reclutching?
Thinking about changing springs for the clutches as well, but dont know what to choose.

Also, i think about bying adjustable transfer rods for the weight and viper spindles, to raise the front a little bit.

Please, help me out prioritize the above and your opinions for the project.

 

[74Nitro]

If you replaced the trailing arms you should have bought the ones for the viper as they accomodate the taller spindles you want.
If you are using this in deep snow, you'll have to have a very long track with at least 1.75 depth and 8 tooth drivers.

 

[74Nitro]

If it's always run in deep snow conditions you won't need any idler wheels and you just run two in the middle at the back if you wanted to.

 

[J@ckrabbit]

If you replaced the trailing arms you should have bought the ones for the viper as they accomodate the taller spindles you want.
If you are using this in deep snow, you'll have to have a very long track with at least 1.75 depth and 8 tooth drivers.

Unfortunately, I moved too soon and bought vmax arms. Do you mean that viper spindles are not going to fit? Also, was thinking about only extending the pro action, so 144 max right?

 

[74Nitro]

Unfortunately, I moved too soon and bought vmax arms. Do you mean that viper spindles are not going to fit? Also, was thinking about only extending the pro action, so 144 max right?

They are longer, but maybe a spacer could be added, I'm not sure.
I don't know if the 121 can be stretched to 144.

 

[Maim]

that track is a 1.25 ripsaw from the look of it and the closed every 3rd window. been there, done that.

looks like it should make another season if you make sure the studs are all good an tight as i see some tear outs on the outer band.

have not heard of too many guys going 144 track but they where done. 136 was more common. you could look for some used parts as there are guys around still parting out some of these old girls. a sx viper mountain (144 track) or a mountain max(141) both had tunnel extensions you could use for 136.

cb performance is a good place to get a track from.

i am running composit cross country 1.5 x 144 on one apex and it has over 8000 mi of use/abuse. running a 136" x 1.25" on a sx venture 700 and i like it so far. i do not run studs at all. composit are cheaper than camso tracks.

8 tooth drivers and a 1.38-1.5 lug track should not be that big an issue even pre studded. you can also go i grips in the lugs of a track for studding like a pre studded.

 

[J@ckrabbit]

that track is a 1.25 ripsaw from the look of it and the closed every 3rd window. been there, done that.

looks like it should make another season if you make sure the studs are all good an tight as i see some tear outs on the outer band.

have not heard of too many guys going 144 track but they where done. 136 was more common. you could look for some used parts as there are guys around still parting out some of these old girls. a sx viper mountain (144 track) or a mountain max(141) both had tunnel extensions you could use for 136.

cb performance is a good place to get a track from.

i am running composit cross country 1.5 x 144 on one apex and it has over 8000 mi of use/abuse. running a 136" x 1.25" on a sx venture 700 and i like it so far. i do not run studs at all. composit are cheaper than camso tracks.

8 tooth drivers and a 1.38-1.5 lug track should not be that big an issue even pre studded. you can also go i grips in the lugs of a track for studding like a pre studded.

Thanks Maim, been reading a lot of pros and cons for swapping to 8 tooth. I remember older posts, mentioning loss of top speed and gain in acceleration. Is that the case? Also, will i need to tune the clutches or change something else? I'm concerned, because lots of members propose to leave the drivers alone, and thinking if its possible to use i grips with the current drivers into a 1,35 cobra. Also definitely extros for reduced ratcheting, right?

Found an extension kit 121-144 from tracks usa, with tips up design, do you think that the length of the extension will be a problem compared to a 136?Just seems to me that there is little difference in changing to 136 as basically only 6-7 inch will be the gain on the ground.

 

[Maim]

you might still need to tune the jets and maybe the primary for your altitude but the 8 tooth drivers will take care of the re gearing when going from 121" to 144". i am a trail rider/brush popper so top speed was not high on my list. going with longer track always scrubbs top speed as well as a taller lug track even before changing drivers or gearing.

extros are always a good idea when replacing drivers and do help with ratcheting. just be aware that the 9 tooth ones will contact the rail tips with out machining the tips down a bit for clearance with skid mounted in stock location. skid relocate is not good for trail riding, been there done that.

if going from 121" to 144" with or without rail extensions, i would reccomend adding an axle with wheels between the rails at the tip up to reinforce them and cut down on slide wear. the axle kit i used when i made a 09 phazer rtx into an xtx was for between the rails on an enticer for adding wheels to the skid. you can use outside rail wheel mounts as long as you have a shaft to link the rails at that point to help prevent bending.

 

[J@ckrabbit]

Hey guys, a bit out of season, but project update: Decided to go with light mods, and bought a 136 1.5 intense, which i'll use with the 9 tooth drivers.
Chose the slp extensions 121 to 136, due to cost and i'll try to lengthen the tunnel with a custom extension, and move the cooler to the back. No studs, no front front cooler protectors, should i remove the tunnel protectors(on the top of the tunnel) as well? They are broken at the rear anyway.
I had to replace the limiter straps, and a friend of mine custom modded straps a bit longer, and without measuring exactly installed them. Had to make them longer, because we swapped the front skid suspension, with a longtrack yamaha(02 viper or mm-not sure) one.

Please correct me if wrong, but from what i read so far, i think we may have changed the attack angle a bit(good), less ski pressure/more hyfax wear(good-probably, for intended use), and did we make it prone to stabbing if not using the track tight? Do you think an antistab kit is needed?

Also painted the hood, labor intensive as f@ck!

 

[J@ckrabbit]

Project Update: SLP extensions installed, intense 1,5 136 installed. Do you think that I might get away without extending the tunnel?Thinking about moving the flap back 5 inches approximately,with a custom mod that doesn't require rear cooler relocation. Do you think I'll be ok or overheating will be an issue?

 

[Maim]

as long as snow hits rear cooler, it will probably be fine heat wise. just make sure track doesn't hit cooler on full suspension compression.

 

[J@ckrabbit]

Maim you're right, no overheating problems so far, just a couple of tanks ride though. Even with 2 people riding, the rear end didn't seem to compress too low.
I do have an issue with primary clutch probably, the belt started squeeking. Probably needs cleaning&lubing?Also factory spring, so needs refresh too right?When i start, seems to engage in too high rpms and boggy like. At first, i thought it was the track rubbing at the cooler, or maybe due to snow packed tight(kept my 9 tooth drivers). But after the sound, started to smoke too and didn't engage until cooldown.
Also, i'm a noob in this, and i can only speculate.
As for the track(intense 1.5), guys wow! Wet and heavy snow conditions, and worked like a charm!

 

[Maim]

take primary apart and wash in soapy water with a scrub brush. use a scotch brite pad or sos on the faces where the belt rides to take off the glaze. dry with compressed air. never use lube on a snowmobile clutch. a new spring would not hurt in the primary but from the sounds of it, there is now too much resistance from the longer track. sleds with same motor and the longer track are usually geared different than the short track sleds.