What's your sguestions

[phil_apex]

Hello,

I have a 2010 apex GT and I have lost top speed. I blew a belt at 190 km/hr (on dream meter) when the machine was new 700km. I now have 3050km and can only get 144 km/hr on speedo and 135 km/hr on gps at around 1100 rpm. When I blew the belt the machine was all stock. I have dropped the top gear from 24T to 23T, installed the ram air lid and gutted my exhaust. I noticed that the throttle response improved with all this.

I have noticed that I could smell the belt when the throttle was pinched so I cleaned my clutches, scrubbed a NEW belt and reinstalled everything. I then tried a run again and still same results no top speed and smell the belt but not as much.

My question is did the air box lid, the gutted exhaust and the 23T gear rob me of my top speed? Or in a more unbelievable theory did this actually improve engine torque that much that the stock clutch setup is not grabbing the belt enough and slipping way to much?

Any thoughts or suggestion would be greatly appreciated. I want me speed back, the biggest reason why I bought the apex.

 

[phil_apex]

I forgot to mention the machine runs great, there are no code showing and I have recently pulled the plugs and they look fine with a nice colour which would make you think that the fuel mixture is fine

 

[WinderFab]

You should never smell your belt...
Remove the belt and raise the rear of the sled off the ground, turn secondary clutch by hand, track should turn fairly ease, track tension adjustment by yamaha manual is way to tight...
Got mine set at 3/4" of track sag when sled is off the ground and never had a problem...
Have you checked track tension ?

 

[MrSled]

You dropping the gear did the job...

 

[rwill2cruz]

You dropping the gear did the job...

Going from 24 to 23T did what for him?

 

[karlburns]

Dropping a tooth on the top gear should give you more on the low end but less top speed. That's why when you get a bigger lug you drop a tooth to get more power to the track. At least that's my backwoods teachings.

 

[phil_apex]

Karlburns, I don't think you would loose 40-50 km/hr by droping to a tooth, 23T is the stock on the attack. I know you will loose some but not this much.

Anyone have any real life experiences with how much you would actually loose by dropping a tooth?


Fabio, I checked my track tension and it wAs fairly loose, I could spin everything by hand . I didn't check the track with weight. I just pushed on it and spun it by hand. I am going to take my skid out during the off season and go through it and when I put it back on I am going to set the tension with the 20lb of weight or whatever the weight is in the manual. Also chain case is adjusted proper, and the bearins are good in the secondary shaft. When you set your to 3/4 did you use weight and did you measure the way it says in the manual? Also did you need anti ratchet drives or is it ok with stock?

 

[sgauthier]

newer Yamaha's should not be blowing belts. the only reasons it would do so is if you're ctc or offset is not correct, not running an oem belt (even that really shouldn't cause that at 700km but you never know) or if you have any type of drag in our drive line that would cause excessive heat in your clutches. did you or someone ever take your secondary apart at any time and not put it back on in the proper place/twist? I know having the secondary spring too tight causes a lot of heat in your primary so that could cause the belt to heat up, slip or even blow.

dropping down one tooth should not affect your top end by 50 km/h, maybe 10 or so but that's about it.

 

[MrSled]

Going from 24 to 23T did what for him?

I have seen this many times... if you dont machine the clutches and do some clutching to get you back to overdrive you will loose your top speed and gain low end acceleration.... in loose snow is where the gearing changes hurts you the most.

 

[MrSled]

newer Yamaha's should not be blowing belts. the only reasons it would do so is if you're ctc or offset is not correct, not running an oem belt (even that really shouldn't cause that at 700km but you never know) or if you have any type of drag in our drive line that would cause excessive heat in your clutches. did you or someone ever take your secondary apart at any time and not put it back on in the proper place/twist? I know having the secondary spring too tight causes a lot of heat in your primary so that could cause the belt to heat up, slip or even blow.

dropping down one tooth should not affect your top end by 50 km/h, maybe 10 or so but that's about it.

Poorly clutched sled and or misalignment will add the excess heat and blow belts... also cranking on the sled on and off the throttle on warmer temps above 32 will kill belts...

Maybe with the mods you made even the gearing down, the belt is slipping bad and putting a ton of heat into the clutches.

 

[phil_apex]

The belt ony blew once, I think the belt was a bad belt. I never had any more problems with the belts after this. I did change the second belt because it was worn.

I am thinking a clutch should solve the problem but just wanted to see what everyone's thoughts were

I am think about getting Ulmers clutch kit but having hard time to get him to answer me. I also wanted to get them machined. Is there any recommendations for shops that do this?

 

[MrSled]

The belt ony blew once, I think the belt was a bad belt. I never had any more problems with the belts after this. I did change the second belt because it was worn.

I am thinking a clutch should solve the problem but just wanted to see what everyone's thoughts were

I am think about getting Ulmers clutch kit but having hard time to get him to answer me. I also wanted to get them machined. Is there any recommendations for shops that do this?

Are you calling him?? or email? You can leave him a message on here too.

 

[karlburns]

Karlburns, I don't think you would loose 40-50 km/hr by droping to a tooth, 23T is the stock on the attack. I know you will loose some but not this much.

I dropped my attak 2 teeth, dropped to a 68 link chain when I went to a 1 3/4 lug. I lost close to 15-20 mph I'm guessing but never did run it wide open on hard pack because I didn't want to start slinging lugs. Changing gearing alone will make a big difference that's why you could feel it on the low end.

 

[sgauthier]

3 belts in 3100km, i've got 12000km on my XTX and i've only replaced it once just cause i thought i should ? it should not need replacing with that low of mileage (unless it's got a defect or some kind) if the ctc and offset are correct, only shims should be needed to the back of the secondary to get it to sit back up above the sheaves.

you still haven't answered whether you have checked your ctc or offset and if you have ever had your secondary apart. you can get some top end back with a good clutch kit but it will do nothing for your belt life.

 

[karlburns]

On my attak I had two belts that I put 6000 miles on between the two. I then blew 3 in 1000 miles after changing my gearing before I messed with my clutches to solve the problem. I don't claim to be a clutch expert so I paid someone to do that part but put another 500 miles on after with zero problems so I know it was in the clutches. Before I took it to him I looked everything over and cleaned it all but still was having issues. Like I said though I swapped track, skid, gears, and chain all at the same time. I had my track adjusted as loose as I could without it ratcheting but still blew belts.