Rear suspension Apex LTX GT bottoms out

[Bluebullet]

I finally have the sled to wear it corners well , steering effort is nice and weight transfer feels good. However With electronic shock on max it still bottoms out pretty easy. The adjustment is sweet when on nice flat trials I set it on soft and it really floats well and soft. I was wondering if i tighten down a couple turns on the mono thread ( more spring compression) if that will stiffen my ride some and change my ski pressure? Please let me know what you think. I am on the boarder with rider weight around 220lbs for the fat boy spring. The sled with the shock on stiff handles the stutter bumps pretty good it is just the unseen deep one that gets ya.

 

[Bluebullet]

H&K I have the GT electronic adjuster on the handle bar with the OHLINS shock, but it does the same thing. Did the stiffer spring change your rear height? thus changed your ski pressure?
Thanks Blue

 

[sx7001]

You will never stop a "mono" shock from bottoming out. The suspension was designed for groomed trails not ditch banging. Add all the spring you can get with all the valving possible, it will still"CRASH" out when you drop in a big hole.

 

[Bluebullet]

SX I agree on the groomed trails and I am still trying to find out about spring setting on the shock if tightening down on the threads will help some and or change the handling of the sled? Or if it will just rebound and bounce me off the seat? My first mono. Thanks Blue

 

[LJ 452]

Depending on what year your's is, and whether or not it's been revalved will determine what direction to go. The first few years were way to soft on the compression stroke. At your weight you are right on the boarder of heavy spring or not. You need to check your set in and see where you stand. It's in the manual and will really allow you to determine what's needed. The spring should really NOT be used for firming up the shock travel, the spring simply holds the rider weight. Keep in mind you may want to be on the low side of set in as the ice build up will add several pounds. This is why you will find the sled bottoming more mid day than in the morning. I believe there are two or three heavy spring options for the ohlins so choose wisely if you do. If you are only occasionally maxing out the comp. adjustment and rarely bottom out, I would revalve the shock regardless as it sounds like you are typically in the high end of the adjustment anyway. Also make sure your rebound isn't cranked all the way up as that can give you the effect of bottoming after several bumps, since the shock can not return to it's normal travel fast enough you essentially loose travel after each consecutive bump.

A revalve is one of the best things you can do to the Yamaha snowmobiles. It really changes things. As mentioned the Mono is not a big bump, skid but you can get it to ride VERY smooth over the stutters and take the occasional big hit fairly well if set up correctly. Just keep an eye on the arms as they are the weak link.

 

[Bluebullet]

Thanks LJ, My sled is a 2010 Apex LTX GT. Pretty much what I figured. I have the electronic ohlins and usually run damping adjust on the firmest setpoint because I found it is the best for my weight. I found the set in set points for spring and I am set to about 160 - 180lbs, so I will probally make the adjustment to get closer to my wieght. Once I am set in correctly I should get better on the fly adjustment rates. I plan on sending the shock out to Brad at pioneer this summer to get revalved. Thanks again

 

[darv]

you take the weight off say it is 290mm long then sit on sled with gear or some thing that weights 20lbs with then have someone measure the length of the spring say it is it is 250mm now take the 290 less the 250= 40mm that sag you want 40 -45 mm of sag . what works good in these sleds is the 7.1 spring and a revalve by one off the shock guys. hope this helps. if you want more help you can call me.

 

[sk-rx1]

You might try adjusting the transfer rod toward min. It does force the entire suspension to move together. Many say it has very little effect but it might be worth a try.

 

[Bluebullet]

Thanks guys, Pulled the manual out tonight and am going check my set up. I can finish my season the way it is anyway. Next year new revalve and heavier spring is in the budget!.

 

[CaptCaper]

I had Pioneer do the revalve with a big boy spring and it made a big difference.

 

[sleddog66]

I had Pioneer do the revalve with a big boy spring and it made a big difference.

Just did the same this summer. X2 on big help. Oh ya, I weigh 200lb + gear

 

[LJ 452]

Thanks guys, Pulled the manual out tonight and am going check my set up. I can finish my season the way it is anyway. Next year new revalve and heavier spring is in the budget!.

Just don't exceed the minimum spring length, otherwise you can coil bind the spring. Nice thing with the Ohlins is that you don't need any special tools to swap out springs. The threads are long enough to just loosen the spring tension until the spring falls out. When you replace the shock be sure to use plenty of tie wraps and even electrical tape to ensure the wire stays put. Also follow the updated print on wire route, take pics of how it is before removal etc.

 

[Bluebullet]

Thanks LJ! Good idea taken pics and checking the wire routing I heard thier were issues. Hope I remember next summer!

 

[Bluebullet]

what I found?

So Here is what I found yesterday:
Used the Ohlins 136" preload setting Chart from Toms FAQ section
Rear spring prelaod was set too:
11.25in or 286mm track off ground
10 .18 track on floor no rider wiight
summary suspension was set up for a rider of 130lbs !

Now set :
10.7in or 274mm track off ground
9.33in or 238mm on floor no rider weight
Sag is 1.70in or 43mm with 220 lb rider weight
Sag reading per my manual instead of just reading the lenght of spring
measuring from sping bottom to center of mounting bolt is 1.7in or 43mm

What do you guys think did I do this correctly? should the sled changethat much with no rider weight?
Oh yes I also found a bad bearing in one of my center wheels. all the others seem good. I love finding issues and fixing stuff in the confines of my garage!
Blue