• We are no longer supporting TapaTalk as a mobile app for our sites. The TapaTalk App has many issues with speed on our server as well as security holes that leave us vulnerable to attacks and spammers.

Trying The 8DN BELT

Anyone done the marker trick. Also, what is everyones center to center? How adjustable is it on these sleds?
When using the marker, accelerate slowly up to top speed so you get a true rub off mark.

If you can change the center to center, even a couple millimeters, it makes a huge difference on a timer or top speed.

once you get it to full shift out and top speed, then try some OD. If your using a belt, that is a little long for the center to center, your primary will bottom out before the secondary. If center to center is correct for the 8dn (268.5mm as I remember) then both clutches should bottom out at the same time.

do a search on over drive mods, there are alot of them on here. Once you get the sled to bottom out the clutching and not be slipping the belt, there will be a few more mph in some OD machining.

I havent looked but do they use extrovert drivers on vipers. These are known for robbing speed. When your looking for a couple here and a couple there, everything counts.
 

BETHEVIPER said:
Anyone done the marker trick. Also, what is everyones center to center? How adjustable is it on these sleds?
When using the marker, accelerate slowly up to top speed so you get a true rub off mark.

If you can change the center to center, even a couple millimeters, it makes a huge difference on a timer or top speed.

once you get it to full shift out and top speed, then try some OD. If your using a belt, that is a little long for the center to center, your primary will bottom out before the secondary. If center to center is correct for the 8dn (268.5mm as I remember) then both clutches should bottom out at the same time.

do a search on over drive mods, there are alot of them on here. Once you get the sled to bottom out the clutching and not be slipping the belt, there will be a few more mph in some OD machining.

I havent looked but do they use extrovert drivers on vipers. These are known for robbing speed. When your looking for a couple here and a couple there, everything counts.[/quote

Yes they do have extrovert drivers. And my dealer said that im getting full shift out. Now I will test it when I get it home tomorrow.
Click to expand...
 
Conspiracy theory#1? Not to throw a monkey wrench in this thread but a 'thought' crossed my mind on this whole belt/clutching issue/findings. I find it odd that Yamaha didn't foresee performance and consistency issues with this new shorter belt. Here is my thought...what are the chances Yamaha knew exactly what they were doing when going with this shorter belt? Maybe purposely dumbing down the Viper to be on par with the AC7000 performance? What I mean is...some of you guys who are improving (sometimes improving acceleration and top speed by big amounts) the Viper performance by switching to the 8dn belt. Could it be that the Viper would have been head and shoulders above the AC7000 version and that just wouldn't fly with the AC folks because AC clutching just isn't up to par with Yamaha clutching? I mean cmon...Yamaha clutches seem to be spot on performance wise and also with belt durability and reliability. Hasn't Yamaha been using the same clutching/belts for like 20yrs now? I was just thinking why/what's with the change now?
 
Could very well be! I didn't really understand why my clutches were that bad as well, so maybe your right! I would not argue! :Rockon:
 
The thought crossed my mind and was just throwing it out there 09Nytro. What might be your answer to the matter other than constantly mocking or making fun of peoples posts/thoughts?
 
MCApex44 said:
The thought crossed my mind and was just throwing it out there 09Nytro. What might be your answer to the matter other than constantly mocking or making fun of peoples posts/thoughts?
Click to expand...

It might be way out there, but that could be a good reason! Why would the 8DN work so good with just a little bit of adjustments that take half an hour. Either way I like it! ;)!
 
YamahaTim said:
MCApex44 said:
The thought crossed my mind and was just throwing it out there 09Nytro. What might be your answer to the matter other than constantly mocking or making fun of peoples posts/thoughts?
Click to expand...

It might be way out there, but that could be a good reason! Why would the 8DN work so good with just a little bit of adjustments that take half an hour. Either way I like it! ;)!
Click to expand...

Oh yes I 100% agree the thought is "way out there"...lol. I wont deny that. It's just this new belt Yamaha went with just seems odd...especially after some of the improvements being seen with the 8dn.
 
MCApex44 said:
YamahaTim said:
MCApex44 said:
The thought crossed my mind and was just throwing it out there 09Nytro. What might be your answer to the matter other than constantly mocking or making fun of peoples posts/thoughts?
Click to expand...

It might be way out there, but that could be a good reason! Why would the 8DN work so good with just a little bit of adjustments that take half an hour. Either way I like it! ;)!
Click to expand...

Oh yes I 100% agree the thought is "way out there"...lol. I wont deny that. It's just this new belt Yamaha went with just seems odd...especially after some of the improvements being seen with the 8dn.
Click to expand...

I know right...that's why I liked what you said! Who knows what they were thinking, maybe hoping someone would try the 8DN. Could be way right! It's better thinking that than Yamaha screwed up and made a crappy belt ;)!
 
I read somewhere that cat couldn't get the same angle on their clutches as Yamaha. So is this belt a compromise to work for both? Just changed yours over to 8 dn tonight mcapex44 getting some miles on belt to break in should be able to do some tuning wed, seems much smoother but will have to do some clutching , did one holeshot and skis were in the air until I lifted , other belt would spin an over shift then hook an pull rpm back down, I think you will like this when dialed in.
 
baggs66 said:
I read somewhere that cat couldn't get the same angle on their clutches as Yamaha. So is this belt a compromise to work for both? Just changed yours over to 8 dn tonight mcapex44 getting some miles on belt to break in should be able to do some tuning wed, seems much smoother but will have to do some clutching , did one holeshot and skis were in the air until I lifted , other belt would spin an over shift then hook an pull rpm back down, I think you will like this when dialed in.
Click to expand...

I don't think it would work in a cat. But it works for the Viper! :Rockon:
 
baggs66 said:
I read somewhere that cat couldn't get the same angle on their clutches as Yamaha. So is this belt a compromise to work for both? Just changed yours over to 8 dn tonight mcapex44 getting some miles on belt to break in should be able to do some tuning wed, seems much smoother but will have to do some clutching , did one holeshot and skis were in the air until I lifted , other belt would spin an over shift then hook an pull rpm back down, I think you will like this when dialed in.
Click to expand...

Sounds good...thanks again! Wish I could be down there with you testing it against another sled. The wife picks the worst weeks to go out of town for work. lol
 
Hard for me to keep up with all the posts...but here it goes.

I used to do the black marker reading but when your on a pass (especially on asphalt) I have to grab the brake hard and when that happens....it gives an untrue reading cause the belt rides up the primary so much. I, myself use my timers, radar and GPS to get results. If the results don't work, I go back to scratching my head. It's been years now (14 to be exact) working with yamaha clutching and finally getting the hang of what works and how it works. I could keep these tips a secret, but I want every Viper owner to kick but on the trail, make everyone say "WTF!!!!!!" "How the hell!!!?" :)

I don't see the belt working on cat clutches, but then again....haven't tried it.

Hmmmm - I don't think Yamaha would make a belt to slip so it doesn't perform more then the cat.....hence we have slipping and performance issues. The question is....did they change compound in the belt after the prototypes? All companies I work with try to save a buck somewhere....makes you think, don't it? I rode the prototypes for 3 days straight and never experienced slipping, over-revving or any clutch issues. I do know the clutching then is not what is in the Viper right now....they said they were going to change it.

I had to try the 8DN belt because I wasn't getting anywhere with the stock belt. Abnormal heat and slipping, hit rev limiter one day, down on rpm the next and then perfect and haul #*$&@ later in the day. Wonder why I had so many headaches last month.

Center to center is definitely shorter on the viper compared to the Nytro, Apex or SRX. I have a tool that puts the engine where its supposed to be but doesn't give me a measured length. All I know is it looks about 7mm shorter with no adjustments that can be made.
 
You must log in or register to reply here.

Similar threads

CharlieAZ
05 Yamaha Vector RS ER Belt Deflection
Replies
8
Views
1K
thrasher
thrasher
yamahahaapex
Sidewinder Belt Blowing
3 4 5
Replies
68
Views
15K
Fleecer
Fleecer
max rolph
Clutch alighnment... TAPP and STM KNAPP
Replies
0
Views
2K
max rolph
max rolph
blevis213
Xs825 belt break in
3 4 5
Replies
68
Views
8K
1nc 2000
1nc 2000
jross2828
Upper Chaincase Bearing - Cato-strophic Failure
2
Replies
18
Views
3K
jross2828
jross2828


Back
Top