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lacking top speed, please help!!

Crf458

Newbie
Joined
Feb 8, 2015
Messages
12
Location
Ontario
Country
Canada
Snowmobile
2015 Yamaha SrViper Xtx-se
I have a 2015 Xtx Viper with just shy of 900 miles and cant seem to get the top speed i've been told about and seen everyone else obtaining. My viper has an MBRP race can, K&N air intake, 8DN belt, Power commander computer and Ulmer clutch kit. Even with all these add ons i still lack the top speed im looking for.
In near if not perfect conditions checking my max RPM it's usually in the 9100 range and all my sled is able to do is 87 to 88 mph. My viper accelerates like a bugger all the way to that 87 mph and then just stops gaining speed all together, so to me it seems like its a computerize break in not allowing my engine to rev out. I've marked my primary clutch with a marker to determine if i have more clutch available or if clutching was my issue yet im still an inch away from using all the clutch.
I followed (for the most part) the recommended break in procedures and yet still having these issues. Is there anyone else out there with the similar issues? or anyone have any ideas of when complete break in should be done?

Please Help!!!
 

You are not alone. Many complaints about top speed some worse than others.

Do you have the 2.25" track?

Apparently some XTX got geared "down" to a higher ratio/slower speed.
 
You are not alone. Many complaints about top speed some worse than others.

Do you have the 2.25" track?

Apparently some XTX got geared "down" to a higher ratio/slower speed.
Not to sure what my gearing is but the gearing is stock. My track is a 1.6" track so i wouldn't think they would of geared down for the smaller track
 
To check gear ratio you need to mark drive roller tooth and note the clock position. Note clock of secondary as well. Rotate the secondary until the drive makes one or 2 or more full turns while counting the revolutions of the secondary. Divide the secondary count by the primary count.

I don't know that anybody can say for sure which gearing was actually used in which sled. It should just be the LE's that got the different gearing, but...
 
Your Max rpm should be higher with the power commander. Mines stock with a OSP pipe and my max rpm is exactly 9268(hitting rev limiter). I'd be playing with the clutch kit you put on. My dealer said after 600km your break in is complete

(How you doing against the bombi's?) if you don't mind me Asking
 
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Your Max rpm should be higher with the power commander. Mines stock with a OSP pipe and my max rpm is exactly 9268. I'd be playing with the clutch kit you put on. My dealer said after 600km your break in is complete

(How you doing against the bombi's?) if you don't mind me Asking
Think the highest RPM i seen was 9180 or so, yet i installed all those parts ( except the MBRP can ) all in the same day and other than sound and a little better throttle response there was no RPM or top speed change. and you'll have to excuse me im rather new here, what do you mean by bombi's ? haha
 
Think the highest RPM i seen was 9180 or so, yet i installed all those parts ( except the MBRP can ) all in the same day and other than sound and a little better throttle response there was no RPM or top speed change. and you'll have to excuse me im rather new here, what do you mean by bombi's ? haha

Did you do the work yourself? Not sure of your knowledge, maybe worth taking to an expert. PCV should Giving you more rpm but maybe clutch setup is stopping it from doing so. You must see a different in bottom and middle range?

The bombardiers, have you gotten a chance to race with anything?
 
You say you are a inch away from the top of the primary .... Sounds like you aren't getting full shift in primary .... Che k your clutches ... You my have to get your clutch Machined .....
 
Did you do the work yourself? Not sure of your knowledge, maybe worth taking to an expert. PCV should Giving you more rpm but maybe clutch setup is stopping it from doing so. You must see a different in bottom and middle range?

The bombardiers, have you gotten a chance to race with anything?
Pretty knowledgeable with everything during the install. had to give Ulmer a call but for a simple clutch tip dealing with the secondary but quickly had everything set straight. I am going to try my stock belt again with the clutch kit compared to the 8DN and see what the difference is there
and havent raced any bombi's just a bunch of kitties, but seeing i lack top speed i eat them off the line but cant hold them off for long
 
You say you are a inch away from the top of the primary .... Sounds like you aren't getting full shift in primary .... Che k your clutches ... You my have to get your clutch Machined .....
no not getting full primary at all but never have been. I shouldn't have to get the machined straight from stock with the stock belt ??
 
Pretty knowledgeable with everything during the install. had to give Ulmer a call but for a simple clutch tip dealing with the secondary but quickly had everything set straight. I am going to try my stock belt again with the clutch kit compared to the 8DN and see what the difference is there
and havent raced any bombi's just a bunch of kitties, but seeing i lack top speed i eat them off the line but cant hold them off for long

Awesome, be curious to hear how you do agAinst the ski doo 800R. I'm side by side with an XRS to 95 mph.

Good luck with the setup!
 
Did you do the work yourself? Not sure of your knowledge, maybe worth taking to an expert. PCV should Giving you more rpm but maybe clutch setup is stopping it from doing so. You must see a different in bottom and middle range?

The bombardiers, have you gotten a chance to race with anything?
Pcv does not give you rpm unless you have ignition module.
 
no not getting full primary at all but never have been. I shouldn't have to get the machined straight from stock with the stock belt ??

Just for test put your secondary spring in 3-3 position. Remark your primary. See what happens.
 
Just for test put your secondary spring in 3-3 position. Remark your primary. See what happens.
I can give that a try, if I remember right there in 6-1 right now and that's what was Stock and on ulmers set up sheet.
 


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