14 MPI Viper RPM and Top speed

[Studroes144]

The secondary is all ulmer so I’ll leave that alone and play with the weights while I’m on the trail this week. Thanks for the input

Hard to really start playing with stuff without knowing what the actual weights are, they could simply be just too heavy for your sled even empty and you’ll never be able to get it right. If it ran good for you with the complete Ulmer kit except for hitting the rev limiter once you were at higher speeds then I’d put that primary setup back in and just add weight to the tips.

 

[WootTootViper]

If I gave it over half throttle at all with the old setup it would just nail rev limiter so this is definitely an improvement.

 

[ishpeming fan]

I would call or email Allen at Ulmer racing, he is very helpful with any questions about his products

 

[WootTootViper]

Okay guys so I rode on the set up it had on an airstrip after a light freezing rain so she bit in hard. It was doggy in the trails and pulled like a freight train from 50-105 max rpm consistent at 8400. So I took out the tip weight that was in there ~ 1/2 set screw and I installed the next size down. Now in the trails I have a rocket that pulls from 0-90 like crazy but literally hit a wall at 90 and won’t go any faster. Any tips to get that top end back and leave the low and middle where it is. Oh and my rpms jump up to 8700 ish and it kind of slowly goes down to 8200 at 90 mph. Thanks for your help

 

[74Nitro]

Okay guys so I rode on the set up it had on an airstrip after a light freezing rain so she bit in hard. It was doggy in the trails and pulled like a freight train from 50-105 max rpm consistent at 8400. So I took out the tip weight that was in there ~ 1/2 set screw and I installed the next size down. Now in the trails I have a rocket that pulls from 0-90 like crazy but literally hit a wall at 90 and won’t go any faster. Any tips to get that top end back and leave the low and middle where it is. Oh and my rpms jump up to 8700 ish and it kind of slowly goes down to 8200 at 90 mph. Thanks for your help

You need to see RPM in the high 8's at high speeds imo.

 

[Studroes144]

Before you do too much more I’ll give one big tip. If you’re doing long top speed runs and can’t keep the sled higher in the revs, don’t keep holding it wide open. At 8200 you’re making full boost but since it’s low you’re creating a lot of cylinder pressure..not a good combination in a turbo sled. 2nd tip, try to find out what weights you have, Dalton weights should have they name/style etched in the side of the weight. Knowing the base weight of them is going to be very useful in know if they’re going to work for your sled and also what primary spring combo to go with. You can always just throw a really stiff primary spring in to get the revs up, but still probably won’t get you quite what you’re looking for in top end performance.

 

[InRBigness]

I have a 2016 XTX with the MPI turbo. I run the Ulmer clutch kit as recommended by Allen. I run an 8DN, MPI quiet muffler and no other updates to power except an external Cold Air Intake. My top speed on GPS was 107MPH. It was -28C at the time. There may have been a bit more in it, but I thought that was fast enough. It does take a bit to get there though.

 

[WootTootViper]

Good tip on the cylinder pressure never thought of that thanks. Yeah I’m hoping to get it figured out where I can just get it to sit at 8800-9000 rpm when I pin the throttle the whole range. When I get home from this trip I’ll ding into what weights/spring I have. I dropped 400 bucks at the shop down the road yesterday on a new helmet/shield and gloves hoping that is enough incentive to get bumped to the top of the list for them to look at my sled tomorrow morning. I’ll report back.

 

[WootTootViper]

Ok guys here’s what I have for clutching. I put the super tip 50YS back into my clutching. The primary sping is all black with a single pink dot. I have 8 washers in the tip (4 on each side), 8 washers (4-4) in the middle and 1 washer in the heel with an o-ring. The secondary is machined for an 8dn belt with a red secondary spring wrapped at 6-1. And the billet helix is stamped with a K. The sled jumps to the rev limiter when it’s given gas. It needs dropped about ~100 or 200 rpm through the pull. My rev limiter is around 9200 on max recall. Iv read vipers like tip Weight. Also what does different placements of washers effect through it’s range. Thanks.

 

[cannondale27]

Put the stock pink spring in secondary at 6-1 wrap. Clean your clutches and put a Tungsten in tip and see where you are at. Your last sentence tells me your belt is slipping.

Okay guys so I rode on the set up it had on an airstrip after a light freezing rain so she bit in hard. It was doggy in the trails and pulled like a freight train from 50-105 max rpm consistent at 8400. So I took out the tip weight that was in there ~ 1/2 set screw and I installed the next size down. Now in the trails I have a rocket that pulls from 0-90 like crazy but literally hit a wall at 90 and won’t go any faster. Any tips to get that top end back and leave the low and middle where it is. Oh and my rpms jump up to 8700 ish and it kind of slowly goes down to 8200 at 90 mph. Thanks for your help

 

[WootTootViper]

Put the stock pink spring in secondary at 6-1 wrap. Clean your clutches and put a Tungsten in tip and see where you are at. Your last sentence tells me your belt is slipping.

I only have the red spring for the secondary and the clutches are running cool after a few good long pulls at the end of a night of trail riding I put my hand on them and they weren’t too hot. That run was with the dalton weights... I’m going back to the supertips where my rpms were too high. I ordered the tuning kit and it got here today. There are no black marks on the sheaves of either clutch. How do you recommend cleaning them?

 

[cannondale27]

I only have the red spring for the secondary and the clutches are running cool after a few good long pulls at the end of a night of trail riding I put my hand on them and they weren’t too hot. That run was with the dalton weights... I’m going back to the supertips where my rpms were too high. I ordered the tuning kit and it got here today. There are no black marks on the sheaves of either clutch. How do you recommend cleaning them?

Acetone. For any black marks or grey then scuff. Clean with Dish soap and water.

 

[WootTootViper]

Ok I’ll have to tear them down after my next trip. Iv never worked on clutches before so I don’t want to learn with a ride comin up so close. Just scuff with like 0000 steel wool?

 

[cannondale27]

Ok I’ll have to tear them down after my next trip. Iv never worked on clutches before so I don’t want to learn with a ride comin up so close. Just scuff with like 0000 steel wool?

I like a Brown Scotchbrite pad but we used to use steel wool. Just dont want the particles left in clutch workings.

 

[WootTootViper]

Ok thanks y’all got any tips and tricks and things to look for