Pro RMK doesnt build full RPM but will slowly creep up

[TrivanovicRobert]

So my 2013 Pro RMK is my old sled that I kept for my girlfriend to ride, I hopped on the other day and realized the sled is low on RPM but will slowly creep up if you hold it wide open for long enough. Primary clutch is rebuilt, has a new primary spring, and new exhaust valve springs, and the valves have been cleaned. Whats next to look at? I didnt notice exactly what RPM it was making, probably around 7000.

 

[Betterview]

Belt could be narrow, or the secondary has issues. Could be helix, buttons, spring, or a combination. I am assuming the primary got new weights and rollers. Make sure the correct weight weights were put in for your altitude. Another thought. If the sled has been stored all summer check to see if rodents have used your exhaust for storage or made a nest in it.

 

[NapaMatt]

bad gas???

 

[frntflp]

RPM of 7000? Should be more like 8150 or 8200 at WOT. Clutch issues, I'm thinking. Broken or warn parts, something sticking, etc.. Verify primary work was done correctly, what about the secondary ? If the exhaust valves are opening correcty ...... ? .....Next is clutching. IMO

 

[Murph]

7000 rpm.... check exhaust valves. Sounds like they aren’t opening.
Bellows intact?
Solenoid closing?

 

[TrivanovicRobert]

7000 rpm.... check exhaust valves. Sounds like they aren’t opening.
Bellows intact?
Solenoid closing?

I clean the exhaust values and changed the springs and gaskets on them, they are moving freely at the actual valves, what else should I check with them?

 

[TrivanovicRobert]

The primary clutch is a newly rebuilt clutch as the issue was before the new primary clutch too. Its been happening for a while now so not bad gas. The exhaust valves have new springs inside and are moving freely. Im thinking secondary clutch issues, unless theres another part of the exhaust valves that im missing that might be the issue.

 

[TrivanovicRobert]

https://www.snowest.com/forum/threa...sh-and-no-top-end-power-valve-problem.345760/ Found this post and realised thats exactly what my issue was. Took a better look at my exhaust valves and realised those little ports in mine were plugged up too, guess I didnt clean good enough, now just need to try it out but im fairly confident that was the problem

 

[MKULTRA]

I don't think it was common on the pro ride but the actuator cable breaks on the axys.

with the EV off you can move the actuator and see if it controls l the EV

it could be a bad actuator too although not common.

 

[Alpine Xtreme Edge]

I don't think it was common on the pro ride but the actuator cable breaks on the axys.

with the EV off you can move the actuator and see if it controls l the EV

it could be a bad actuator too although not common.

The pro-ride chassis doesn't have an actuator with cables connecting to exhaust valves, instead they work off exhaust pressure with a solenoid that bleeds pressure until a specific rpm that the ecu tells the solenoid to close, thus letting the pressure open the valve fully.

The tiny pin hole port above the valve in cylinder must be clear of obstruction for that function to operate correctly.

You do make an excellent point for and relating to axys chassis motors regarding the actuator/cable breaking issue.

 

[MKULTRA]

The pro-ride chassis doesn't have an actuator with cables connecting to exhaust valves, instead they work off exhaust pressure with a solenoid that bleeds pressure until a specific rpm that the ecu tells the solenoid to close, thus letting the pressure open the valve fully.

The tiny pin hole port above the valve in cylinder must be clear of obstruction for that function to operate correctly.

You do make an excellent point for and relating to axys chassis motors regarding the actuator/cable breaking issue.

oh crap totally forgot about that lol and I had a pro ride

 

[TrivanovicRobert]

Tested the sled out after doing a good clean of the exhaust valves and it hits 8050rpm but it seems to hit 7300iah fast and then the last bit has a slight delay. Im not sure if im just used to my last two sleds (17 axys turbo & and 19 alpha) or if this thing is low on power. Just seems gutless to me the way it is. But the new alpha and my old axys turbo are both pretty impressive sleds so I may just be comparing to the wrong sleds... The 13 pro is bone stock even has the stock can and all stock clutching.

 

[VHOK]

Test the resistance of your spark plug caps, suspect high resistance. This creates a weak spark potential and poor burn. I think the resistance Value is 5K ohms but need to verify that in service manual. I replace both spark plugs and caps as part of preseason maintenance.

 

[prairieguy]

Have u done compression test? I just went through this and was low on compression


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[kanedog]

My money is on the secondary.
Keep up the Snowest updates. We should start a betting system on Snowest. When someone has a sled issue, we could lay odds.