Install the app
How to install the app on iOS

Follow along with the video below to see how to install our site as a web app on your home screen.

Note: This feature may not be available in some browsers.

  • Don't miss out on all the fun! Register on our forums to post and have added features! Membership levels include a FREE membership tier.

2010 assault only runs under 7k rpm

PaulAnd

Well-known member
Premium Member
2010 assault cfi 800 1250 miles all original no mods, april flash and 10-64 weights had it running very good last year 0-3000 ft. Went out last weekend first time since last year, midwest... sled would not rev above 7k rpm without det.. shut off and restart engine would run again same. Next day voltage regulator goes out.. I replace it and hope my det issue is fixed, still has det issue... get it home.. ran it to dealer, they say only has det codes stored, they recomend changing fuel filter, I get it home and test fuel pressure, its at 59, pull filter its clogged, cant blow through it. I pull fuel pump to see what tank looks like, the clear sump hoses are completely broken off and cracked.. pull y-pipe no obvious scoring, pull head anyway... I cant beleive the amount of play at top of piston!!! there is enough room to pull the top ring out... I can see how the rings could easily come past ring locator pin and destroy engine at this point.. at least .030 at top of piston/cylinder. Pull the jug the wrist pin and bearing are also blue.. rod looks ok. no obvious cracks in cylinder or piston skirts. I think pushing the stock engine past 1000 miles might be risky without at least a look at piston to cylinder wall clearance. Sorry for the long post, hope its somewhat helpful.
 
Ok fine, i'll be the test bed.. trying the RK TEK polaris drop in kit, fixed the fuel pump sump hoses, new fuel filter, fresh belt, putting in the 10-60 clutch weights for my WY trip in 2 weeks. taking out the leaking GIZMO, installing slp bypass instead.. RK TEK's kit looks nice.. using a coated Wossner piston, head looks nice also, will give it hell in 2 weeks and return i Hope with good news, cylinders looked good, had the spec written down.. lost the note.. I think 3.4365? havent had the chance to measure new piston, will do so before install and post.
 
After installing top end it ran well.. alot smoother.. had a slightly higher idle than it did before, went from 1700 to 1850, so for the hell of it I rechecked the tps and idle settings... .710 at base .930 idle.. during sweep of tps found it open @ full throttle.. I had a very hard time finding a dealer that had the sensor.. and they are on backorder from Polaris, after installing new tps it now idles at 1750... I'm almost positive the tps was why engine would shut down under full throttle, will post how it fares in Cooke City next week
 
After aprox 150+ Cooke City miles last week... All I have to say is WOW what a difference! The RK TEK drop in head kit is AWESOME! Had 8250 rpm on 10-62 stock prim. and sec. springs, pulled harder in the mountains 6k to 12k than it ever did flatland with stock top end... it pulled on every sled in the group even with a clutch bog off the line... including 2012 freeride 154, backcountry 800r, easily pulled on the summits on trail, It got highmarked due to skill level by the summits :( ... everybody in the group this year commented on how well the sled ran this year out west...
My first impressions on this kit... my arms and shoulders are VERY sore, runs way smoother and way more powerful. The only complaints (not from me)... the huge trench left behind by the stock track that the other sleds fell into..
 
1 more note, with the t-stat gutted, I rarely ran the scratchers down on hardpack snow... with hard snow no scratchers 130, hard snow with scratchers 100, no scratchers soft snow 80-90, noticed no difference in runability at all at any temp, the snow conditions in Cooke City.. hard snow in A:M soft in the P:M, The other sleds in the group ran with scratchers down most of the time, toward the end of the week I didnt bother with the scratchers, the sled just didnt get that hot.. average daily temps 20 to 60 degrees
 
Premium Features



Back
Top