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Valve check?

I do know of a few Apexs that the valves got tight in at @12000 miles.
Are the valves stretching, the valve faces wearing or the valve seats pounding out?
None of us know since only sleds that for sure had tight valves were fixed by dealers and issue was fixed by replacing everything. We who suspect tight valves don't even know that they are yet. It could also just be a coincidence that a crappy tune which was updated this year has the same symptoms of tight valves. I am hoping it's just the tune.
 

Absolutely it all can add up.
All I can say with my issues is once I got it started and the temp light went out it always ran like a SWISS WATCH
Always pulled rpm, and had no drivability concerns.
My last trip was 2k with a blown muffler the entire time and it ran its #*$&@ OFF accept for my RT foot getting real hot lol
I was thinking about this statement. Not saying you aren't right and am comparing a Dirtbike to a snowmobile. Buddy had CRF450 he could not start it in morning. Adjusted the valves started bike and ran 2hr race. Shut bike off and it then would not start again. Tight valves effect starting much more than anything else.
 
I don’t know man.....
Tight valves cause strange drivability issues for sure. I deal with the bucket shin design issues all day long with the Subaru wrx/sti/ Fb engines.
I’m trying to put together the pieces to this mystery like everybody else.
14 mapping started better but had kick back and had extended crank issues. Then we’re flashed with the lastest and greatest and are all f&ck &up.
15 mapping has rolling idle issues, inconsistent crisp startup’s, minor kick backs, flashed with the latest and greatest and all f&ck &up.( describing my 15).
-10 and up it would start without backfire so if my experience was just tight valves I would have starting issues north of 0 degrees.
I will say crappy fuel mapping being to rich or lean or inconsistent will deteriorate a valve train eventually.

What we need to know....
Vacuum readings from startup to operating temperature.
Cylinder leakage / hot/cold
Compression hot/cold
Valve clearance specs cold/hot.
Just a technician’s opinion.
 
None of us know since only sleds that for sure had tight valves were fixed by dealers and issue was fixed by replacing everything. We who suspect tight valves don't even know that they are yet. It could also just be a coincidence that a crappy tune which was updated this year has the same symptoms of tight valves. I am hoping it's just the tune.
I have EVO flash and after I ran it, I experience crappy idle when the engine is hot. If I don't put a little throttle in a cold start they would stall if. Sometime I had thinking maybe is because of my mbrp header but seems I have the same valves issue at 8,000 miles
 
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I don’t know man.....
Tight valves cause strange drivability issues for sure. I deal with the bucket shin design issues all day long with the Subaru wrx/sti/ Fb engines.
I’m trying to put together the pieces to this mystery like everybody else.
14 mapping started better but had kick back and had extended crank issues. Then we’re flashed with the lastest and greatest and are all f&ck &up.
15 mapping has rolling idle issues, inconsistent crisp startup’s, minor kick backs, flashed with the latest and greatest and all f&ck &up.( describing my 15).
-10 and up it would start without backfire so if my experience was just tight valves I would have starting issues north of 0 degrees.
I will say crappy fuel mapping being to rich or lean or inconsistent will deteriorate a valve train eventually.

What we need to know....
Vacuum readings from startup to operating temperature.
Cylinder leakage / hot/cold
Compression hot/cold
Valve clearance specs cold/hot.
Just a technician’s opinion.
Yea. I will do a cold valve check and go from there. I know I can tune mine decent enough at least with the can on it. The stall thing really bothers me though. It’s almost like a ignition cut off. Idling normal then out like a light. Buddies same thing.
 
I have EVO flash and after I ran it, I experience crappy idle when the engine is hot. If I don't put a little throttle in a cold start they would stall if. Sometime I had thinking maybe is because of my mbrp header but seems I have the same valves issue at 8,000 miles
Maybe not valves. What tune did Evo base yours on? There was options. Heck I have even seen issue like that from too tight belt deflection. Have to check everything else before condemning the motor itself.
 
Always had a start up stall but once running it never just shut off. That’s interesting. Curious to know if you find that issue!!!
Did the nytro with Japan elections have any valve clearance issues causing havoc?
 
Maybe not valves. What tune did Evo base yours on? There was options. Heck I have even seen issue like that from too tight belt deflection. Have to check everything else before condemning the motor itself.
It's EVO flash 4. I just checked my belt deflection and it is ok. It's seems a little bit worse this year when I started it in a cold day. In the firts minutes I have to put a little throttle. I had never touch it before this year
 
I know car guys works a lot with cams-/valve timing. Maybe we should check that on our sleds too? What happens if the camshafts chain is loose?

Some pics to Illustrate

JWTcamgears.jpeg
valvetmg.png
TechInsructiontTemplate_clip_image002_0000.jpeg
 
I know car guys works a lot with cams-/valve timing. Maybe we should check that on our sleds too? What happens if the camshafts chain is loose?
Similar running issues can have different causes. The first time I had warmup issues we checked out cam chain tension because it seemed likely to be the cause. We continued to try this and that with no luck. The factory sent out a new clutch shaft/coupling with the thought that it was effecting the sensing of the crankshaft position. I checked out the the operation of the idle speed control with the thought that it was not doing its job. Finally in my case tight valves was found to be the root cause. For all those concerned I am hoping that tight valves was caused by the way I drive my but I am starting to think not. More than the way I drive is how much I drive year after year. In my case adjusting the valves to eliminate tight valves immediately got rid of all symptoms on both occurrences. The second time around Lighthouse Motorsports in Rosemount MN figured out a way to adjust the valves with minimal disturbance of the engine. For those that think they have tight valves hopefully they are wrong but if not I would recommend Lighthouse Motorsports.
 
I have my sled apart 4000 miles so i measured my valve clearances at room temp. picture show results, don't think spec written on sheet is right. What are the specs ?????
VALVE CLEARANCES2.jpg
 
I have my sled apart 4000 miles so i measured my valve clearances at room temp. picture show results, don't think spec written on sheet is right. What are the specs ????? View attachment 139929
look the up and this is what I found , in Arctic cat manual for 7000, 2014
Cold
intake 0.0059 -0.0087 in.
Exhaust 0.0083-0.0098 in.

edit to fix typo
 
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Allen,

Think the upper dimension on intake is .0087
 


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