860 only pulling 7400?

[800CatRider]

I have carl's cycle 860 in my 08 dragon. Just picked it up so today was my first ride. Engine ran pretty good other than the mag side spark plug looked a little lean during the first part of the day and there was a small stumble in the mid range. What the real problem was that I was only getting about 7400 RPM in any fresh snow (flat or on a climb). I went to the lake below to see if I could get higher RMP on a flat, open pull, and even then it would only reach about 7800 near the very end of each run. It has a green spring in it with 10-66 weights. Couldn't tell you the helix or spring in the secondary as I haven't taken apart the secondary. I would have just called carl's but they were closed when I got home and are closed sundays. Any reasons or recommendations as to why Im only getting 7400 rpm? By the way, elevation was 6500 ft. I didn't think 66's would be too heavy for an 860 at our elevation, but maybe Im wrong.


EDIT: Just went out and pulled the power valves. Bellows looked good. No cracks or signs of wear. Pistons on the exhaust side looked good for 900 miles. Just a couple very small lines I doubt your finger nail would catch. No wash past the fist ring either.

 

[red99powerstroke]

I just put the 860 kit in my 2010 163 and only have one trip west on it. The first 100 miles it was spot on 8250 RPM with 62's at 10000 plus feet but by the end of the trip it was getting broke in and was pulling 8600 so I am thinking I need 64 or 66's at that elevation.

 

[800CatRider]

Think I found the problem. Is it normal to have about 1/16 of an inch between the piston and the cylinder? Probably why Im only getting 119 lbs on each side Unless for some reason this is to account for expansion or something, but for some reason I think not.

 

[sled_guy]

You have 1/16th inch of piston clearance? Yeah, that's not right.

sled_guy

 

[800CatRider]

Sled-guy, you've had 860s before, right? Well along with the pistons being way out of spec (hopefully not the cylinders), the pistons look waaaay to lean. Is there anyway I could be losing my injectors? Or could that be from the clearance being way off?

 

[sneakyninja]

lol should sound a little like a diesel running with .062" clearence. rattle rattle rattle. think you got the stocker piston in it. i would slap the person who built that. you should only be able to slide a .004-.005" feeler gauge inbetween the piston and cyl. with the rings off. and check the ring end gap should only be around .016-.018". YOU MAY HAVE PROBLEMS if numbers are alot bigger.

 

[sneakyninja]

oh and piston clearence is checked at the skirt of the piston. also how did you check this? you cant just look down the spark plug hole and gauge this the pistons are also radius on the sides at the top side of them so it may just look that way to you. look at your plug and see if you got alum in it and pull the pipes and look at the piston side to see if the exaust side is burning up on the top side of it. could have det or lean. allso look at your piston wash should have carbon washed off from where the intake ports are maybe half inch in from piston out side. the carbon build up should look a little like a star that way you know you got fuel wash still and not running too lean. may be hard to judge with fresh motor and after just cruzing to the parking lot. if the whole piston is carboned up and theres no indication of piston wash too lean. also check the cyl sides with pipe off and see if there scuffing YOU DO NOT WANT that. if appers to have metal transffer from alu piston to cyl wall dont run it at all.

 

[sled_guy]

Yeah, I've worked on a couple of 860s.

I don't think you can make any assumption about the lean condition if the thing has huge piston clearance or other running issues.

Yes, the injectors could be giving you problems, but if it is so lean that it won't pull RPM you would burn it up.

Do you have it torn apart? Who put it together? Is it brand new or used?

sled_guy

 

[800CatRider]

Torn apart, but haven't taken the cylinders off yet. I wanted to wait to pull it all apart until the new pistons and rings showed up so I don't get anything inside the crank (small shop = lots of dust). The engine was sent to carls to have it built, not the entire sled, about 900 miles ago.

 

[800CatRider]

Well I bought new pistons and rings and installed them. It starts a lot easier and has much more compression, but still is only getting 8000 max at my house (like 2500 ft). Is there anyway it could be the ecu or VR? The guy I bought it from had the ECU burn up on him right before I bought it and had to get a new one from carls. Is there anyway that it doesn't have the right flash on it?

 

[sled_guy]

The flash is based off of injector color. Seems like Carl's labels the ECU when the flash it with the color of injector it was flashed for if memory serves.

Have you pulled the primary apart and checked it out good?

sled_guy

 

[800CatRider]

Just pulled everything apart tonight. And I mean everything. Checked the muffler the best I could to see if the baffle was falling apart and causing restriction, but no matter how hard I shook it there was no rattle noise. Primary might not look perfect, but there is zero binding when you slide the outer sheave and the cap bushing isn't worn out. The weights aren't hitting the spider on full engagement, and the secondary rollers are tight. Got it to pull 8-8100 with the new top end, so thats a good sign. I'm taking it out tomorrow so I guess we will see if it breaks in and starts performing.

 

[Vinnee]

Did you ever call Carl's? There was never a time that they didn't have constructive and valuable information about my 860 when I needed it.

 

[800CatRider]

I've called them probably 15 times in the past two weeks.