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Redbaronjg
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Serious. This is honestly the first time I've ever heard any good spoken of twins on a doo
Problems with my 860
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Redbaronjg
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I'm going to put it out there so we can forget about it, I will bet anything octane is not my issue. I already run much higher race mixture than Anyone has said is required, I'm even high for low elevation riding, and have ran different brands with no noticeable change. The only reason I mentioned it before was so you all could see that it's being taken care of. Not trying to be ignorant, but the fact is there is no way octane or bad fuel is my issue.
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Redbaronjg
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It's a specialty sled 860 with the rk tek 14:1 heads
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Redbaronjg
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Thanks. I have the ECM update on mine as well. My dynoport has no restrictor in it, but I'm selling the mbrp can, gonna swap that out. Picked up my jets and gonna try those. Thanks for the info, exactly what I was hoping for.
pfi572
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Specialty is the same as RKT. They have a agreement between the two of them.
slededjr
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Ran twins on every doo I've owned with zero issues. Crank shop or jaws. Some are a little tricky to get dialed in but when they are nothing compares. 1300 on my twin bb set up and huge gains.
Why are your plugs coming loose then do you think? I had to run 50/ 50 with my 13.5 to 1 at 2500 ft or plugs loosened. Had .5 mm base gasket. Cc'd with this set up and came out to be 13.8 to 1. Put 13 to 1 domes in with .7 mm base gasket and Cc'd again came in at 12.96 to 1. Now runs on straight 91 at 2500 feet no issues.
Rk Tek head also. Just did another one a month ago for a guy, 13.5 to 1 domes, and .8 mm base gasket Cc'd came in at 13.2 to 1. No issues on 91 with this one. If you're not detonating then crank must be really out of spec which I doubt, or there's a issue with the domes. Kelsey makes one of the best heads out there. I'm only suggesting ideas and mentioning personal issues I've run into. Not criticizing your set up. Just trying to help.
Why are your plugs coming loose then do you think? I had to run 50/ 50 with my 13.5 to 1 at 2500 ft or plugs loosened. Had .5 mm base gasket. Cc'd with this set up and came out to be 13.8 to 1. Put 13 to 1 domes in with .7 mm base gasket and Cc'd again came in at 12.96 to 1. Now runs on straight 91 at 2500 feet no issues.
Rk Tek head also. Just did another one a month ago for a guy, 13.5 to 1 domes, and .8 mm base gasket Cc'd came in at 13.2 to 1. No issues on 91 with this one. If you're not detonating then crank must be really out of spec which I doubt, or there's a issue with the domes. Kelsey makes one of the best heads out there. I'm only suggesting ideas and mentioning personal issues I've run into. Not criticizing your set up. Just trying to help.
slededjr
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A lot of vibration by chance while running?
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flabbajabba
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Are you sure on that^ ?
I talked with Kelsey not to long ago and didn't think they were the same kit?
pfi572
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They may have changed then in the last few years .
When I had mine specialty was the same porting and porting was done in Edmonton to help with turn around .
When I had mine specialty was the same porting and porting was done in Edmonton to help with turn around .
tukernater
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Can you try a different ECM ?I just went threw this with my buddies 872 it turned out his ECM went full timing at a certain RPM and it started @5000 feet? New ECM and motor is running great again .He did the same more race fuel, bigger jets and went back to stock can.Cheers hope this helps.higvoltagesledheads is the guy it happen to. PM him you guys problems sound the same.
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Redbaronjg
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That's not what rktek says. As far as they're concerned specialty buys their heads, but the rest of the build they know nothing about. They didn't really offer much tuning or troubleshooting help because of that, which is why I came here.
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Redbaronjg
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I'm sorry, I realize I did not word that comment about fuel very well. I only meant it as, the octane is there, i may need more of it being delivered to richen it, but there should be no way that 60% c111 with 91 premium is not enough. Could just need more fuel altogether. Out of curiousity, on your 13.5:1 head with .5 gasket, what kind of pressure were you gettin for compression? Open or closed throttle?
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Redbaronjg
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There's vibration, as with every sled. Wether it's more or less than normal I cannot say, never really compared it. I would lean towards it being normal. I've never got a feeling that there was any excessive movement in the engine
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Redbaronjg
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It's possible they have just copied the design. Rktek has no knowledge of what they are building though, not from what they told me
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Redbaronjg
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Was his altitude sensitive? Mine Seems to happen any elevation. I'll try to track him down. I assume a dealer could pick up on the timing by jus hooking onto the computer? I don't have a spare ECM to try with, and frankly they're a bit of money to just dump if that doesn't turn out to be the problem.
slededjr
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No offense taken. Just trying to help. I know what you're saying about the octane you're using. The only thing I know of to cause plugs to come out would be detonating, a crank way out of spec causing lots of vibration, bad threads in domes. I think with your fuel mixture ( 25L of c111 and 15 L of 91) should give you a total octane of 100.6 I think? I can't remember compression reading for sure with out going and digging out old notes but keep in mind that number doesn't mean anything because there are too many variables to change that such as ring end gap, put on to cylinder clearance, type of dome on piston. Try 30L of your race fuel and 10 L of 91, or 25L race fuel and 15 L of 94 gas at P can or Husky. The 30 to 10 will give you 103 octane, the 25L of the c111 and 15L of 94 will give you 101.8.
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slededjr
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I have a spare ECM if You want to try it.
tukernater
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I will call him and get him to PM you.
tukernater
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Yep ran into this 5-6 years ago that's why I asked?
SS does the jugs and porting, kelsey supplies the head. Shr does it the same way. kelseys head is one of the best out there, his jetting is spot on with his own 860 engine builds.
Any head way on the 860 problems? plugs backing out is a sign of deto, check timing advance, ive heard a bad story or two of specialty sleds big bores, between snowest and dootalk. Not to say they cant build a good motor, maybe something slipped between the cracks on this 860.
I wouldnt be to quick to point the finger at mbrp can, lots of guys with 860, 872s and 880s with that can (not the trail one the loud big core one) Skinz ultra Q is a nice can, super q is the quiet one, ultra q is the one that looks mbrpish
Any head way on the 860 problems? plugs backing out is a sign of deto, check timing advance, ive heard a bad story or two of specialty sleds big bores, between snowest and dootalk. Not to say they cant build a good motor, maybe something slipped between the cracks on this 860.
I wouldnt be to quick to point the finger at mbrp can, lots of guys with 860, 872s and 880s with that can (not the trail one the loud big core one) Skinz ultra Q is a nice can, super q is the quiet one, ultra q is the one that looks mbrpish
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