D00 860 big bore kit

[beezer11]

my son has one in his 08 XP. ran great then started to loose power. He runs C111 fuel. The sled has only been riden twice since the conversion at Specialty. Anyone else run into the problem with Big Bore kits.

 

[foghorn]

I just bought a 09 with a specialty installed RK Tech 860 with 750 miles on it I haven't been out but guy has had no problems with it.You say he is using C111 but is he mixing 50% or 20%.Did he lose power till it stopped or just seems to not have the balls it use to have.I would check compression first thing.Are clutches shifting all the way out.

 

[beezer11]

he runs 4 gallons c111 per full tank. HE lost power coming out on the trail at Owlshead in Sicamous. He was with a large group of riders and no one had seen that happen before to the 860 kit.

 

[markoo]

It could be anything from a bad piston to a bad clutch spring.

 

[Modman]

It could be anything from a bad piston to a bad clutch spring to an iced up track.

Need more information - "lost power" is pretty generic

 

[glengine]

he runs 4 gallons c111 per full tank. HE lost power coming out on the trail at Owlshead in Sicamous. He was with a large group of riders and no one had seen that happen before to the 860 kit.

That seems like alot of VP per tank. You shouldn't need to put any more than 2 or maybe 3 gallons per tank max. I've installed LOTS of these kits.

 

[maxwell]

compression check...cluctch is stuck midshift somewheres....more details....

 

[beezer11]

i personally thought it was too much, but he states that what he was instructed to do. He tells me that pistons are burn't and pots scored. To me it would be something was leaned out. Makes me also wonder about VFORCE reeds also installed at the time of the big bore kit.

 

[glengine]

i personally thought it was too much, but he states that what he was instructed to do. He tells me that pistons are burn't and pots scored. To me it would be something was leaned out. Makes me also wonder about VFORCE reeds also installed at the time of the big bore kit.

I've done lots of the kits and alot of them got v-force reeds at the same time as the big bore was done and never had an issue with that. How are the pistons scored? All the way around? 4 corner? just exhaust side? How the piston is scored can tell alot about what caused it. Was it a hard packed trail? Scratchers down? Did the overheat light come on?

 

[Modman]

Did he re-jet for the elevation up top?

 

[beezer11]

I've done lots of the kits and alot of them got v-force reeds at the same time as the big bore was done and never had an issue with that. How are the pistons scored? All the way around? 4 corner? just exhaust side? How the piston is scored can tell alot about what caused it. Was it a hard packed trail? Scratchers down? Did the overheat light come on?

i asked him whether the overheat light came on to shut the machine down and he stated no. the trail as well was not hard pack so overheating should not have been an issue normally. If memory serves me correct the jetting should be 480. Will have to recheck that as i have not done much with his sled in the past year. But either way, if a Big Bore Kit is sold and installed by a retailer, would it not be a question from the start in asking what kind of riding do you do?

 

[glengine]

i asked him whether the overheat light came on to shut the machine down and he stated no. the trail as well was not hard pack so overheating should not have been an issue normally. If memory serves me correct the jetting should be 480. Will have to recheck that as i have not done much with his sled in the past year. But either way, if a Big Bore Kit is sold and installed by a retailer, would it not be a question from the start in asking what kind of riding do you do?

480's should be just fine in that sled with the big bore. Also with the dpm on the doo's there is no need to re-jet for elevation because the dpm still works fine on them with the big bore installed. I would be curious to know what the pistons look like or even if you could post pics of them.

 

[maxwell]

me too...running 470s in my 860. got about 500km on it

 

[beezer11]

shall see what i can do and forward to you soon. My conversations with my son they tell him the tops of the pistons were eroding??????????? Have been selling parts for 38 years and never heard that term before, not even when i was selling arctic cat parts lol.

 

[maxwell]

lol...

eroding piston..thats a gooder.

must be some serious water flow over the piston head...

did it have grand canyon marks in it?

 

[glengine]

That to me sounds like a term that might have used in regards to detonation possibly. Was this the first tank of fuel he has put thru the sled?

 

[beezer11]

approx 5-6 tank full. He rode in Vale before going to Sicamous and all was great. I asked him how he rode on the first run wether he was working it real hard and he said no as he wanted to let things run in before really working it. He stated that he did do short burps but nothing extended periods. In Sicamous he did do a few pulls, and mostly played around in the trees, with the younger riders.

 

[Modman]

That to me sounds like a term that might have used in regards to detonation possibly. Was this the first tank of fuel he has put thru the sled?

was thinking the same thing Glen, but he said it was mixed 4 gallons of C111 that should be lots of octane for an 860 at 5000 ft?

 

[glengine]

was thinking the same thing Glen, but he said it was mixed 4 gallons of C111 that should be lots of octane for an 860 at 5000 ft?

I agree. Depending on what compression ratio the domes are at 4g/tank of c111 that should be over kill on C111. It shouldn't need more than about 2 gallons per tank of C111.

 

[beezer11]

compression ratio used to be 14:1 lol. He has been told today that it had leaned out in mid range, caused by what I asked and they have not told him. Something smells funny to me!