XP big bores - lets compare

[Insaneboltrounder/sjohns]

The difference is , dippchiitt. Is that i dont have a 860 or claim to be a knowitall blow hard like he is. I , like others , am paying attention to those who do have a clue. He is here making noise and basically screwing up this thread , kinda like you just did.
The difference between what he actually knows and what he thinks he knows is vast. But thanks for your opinion , you know what they say about those.

Apparently your rep is as high as his around here , congrats on that too. You must be as charming as your buddy . sj

 

[Van Epps]

Your light weight metal motor expands and contracts " MOVEMENT " just like those TRA ramps Joe & BJ.



OT

LMAO..........like a dog with a bone!

 

[Original Tetonice]

The difference is , dippchiitt. Is that i dont have a 860 or claim to be a knowitall blow hard like he is. I , like others , am paying attention to those who do have a clue. He is here making noise and basically screwing up this thread , kinda like you just did.
The difference between what he actually knows and what he thinks he knows is vast. But thanks for your opinion , you know what they say about those.

Apparently your rep is as high as his around here , congrats on that too. You must be as charming as your buddy . sj

You remind me of the punkid that sits in the back of the classrom and disturbs the rest of the classrom.You know the type....Vast in BS and contributor of none

OT

 

[Slick]

The difference is , dippchiitt. Is that i dont have a 860 or claim to be a knowitall blow hard like he is. I , like others , am paying attention to those who do have a clue. He is here making noise and basically screwing up this thread , kinda like you just did.
The difference between what he actually knows and what he thinks he knows is vast. But thanks for your opinion , you know what they say about those.

Apparently your rep is as high as his around here , congrats on that too. You must be as charming as your buddy . sj

Is that your opinion ? Well I don't think this thread needed some snot-nosed, self professed, ain't I special, content judge, to understand what was going on. And the red, it comes from me telling dumb-a$$ mouthpieces, like you for instance what a whole bunch of other folks are thinking. And you know what , dipchitt, my life hasn't changed much. So kiss mine and dump your red, and keep yapping.

 

[byeatts]

Hey guys. Thinking about doing a big bore on my XP. Just wondering what the main differences are between the different options out there. And what your opinion of the "best" one out there. Also any real world comparisons would be great. Do they all use the same pistons? Claimed HP?

Options:

Big John 860
RKT 860
Turbo Al 888
Split Second 860
Motts machining 880
Engine Tech 860

Im thinking either Engine Tech because Ive heard good things about Art. One thing that concerns me is that he is from out east. Not sure if he does any testing in the mountains or not. Either that or Split Second. Ive never heard anything bad about Ralphy. Plus, I think he kind of caters to the mountain market doesnt he??

Wow this post sure went sideways! Everyone -this started as a constructive resource to really learn about the differant BB setups, How about getting back to the topic,Viewers dont wish to hear anymore of this,Theres much to learn about builders setups and this turned to an embarrassing display.

 

[NoSecondChances]

Good Question..imo No because the touching points remain the same regardless of the bigger bore, piston, 1 ring or 2 ring it still must grad cylinder wall. Metal on Metal = Heat

BJ, at 9000' did you not see the plus/minus ? I also calculate X .03% per 1000 feet... M in Ramp means moveable

OT

WB asked about the increased surface area of the piston on the cylinder wall, yes piston temps would be lower with the increased surface area contact in the BB. The touching points do not remain the same in a BB vs the OEM bore since the contact for the increased piston surface area and larger dome would dissipate more energy to the cylinder.

Metal on metal will generate heat yes, but not to the extent you are thinking and most often tolerances in the BBs are as low as OEM or slightly higher, so friction loss would be negligable so long as there is sufficient lubrication and the piston design is transferring heat efficiently to the cylinder wall and maintaining the correct tolerance. In addition to a big bore with increased compression, race fuel would reduce CHT's in the combustion chamber, so heat is less of an issue with adding a BB as most of these fuels burn cooler than regular pump fuel. Not adjusting the timing correctly to compensate for the longer burn time of the fuel could result in more fuel burning in the pipe and generating heat this way as well.

Most often times the added heat in a BB is due to the tuner looking to go with leaner jetting (burndown) or running pipes etc, that the chassis does not have sufficient cooling for. Lots of the conservative BB setups last a long time but do not make the big power like the "on the edge" kits. A perfect example is my triple - My big triple does not like heat! Those three pipes spewing heat under the hood, with the regular hood on - not the mesh one, anything under 30 mph and it starts to load up and bog after some slow running, get it moving and get some cool air into it and cooled down, its a whole different animal . Again, not what the chassis was designed for so it suffers a little bit at the slower speeds due to the added heat from the pipes.

There's a lot more engineering to it than just the moving parts of the BB kit itself.
NSC

 

[Slick]

Wow this post sure went sideways! Everyone -this started as a constructive resource to really learn about the differant BB setups, How about getting back to the topic,Viewers dont wish to hear anymore of this,Theres much to learn about builders setups and this turned to an embarrassing display.

Sorry

 

[BrianB]

I was looking back at the SnowTech December 2007 issue, and there is the article on Stage Tuning the 2007 Summit 800R with SLP. They claim 171.9 hp at 8500 rpm with bolt on parts (an SLP Silencer, Heads, Y-Pipe, High Flow Intake, V-Force 3 Reeds). This is roughly $1200 in parts, which could be installed individually to try and avoid being lost on tuning.
How does this 172 hp compare with what the BB engines are putting out?

 

[Original Tetonice]

WB asked about the increased surface area of the piston on the cylinder wall, yes piston temps would be lower with the increased surface area contact in the BB. The touching points do not remain the same in a BB vs the OEM bore since the contact for the increased piston surface area and larger dome would dissipate more energy to the cylinder.

Metal on metal will generate heat yes, but not to the extent you are thinking and most often tolerances in the BBs are as low as OEM or slightly higher, so friction loss would be negligable so long as there is sufficient lubrication and the piston design is transferring heat efficiently to the cylinder wall and maintaining the correct tolerance. In addition to a big bore with increased compression, race fuel would reduce CHT's in the combustion chamber, so heat is less of an issue with adding a BB as most of these fuels burn cooler than regular pump fuel. Not adjusting the timing correctly to compensate for the longer burn time of the fuel could result in more fuel burning in the pipe and generating heat this way as well.

Most often times the added heat in a BB is due to the tuner looking to go with leaner jetting (burndown) or running pipes etc, that the chassis does not have sufficient cooling for. Lots of the conservative BB setups last a long time but do not make the big power like the "on the edge" kits. A perfect example is my triple - My big triple does not like heat! Those three pipes spewing heat under the hood, with the regular hood on - not the mesh one, anything under 30 mph and it starts to load up and bog after some slow running, get it moving and get some cool air into it and cooled down, its a whole different animal . Again, not what the chassis was designed for so it suffers a little bit at the slower speeds due to the added heat from the pipes.

There's a lot more engineering to it than just the moving parts of the BB kit itself.
NSC

I'll agree to most of that.....IMO the magic of owning a BB Kit was to turn as big a power as the motors tolerance will allow under optimum conditions. Conservative BB kits are just that conservative and imo defeats the purpose of owning.

We've been talking about the heat created between cylinder wall/piston/ring...How about the heat at the combustion chamber the top of the piston(s) can get pretty hot as well BB or Stock. As the REV's increase so does the internal heat. In the cumbustion heat can rob power a good head design will have better cooling in a effort to reduce combustion chamber heat and performance optimum. A simple look at the aftermarket domes will reveal the cooling machined right into the dome surface all in an effort to keep the temps in check.

imo a quality aftermarket head has as much to do with the BB performance than any othe BB machining....Have you ever run a BB without a head cut ?? LOL

OT

 

[bonecracker]

Wow this post sure went sideways! Everyone -this started as a constructive resource to really learn about the differant BB setups, How about getting back to the topic,Viewers dont wish to hear anymore of this,Theres much to learn about builders setups and this turned to an embarrassing display.

Exactly. This is why I posted before. These good posts always seem to go sideways and it seems to be the same people that make the turn on the thread.

Thanks to all the engine builders and knowledgable people that contribute to these informative threads as well as the guys asking the good questions to help have a good discussion. (sorry for the fake beer, I'd buy a round if I could)

 

[Original Tetonice]

I was looking back at the SnowTech December 2007 issue, and there is the article on Stage Tuning the 2007 Summit 800R with SLP. They claim 171.9 hp at 8500 rpm with bolt on parts (an SLP Silencer, Heads, Y-Pipe, High Flow Intake, V-Force 3 Reeds). This is roughly $1200 in parts, which could be installed individually to try and avoid being lost on tuning.
How does this 172 hp compare with what the BB engines are putting out?

I think you need to add the complete exhaust to hit SLPs's number of a 172 HP at sea level. I ran with a few SLP packages this season and for a bolt on kit it runs strong every day.

OT

 

[frog]

Off topic but what is the cause of TRA ramp movement????


Is it caused my human intervention, adjusting the clickers???


Is it caused by the rotation of the clutch when the engine is running???

I know that the governor cup is a "fixed" part and does not move so I am a little confused on the moveable part. The arms are attached to the "moveable" sheave so those move as rpm's increase or decrease but, ramps???


Anyway, BB kits can be very reliable and are very reliable because of the nature of their design. Not massed produced, tolerences are usually scrutinized to the point of perfection when assembled by the proper individual and when using the proper kit from the right supplier, use better parts for better reliability and performance.

If you want a race engine BB kit then you are going to be rebuilding on occasion but that would be case with a race version of a stock engine as well.

I would put BJ's BB kit up against any other 2-stroke 800 for reliability, I have seen him assemble the engines and have seen the parts that he uses and met the man that does the porting and I would not hesitate to run his engine on any day at any elevation, that is why I am going to BB my 07 with his kit.

 

[Original Tetonice]

Off topic but what is the cause of TRA ramp movement????


Is it caused my human intervention, adjusting the clickers???


Is it caused by the rotation of the clutch when the engine is running???

When calibrating down from higher setting to lower settings BOTH.

OT

 

[frog]

So you are saying that they are moveable in literal terms not technical terms?


Gotcha.

 

[Original Tetonice]

So you are saying that they are moveable in literal terms not technical terms?

In literal term they move weather your clicking up or down the ramp literally will move..... As well as technical, the movement of the will increase or decrease engine rpm 150 to 200 rpms caused by the movement of the ramp along with other factors such as the arm/roller as it makes contact with the ramps profile.

 

[DaveB]

Aaaaaannnnyyyway.....

ENOUGH.

So how's everyones BB's running? Hmmmm? (mine still sucks)

 

[Original Tetonice]

DaveB, take BJ up on his "fix it fur you offer" he made it sound he would do it fur FREE.....If he can fix it you will prop him up and vise versa if he can't fix it.

OT

 

[DaveB]

I make decent $ and would NEVER expect anyone to do anything for free. I got myself into this mess.....

I intend to tear into it after I have had a few weeks/months to forget how mad I am at it....and if I can't get any help from SS/my dealer, I will definately send it John's way.

 

[NoSecondChances]

I make decent $ and would NEVER expect anyone to do anything for free. I got myself into this mess.....

I intend to tear into it after I have had a few weeks/months to forget how mad I am at it....and if I can't get any help from SS/my dealer, I will definately send it John's way.

Did the port timing change at all with your BB kit?

 

[DaveB]

No idea.