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to the people that know there s_it has this been ported? it looks like to me there are some tool marks with the one on the right side of the photo. I've been told there has NOT been any porting done on the intake at all by the person that is rebuilding my crank. this is a 860 kit that i put on last year and was my first mod so my knowledge on snowmobiles is limited (and on everything :headband ) I'm not going to relay which 860 kit it is in till all the facts are brought to the table (to much politicks involved with that)
 

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to the people that know there s_it has this been ported? it looks like to me there are some tool marks with the one on the right side of the photo. I've been told there has NOT been any porting done on the intake at all by the person that is rebuilding my crank. this is a 860 kit that i put on last year and was my first mod so my knowledge on snowmobiles is limited (and on everything :headband ) I'm not going to relay which 860 kit it is in till all the facts are brought to the table (to much politicks involved with that)
I agree, them ports have not been touched in that respect. I've done enough porting jobs to know that they are nicely cleaned but not ported.
 

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No work on the intake side but most of these big bores do alot on the exhaust can you post some picks of the exhaust side
 

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If anything was done on the intake on these pics you see little, though it looks like maybe they have been touched a little. Pics are tough, a real life view is always better.
Plus maybe the transfers were opened up a little, your pics don't show the transfers and as mentioned the exhaust could had been ported, you also don't show that.
Porting doesn't just consist of intake grinding. Another thing is many shops will do little to the intake other then slightly clean them up, open up the transfers abit and then spend more time on the exhaust side.
This way it keeps the runnability and trailability of the motor, messing with the intake and transfers too much can effect that, in which case most shops don't want that.
 

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to the people that know there s_it has this been ported? it looks like to me there are some tool marks with the one on the right side of the photo. I've been told there has NOT been any porting done on the intake at all by the person that is rebuilding my crank. this is a 860 kit that i put on last year and was my first mod so my knowledge on snowmobiles is limited (and on everything :headband ) I'm not going to relay which 860 kit it is in till all the facts are brought to the table (to much politicks involved with that)
I had an 880 port job just like that several years ago, Probably the same builder
 

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Is that shr new port work Ihave a big bore from him but it dont look like that but its from 08 09 any picks of the exhaust port
 

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If you look close at Irondogs before and after pics, you'll notice there are 2 ports added on the intake side as well as the clean up and knife edging.
 

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If you look close at Irondogs before and after pics, you'll notice there are 2 ports added on the intake side as well as the clean up and knife edging.
Irondog's pics are of an 800 Series III engine intake.. Which are totally different from the 800R intake.

Those extra intake ports where recommended by DNE , but they did it quite different than shown in the pics.

RK Tek perfected this by changing the intake mod via keeping the "new" ports high to align with the upper reed opening and wider to add more bulk flow. This method of "port adding" in the intake windows you view in that pic are the RK Tek "Mod" method and are used by many Series III Engine builds today.. Including SHR which is very evident via Irondog's Pics.

ANY porting alterations (like enlarging windows or redirecting flow) done to the intake of an 800R engine will result in POWER LOSS!! everytime!!!
The 800R engine is NOT the Series III engine and can not be treated as such.

BRP took the porting from the RK Tek 827 engine and incorporated most of it in the 800 R engine porting arrangement. This was a great move on BRP's part and that , coupled with the Mono-Block yielded even better transfer flow that could be obtained with the RK Tek CNC Transfer Tunnel Porting. By making the block wider, Larger transfer tunnels could be easily acheived without having to mod the case like with the series III engine.

The R engine is quite a step above the Series III Engine in every way , shape , and form.. The cooling of the intake track was a great addition that keeps the intake charge "cooler" and more dense...

Again, comparing the Series III engine to the R engine is apples to oranges..
 

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Ditto on what Kelsey said...

The intakes on the 800R are so well done a simple clean up is all thats required/if anything...any "actual" port changes will lose power (even Boyeson tried intake mods, lost like 10+ hp...and hes the guy who designed this style of cylinder-LOL)...as for "looking at the intake" for porting, your looking at the wrong place...look down from the bore at the exhaust port/sub ports...looking from the ypipe in will show very little also...what you have done is question a ported motor by representing the 2 areas that dont require/need porting...and ignore (no blame onto you) the part of the cylinder that IS ported and what makes the power...

a couple of you should know better
-BJ
 

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Discussion Starter · #18 ·
Ditto on what Kelsey said...

The intakes on the 800R are so well done a simple clean up is all thats required/if anything...any "actual" port changes will lose power (even Boyeson tried intake mods, lost like 10+ hp...and hes the guy who designed this style of cylinder-LOL)...as for "looking at the intake" for porting, your looking at the wrong place...look down from the bore at the exhaust port/sub ports...looking from the ypipe in will show very little also...what you have done is question a ported motor by representing the 2 areas that dont require/need porting...and ignore (no blame onto you) the part of the cylinder that IS ported and what makes the power...

a couple of you should know better
-BJ
I'll see if I can get better photos to share with all of you
 

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Ditto on what Kelsey said...

The intakes on the 800R are so well done a simple clean up is all thats required/if anything...any "actual" port changes will lose power (even Boyeson tried intake mods, lost like 10+ hp...and hes the guy who designed this style of cylinder-LOL)...as for "looking at the intake" for porting, your looking at the wrong place...look down from the bore at the exhaust port/sub ports...looking from the ypipe in will show very little also...what you have done is question a ported motor by representing the 2 areas that dont require/need porting...and ignore (no blame onto you) the part of the cylinder that IS ported and what makes the power...

a couple of you should know better
-BJ
The photo area of the cylinder hasnt been touched as much as i,m used to seeing on intake side.Theres been work done to enhance the flow.All flaws ,ridges ,All vertical casting ridges which should be removed,walls should be seamless,I know this to be fact because I have several of your specimens and they are substantially different and have "Workmanship".Agreed there are other important areas to look towards.I guess his question is could ther be improvement with additional work. I have had luxury of assembling different builders kits for the local area and then get to see them perform. I,m no expert at porting as all you builders are but can easily see what working.I received a BB several years ago and paid for "porting", This motor came assembled and I pulled it down before installing, I had been charged for porting and there wasnt a single thing done other than raising exhaust port.It was just slapped on.I guess i,m used to looking at your work and it sets the standard. Rarely does a builder get to assemble other builders motors
 

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The photo area of the cylinder hasnt been touched much on the intake side.Theres been little work done to enhance the flow. flaws ,ridges ,there are vertical casting ridges which should be removed,walls should be seamless,I know this to be fact because I have several of your specimens and they are substantially different and have "Workmanship".Agreed there are other important areas to look towards.I guess his question is did his builder give a honest effort to provide a strong runner.I get the luxury of assembling different builders kits for the local area and then get to see them perform. I,m no expert at porting as all you builders are but can easily see what working.I received a BB several years ago and paid for "porting", This motor came assembled and I pulled it down before installing, I had been charged for porting and there wasnt a single thing done other than raising exhaust port.It was just slapped on.I doubt his next cylinder will look like this.
Casting Flaws provide little to no flow obstruction and are a "non issue" in terms of flow.. Sometime removing casting flaws can result in "poorer" flow..

In short...casting flaws are nothing to be concerned about when they are on a vertical wall.. When they are on an upper roof, then they can be a SMALL player ..Bulk flow attaches to the roofs on intakes not so much on the sides or bottoms. There has been MANY tests and papers that address the lack of importance of removing casting flaws.. Same with polished exhaust ports.. No power to be had.. just maybe a little less carbon build up after 1000's of miles.. but no measureable power gains to be had in a polishes exhaust port. Reshaped port is another story..

Seeing a non casting flaw engine with an exhaust port that you can comb your hair in, are tactics to give the customer the "ILLUSION" that they have a finely ported engine. When the reality is.. that usually all you get are the casting flaw removal and the polish job and the REAL areas that need addressing for power gains have not even been touched.. I have seen this MANY times with cylinders that come into my shop...
A dull and casting flaw riddled cylinder that has the proper porting in the areas that matter will outperform the smooth and polished (customer happy) cylinder ALL DAY LONG!!

The idea that "bigger" is always better interms of making power is very OLD SCHOOL.

One has to be very careful as to the areas one modifies on these modern engines. These are NOT the engines of "old". Slight chnages in the critical areas can result in power gains AND/OR big power losses!!! Only experience and years of testing can determine where the "sweet" spots actually live. Shops that have just "popped" up in the last 3-4 years and claim to be engine "experts" (like the shop sending the pics of this build) simply do not have the expertise or experience. It is really that simple! People please proceed with caution when dealing with these sort of shops.

On the OP pic, there is quite a bit of clean up done, in the areas, of the intake, that actually matters that will improve flow and direct it better. If you compare the pic to a STOCK intake one could easily spot the changes.. comparing it to NOTHING results in speculation and comments that do not have any relevance.. The roof and floors of the 800R intake require the most attention and this can not even be seen in the pic.

The attached pic shows where there has been work done to improve flow. again, until you compare it to a stock 800R intake it may not be as apparent..

This is a classic case of another builder trying to extract money from a customer (the OP) who does not understand engine porting via "bad mouthing" another shop's workmanship... This "other builder" is known for these sort of antics and this is very unfortunate that he continues to conduct himself and his business in this manner.
 

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