372XP Big Bore Kit

[TexasTimbers]

I guess they are right popular Bailey's sells out soon after they get them. I was going to get one but they are sold out now, and although they have been re-ordered there is no ETA on the that shipment.

Has anyone here tried one on a 372? I read in the archives where one has been doing well on a Stihl.

[Big Daddy]

Hello kevjay
I had read on another site that a fella has been using a 372  Big Bore kit, in the woods for three years now with no problems...

[Ironwood]

You need more power? or is the old head worn out? Reid

[treeape]

Hello kevjay
I had read on another site that a fella has been using a 372  Big Bore kit, in the woods for three years now with no problems...

               Really, I thought they just came out a few months ago :D

[Dale Hatfield]

I think the big reason they sell so fast is that they are cheaper than  stock. More HP for less money who wouldnt try it
Dale

[TexasTimbers]

I want more power the head is fine. I have modded the muffler and the difference was very gratifying. Giving it another little kick in the pants can't hurt anything. I hope.

[Captain]

I've got one to try out on a tired old 372xp I got from a customer.  Just need to find the time.  In hopes it will be the "logyard" and "employee" saw.  If it gets damaged, I'll be a lot happier than if my Walkerized MS460 does......

Captain

[SawTroll]

I think the big reason they sell so fast is that they are cheaper than  stock. More HP for less money who wouldnt try it
Dale

Not so sure about the added hp, no reports on that so far (that I have seen).

[Big Daddy]

treeape
I looked for the post where I had read about the Big Bore saw, I am sure it said three years. I bet SawTroll could shead some light on the subject of how long they have been around... 

[treeape]

treeape
I looked for the post where I had read about the Big Bore saw, I am sure it said three years. I bet SawTroll could shead some light on the subject of how long they have been around... 

           I'm not doubting what you read, but.......................................... The 372 BBkit has only been out a few months. Some prototypes a little longer.  The 066 and 046 were out way before the 372 kits and I believe they have only been out for a year to year and a half. Sending an email to Baileys would answer this question.


     I also agree with Saw Troll in that while the big bore kits have a larger cc, I have not seen any claims they make more power in stock form.

[jokers]

treeape
I looked for the post where I had read about the Big Bore saw, I am sure it said three years. I bet SawTroll could shead some light on the subject of how long they have been around... 

           I'm not doubting what you read, but.......................................... The 372 BBkit has only been out a few months. Some prototypes a little longer.  The 066 and 046 were out way before the 372 kits and I believe they have only been out for a year to year and a half. Sending an email to Baileys would answer this question.

Yes, I also agree with treeape that the 372 BIG BORE kits have only been available for a few months and that Bailey`s could and would easily confirm this for you.

     I also agree with Saw Troll in that while the big bore kits have a larger cc, I have not seen any claims they make more power in stock form.

Infact from what I understand it appears that the mold for the big bores was made by boring an oem cylinder and using it as the form to make the mold. Because of the angles present in the ports this method has the effect of detuning the cylinder. I have also been told by someone knowledgeable and trusted that the combustion chamber is larger on the BB cylinder which has the effect of lowering compression.

Conversely I know of a professional cutter who was using a saw outfitted with one of these kits six days a week and it had been for about six weeks last I knew so the quality must be decent in contrast to the reports that I had heard regarding the chrome peeling from the bores of the earliest 460 and 660 kits.

I`d have to say that if a guy is just trying to revive a saw it would be money well spent.

[Big Daddy]

treeape and jokers
I found the thread I was refering to and did I miss it, The thread said the guy was running a BB Kit for quit a few hours.. Thats not even close to Three Years. Leasson learned check facts before opening mouth...

[SawTroll]

treeape
I looked for the post where I had read about the Big Bore saw, I am sure it said three years. I bet SawTroll could shead some light on the subject of how long they have been around... 

If so, it was not the kit sold by Baileys lately, those appeared in production version just a few months ago......

Ooopppssss, that was already covered.....

[jokers]

treeape and jokers
I found the thread I was refering to and did I miss it, The thread said the guy was running a BB Kit for quit a few hours.. Thats not even close to Three Years. Leasson learned check facts before opening mouth...

I`ve had my moments also Big Daddy, atleast you are man enough to admit that you misread the original thread.

[minesmoria]

Walkers saw shop said they had problem, with the big bore kits they are maed over seas.

Thats  why their cheaper.

[sawguy21]

Somebody once said "The bitterness of poor quality remains long after the sweetness of low price is forgotten." How true.

[Striker]

My question is, if you do not realize a gain in horsepower, why install  big bore kit? I have a tired 066 that i was considering a BB for.

Jeff

[Big Daddy]

Hello Striker
I think you can sum it up like this. If your driving though the mountains in a heavy truck, and you have a big block motor it wont have to work as hard as it would if it were a small block. 

[rahtreelimbs]

Hello Striker
I think you can sum it up like this. If your driving though the mountains in a heavy truck, and you have a big block motor it wont have to work as hard as it would if it were a small block. 

Quite a contrast.......doesn't quite apply here though!!!

[Big Daddy]

Why?   more cubes,= more power,= less work.

[treeape]

Why?   more cubes,= more power,= less work.

   If we took 2 identical running 372s and opened up the muffler on one, that one would be the faster saw. Why, the cubes are still the same? We just made it more efficient. Just because the big bore kits are larger in CCs does not mean they make more power.

          The big bore kits are popular because of the price.

[Big Daddy]

Good Point

[rahtreelimbs]

Why?   more cubes,= more power,= less work.

The jump isn't near the same!!!

[SawTroll]

Why?   more cubes,= more power,= less work.

   If we took 2 identical running 372s and opened up the muffler on one, that one would be the faster saw. Why, the cubes are still the same? We just made it more efficient. Just because the big bore kits are larger in CCs does not mean they make more power.

Yep, the cubes is only one of several factors........

          The big bore kits are popular because of the price.

[weimedog]

I'm going to bring this back to life. Early in this thread a very relevant point was made about how these AM pacific rim built cylinders were reverse engineered & the resultant change in port geometry. I have to say that looks to about right based on the AM BB kits I have seen so far. To put numbers to this discussion, two saw I built this last two weeks, one a stock cylinder and the other a BB kit. I would bet the BB kit I used is the same as many on the market with different brand names... To try and help these saws along both were built w/o base gaskets.

Numbers for stock cylinder w/o base gasket:
Squish: .021"
Intake: 76 degrees BTDC   (When these ports open)
Exhaust: 103 degrees ATDC
Transfers: 126 degrees ATDC
Blow Down (Degrees after exhaust opens that the transfers open) 23 degrees

Not bad numbers, might want to advance the intake closer to 80 degree's and good compression. This saw runs well and will stay put together as is because it RUN's really well and I want it as a test standard.

After market BB top end numbers w/o base gasket:
Squish: .032" (This would be around .052" with a .020" base gasket!)
Intake: 75 degrees BTDC (Would be a bit less than 74 degrees with a base gasket)
Exhaust: 104 degrees ATDC
Transfers: 132 degrees ATDC
Blow down: 27 degrees

Larger squish along with a larger combustion chamber means lower compression. Along with the lower compression, that bigger blow down number along with less advance in the intake timing means to me this saw will make less power than stock even though it's 52mm bore vs. 50mm. And it appears that the ports, all of them; are ever so slightly smaller than the stock ports. Plan to finish up and run this side by side with the stocker to either embarrass myself  or verify my assessment. With these little 2 strokes, port timing and compression mean more than 2mm of bore. Time will tell if I'm right....waiting for winter to give up so I can down the farm road and back into the woods!

(The good news it the casting quality is actually quite good, a bit of die grinder time can fix a lot of ill's or make a mess, but with the cost being less than 1/3 of stock...its a gamble I will take after I run it for a while to give it a chance to live as it was expected to be used)

[tlandrum]

friends don't let friends run aftermarket bb kits lol

[Timberjack_395XP]

I think that seems to the common wisdom that porting & advanced timing make a saw better than a few more cc's but there's pro builders in here that have done so many different combinations of things I think you have to figure out how you want to use the saw before so you can decide to go about getting the desired outcome. big bore just sounds good when you say but knowing how to apply it efficiently now that's ticket

[weimedog]

Actually my premise is that many times its better to just clean up a used stock but salvageable cylinder and either put a new OEM or Meteor piston in than to buy a new Aftermarket cylinder kit, any aftermarket kit; with the possible exception of Meteor. Until I find one to prove me wrong.....