Joeak47's thread on cast piston VS wiseco forged piston.

[dksix]

I had never seen a cylinder bored, or I should say I have never seen a cylinder bored at an engine shop on a specialized boring machine. After I asked the question I goggled "cylinder boring" and found the KOR has a great series of YouTube video's on a complete sleeve install (even better than his excellent series of vid's on porting) and watched them all. When I saw you spring loaded hone as the answer to my question I thought you had misunderstood the question.
I can see people using a lathe for single cylinder boring but I wouldn't want to try spinning a 4 cylinder on a lathe.

 

[joeak47]

That picture of the "Cheap,wobbly,spring loaded cylinder hone from walmart" cracked me up. I couldn't help posting it. I wonder who else fell for it.

YES! Ken has great videos! It has me motivated to do some of my own.

 

[joeak47]

I'm going to take the blaster and its "Cheap cast piston" out for a flogging tomorrow. I'll go out at the hottest part of the day which is forecasted to be right at 98 degrees. I'm going to do the same hard and fast test run like last time. I'm going to ride it like I stole it. I'll take more tempurature readings and see if anything has changed

I'm thinking of starting to post a batch of videos on how I apply my "Aggresive Trail" port to blaster cylinders. I'll be using the racelogic porting templates as the starting point and go from there,so you can see how I do it. I'll show you what tools I use (inexpensive) ,and the techniques. There is minimal items to purchase. Ken O'Connor made videos of how to port a cylinder with a dremel,and in my opinion did a wonderful job!!! They were fun and informative! This got me motivated to do some videos too. I use a common air tool to do most of the work,but with simple and easy technique that gives you total control of the carbide bit. If you have an air compressor and want to try my method,I believe that you will find that you are fully capable of doing it AT HOME with great results! You'll have to invest about $60 in tools and materials not including the templates that are on sale right now.

Check this out >>> Race Logic: World Class Performance

 

[dksix]

That picture of the "Cheap,wobbly,spring loaded cylinder hone from walmart" cracked me up. I couldn't help posting it. I wonder who else fell for it.

YES! Ken has great videos! It has me motivated to do some of my own.

I was just confused. I didn't see anyway you've gotten this far with builds using that to bore but didn't catch the punchline either.
I curious about your user name. I have used a couple AK receivers that came from AZ back in the day.

 

[best]

I have bored single snowmobile cylinders both in the lathe and on a milling machine or boring mill. Whatever tool was available to me when I was in the shop. Heck, I even did a 4 stoke motorcycle engine in the radial arm drill press with a bar sliding through a bushing at the bottom to rigid it up. I worked in repair shops so you get used to thinking of other ways to do things. Again, not what you'd want to do on a production basis.

Like Joe says, boring is reserved for gross size changes. Cleaning up big scratches, or odd wear (like from a sand erosion or head gasket water, or missing pin clip). A fine cut is hard to do, although you can mount a grinder to the tool post to square things up.

Joe I doubt many folks here would want to purchase a rigid hone just to do their Blaster cylinder. Hones take a bit of learning to use even on a straight cylinder, but get rather difficult with a windowed and skirted cylinder. It does take an acquired skill to feel the cut, keep it lubed and meet the tolerance while keeping it all parallel and not drop out the bottom. Quite a bag of skills to learn in an afternoon.

That said, I looked on line and was surprised at the price of them now. $150-$200? I paid that for mine 30 years ago, wow. Even at this low price, paying an expert $50 to do the job would be worth the money.

 

[dksix]

Joe and Best, I'm not looking to try to do my own but I like knowing how things are done. Rarely will there be a mechanical process come up that I'm not interested in learning about.

 

[Rich]

Cast is fine for a stock motor and its expansion rate is predictable so you can run a tighter bore.But I would not run cast on a highly moded motor that runs at very high rpms.This is where forged pistons come in and are heavier and can hanldle more abuse but at the expense there expansion rate is a bit more unpredictable and you half to run a slightly larger bore.The cast piston is only made for motors that are not intended to be moded.The more modern bikes and some vehicles they come stock with forged but have an added coating to keep them from expanding so you can run a really tight bore and prolonged life I believe.It really depends on the application imo.

In the test is the porting between the two pistons the same along with jetting as well.Just out of curiosity.

 

[best]

Cast is fine for a stock motor and its expansion rate is predictable so you can run a tighter bore.But I would not run cast on a highly moded motor that runs at very high rpms.This is where forged pistons come in and are heavier and can hanldle more abuse but at the expense there expansion rate is a bit more unpredictable and you half to run a slightly larger bore.The cast piston is only made for motors that are not intended to be moded.The more modern bikes and some vehicles they come stock with forged but have an added coating to keep them from expanding so you can run a really tight bore and prolonged life I believe.It really depends on the application imo.

In the test is the porting between the two pistons the same along with jetting as well.Just out of curiosity.

Rich, that may be a general rule that you have heard before, not a fact that you know, unless you have some experience to share.
I have heard that before and given the same advice, but experience has brought it into question.
For years I have run a cast piston at over 10,000 rpm in a 40hp 125 down the highway at speed with no failures.
That goes against the advice you are giving, why can I do that?

Joe is exploring that question.

We all have things that have been repeated so often that we hold them true without questioning.
I think we have to do more questioning, more exploring, and less repeating of things we have heard.

 

[joeak47]

Cast is fine for a stock motor and its expansion rate is predictable so you can run a tighter bore.But I would not run cast on a highly moded motor that runs at very high rpms.This is where forged pistons come in and are heavier and can hanldle more abuse but at the expense there expansion rate is a bit more unpredictable and you half to run a slightly larger bore.The cast piston is only made for motors that are not intended to be moded.The more modern bikes and some vehicles they come stock with forged but have an added coating to keep them from expanding so you can run a really tight bore and prolonged life I believe.It really depends on the application imo.

In the test is the porting between the two pistons the same along with jetting as well.Just out of curiosity.

With the "aggresive trail" ported cylinder,matched tranfer ports to case,and squish band hemi head,I know I'm in the 30+ HP range (probably closer to 32) and run the hell out of my blaster in extreme heat which has been 105 degrees lately,and pull 8,000+ rpms sometimes more on a regular basis.

I agree with "Best" on this one. there are so many myths,guesses,and old wifes tales that people take as fact,because somebody told somebody,who said it to someone else,who said this is how it works,etc,etc.
Look at how many myths the "Mythbusters" have proven,or disproven.

I promise to test the hell out of my "Cheap cast piston",because I want to know.

 

[Rich]

With the "aggresive trail" ported cylinder,matched tranfer ports to case,and squish band hemi head,I know I'm in the 30+ HP range (probably closer to 32) and run the hell out of my blaster in extreme heat which has been 105 degrees lately,and pull 8,000+ rpms sometimes more on a regular basis.

I agree with "Best" on this one. there are so many myths,guesses,and old wifes tales that people take as fact,because somebody told somebody,who said it to someone else,who said this is how it works,etc,etc.
Look at how many myths the "Mythbusters" have proven,or disproven.

I promise to test the hell out of my "Cheap cast piston",because I want to know.

Yes you have some valid points.Not to dissagree just throwing the difference between the two.As for a 125 at 40 hp thats about 5 more hp these days on a factory motor isnt it.As Best says.I am not here to dissagree not at all they just have different applications.Where one is better the other lacks and vise versa.With a highly moded motor in all do respect on any motor they use forged pistons for a reason and its more on the side of piston failure a cast piston is more likely to do more damage to an engine as a whole.....You do have me thinking on the heat difference between the use of each cylander thats intresting looking forward to seeing more of your comparison results.......Ps yeah its hot hear too not to far away from navada and its getting hotter.108 uffggg.And yes like you said I am also a big fan of myth busters.

 

[OConnor Racing]

This is a GREAT THREAD!!! Tons of super info, discussion, opinions and facts. Nice to see this place getting back to business. I’m not going to get into cast being better than forged or vice versa. I will tell you I’ve run both types in Blasters with no issues. I only run cast, OEM pistons in the race bikes we build and change them often (new top end every 5 hours for 125 and every 10 hours for 250). What really interest me are the temps that Joe’s recording. Temps in the 300 + plus range would make me feel like a long tailed cat in a room full of rocking chairs. I’m going to run a few tests of my own today and report back later. It’s going to be in the high 90s today here in CT. I plan on working at the shop until 2 PM and then going for a ride / fishing trip with the crew from KOR. We’ll be riding about 5 miles to the fishing spot on a variety of different machines. I’ll take temperature readings on everything as soon as we stop and we can compare differences. Here’s a list of what we’ll be riding today.

Tarmo: 1986 Honda XR 500R on pump gas. KOR built engine this year with a Wiseco top end. Cobra pipe.

Jess: Blaster, KOR built Mac Dizzy replica running a Wiseco piston that’s two years old. 160 PSI, pump fuel, Toomy pipe, 34 mm Mikuni.

Liz: Blaster with New KOR built engine. Wiseco piston, ported, head modified, stock carb and pipe. 160 PSI.

Dave: KOR built 1993 Suzuki RM250. Dave is running a sleeved, ported cylinder on a 50/50 mix of C12 and pump fuel with a pro Circuit pipe and Wiseco piston. This bike is liquid cooled.

Garrett: New KOR built Blaster from a bunch of left over parts. Used main bearings, used crankshaft (Vito’s stock stuffer) ported cylinder bored to 68.25 with a Vertex cast piston and head mod. 160 PSI. FMF pipe and stock carb.

Ken: Blaster 240 from a stock cylinder, +4 balanced crankshaft with a 5mm long rod, 35 mm PWK, CPI big bore pipe, ported with head mod. 175 PSI running 50/50 C12 and pump fuel. Woosner forged piston.

Here’s my prediction.
The RM will run coolest followed by
XR500R
Liz
Jess
Garrett
Ken

Awk knows these trails and will confirm they are very fast fire roads. Off to work.

 

[joeak47]

Ken,The 300 degree plus seems to be average (out here). maybe humidity is a factor too? I'll be able to test all three blasters at the same time once my wife gets the cast removed from her foot ,and my buddy can get a day off.

The blasters are as follows...

2003 >>> "Aggressive Trail" ported cylinder,squish band hemi head (22cc),matched transfer ports to case,complete DMC alien exhaust,UNI filter (need it in the desert),no air box botton,and stock carb (velocity),"cheap cast piston" ,stock gearing,and stock oil injection.

2002 >>> "Aggressive Trail" ported cylinder,bone stock head (23cc),matched transfer ports to case,FMF fatty pipe and turbine core 2, stock filter,no air box lid,and stock carb (velocity),wiseco forged piston (66mm),stock gearing,and stock oil injection.

2004 >>> Bone stock bike all around ,but with that goofy restricted rubber air horn removed from the air box lid.

I still have to test the stock bike in the heat and see what temperatures I record.

When I was running the test's, the temperatures were 96 degrees,and 105 degrees ambient (seperate days). After a l-o-n-g hard blast on this section of the trail (about 2.5 miles) with lots of turns, straits,and full throttle... I would immediately hop off the blaster,and infrared the cylinder on both sides and all around (top to bottom),on the cylinder all around,on the reed box part of the cylinder head,engine case,etc,etc

Its fun to see what temeratures there are. You learn lots of things this way.
I was thinking of installing a pyrometer in the head pipe next,...to measure exhaust gas tempuratures.

Its also amazing how fast that air cooled cylinder cools down when watching it with the infrared thermometer!

By the way...On the 105 degree test day the freakin seat clocked 147 degrees!!! That'll put some spice in your life! Thank god I wasn't wearing shorts.

I'm also kicking the idea around about trying the "mix it yourself" fuel to see if I notice a difference between that vs the oil injection system (heat,power,etc),but that is on the back burner.

Looking forward to your tempurature tests!

 

[best]

Howdy Ken, glad to see you! Thanks for all you have shared!
I gotta say, after messing with multi-cylinder and watercooled engines for years, these Blasters are a joy to experiment with.
I can easily see why you keep your hand in them.

Hey guys, I have access to an infrared camera.
I have never used it for a purpose like this but it may make interesting viewing.
I am away from home right now so I'll see if I can hook up with Triplecrown and get some heat pictures of his engine Monday.

I am fitting my Blaster up with "universal" motor mounts so I can swap back and forth between the 250 and a KTM 300/380 or Blaster 200 motor.
All this work on Blaster motors has gotten me interested in getting more involved and running a real Blaster.

Joe, to test the oil pump you could just re-route the line in a loop to run pre-mix.
Keep in mind the jetting change required, but I suspect the 20:1 oil pump mixture independent of fuel is a good thing and you want to return to it.

The fast cool down was the reason for the air cooled Chenowth Fast Attack Vehicle.
Aircooled engines lose their infrared signature in minutes, watercooled in over an hour, or so I was told.

About 125 hp, MX manufacturers are loath to release hp figures for their engines. The fact is max hp is not what these bikes need to win races in many cases. Case in point is KTM's 2003 250SX that was probably their strongest hp engine ever built but pretty much drove Jeremy McGrath from racing. It is a sharp and peaky monster in its stock form, hard to control, yet gives impressive figures on a dyno.

About those dyno figures, manufacturers like to take the power reading directly off the crank shaft, giving nearly 40hp for a competitive 125 and nearly 50hp for a competitive 250. Run that power through a gearbox and you will see 5hp worth of losses. Run it to the back tire and you will see 10hp worth of losses. If you don't tune it right you can have 20hp worth of losses. Does my 125 make 40hp? Probably not but probably pretty close at the crank. I do have it detuned for regular fuel, but piped for peak so who knows? but I bet it is close. I mean, I really would bet...

So if you any doubt what a cast piston 125 can to, I'll throw in some fluff.
There is review on the KTM105SX just because it documents the 90mph top speed.
Yeah, my 125 will do 90mph but in current dual purpose trim I sprocket to 80mph or so to keep 1st from being too tall.
Sweet ride on the street man, screaming meany. Faster and quicker than a lot of 500s.
Here is the fluff:

2008 KTM 105 SX - Top Speed
2009 KTM 125 SX - Top Speed

 

[OConnor Racing]

Three of the six riders felt it was too hot to ride so they didn’t do the test. We lost the RM 250, Garrett and Liz. We started by shooting the seats with the infrared gun. Mine was 153( blue), Jess was 157(black) and Tarmo was 147(Black gripper). The ride finished with a similar 2 + mile 6th gear run to the finish point. Tarmo was running 252, Jess had 266 and I had 270 when measured on the cylinder. Tarmo had a head reading of 230, Jess had 265 and I had 275. The temps were in the mid 90s and the humidity was in the 90s as well. The jetting seemed spot on and everything ran well. All readings were taken within a minute of shut down. We fished a very secluded spot in the river and scored 15 small and large mouth bass in about an hour. It was a fun trip and I’m probably going back today.

 

[sicivicdude]

I'm perplexed about this sudden uptick in cylinder temperatures in relation to state of tune without the mention of jetting, compression, or pipe design. Ken, you yourself experienced the difference between two different pipes in relation to temperature at the cylinder.

Before we discuss engine heat, we need a FULL rundown of the things that might affect it (other than ambient temperatures ) I have an infrared thermometer and because of inconsistencies in the measuring technique (not being to measure the exact same point on the engine EVERY time) have never messed with it. The exception to this rule would be someone with a "spark plug ring" type temperature sensor on a trail tech type unit. This is a "standard" testing point between all engines and could be used to reliably measure temperature changes in response to pipe, jetting, ambient temperature, and current head design.

 

[OConnor Racing]

I use my infrared all the time. Readings on the sides of the cylinder and head, if taken within an inch or so of the same spots, don’t vary more than a degree or two. It’s just a tool to record benchmarks. What sparked my curiosity was Joe running in the 300+ range. Just making sure mines not. By the way….the fish were 79 degrees. Not sure what pipes they were running or how they were jetted. Temps were recorded behind the dorsal fins.

 

[motoman159]

I use my infrared all the time. Readings on the sides of the cylinder and head, if taken within an inch or so of the same spots, don’t vary more than a degree or two. It’s just a tool to record benchmarks. What sparked my curiosity was Joe running in the 300+ range. Just making sure mines not. By the way….the fish were 79 degrees. Not sure what pipes they were running or how they were jetted. Temps were recorded behind the dorsal fins.

The fish must have been dt200 liquid cooled swapped, good choice

 

[joeak47]

Ken, the humidity on my two test days was 22% That could be a factor. Not sure what the temperatures of the fish are out here.

My runs weren't just in 6th gear. Lots of small rolling up hills,sand washes,and down hills. 4th and 5th gears,then 6th at the end of the run. That plus the humidity might be the factor.

Just to add a few things...

Yamaha's ever so popular two stroke "air cooled" KT-100 kart racing engines run cylinder head tempuratures in the 380 to 500 + degee range! These engines are also ran in the 15,000 RPM range!

http://www.redlineoil.com/content/files/tech/Two-Stroke Technical Info.pdf
There's more info out there saying the same thing.


The four stroke clone engine (chinese copy of the honda GX200) kart racers are running in the 375 to 450 degree range,and they have valves and springs to worry about!

4 Cycle Karting Forums - Clone Cylinder Head Temp?

 

[Rich]

I beleive you do half to take the reading on the top of the head by the plug inbetween the fins for the most accurate reading.I think the fins are hotter displacing heat from the actual head temp.On a water cooled you would take the reading by the thermostat I beleive.I could be wrong though as all my tools for measuring heat are for scale rc aircraft but it works just the same.

 

[joeak47]

I beleive you do half to take the reading on the top of the head by the plug inbetween the fins for the most accurate reading.I think the fins are hotter displacing heat from the actual head temp.On a water cooled you would take the reading by the thermostat I beleive.I could be wrong though as all my tools for measuring heat are for scale rc aircraft but it works just the same.

Rich, My ifrared thermometer works great for checking the tempuratures.I use it on everything. Your going to get slightly different temperatures all around the cylinder and head when you check. The cylinder and head are just one big heat sink anyway connected together with a nice soft copper head gasket. Its easy to come up with an average temperature when you take measurements around the cylinder and head.

The tempuratures I'm running are "right on" when compared with the ambient tempuratures,humidity,and hard running that I did right before I took the measurements.

What