LED Cylinder Work Update

[arlaunch]

I chose LED Performance to modify my 1986 ATC cylinder head due to reputation and they are located in my town.

I purchased a nice 1986 TRX bottom end that had been completely gone through. The fella i purchased it from used to work in the engine shop of a local Honda dealer in my area.

All the bearings and seals were replaced in addition to having Race Reflections polish the left and right covers.

The bottom end needed a stator. I had one on hand from a 1985 bottom end that was laying around in my man cave.

In addition to that i installed the 1989 clutch update.

Unfortunately i could not get it put together last week due to life happening. Will try again when time permits. Likely that will be in early August.

I was real impressed with the cylinder work. It appears to be first rate, and top notch.

Have a look.




This is a 1986 cylinder and head that i purchased from Ebay about a year ago. It had never been bored or ported and was in really good shape.




I had a Duncan Racing exhaust flange from a previous motor that need new rings and a good clean up, LED had some nice new O'rings on hand that fit perfectly.




Arlan totally pimped out the cylinder head and adjusted it for 20cc total. It is all set up to run 110 racing gasoline.




Due to the much higher anticipated compression, Arlan informed me that setting the cylinder up to accept O'rings should keep all the pressure where it belongs.




Starting from the intake side of things, I noticed a really neat looking intake hanging on the wall from the moment i walked into the shop. I inquired about it and he told me that it is designed for 3rd gen Honda ATC's.

I totally got up sold and am totally happy. This thing is F'ing huge! It should help my 39mm PWK out big time?

I have the carb set up with a DEJ needle 4th clip down, a 52 pilot and a 180 main for break in.




I went with a Vforce 3 reed cage due to LED's recommendations and great prices these days on Ebay. My UPP racing intake is larger than stock. i noticed upon assembly that the slot going into the Vforce system had a large squared off overhang on the top and bottom. I ended up Dremmel grinding it flush with the intake manifold.

The intake looks great! The Boyesen ports were opened up large enough to provide my crankshaft bearings which will soon be under duress some additional lubrication without compromising the cylinder head to stud stress ratio.

That is also the reason why i chose the 86 head over the 85 because it is a little bit thicker in that area (it seems?)




The port tunnels are big, smooth and angled with extreme prejudice toward the back of the cylinder walls, so recharging is maximized in the mid range. I asked Arlan to build me an absolute mid range monster. I am pleased with the looks of things so far.



The exhaust ports where raised just a tiny bit but widened to the point where piston rings can still negotiate the large holes safely at around 8500 rpm



The exhaust channel was enlarged and smoothed out and looks to be free and clear of obstructions.



I have a Paul Turner High Rev on hand but plan on getting a custom rolled pipe and silencer from LED in the more distant future as funds allow.

[atc007]

Thanx for the look inside. A little intriguing to me His name says it will run great !

[RubberSalt]

As an amateur port work professional, that looks pretty good.

The only change is make is a small one. I'd polish the living heck out of the exhaust channel. This will help reflect heat and keep it from building carbon deposits as fast(shouldn't be a problem the way it is lol).

A few things I wondering. Can you provide a port map? I'm wondering about this my self. They are very easy to make with paper and pencil or crayon. The compression will help determine how big the exhaust port will need to be. I'm wondering if they did their math lol

http://www.macdizzy.com/cylinder_map.htm

[christph]

I'm going to port my 86 250R cylinder soon and was thinking about sending it to LED. I'm curious, how much did they charge?

[arlaunch]

I chose not to polish because IMHO the labor or cost of labor is not worth the gains.

I remember reading an article from a very reputable engine builder about polishing exhaust chambers. I don't remember the details but... his conclusion was there are small gains to be made from polishing the bridged area and much, much smaller gains coupled with much, much more work and $USD's to polish the exhaust chamber.

That is debatable online and always will be until somebody forks over the money and time to do a scientific experiment on the dyno. Which is fun to talk about but, outside of the scope of this engine build.

I will consider doing a port map. I have done them before and am interested in this type of thing.

Though i would think twice before divulging Arlan's specs to the free world openly on line as i want to continue to be a customer over there.

Can you elaborate on the compression determining the exhaust port size?

I am very, very interested to hear what you have to say on this.

I have read for hundreds and hundreds of hours on this stuff and, do not recall anything about that.

As far as math goes i am certain the math was not done this go around as my bottom end never made it into the shop and had a degree wheel attached.

Arlan told me he based the port work on a bunch of OEM cylinder testing/work he did with several pro TRX racers back in 2003.

After that the fad was mostly Pro-X cylinders and 4 cycle engines.


I will politely admit that i am not defending his work or this cylinder in any way, shape or form because i have not even fired the thing up yet.

That will be documented here though.

Let the fun continue!

Thanks for the interest everybody.

[arlaunch]

I'm going to port my 86 250R cylinder soon and was thinking about sending it to LED. I'm curious, how much did they charge?

It was around $500 for the cylinder porting, cylinder O'ring machining & head re-chambering.

You will want the larger copper or aluminum washers on there to ensure more even tensioning on that head.

I wanted all OEM Honda and chose to get the head re-chambered.

The Cool heads might be a better option than the stock head as they have just as good of a combustion chamber design and provide better cooling. Kind of a win win situation as the head will be much hotter with the added compression.

The factors to consider are these though:

1. Cool heads cost more
2. I am not sure if they make O'ring heads to deal with compression or not. That would have you scrambling for information in advance from a couple of companies.

Arlan would know how to navigate those waters with his eyes closed though.

All good fun.

I just wanted an old school Honda 250 with the short rod.

I only weigh 155lbs with my riding gear on and don't need a lot of low end torque.

Heavier fellas may feel different about that?

[RubberSalt]

10-4 on releasing.

To simplify it, more compression=more efficient burn. This causes more exhaust gasses that need to be expelled. In order to do this, larger ports. The larger ports can either be achieved by going wide, or going tall.

Being that going tall causes lower compression and more time area, going wide is the best route. This is done with either triple ports or bridged exhaust ports, of both.

If the bottom end is stock, then he's got good data to go off of. I wouldn't worry about it.

As for the exhaust port polish, I only do it to keep it clean. Can't stick to shiny lol.

At the same time. I go a little ocd. Some of the OEM stufstcasted jugs are more than smooth enough to stay clean. The quality oil we have and the compression these machines come with factory is typically plenty to keep it all clean.

If anyone was to dynos to see if there was any gain, I'd like to see the exhaust coated with a thermal barrier, like the piston crowns get. After all, hotter exhaust=higher rpm=more power(assuming it's not do to being lean). Sound travels faster through less dense materials. Hot gasses are definitely not dense.

Maybe I should wake up more before I type. >.<

[The_Steve_Man]

Arlan has been building top performing motors for many years. He definitely knows what he is doing.

As far as rechambering the head, here is a little info about it from Bubba Ramsey.

[RubberSalt]

Shoulda saw our last top end that went.. Bubba would have beat us badly lol.

This was for 1 of our blaster builds. Brother found a funny chambered blaster head on ebay for $15. Other than it being re-chambered, we knew nothing about it.

We went to assemble the machine while at the dunes (well the camp site). The head was touching the piston, even with the head gasket on! We started grinding the squish down until it cleared. Ever so tight fit. Compression tested at 120psi... lower than stock. wth!

That 200cc machine out paced everything we put it up against that would race us. The list isn't long, but they are notable wins!
trx250r (2 of them), 700 raptor (lightly modded), My tecate with KX cylinder+other parts, several 450rs, and a banshee that was modded.

3 days of hard riding and it died. We pulled it apart, it turns out the piston was just kissing the head. It was running hot, stuck a ring (thats what killed it on the side of a dune). We've got a new piston kit, now to find a new head and get it modded properly. lol (the list of mods is extreme!) Apparently, the funny low comp head was way more efficient than the oem. We just needed more clearance on that 0.000 clearance squish band lol

Long story short, don't build while hung over!

[RubberSalt]

I'd like to see how that machine runs before and after getting that pipe. Take some videos after the break in. With Led doing the port and head work, and assuming the bottom end is stock, they should really be able to provide a good running pipe.

Would you go for more torque, or just peak power? I've always been a fan of the pipes that keep you within the power band between shifts. Nothing like shifting to 3rd or 4th and realizing your 500 RPM from being on the pipe.

I like how they did the intake. Something that is frequently over looked on design. It isn't as much of a performance increase on 2 strokes as it is with 4 strokes, but the shape of the intake can have a performance advantage. OPn a 4 stroke, when the intake valves close, there is energy in the moving air still traveling to that valve. Once it collides, it reverberates back. This wave of energy (similar to that of the 2 stroke pipe) heads back out of the intake to the air filter. It bounces off the filter and heads back in. It does this until the valve is open. With the proper intake length, you can take advantage of this. OEM car's have a lot of this engineered in these days. It's the parts that make no sense. This Subaru engine is an example.


I don't know, but i doubt your intake was intended to take advantage of this effect. It looks like it's designed to flow well and look good doing it. This dark magic is in the same playing field as boost bottles.

[250rRoostmaster]

You will love his cylinder work, trust me!

[ceaserthethird]

Love stopping in at Arlan's shop, Pipes hanging on the wall and his stainless intake kits are bad to the bone. Please post lots of pictures of your build.
and if you can some video recordings too.

Keep us posted

Ceaser

[John Tice]

In recent years with the CAD “Computer Aided Design”, 3D printing & Investment castings; a number of custom & high performance minded people have been producing specialty & big bore cylinders. With maximum performance in mind the cross section dimensional engineering has been compromised. Many of the cylinders they have been developing have cracks between the ports & water jackets. With a sleeve installed; stability & strength is added & the cracks can sometimes be repaired. In the process we sometimes can TIG “Tungsten & Inert Gas” weld the cracks & repair the water leaks.

One of the last additions to my website; many of the porting guru’s are starting to overdue their work. Arlan’s one of the best in the business; when is enough enough? Keeping in mind that ports can develop cracks that don’t show. This is when the cylinders come to us for repairs & modifications.

John Tice
503-593-2908 Alternate 541-508-3944
www.smallenginemachineworks.com & www.nwsleeve.com
Turning Custom Cylinder Sleeves Since 1971
http://forums.everything2stroke.com/...d-the-Shop.com

[arlaunch]

This baby has a 20cc head and 110 octane fuel is ignited from an NGK B8EGV plug gapped between .020 and .024



I use a portable small bike tire pump to do leak down tests. It held 6psi for 6 minutes. That test is always nerve racking.

Arlan told me to set up my 39mm PWK with the following: #180 main/#52 Pilot and a DEJ needle set up 4th clip down.

Break in was easy. I installed a Wiseco 66.50mm Pro-Lite piston. I used K&S 110 octane race gas mixed with Amsoil dominator at 50:1. I started it and let it idle in the driveway for several minutes, several times. Then i babied it around the neighborhood multiple times for a gallon or 2. After that i took it to the play ground and just rode the thing the way i wanted to.

Jetting was perfect. I made no change. Having an engine builder is really worth the money. Pay a little and leave the drama for the lama.



The intake: You can hear it when this thing starts flowing. I have a +4 inch LSR swing arm and it wheelies in 4 gear in the sand with worn out tires.



High compression is amazing! This thing gets on the pipe much, much lower in the RPM range. Power is smoothed out and much more broad. This is noticeable the most, at the top of hill climbs when you pull the dune without having to shift down. That really makes the machine much more friendly to drive. I took the Fat Boy 2 off and replaced it with an FMF turbine core i had laying around. I did this because my Fatty 2 needs a repack, and I had FMF packing on hand. I wanted the bike to be a bit more quiet at the dunes. Even with brand new broke in packing this thing is obnoxious. It is really loud. I ride with ear plugs. I will do a noise test comparison when i get the fatty 2 repacked.

I spent the money and got the Duncan Fatboy 2 re-pack kit and the tool. They are in the mail right now. I found out that if you spend over $40 at DRI you get free shipping. The FMF turbine core is a great exhaust pipe but the Fat Boy 2 fits the Duncan pipe a little better.

It will be interesting to see which one is quieter with new packing. I like that both have the exhaust tip turned down. That is the one thing that would keep me from buying a custom exhaust. It seems odd that all tips are not turned down?



Another super cool drivability feature to this motor is that i found myself on several occasions, actually upshifting and accelerating up steep climbs. FAST!!! With the motor this one replaced i normally held what i had when i was on the pipe. As the quest for relocating money from my financial establishment to other vendors continues, I will likely get a custom LED pipe and drop back down to a 38mm A.S.

I have some sloppy suspension that needs to be addressed with Race Tech stuff before anything like that happens though...

I am not sure how much more power this makes than the motor i had in the machine previously? It was no slouch either but clearly does not bark like this thing does.

It seems like the high compression head sliced off a small chunk of the top end rev, then replaced it with a massive chunk of bottom and mid range power. A drag race between the two (old and new) would be interesting. For faster general riding, less down shifting, less bogging, less fatigue and easier drivability, this midrange port set up with high compression is truly fantastic.

Paying close to $14 per gallon however is not. HAHAHAHAHA

Just kidding. I don't care!

I could not afford a generation 3 when i was a kid. Wanted one ever since. Now i can kind of afford one but..... have no time to ride.

At least i can look at whenever i want.






I will likely gear the machine a bit higher next as i have a ton of rear sprockets laying around somewhere.

[yaegerb]

What was the static compression? I am also curious as to how you have it jetted?