TRX250R chainsaw

[BigMoneyGrip]

Is the heat ever an issue, given the short run times? Does fuel choice mitigate those issues somewhat?

I would agree. The run time would be under a minute and you should be fine. If he does go with alcohol, that would buy him a little more time.
We ran into the problem of not being able to get enough heat in the engine, especially if it was cool outside. Anything under about 80° and the carbs would frost up.

 

[BigMoneyGrip]

Gink, shoot me a PM with your address, I have a present for ya.

 

[Dennis Cahoon]

Heats not an issue, unless you plan on running it for 20 or 30 second at a time. A record 3 cut run in 20" wood is in the high 5 seconds. With Ginks bikesaw experience, should be no problem.......Hahahahaha! Some are running alkie with good luck, not too many running nitro. Not very consistent at altitude or muggy air. Gas is about the most consistent and easiest to tune. Consistent runs are a must when racing these things. Being user friendly, and keeping the chain on is the most important things to work on. Can't wait to see you make 3 cuts Gink!

 

[gink595]

Heats not an issue, unless you plan on running it for 20 or 30 second at a time. A record 3 cut run in 20" wood is in the high 5 seconds. With Ginks bikesaw experience, should be no problem.......Hahahahaha! Some are running alkie with good luck, not too many running nitro. Not very consistent at altitude or muggy air. Gas is about the most consistent and easiest to tune. Consistent runs are a must when racing these things. Being user friendly, and keeping the chain on is the most important things to work on. Can't wait to see you make 3 cuts Gink!

Ya know I don't really have that much ambtion in becoming a full time operator of this thing. Making three cuts will be fun, but that isn't what I'm interested in. It is about making it that I'll find the fun in. Expereince or no expereince I'm confident I can make one I have the tooling now that I can make everything in house for the most part and shouldn't need much out sourceing. Ya know Dennis seeing your build over at the old place really inspired me to do this, from the first time I seen that 250 build I knew it was a matter of time before I would want to build one. We'll see how it goes, I'm sure there will be some challenges to figure out and it may never become nothing more than a convo piece but I'll have fun doing it!

 

[gink595]

Gink, shoot me a PM with your address, I have a present for ya.

Thanks Man!

 

[jropo]

What changes are made when switching from gas to alky. in a Mikuni or Kehin type fuel system (w/jets)?
Is there any performance levels that need to be meet before switching, Or can I just dump alky into, say my stock weed wip?

 

[jropo]

I have a bunch of the stand-alone diaphragm pumps. If you need a couple Frank, you can have 'em, Mikuni and Zama.

I think I have a NIB primer set-up for a Yamaha jet ski if you need that too.

Gink, If your planning on putting the motor on a slant, this system might give you problems, due to the floats.
If you could find a boot that had an elbow it might work. Some aftermarket boots seem cheap, but will work.


I'm sure most guys know about this site, but just in case.

https://www.denniskirk.com/frontpage.jsp

 

[gink595]

Gink, If your planning on putting the motor on a slant, this system might give you problems, due to the floats.
If you could find a boot that had an elbow it might work. Some aftermarket boots seem cheap, but will work.


I'm sure most guys know about this site, but just in case.

https://www.denniskirk.com/frontpage.jsp

Yeah, I was planning on rotating the motor so the float bowl was close to level +/- a few degree's. Once I get a carb/ reed cage and boot I'll be able to start and see what that looks like. I used to order from DK all the time, used to get alot of snowmobile parts from them.

 

[Dennis Cahoon]

If you use a pumper carb you can put your engine at any angle you want.

 

[BigMoneyGrip]

There are changes to be made when going to methanol. It requires about 2.5~3 times more fuel than gas. It is a lot easier to tune than gas. With alcohol, the jetting can be kinda close and it will work. Gas requires you to be close to perfect. When you add the nitro to it, that's when it gets finicky.
Alcohol really shines when you start putting compression and timing in to it. One bike I had was 14:1 and almost 30lbs of boost and still no detonation. Even though you can burn 3 times as much, it's still cheaper than gas. The last methanol I bought was .80 a gallon. a drawback is that it gets in the oil and contaminates it but that ain't a problem with the 2strokes.

 

[troutfisher]

Gink, I use the liquid cooled cylinder on my bikesaw for the oil tank. The clylinder and head hold plenty of bar oil, I have 1/8" line going down to the bar.

 

[jropo]

If you use a pumper carb you can put your engine at any angle you want.

That seems like the ideal set up if you know exactly what MM to use and what and where to open up if need be.

I suggested the Mikuni setup due to the simple plug and play approach.
If your just starting out this might be the way to go, there is a bunch of adjustablity in these carbs. Start rich and jet your way down, play w/ your main needle settings. Once you figure out where your at, then you'll know what Tilly to use, then you can eliminate alot of extra stuff that comes w/ the Mik set up, in favor for the all in one set up of the Tilly.
Only thing I don't like about the Mikuni's is the plunger style choke, I prefer the simple butterfly style choke that the Tilly's use.

 

[edisto]

If you use a pumper carb you can put your engine at any angle you want.

Now THAT would give Gink a reason to say GO BLUE!!

 

[jropo]

Now THAT would give Gink a reason to say GO BLUE!!

Sure is purdy!
I don't even want to know how much them run.
I would imagine if you have to ask, its too much.

 

[jropo]

There are changes to be made when going to methanol. It requires about 2.5~3 times more fuel than gas. It is a lot easier to tune than gas. With alcohol, the jetting can be kinda close and it will work. Gas requires you to be close to perfect. When you add the nitro to it, that's when it gets finicky.
Alcohol really shines when you start putting compression and timing in to it. One bike I had was 14:1 and almost 30lbs of boost and still no detonation. Even though you can burn 3 times as much, it's still cheaper than gas. The last methanol I bought was .80 a gallon. a drawback is that it gets in the oil and contaminates it but that ain't a problem with the 2strokes.

What about lines, fittings, gaskets, rings, 2cyl. oil? Or anything else that likes to fail.
When I think about Alky/Nitro, I think about Funny cars and Monster trucks, waaaay out of my league.

 

[Eccentric]

Gink, I use the liquid cooled cylinder on my bikesaw for the oil tank. The clylinder and head hold plenty of bar oil, I have 1/8" line going down to the bar.

That's a pretty damn slick idea (no pun intended...............well maybe it was LOL). Not only are you carrying the bar oil without need for an add-on tank (saving weight, complexity, and clutter), but you're also putting some fluid in the coolant passages of the jug and head. That will act as a heat sink (once the engine's warmed up.......keeping it at op temp) and will prevent hot spots in the castings. Those castings aren't engineered to be ran dry. There have been oil cooled engines in the past (Rumley Oil Pull tractors for example). Good deal all around.:cool2:

 

[BigMoneyGrip]

What about lines, fittings, gaskets, rings, 2cyl. oil? Or anything else that likes to fail.
When I think about Alky/Nitro, I think about Funny cars and Monster trucks, waaaay out of my league.

Yeah, nitro makes a lot of stuff fail! And usually in a big way. If it's somebody elses stuff, it's always cool. If it's yours, you cry.
Some oil will come out of suspension in alcohol. I always liked to mix a little and keep an eye on it. Most of your gaskets ans fittings will be fine even though the alcohol is kinda corrosive. I always drained the alcohol and give everything a shot of WD40 and I never had any trouble.

 

[MechanicMatt]

There have been oil cooled engines in the past (Rumley Oil Pull tractors for example). Good deal all around.:cool2:

I have read that the older Porsche 911 were really oil cooled. Everyone thought they were air cooled. But they held 19 quarts of oil and would pump it up to the front cooler. Hmmm sounds oil cooled right??

 

[Eccentric]

I have read that the older Porsche 911 were really oil cooled. Everyone thought they were air cooled. But they held 19 quarts of oil and would pump it up to the front cooler. Hmmm sounds oil cooled right??

They were indeed both Air and oil cooled. Forced air over the cylinders, and 19 quarts of oil in a dry sump system. I had a buddy who owned a cherry 1986 911 Targa. Fun car.

 

[parrisw]

I have read that the older Porsche 911 were really oil cooled. Everyone thought they were air cooled. But they held 19 quarts of oil and would pump it up to the front cooler. Hmmm sounds oil cooled right??

Any internal combustion engine that has oil, is oil cooled.

My friend is building a Porsche 914, with a 3.2 6cyl out of a 911.