288 Big Bore

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terry2tmd

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At this point this is mostly a idea. I have a couple good 2100 cylinders and pistons setting around I also have a 394 cylinder that needs repair on the exhaust side it has broken on the left side stud on the exhaust port. The 288 has a 54 mm bore,and a 38mm stroke the 394 has a 56mm bore and a 38mm stroke if the ignition is similar the piston and cylinder should inter change. The intakes are similar solid intake and carb, I would think in looking at them the 288 intake would work, however I would have to come up with a 394 muffler and bolts on the exhaust side.
As mentioned earlier I have also got a few 2100 cylinder and pistons on hand, one is a thin ring set up. They are also 56mm, but I have no clue what the stroke is, yet. I know the 288 muffler will bolt up and I have enough intake pieces to make it a afternoon swap.
Here are the areas I am unsure of, and I come here for help. With as long as the 288 has been around someone else out there has, has to have this idea, and possibly tried it. I am also concerned about port timing, and was gonna do some cylinder mapping to make sure the port timing wouldn't be a issue, but being lazy I actually thought, I would ask anyone if they know the numbers, and if they will work.
like I said earler at the moment this is all idea, until I get some good intelligent input, the good old 288 is staying the same, I considered using the 395 cylinder, but with the impulse hose, intake boot, and a 42mm stroke it seems like a lot of hassle, this 394 cylinder is convient,(I think repareable),and has similar stroke. I am also told that the Jonsered 2094 cylinder, would be considerable, except I would have to use a 2094 exhaust.
Any help would be great guys, If it isn't gonna work just let me know, if it will work all ideas and info are welcome.
 
I might just throw it together and see what happens. I am afraid that a cheap big bore kit would drive the price of 288's through the roof on feebay. Kinda like where the prices are now.
 
Makes you wonder if the extra 2mm will matter that much I guess you could cut the cylinder base down a little if you needed to, I got a buddy with a great mill. Then again maybe you could make it up in the ports, I doubt that though largely you would lose compression. The ironis part is 2100 cylinders are available, and usually quite alot cheaper then 394 cylinders.
 
I would actually like to use that cylinder, because the stroke of the 394 and the 288 are the same, so I would suspect the port and ignition timing are really close. You couldn't point me towards a guy that could do that repair could you?
 
http://www.arboristsite.com/showthread.php?t=138032&highlight=
Theres a stroker build.

Subscribing..

Also, dont trash that 394 cylinder, they can be fixed!! Well most of the time

THAT WAS A AWESOME THREAD!!!! THANK YOU! I don't deal in a lot of hard woods, around here we get alot of cottonwood, locust, and Chinese elm, mostly nusance trees people want removed. They are usually huge, and have a ton of nail, and other assorted iron matter in them from either nailing the old fence to them or Little Jonny and his Buddy's trying to build a tree house in them. The worst and nastiest among them has to be willow, hard as a rock, and the wood tends to heave closed behind your bar, and will literally lock your bar and chain in the tree. I hate the stuff, and have seen more then one 372 go to saw heaven, because of this. Overheat the saw so bad the main bearings sieze, a determined and stupid lot who think the 372 is invincible. I have made good money cutting willow, but I have never approached one with anything smaller then my 288, and I always bring two saws, run one while the other cools.
I was just looking to give my 288 a little more grunt, but It is a winder too, and while I like strokers(gives me a idea of what to do with all the 2100 parts I got laying around) I was just looking to get a little more with a simple piston and cylinder change, I am really beginning to think the best way to go would be to use a 395 cylinder, and rig up a cable throttle set up, I hear the 395 has improved transfers that will help keep top end, problem is the 395 also uses I think a 42 mm stroke, I THINK. This is why I am here to find someone who has really built this kind of thing, I want it to say 288 on the side, and run with the big, big boys!
 
Fwiw. The 181, 281, 288 AND 394, share crankshaft, so if the cylinder/cases 'interface' matches? Go ahead and try it out!
 
Yeah the 394 and 395 are a little different but the cases and cranks are the same. The cylinder and intake/carb is the major difference.
 
Yeah the 394 and 395 are a little different but the cases and cranks are the same. The cylinder and intake/carb is the major difference.

There is a variation between 394/288 vs 395 cranks. A 394/288 crank uses a half mooned keyway to hold the fly wheel in place. There is a name for the type of keyway, for the life of me I cant think of it right now. The flywheel has a milled slot to hold the key way and the crank is milled for the keyway as well.

A 395 crank is milled for the flywheel. No key way like a 394/288 crank. Instead of a keyway there is a bump inside the flywheel to act as a keyway.

All this means is if you use a 395 crank, get a 395 flywheel. Use a 394/288 crank-get a 394/288 flywheel. Other than this aspect, the cranks will fit in 288, 394, 395 cases.

I am not sure if the holding angle of the cranks are same. By this I mean I am unsure if you can remove the bump or keyway (thus intermixing 395 crank to a 394 flywheel or vice versa) and rely on toothpaste grit to hold the timing.
 
Terry you just need to do simple measurements with rule and verniers. You have the parts so you are the one in the position to tell us the fits and don't fits. Get measuring.

Don't worry about the ignition, it's relative to the crank.
 
Thank you all so much guys, this is what I was hoping for, and why I love this site, I am gonna try this, at the moment all I am looking for is someone to repair the 394 cylinder I currently have, the left side exhaust port is broken off, but the inside of the cylinder is nice, I mean really nice! Thanks, I promise now if I get this going there will be video, if I have to steal a video camera!
 
Thank you all so much guys, this is what I was hoping for, and why I love this site, I am gonna try this, at the moment all I am looking for is someone to repair the 394 cylinder I currently have, the left side exhaust port is broken off, but the inside of the cylinder is nice, I mean really nice! Thanks, I promise now if I get this going there will be video, if I have to steal a video camera!

Keep us posted on your progress
:cheers:
 
A 288 with a 394 top end. Yes I have already done one. Seems like a cinch at first but it is not. Measure the distance between the crank center line and the deck on the 288. Now measure the same on the 394, big difference. This big difference is expressed in the port timing and ability to get any compression.
I did it and you can too but know this, it is not a bolt together project. Machining is neccessary. Mike (same guy that did "heart of a lion")
 
I would actually like to use that cylinder, You couldn't point me towards a guy that could do that repair could you?
Find a good tig welder. If you cant find anything local, I might could pull some strings and get another one welded up :)

Good luck with the build! Maybe Mike could stay around and help ya out. He seems to be pretty good with saws! :)
 

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