Pulled the motor (( Internal Combustion Engine ? )) and tore apart the top end only to find no head or cylinder gaskets. They were both metal to metal. Didn't have any blow-by but I'd think it could be prime spots for air leaks.

Bought the whole gasket set to put it back together but was wondering if anyone runs them like that. Seems it would boost compression too high (should have done the test before I pulled it apart).

Ya, there should be gaskets there. Factory gaskets were tin and 3 layers sandwiched together. Some of us, only use 1 layer to bump compression a tad, but you need a gasket of somesort!

Gary

Personally, I wouldn't use the cylinder base gasket that comes in the gasket kit unless it is made out of aluminum. The Athena and Vesrah gasket sets both have paper gaskets that can blow out causing an air leak and a melted piston.

That being said, Speedchaser makes a very nice .016" thick base gasket I highly recommend! Contact him direct or he has an ebay site.

http://www.ebay.com/itm/FL350-HONDA-ODY ... 39&vxp=mtr

I also 2nd Nuke Em's suggestion to use only one thin piece of the three piece head gasket. During installation I would also suggest using Permatex's Coper Spray A Gasket.

Rand

I bought the Athena kit so I guess I should check deck & cylinder height run-out to decide whether to purchase the metal gasket or go bare back. The paper head gasket is okay though?

With the Permatex Copper, do you use it on all metal-to-metal mating surfaces? Not with paper. right? Sorry if the question seems silly but this is my first motor (( Internal Combustion Engine ? )) <-WTF?? tear down.

I used some Athena kits back in the 90s with no issues. Long term, 10+ years maybe less, paper gaskets break down and will cause issues...in my opinion. I have never sprayed it on paper stuff, but cant imagine it would hurt anything. I do 2 coats. Again, my preference is the tin gaskets but yours will work, especially if you are learning...use em. You are rebuilding a fairly stock set up I assume and all the clearances are large anyway so the little thicker wont effect it much. My 2 cents! lol

Gary

Maybe it should read ((Its a Engine stupid NOT a M0tor)) then you would understand, if you cant understand go find any place in the owners manual or the service manual where it refers the Engine as a motor (( Internal Combustion Engine ? )) don't bother to look because it does not say it because its a Engine stupid not a motor (( Internal Combustion Engine ? )) haha

As long as we're correcting grammar.....

your correction should read....."Its an Engine Stupid, NOT a ..... well you know.

just sayin.....

Rand

Guess I don't really give a sh!t what the pretentious among us want to call the lump behind the chump, as long as reasonable people, who are willing to help a newbie, don't care either.

Think I'll just go with the Athena kit all the way. If the deck height looks close to max run-out, we'll go with some copper as well.

Thanks Gary & Rand

You're welcome.

In order to solve the FL350's overheating issue, Honda went hog wild and made the squish band close to 1/8"! A good squish band should be in the neighbor hood of around .040" to .050". By using the thinner base gasket and one of the thin pieces of the head gasket, you can bring the squish band to around .090".

This will give you some additional power. Not a bunch but it is a noticeable difference.

Rand

Being that this is your first rebuild, make sure to look up piston prep for the fl350, relieve the exhaust bridge, drill the oiling holes in the piston, chamfer the sharp edges off your ports.

In the interest of full disclosure, I had just rebuilt my starter and was enjoying the first run after that when a WOT (Wide Open Throttle) gave me more speed than normal. Looked in my mirror and no exhaust smoke. Thought maybe I was running lean when the (Internal Combustion Motor??) quit. Turns over but doesn't start, though turning it over I noticed bubbles in the fuel line. Thought I might have holed a piston. Maybe I didn't tighten the fuel clamps enough.

Pulled the cylinder head and piston and both looked great. Pulled the cylinder and the rings look normal. No scoring on piston or cylinder. Measured .019 play between rod big end and crank, so that's in spec. Radial play seems excessive but I haven't measured it yet.

At this point my plan is to get the new gaskets and button it back up. Am I missing something?

So your holding out on us. Bad Bad. So you pulled your head because you had more speed than normal ---- Not to many of us would complain about that ----- Baahahahahaha.
Seriously though you could still have an air leak so do a pressure AND vacuum test before you run it.
Also humour me and do a flow test on your fuel pump. You need 4.5oz in 10sec approx.
Trust me on this one as I will be doing this once a year and after any rebuild on each oddy I got.

I would only use the aluminum cylinder base gasket after seeing what happen to Lee's paper cylinder base gasket, his blew out I wonder if that is why Honda used aluminum in the first place?



A better look with arrows pointing to the crime scene, I had installed that gasket in the picture you can see even when using the yamabond on the gasket it still blew out, with the OEM gasket being made from aluminum then sealed with something that feels like cured yamabond this tells me that Honda had thought the cases or the cylinder or both might expand and or contract enough where they would allow the gasket to be blown out when under the right conditions.



Speedchaser makes the cylinder gaskets now that Honda has discontinued.... I will NEVER use another fiber gasket on the FL350 cylinders...

viewtopic.php?f=4&t=7565&start=0



I would use the OEM head gasket as Nukem has described in his replies, single layer with the copper coat spray, I would also lap the head and the top of the cylinder to ensure they are both flat, I ASSume they are flat since they showed no signs of leaking without a gasket, check the head torque after break in and after any days of running the Ody really hard on a really hot day or any other condition where it might be over heated just to make sure the studs have not stretched.

Blown cylinder gasket

Sorry I am not that smart glad you guys are..

Athena gasket seller is out (why do they post auctions for items they don't posses???), so went with another kit that comes with metal head gasket. Bought Speedchaser's metal cylinder gasket and will copper spray both.

I'm going to replace all fuel lines and clamps, and will perform the fuel flow, pressure and compression tests before start up.

I once ran a FL350 Engine with just a 1mm Viton "O" ring as a gasket, on a much modified race oddy. I don't think it ever failed either but i always used an alloy base gasket.

Last suggestion would be a " leak down test" when you are done, before reinstalling the Engine. If the crank seals get old n hard(Don't say it Baz!) And start leaking air so the Engine will lean out n burn up the top end. Been there n done that a few times. Lol. Good luck!

Yep, definitely going to do a leak test since it's probably what got me here in the first place.

Any tricks to compressing the rings to get them into the cylinder?

Filastein,

See the link:

http://www.dansmc.com/pistons.htm

About half way down he talks about installing the piston.
I had to read it a couple of times to pick up on what he is saying.
Basically, install one of the wrist pin clips and the rings.
Install the piston in to the cylinder and push it almost all the way threw, so that the wrist pin hole is exposed.
Then assemble the the piston to the rod, insert the wrist pin and the remaining clip (all the while the piston is half hanging out the bottom of the cylinder)(remember to add the cylinder base gasket first).
Then push the cylinder down and bolt it up.

I've assembled the piston to the rod then dropped the cylinder down over the assembly before.
It was always a pain to get the rings in (compress rings with fingers and push the cylinder down with my chin)(not recommended).
I always envied my buddies with the 2 piece ring compressors.
Method above can use a standard auto style ring compressor.

Just want to revive this thread for a moment.
It was posted in July when I already had both my brothers and my Engine completed and installed or at least nearly all installed.
This happened to my machine last Friday (see pics)
You can see the base gasket blow out.
The good news is no poofkaboom. It was running right to the end when I loaded it on the truck but it would hardly idle and stalled when we were going down hill and no throttle. Funny part is the mid range and top end ran well when we were high in the mountains.
You will notice it has a cork type base gasket material. My brothers machine has the same.
I made these with gasket material I bought locally at the auto supply shop.
We got both our machines running real good now and then this happened FFFFFFFFFFFF.
I am now in the process of tearing both engines apart again and installing the metal base gaskets.
Just an opinion here so feel free to shoot at it ---- even though both machines have home made liquid cooled heads and cylinders I am thinking that the none metal material just cooks from all the heat. This caused it to blow out. I have not remove the engines yet but that is what it looks like to me. It just looks cooked. Neither Engine ever got hotter than 230'F according to the temp gauge, and that was going full throttle up the mountain. We don't go slow (my brother and I have to file flight plans every time we go for a ride).

Blown cylinder gasket

Someone say "Old and hard"?

With all the things Honda got wrong with the fl350 the metal base gasket is not one of them.
Not all engineers are dumb dumbs. We all make mistakes and there is photo evidence of mine here.
Moral of this story --- run a metal base gasket.

The cylinder nuts were not even tight.
I got lucky.

Blown cylinder gasket

WTH that's the same thing that happen to Lee's 350 but not as bad.

Speedchaser makes the gaskets viewtopic.php?f=4&t=7565&start=0