Anybody have luck removing head AND base gasket?

[ratty]

Anybody have luck running engine without head AND base gasket?

I have read a few threads here and there where people have run engine without both but it seems like the base gasket always gets put back on due to leaks. Has anyone successfully removed both with long term results.....improvements, gains losses.....etc?

 

[reg454]

When I removed the lower gasket it was hard, it was stuck and i had to grind it off with a file I think they glued it on. But after it was off I used high temp rtv sealant the orange kind and no leaks but make sure to leave the top metal gasket on because you can damage the top from not enouph room.

 

[Mike Hunt]

really? taking the top gasket off will make that much of a difference?

 

[mechanickid]

it depends on your engine, with some the top dead center is already close to the head, and you can only use thin gaskets in both places before it "pings" with others your can remove both and even grind a little away and still be okay, i would experiment and see how it works, everytime you change it it effect the timing a little.

 

[ratty]

it depends on your engine, with some the top dead center is already close to the head, and you can only use thin gaskets in both places before it "pings" with others your can remove both and even grind a little away and still be okay, i would experiment and see how it works, everytime you change it it effect the timing a little.

When you say "ping" do you mean detonation...or do you mean physical contact between the head and piston? I haven't put any clay in there to check the clearance yet, but with both gaskets removed there is no contact with my particular setup.

 

[2door]

My question would be what are you trying to accomplish by removing the gaskets? The performance gain from the slight compression increase will be negligible at best and you run the risk of doing some serious damage to your engine either from an over lean condition from leaks or contact between the piston and head/plug. If your current gaskets are leaking, replace them but why remove them completely?
Tom

 

[ratty]

My question would be what are you trying to accomplish by removing the gaskets? The performance gain from the slight compression increase will be negligible at best and you run the risk of doing some serious damage to your engine either from an over lean condition from leaks or contact between the piston and head/plug. If your current gaskets are leaking, replace them but why remove them completely?
Tom

Truth be known, I have lapped my head and cylinder after cutting about .005 off each one. All this adds up to .040 total being removed by deleting the head gasket(which was .030") . I am basically looking for free horsepower. I have not started the engine since the mods. I have not even tried to calculate before and after compression, but it couldnt hurt. Not to sound lackadaisy, but if it costs me a piston or cylinder in the pursuit of more power, so be it.....parts are cheap. I have read several posts stating that just removing the base gasket and using only sealer, will net a significant power increase. Maybe it has more to do with the port timing, I dont know. I do know that my base gasket is worth about .035 of thickness. I am gonna try it with no head gasket first, then go on from there. I should mention that I also have trimmed the bottom of the piston skirt to open the intake port, and widened the transfer ports a wee bit, and removed the casting flash from the intake and exhaust ports in the cylinder. None of these are major modifications, but I just want to increase my power as much as possible (without going nuts) so that poor little engine can pull my fat a** up hills!

 

[spad4me]

Just my two cents.
The Most power increase is from a tuned pipe with a jet change.
About 1/3 more power.
Removing the lower gasket and trimming the piston skirt.
some more power.
I then tried opening up the transfer ports.
The easy way was to grind the top of the piston Dont go into the ring lands just remove material in front of the ports.
The pipe resulted in the most gain 1/3 more power.
The other mods added about 10 percent on top of the previous gains.

 

[camlifter]

i've been playing with these motors for awhile now and i've come to a few conclusions,
porting, raising compression, changing the length of the intake, trimming the piston, different carbs, and all the mods most people try don't really do much, i have a huge pile of useless parts to prove it. i've tried dozens of different combos in the pursuit of more power. yes you can gain a little, maybe, but a change in pitch of the sound of the engine or just the hope that all the time you spent wasn't wasted doesn't mean you really gained any power. the cost in time and money to the miniscule gains just isn't worth the trouble. NOW the things that do work, a tuned expansion chamber pipe is good for a big noticeable gain, also getting the carb jetted right makes a huge difference. the delorto and other carbs i've tried were no better than a properly tuned stock carb.

 

[2door]

Ratty,
I have no personal experience with raising compression (on a bicycle motor) but what I have heard from several people who have switched to the so called 'slant plug' head that does raise it, is that they have had clutch slippage problems especially on start up. This might be something you need to consider when you get the engine back together and running. Please post your results. And good luck.
Tom

 

[ratty]

Hey Tom,
Thanks for the heads up, no pun intended! I wish I had been taking pics so far....I don't know why I didn't. I suppose I'm always in a hurry and/or lazy. I am trying to get it put together to ride tonight if possible, but it's getting late so I gotta hurry. I have been doing some other repairs and upgrades along with the engine work, so it's taking a bit longer than usual. I will post results as soon as I can, hopefully that will be tonight! Heres a couple of pictures of where I am now. This is the bike that started it all for me. Its a Huffy Stalker; it has a factory matte black finish with all blacked out trim. It's the testbed for all my experimental work, and the basis for my handle here. It's an old ratty 12 speed!

 

[motorhead419]

I use some real thin .008 gasket material for my base gasket. That way you gain compression, and you don't have to worry about sealer hanging over the ports interfering with your flow. I feel much safer from air leaks with some type of gasket. As you know an air leak will kill a 2-stroke.

 

[ratty]

Ok, I finally got it put together and managed to squeeze in about a 3 mile ride before the darkness. All I can say is wow. This has given me the best results yet. My powerband is a LOT wider, and there is quite a bit more low end power. And it really runs smoother. A lot smoother. Prior to this, my top speed on the flat surfaces was about 25-26 mph, tonight I got it up to 29 mph in the same spots, and the motor didnt sound like it was about to blow apart. The hill climbing wasnt as dramatic of an increase, however. I did have more power up the hills, but not like I have in the flats. I weigh about 250 lbs, so I am not complaining. The lower rpm power did give me a better stamina going up hills.....16-18 mph up relatively steep hills (without touching the pedals) with my weight is nothing to scoff at.
Prior to these mods, not necessarily in this order, I replaced : the spark plug with an Ngk, gasket matched the intake and exhaust pipes, completely gutted the muffler and brazed on a lawnmower muffler as a silencer, put an o-ring between the carb and intake, and lowered the clip on the carb needle one notch...thus raising the needle. Usually, I do one mod at a time so that I can keep track of power gains or losses, but I wasnt about to pull that cylinder off 8 times to track it that close. I would also like to add that the area around the head/cylinder where the head gasket once was is bone dry; absolutely no signs of leakage.
Prior to tonight, the biggest gain I got was the exhaust work, after gutting the muffler. I tried to drill out the baffle, etc. but I wasnt happy with those results. Gutting is the way to fly. There is a 1/2" hole in the end cap of the muffler exiting into the muffler. I am going to have to get lock nuts for the exhaust pipe, I cant go a mile without those frikkin nuts backing off.
Remember, the increase in power is the result of several small modifications. Right now I am happy with what I have, but I am going to get a tuned pipe soon. The SBP kit looks like the best deal out there, and Ghost and Pablo seem like really decent folks to deal with, although I do not know them. Thanks for everybody following along so far. I highly recommend cleaning up the ports, and the head gasket trick is worth the effort. Plus its pretty much free. Just watch your clearance, make sure the piston doesnt hit the head. I will update soon after more happy time!

 

[xlite]

i've been playing with these motors for awhile now and i've come to a few conclusions, porting, raising compression, changing the length of the intake, trimming the piston, different carbs, and all the mods most people try don't really do much, i have a huge pile of useless parts to prove it. i've tried dozens of different combos in the pursuit of more power. yes you can gain a little, maybe, but a change in pitch of the sound of the engine or just the hope that all the time you spent wasn't wasted doesn't mean you really gained any power. the cost in time and money to the miniscule gains just isn't worth the trouble. NOW the things that do work, a tuned expansion chamber pipe is good for a big noticeable gain, also getting the carb jetted right makes a huge difference. the delorto and other carbs i've tried were no better than a properly tuned stock carb.

That's the best summary of the situation yet. IMO most "improvements" are imagined. Several of the guys I did engines for came back claiming mods doubled their power. A quick run up "Dynomometer Hill" showed little increase in top speed or torque. Ahhh... the power of the human mind.

 

[ratty]

I have a dynomometer hill of my own in my neighborhood, its what I gauge my standards by. It is approximately a 100 meter run, kind of steep, not sure of the grade or anything like that. When my engine was stock, it would not pull me up that hill without pedal assistance. If I didnt pedal, the engine would die about 3/4 way up. Now it pulls me up that same hill at about a steady 16mph average with no assistance, so I did happen to sneak some power out of somewhere. I would not say that I doubled the power, but definitely some gain. I do agree though that 'seat of the pants' power gains are usually deceptive....its really hard to tell. Now if I could just sneak some money by the wife for that expansion pipe......

 

[xlite]

My comment was based on the 20 or so guys who came to show me their "hop ups". Compression increase was one of the few things that made a difference in my case too. In addition to the gasket a slant head and colder plug with longer threads actually did put some spunk in 2 of my bikes.

Other things that made a difference were closing the jet and tuned pipe. All that other stuff that camlifter mentioned really didn't do anything noticeable in my case either.

I have a dynomometer hill of my own in my neighborhood, its what I gauge my standards by. It is approximately a 100 meter run, kind of steep, not sure of the grade or anything like that. When my engine was stock, it would not pull me up that hill without pedal assistance. If I didnt pedal, the engine would die about 3/4 way up. Now it pulls me up that same hill at about a steady 16mph average with no assistance, so I did happen to sneak some power out of somewhere. I would not say that I doubled the power, but definitely some gain. I do agree though that 'seat of the pants' power gains are usually deceptive....its really hard to tell. Now if I could just sneak some money by the wife for that expansion pipe......

 

[ratty]

I agree with you guys xlite. I just wanted to point out what all I had to do to make the little increase that I did. It took quite a few tweaks to get to an acceptable level of power, just enough to pull me weight around at a comfortable pace and know I can pull it off. Thanks for your input, I hope to pick up a couple of slant heads soon.

 

[camlifter]

i have one engine with a bunch of mods, higher compresion, ported jug, keiin carb, 1 inch longer intake, big open air filter, trimed piston skirt and an e/c tuned pipe. it runs really good. but we also have a freak stock motor that will hang right with it, it's only mod is a gutted stock pipe. a good pipe and carb tune are are the mods you can feel in the seat of your pants, everything else is just for fun and learning. the motors we've had that ran the best regardless of the mods are the ones we broke in like we stole them. 32-1 mix right from the start and wot from the moment they fired up. the ones we babied ran like turds.

 

[motorhead419]

I agree with the break-in theory. I used to drag race and we sure didn't break them engines in. I got my first 80cc (66) kit from gas bike and it has the 6mm cylinder studs. I've did a bunch of mods to it and it screams (beat it hard from day one) and I've never had a problem with it. I got a new kit with the bigger 8mm studs and my old engine kills it. If you get a slant head they have holes for the 8mm studs, so I got some dowel pins that they use on motorcycle engine sidecovers to locate the covers and put them in the head holes to take up the slop for the little 6mm studs. This keeps your head centered so you don't have to guess at its location with the smaller studs.

 

[ratty]

I did notice one thing that I didnt mention about my ride last night. The engine pulls really well up untill a certain rpm, and the its like the power runs into a brick wall. I dont have a tach yet so I dont know the rpms, but it revs up so far and then stays there. Its not like a rev limiter, but it will only rev so high as if it would not over rev and cause damage. I cant make it spin faster. Like it gets to 6500 rpm or whatever it really is and I could run it all day like that holding the throttle WFO. I checked and the slide does open and close all the way. What is that all about? Does that make sense?