freewheeling frank
New Member
the biggest sucess i have had with creating a good powerband is with jetting, but i live at 7000 feet once i figure this out maybe then its time for port mods, any other high altitude dudes out there?
no head gasket
- Thread starter billycraven77
- Start date
GearNut
Active Member
7000 feet? Think really small fuel jet.
Somewhere I read a thread about a guy that stripped an end off of a bread bag twisty tie to expose the thin metal wire. He then removed his fuel jet from the carburetor and filled it up with solder using a butane torch to heat the jet. Before the solder hardened he stuck the wire in the solder, all the way through the jet, and held it there untill it cooled. Pull out the wire and you have a really small fuel jet. If it is too small you can use the wire like a ream and slowly enlarge the hole.
Somewhere I read a thread about a guy that stripped an end off of a bread bag twisty tie to expose the thin metal wire. He then removed his fuel jet from the carburetor and filled it up with solder using a butane torch to heat the jet. Before the solder hardened he stuck the wire in the solder, all the way through the jet, and held it there untill it cooled. Pull out the wire and you have a really small fuel jet. If it is too small you can use the wire like a ream and slowly enlarge the hole.
GearNut
Active Member
It is best done with a devise called a pin vice. It is sorta like a teeny hand drill you spin with your finger tips. Like winding up those cheap happy meal toys that hop around the table. I have seen these sold with rediculously small drill bits, all in a kit, at hobby stores.
About $8 to $10.
The bits are sooooo small that a regular chuck on a regular drill could not close up enough to grip the drill bit.
About $8 to $10.
The bits are sooooo small that a regular chuck on a regular drill could not close up enough to grip the drill bit.
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Humsuckler
New Member
pin vice. cool. i just googled it.
Humsuckler
New Member
just an idea that bloomed from how we use jigs for drilling hole patterns at my job....
you could take a block of wood and drill a hole the diameter of the removed jet just deel enough to countersink it, and in the exat center of that hole a pinhole to the other side, where you make a hole countersunk for your pin vice
get where im goin?
you could take a block of wood and drill a hole the diameter of the removed jet just deel enough to countersink it, and in the exat center of that hole a pinhole to the other side, where you make a hole countersunk for your pin vice
get where im goin?If you remove the base gasket you are lowering your port timing, which will almost always give you more low end, though you can at some point have your port timing to low/early.
On the other hand removing the head gasket does nothing but increase compression.
Use Threebond 1211 sealant to act as a head gasket, in either case. You also need to check your squish clearence before removing either base or head gasket. you should be running a minimum clearance of 0.7mm squish
On the other hand removing the head gasket does nothing but increase compression.
Use Threebond 1211 sealant to act as a head gasket, in either case. You also need to check your squish clearence before removing either base or head gasket. you should be running a minimum clearance of 0.7mm squish
Humsuckler
New Member
it is important to have some room for heat expansion of the piston... very important point.
however, on the other hand. the squish is almost non-existent on these heads lol
Riding Rich
New Member
I have a grubee GT-2B 48CC.
Replaced head gasket with pop can as gasket material.
I also run the SBP expansion chamber and a home made boost bottle.
Custom made my 36t sprocket.
All in all i run 35 / 40 mph all day long.
Many miles and it still runs good.
Most of the time I run 2 oz octane booster per tank.
Either NOS offroad or Lucas.
I'm thinking i will be changing my bearings to higher quality tougher rated ones.
No head gasket got me as much boost as the expansion chamber.
But high octane runs better.
NO HEAD GASKET 2 THUMBS UP
Replaced head gasket with pop can as gasket material.
I also run the SBP expansion chamber and a home made boost bottle.
Custom made my 36t sprocket.
All in all i run 35 / 40 mph all day long.
Many miles and it still runs good.
Most of the time I run 2 oz octane booster per tank.
Either NOS offroad or Lucas.
I'm thinking i will be changing my bearings to higher quality tougher rated ones.
No head gasket got me as much boost as the expansion chamber.
But high octane runs better.
NO HEAD GASKET 2 THUMBS UP
Are you saying the squish is non existant because its a dome head with a very wide combustion chamber, or because the squish has a very tight clearence?
Also are you talking center fire head or the slant head?
I guarantee your bike will run better on regular unleaded do not put octain booster in your fuel. think about it? 6:1 comp!
ok...allot of drag cars will run with no head gasket...the machining tolorances on these are VERY small...sorry but how much did this motor cost???i garruntee you the tolorances are way more...your local machine shop probably cant make these tolorances and if they can you would probably be better off buying ten motors and chancing that there might be a combo that would work(probably still wouldnt find one)...dude all any gasket does is fill these little gaps...thats why they exist...dont try silicone...wont work for very long...tried and true metal,paper,cork,rubber...all have there place and all are according to heat and materials in contact with them...put a headgasket in there for the love of god
skipu
Member
agreed very thin copper sheet sheer it to rough it and mini die grinder clean it up case match it done 1/2 hr copper sheet comes in all thicknesses i put little dowel pins in when i case matched mine and it will help to keep cylinder from walking if it trys its just a peave i have LOL!!! peace
motorhead419
Member
Mine does 45 MPH. I got a 34 tooth MANIC MECHANIC rear sprocket assy. Where I got my biggest gains was when I put on a 18mm Mikuni and a straight intake from Jim at MANIC MECHANIC..but when you use a 18mm Mikuni you have to open up the intake hole on the straight intake manifold..It's way to small to get optimal power out of a bigger carb..I have other performance mods too....It isn't easy to get to 40+ MPH...MPH NOT KPH
RebelMoby
New Member
Definately run with a head gasket and a pure copper one is the best - go to a hobby store or a card making craft store and buy a piece of sheet copper there it is cheap and thin enough you can use a hobby knife to cut it. Before you use it heat it with a torch and throw it into a bucket of water so it softens up and will seal the head. Next best head gasket material is a Coke can but do not bother to try to anneal it because it will evaporate. A Coke can will last a while but a copper one will last and last - each time you open your engine to play with it just heat the copper gasket again and throw it into water to soften up the surface again.
Use paper on the base - even butcher paper is good from the deli as long as it is butcher paper and not waxed paper. Just make sure your piston is not taller then the floor of the ports AND the skirt of the piston does not go higher then the bottom of the exhause port.
Do not use silicone (rtv) on an engine anywhere it is not fuel resistant enough - even the high temperature stuff will turn to gel and mess up stuff.
If you are milling your head with the paper on glass (or miror) method the best way to get it flat is the figure 8 way to move the head. Also I would suggest using a BIG black or blue marker and colour the surface of the head and do a single pass and check that the marks are being removed evenly from the surface - that way you know you are flat on the paper covered mirror or glass.
BTW - drag racing engine can get away with no head gasket because you rebuild a winning motor after each event AND your sponsors will pay for it.
Use paper on the base - even butcher paper is good from the deli as long as it is butcher paper and not waxed paper. Just make sure your piston is not taller then the floor of the ports AND the skirt of the piston does not go higher then the bottom of the exhause port.
Do not use silicone (rtv) on an engine anywhere it is not fuel resistant enough - even the high temperature stuff will turn to gel and mess up stuff.
If you are milling your head with the paper on glass (or miror) method the best way to get it flat is the figure 8 way to move the head. Also I would suggest using a BIG black or blue marker and colour the surface of the head and do a single pass and check that the marks are being removed evenly from the surface - that way you know you are flat on the paper covered mirror or glass.
BTW - drag racing engine can get away with no head gasket because you rebuild a winning motor after each event AND your sponsors will pay for it.
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