Recommended mild 212 mods?
- Thread starter Boomstick
- Start date
- Tags mild mods? recommended
If you're putting in the flywheel and rod, I'm going to assume you'll be removing the gov. If that's the case, I can't imagine you won't hit the 45mph mark. Gearing is everything with these. There are a million threads on here to help you. Everyone will have their own comment on what works. It's hard to know what you mean by a mild build. Speed costs money. I think a bigger carb and free flowing exhaust will help. Cams mean everything. There are mild cams and extreme cams. Many of them cost around the same amount. You'll need better valve springs if you're spinning over 5k rpms. You should reach 6 pretty easily if you take out the gov and add better springs. Springs are around $10, and I'd go with 18lb springs if you're keeping the cam mild. That will keep them from floating at 5k rpms.
If you're looking for a mild build because of price, that would be my recommendation. If you're keeping the build mild because you're worried about tearing into these motors, you don't have to worry. Many of the mods can be done with basic tools, and they are very easy to do. Youtube has many videos walking you through your build.
If you're looking for a mild build because of price, that would be my recommendation. If you're keeping the build mild because you're worried about tearing into these motors, you don't have to worry. Many of the mods can be done with basic tools, and they are very easy to do. Youtube has many videos walking you through your build.
Ok, I did a little bit of research on the matter.
What I think I'm going to get/do
Billet rod & flywheel.
Governor delete (obviously)
Champion rockers/hardware (hey, it's what, $30?)
Stiffer valve springs (poundage not yet decided)
Black Mamba Jr. cam
Mikuni knockoff carb (any particular model you guys have in mind?)
Thin head gasket (probably straight copper, haven't decided on thickness).
I doubt I'm really going to do much in the way of head work. I might clean up the intake & exhaust ports a little bit, but that would probably be the most done.
Just want to build a peppy, reliable 212 :smile:
Any recommendations?
What I think I'm going to get/do
Billet rod & flywheel.
Governor delete (obviously)
Champion rockers/hardware (hey, it's what, $30?)
Stiffer valve springs (poundage not yet decided)
Black Mamba Jr. cam
Mikuni knockoff carb (any particular model you guys have in mind?)
Thin head gasket (probably straight copper, haven't decided on thickness).
I doubt I'm really going to do much in the way of head work. I might clean up the intake & exhaust ports a little bit, but that would probably be the most done.
Just want to build a peppy, reliable 212 :smile:
Any recommendations?
Pull your head and bring the piston all the way up. Look to see if the piston sits down in the hole or flush with the deck height. You need the info to choose your rod and head gasket. I've seen several in person, and lots of people posting the piston down in the hole. So I buy a .020 long rod. Open my engine and its flush, installed the long rod and it stuck out .015 so I had to cut the piston down. Ok next engine I do I buy stock length. Open it up and its way down the hole. My fix is to tear down both engines and swap pistons and rods, but f that, each bike has a different use and run well.
You must remove the governer once you decide to really speed things up.
The parts inside will break....
Use G200 18 pound springs with the Momba Jr
Nothing gained from the champion rockers are this point why use them unless they are free?
Use a real stock GX200 head gasket its about as good as you need.
A PZ22 carb is probably the best of its kind for this aplication ( in a slide carb )
But there are many other carbs that will work just fine if you get an adaptor for them.
I prefer to have something I can adjust on the go with a float in it.
Your preference may be different, but do not go over board and buy a racing tilly or race cars unless racing is your only intent.
Any decent small engine car can work for you just don't make iit too big 22mm is your upper limit.
There are adjustable jet kits and bored version of stock carbs that are well behaved.
There are many options...
Trick of my own.....
I use a Tillotson racing carb intake manifold with a techumseh Series 3 carb.
This is both bigger and better performing than a stock carb but it idles and has easy adjustmens.
Your choice depends on what you intend to do with the bike
The parts inside will break....
Use G200 18 pound springs with the Momba Jr
Nothing gained from the champion rockers are this point why use them unless they are free?
Use a real stock GX200 head gasket its about as good as you need.
A PZ22 carb is probably the best of its kind for this aplication ( in a slide carb )
But there are many other carbs that will work just fine if you get an adaptor for them.
I prefer to have something I can adjust on the go with a float in it.
Your preference may be different, but do not go over board and buy a racing tilly or race cars unless racing is your only intent.
Any decent small engine car can work for you just don't make iit too big 22mm is your upper limit.
There are adjustable jet kits and bored version of stock carbs that are well behaved.
There are many options...
Trick of my own.....
I use a Tillotson racing carb intake manifold with a techumseh Series 3 carb.
This is both bigger and better performing than a stock carb but it idles and has easy adjustmens.
Your choice depends on what you intend to do with the bike
I'm cheap for one. I bought the wrong rod, twice now. But if I get all crazy or the stars align I have two correct rods, just in the wrong blocks.
Anyways the stock non hemi piston is considered a dished piston. There is a meaty edge about 10mm wide that runs around the top of piston. So your not removing anything too serious. A flat top piston is in the future for that bike and then I'll swap out the rods. When I say I cut down the piston I'm not talking anything too precise. Think big flat file. It came out nice. Probably removed half the dish or better and boosted compression a bit. I also swapped out the thick factory fibre gasket to a thinner metal style.
Anyways the stock non hemi piston is considered a dished piston. There is a meaty edge about 10mm wide that runs around the top of piston. So your not removing anything too serious. A flat top piston is in the future for that bike and then I'll swap out the rods. When I say I cut down the piston I'm not talking anything too precise. Think big flat file. It came out nice. Probably removed half the dish or better and boosted compression a bit. I also swapped out the thick factory fibre gasket to a thinner metal style.
I found the 14cc head for under $30, so I went for it. You can do a mikuni, but you probably don't. I prefer a rejetted stock carb. I am running the cheater stock from Dover, and I like it a lot. I'd love to try a Tecumseh, like NOS menyioned. I need to get a little more cash first. These things are draining my wallet!
There are places to economise.
Tech carbs come from the scrap box at the local small engine shop.
Pick a nice one for under 10 dollars.....
Manifolds headers ect are as easy as welding some steel plate to some 1 inch steel pipe.
HF has those Chicago electric 89 dollars welders on sale now and then.
I liked it so much I brought one home to Canada.
Headers you can make.
Those valve springs are actualy G200 Stock Honda valve springs I was not kidding.
The local small engine shop again might have them new or used you can make a deal for.
The GXV160 tin top Honda lawn mower has a very good flywheel you can substitue for billet.
Pick through junk.
Thats the way to build on the cheap.
Tech carbs come from the scrap box at the local small engine shop.
Pick a nice one for under 10 dollars.....
Manifolds headers ect are as easy as welding some steel plate to some 1 inch steel pipe.
HF has those Chicago electric 89 dollars welders on sale now and then.
I liked it so much I brought one home to Canada.
Headers you can make.
Those valve springs are actualy G200 Stock Honda valve springs I was not kidding.
The local small engine shop again might have them new or used you can make a deal for.
The GXV160 tin top Honda lawn mower has a very good flywheel you can substitue for billet.
Pick through junk.
Thats the way to build on the cheap.
The list you have will make a nice peppy engine, which is what you said you want. The mamba Jr can handle 26# springs and will actually come with the cam when ordered from smallenginecams. The champion rockers are great, and with a 275 lift cam you don't need any gain from your rockers, I have a couple sets and they are bullet proof. I have gx160 with champion rockers, dyno cm cam (very similar profile to black mamba jr) 26# springs billet rod and fw and 22mm mikuni carb, with a 18cc head milled .075 and 27 25 valves and it is quite the motor. You can get a 14cc clone head for about $30 and do the rest of your list and you would have a nice motor. The other thing you can get is a flat top piston from a hemi predator, smallenginecams has those w/rings for $25.
