Motorized Bicycle Engine Kit Forum  

Sponsors



Go Back   Motorized Bicycle Engine Kit Forum > Motorized Bicycle > Motorized Bicycle General Discussion

Motorized Bicycle General Discussion All topics regarding bicycles with engines.

Reply
 
Thread Tools Display Modes
  #1  
Old 03-25-2013, 12:07 PM
ocho ninja's Avatar
ocho ninja ocho ninja is offline
Motorized Bicycle Elite Member
 
Join Date: Jan 2012
Location: San Jose, CA
Posts: 565
Default Performance head for 99cc/79cc predator

I was browsing aimlessly trough some Parts websites, couldn't sleep.

Been anticipating performance parts for the predator engines for a while from agk and this performance head looks promising. I'm considering getting later on as I get my bike dialed in.

Just wondering if anyone already has tried this head out yet?

http://www.affordablegokarts.com/mm5...gory_Code=99cc
Reply With Quote
  #2  
Old 02-16-2017, 03:00 PM
engineman engineman is offline
Motorized Bicycle Newbie
 
Join Date: Feb 2017
Location: phoenix,az
Posts: 8
Default Re: Performance head for 99cc/79cc predator

Hello The head is misleading to how it reads.If you plan on getting a 99cc head is what I do mean.Do to they state they no longer can get them.And you have to send your head in tells me all I need to know.When I was interested in that head till I read exactly how its worded.So I don't know how much you know about engines and head work.As I do and plan on doing my own.Its all semi easy really.Once you get the valves etc out.For that you use a simple C clamp to compress the valve springs and remove the small wedge keepers that actualy hold the spring plate or keeper in its place.After that its a walk in the park.Short the valve guides.Which most over look and shouldn't at all.Because any obstruction in the port means less air flow.However, you cant run with out certain parts.So you do the next best thing.And at least tapper the guide material from where its exposed to the top.So when done it looks cone shaped.And the material that holds the guide.You simply reshape into a knifed and ramped ordeal.You want in ramped from one end to the other as the air flows in .You want to run it into the intake valve.So that is how you want to form the shape.Think of it like this.With the knife blade running towards and ramped into the valve area or bowl.And that will be the only area you will actually remove material from.The rest of the port work simply is a smoothing affair.And don't let the polishing word lead you to believe its a mirror finnish.Its not but nice and smooth all over.Should be finished in a 220 grit is about it.IF you see a mounded looking area at the mouth of the intake port.DONT remove any part of it!! Just slightly smooth like the rest.When that will be whats called a velocity ramp.And important to keep.As for milling the head.You can do this also if you know what your doing with a flat solid level work surface.Since most don't know how to perform this.Its best to use a machine shop.I can tell you many performance tips and tricks.But you have to know engines before any to all will make sense.One thing that's very very important to all engines.Happens to be oiling and keeping the engine cool over real hot.No one ever gives that any thought at all.Not to will result in a ruined engine mark my words!
Reply With Quote
  #3  
Old 02-16-2017, 07:33 PM
sbest's Avatar
sbest sbest is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2015
Location: Nova Scotia
Posts: 340
Default Re: Performance head for 99cc/79cc predator

Fine advice Engineman!
A pile of porting might gain you a few % more power, likely no more than 5%.
Milling 0.020" off the head might see another few %. Likely no more than another 5%.

One of the biggest thing this head needs is squish area to impart some turbulence, speed up the burn, and resist detonation. While I had the valves out, I'd get a good aluminum welder to zap up some flats by the plug and on the other side.


THEN mill a few thou off to flatten everything up, do the valve seats and all the work you suggest. A cam would go well with more compression and you'd be off to the races with 20-50% more power.

Do you think?
__________________
That's a mighty noisy bike you got there, it must haul a lot of ass?
Reply With Quote
  #4  
Old 02-16-2017, 10:06 PM
culvercityclassic's Avatar
culvercityclassic culvercityclassic is offline
Motorized Bicycle Elite Member
 
Join Date: Sep 2009
Location: Culver City, Ca
Posts: 2,989
Default Re: Performance head for 99cc/79cc predator

I did all the bells on a 99cc and was disappointed with the results, sold that motor. Its best to just do a carb and exhaust and leave it. You want more power do a GX160 which I think is the perfect size for bike or go 212.
__________________
CulverCityClassic
wolfcreativecustoms.com
Reply With Quote
  #5  
Old 02-18-2017, 01:53 AM
engineman engineman is offline
Motorized Bicycle Newbie
 
Join Date: Feb 2017
Location: phoenix,az
Posts: 8
Default Re: Performance head for 99cc/79cc predator

Wow sorry to hear that.I don't at all disagree with your choice of bigger engines.But for one big reason!How will you get it past every COP!I well know many wont know what there looking at.But then count on half to not be stupid.Our state law states 49cc which I cant live with and **** whats 30 more cc.Now to run ether of those and espessially the 212cc GOOD luck brother.When that engine will stick out like a well beaten thumb!Plus for my needs.Anything I'm to build must be completely gone through.That when I'm done.The entire machine spells one word.Performance period.So I will turn enough heads with the one I will be building.The 79cc and I can tell you this.Ive been emailing a tech guy at a performance shop.That deals in all of these engines.Mostly the larger do to kart racing.However they have a bicycle setup with this 79cc and its all pumped up!Huge cam so that's where I'm getting mine.And valve springs.Carb setup and manifold and exhaust.The only other is they milled there head to a whopping 12.5-1!! dynode it at 6.5 hp and he told me.They didn't have great success with the 99cc ether do to clearance for valve and piston.That tied there hands.BUT this 79 predator hasn't the same problems at all.Right down to not breaking down at all.He said we run the **** out of it and then let customers run it even worse! He cant say enough good about it.The other was a greyhound engine. Ok not the same animal at all.Ive researched the predator big time oh my god!To say all of them are a real quality engine and setup for building performance.There all bigger displacement to all others.The 212cc is a stoker engine.That with all the required performance parts and machine work.Happen to be running at 12.5-1 on methanol dude and keep hualing fast ass.Only one guy that went insane pushing his to a insane 15-1 on alcohol did throw a rod through his case.Then most racing built V8 will do the same or bad enough when pushed to that CR.And exactly why any drag raced engines are torn all the way down.And still would be even if they ran a water cooled setup.I used to be in the southern cal speedsking club.I ski raced behind a 950HP dual turbo charged V-drive race boat with a threespeed racing trans.OK and my buddy won his class so he had to go to another.Being flat bottom.So he of course picked the badest that class had.A blown 427 in a Hondo drag hull.That the clown had just ruined by tearing apart the right setup running a lower CR and using gas racing fuel.To methanol and 15-1 CR as fast as he told me that.I walked over to my best friend and told him.GOOD luck as you will not finnish the season behind this boat!Sure enough it went down almost right on the money I placed.To the dime.Basicly it comes down to this.IF you plan to keep any engine running.Keep it no higher than max 10-1 and under 6 grand period.Since this is a tiny dude to begin with.Its going to 11-1 and up to 6grand.When the cam I'm using will run 7 grand and that same guy told me they push it to 7 all the time.So do what you want but expect trouble unless your using it at a track.
Reply With Quote
  #6  
Old 02-18-2017, 12:27 PM
culvercityclassic's Avatar
culvercityclassic culvercityclassic is offline
Motorized Bicycle Elite Member
 
Join Date: Sep 2009
Location: Culver City, Ca
Posts: 2,989
Default Re: Performance head for 99cc/79cc predator

Sounds like you found a shop to take your money, the cam, valve springs and head are the common issues. The huge cam, how does it change the clearance problem from the 52 x 37 to the 99cc 56 x 40? Do you have a spec on his cam? This motor with that HP will need a billet rod and flywheel too.
__________________
CulverCityClassic
wolfcreativecustoms.com
Reply With Quote
  #7  
Old 02-18-2017, 04:49 PM
Tony01's Avatar
Tony01 Tony01 is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2012
Location: San Jose, CA
Posts: 782
Default Re: Performance head for 99cc/79cc predator

No comment.
__________________
I don't always listen to Alice in Chains..... but when I do, SO DO THE NEIGHBORS
MxTrq clutch tuning | 212cc 2spd | CVT tuning

Last edited by Tony01; 03-09-2017 at 02:25 PM.
Reply With Quote
  #8  
Old 02-21-2017, 02:18 AM
engineman engineman is offline
Motorized Bicycle Newbie
 
Join Date: Feb 2017
Location: phoenix,az
Posts: 8
Default Re: Performance head for 99cc/79cc predator

Ive no doubt that did happen.When Ive got out of more than my fair share of real issues with cops.But that hasn't twisted my thinking process into that will be the norm.Bottom line is cops are people only which have badges.With this we all should know.Theres more good people than bad.But not nearly enough to make for clear skys and smooth sailing.Before you know it the day will arrive.With the ******* at your side.And he wont let you go till he finds some reason to give you what he pulled you over for in the first worst place.Or used a lame one.You had best keep wishing or maybe thinking your fine.When all I do know is this.I see you have a license plate.Which is the only way around it.As long as you have a motorcycle operators license to go with it and insurance.At least that is how it is run here in Arizona.Dude they will pull you over for any damned reason! When some will make one up ok.WHY? Why not when this is all about $$$$.That you wont get without a ticket and more can only get better.And not every cop is bad with engines.When if I was one Id be your worst nightmare.I know right off by a quick glance about what cc to cubic inch it is or is not.And I know theres afew cops just like me.Years ago I got nailed by a DPS officer while riding back to my cabin from flagstaff.With a friend on back of my KZ 1000 a old super bike type.Cammer header etc At the time there wasn't much that would beat it.I was doing 85mph when then it was 55 limit.I came around a mountain curve and seen him in the left interstate lane in front.And he not only seen me but knew I would be speeding.LOL **** the bike looked fast standing still.So he slowed down and crossed over to the north bound lane and took off.So did I get back to 85 and before I knew it there he was right behind me!When I walked to him,he told me you didn't expect me to pull that one on you!Why I did was when I had to as your bike will out run this car.It would but not with me on it and it wont out run your radio!From there things got better as he was a nice guy.Like most want to hear something honest and senseable.He told my cousin you come here your getting one too! He tried telling him it wouldn't do the speed my bike was.The cop laughed and told him the year and exact model of his bike.Then he told him the top speed it would do.So there it is for anyone that ether wants to believe it or not.Thats up to you.All I know is I don't want to get pulled over and when I do.I don't want to be telling anyone what I well know better not to be true.Starting with the complete look of what I'm riding will tell anyone with four brain cells.Im full of bull when you cant buy what I'm going to build.And being a street cop they see plenty of them.And not one at all like mine.LOL it will look faster than it really is.When Ive decades of all types of hands on working knowledge for building all types of things that all pertain to go fast vehicles of different types.From engines to metal fabrication and custom paint etc.Except on this build the only thing to see paint will be the engine.As in block and cylinder.The rest will be ether satin finished aluminum with all stainless allens or powder coated.Except the exhaust that will be all stainless.Not a straight pipe ether.
Reply With Quote
  #9  
Old 02-21-2017, 02:48 AM
engineman engineman is offline
Motorized Bicycle Newbie
 
Join Date: Feb 2017
Location: phoenix,az
Posts: 8
Default Re: Clearance problem on a 79cc..........

I don't follow you,when I said in my last email I believe.That there isn't any clearance problem with the 79cc.But there is on the 99cc so I was told and why the shop didn't like it and tossed it for this engine.I don't know the exact cam specs but close enough.Stock is 170 that's all the shop told me ok.As the duration must be the same less what was added for lift to the new cam.You do get duration in lift as well.When it takes more time to climb a taller tree.Along with the same to get back down.The bigger cam they offer is a 241 lift The head is the same you sent in is what you will get back.Only ported and milled if you have the 99cc you have to clearance the piston with valve relief machined into the required spots.Heres the good news for anyone with the 79cc.When this shop has done a real job reworking theres.And have punished it and dynode the mini beast.To get 6.5 hp from it.And run it long and hard without any problems.Theres is at 12.5-1 CR with there cam and 26 lb springs.Turns 7000 rpms Full port and polish and carb work.I know they are not running the carb I will.When no one is and why? They don't know is my guess.Then Ive my own way of how I go about doing things.When it comes to carbs and intakes.Its all about building velocity and getting it out the same way with a slight twist on the back side.In this case the other side.The only other thing I ever had with the engine in backwards was a old drag boatA howard flatbottom V-drive with a pro built big block ford.That I used for water sking and training behind.As I was in the south cal speedsking club.Sking behind a boat a lot faster than mine wasn't.It came my way oddly enough with the perfect gearing for all around waterskiing.As long as you didn't ski over 80 mph that is,.What it lacked on top end it more than made up for on the low end.One of very few boats that would pull out six skiers now!And still have gas pedal left over.Now as for a billet rod.GOOD luck when no one makes one for the 79cc.They told me they use the one and only it came with.So far so good.No doubt when my boat ran stock ford rods.And crank but then ford stuff is STRONG.Mt buddy ran the same engine as I had in my boat.In his monster mud truck with a bottle of laughing gas connected and used at every mud race.With exception of heads and pistons and manifold and he ran a single carb dominator.I ran twin 750 holley 4 barrels.With a set of heads that made anyone who knew what they were looking at FREAK out!As they were closed chamber with a radial port job.Which out performed the 427 heads I had to use later after those cracked.
Reply With Quote
  #10  
Old 02-21-2017, 07:59 AM
sbest's Avatar
sbest sbest is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2015
Location: Nova Scotia
Posts: 340
Default Re: Performance head for 99cc/79cc predator

Even a single 750 Holley is too big for the 99cc engine. You digressed!
Otherwise, great stuff in there. Paragraphs would make it easier to read.
__________________
That's a mighty noisy bike you got there, it must haul a lot of ass?
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 01:14 AM.


Sponsors

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
MotorBicycling.com