which cam is best?

[hugedodge2000]

Ive heard about all the different types of cams from the stock to a12. Which is best and what is the difference between them all? Low and high and what? BTW Im wanting a good low to mid end power cam. Thanks !

[xlint89]

Have you done the usual stage 1 mods first?

UNI filter, rejet, coil, CDI?

Have you done anything to your exhaust?

Have you done anything inside the trans yet? Main spring or different roller?

Installing a bigger cam without doing anything else isn't going to gain you very much.

A12 cams are really good for bottom to mid gains. But you must watch your RPMs. While lifting the valves more at high speed, you creat valve "float" issues and can actually bend your valves.

"float" is when the inertia of the valve's weight causes it to not retract back into the valve seat. Making it really easy for the exhaust valve to be struck by the piston coming up to Top Dead center. Stock springs are pretty weak and cause issues pretty quickly if you start to over rev the engine.

[hugedodge2000]

I have the UNI filter and new CDI box....Im gonna put a 30mm pumper carb with aluminum intake and put a race port and polished head on it and exhaust.....maybe get a 63mm big bore kit as well. Which Cam would be best with that setup. It doesnt have to be fast top end I just want it to climb steep hills. A little speed wouldnt hurt though

[BuggyMaster]

Beware on the pumper carbs. A reason to bump up the carb would be because the factory carb won't supply the engine with enough fuel. For an intake and exhaust mods, the stock carb has been sufficient for me. I've seen a lot of cases where people put on the bigger carb only to realize that now they are over-feeding it. Once the big bore kit and port and polished head goes on, this may be a different story though.

[SLESTAK75]

I love the way the experience of others here keeps me from buying things I don't need, like 30mm carb. My buggy came with a 58.5mm head and i'd like to get the 58.5 big bore to match. was considering an A-12 cam, UNI, intake, CVT tune, orange CDI and coil. I thought a 30mm carb was a must but noticed that many only rejet the stock. Seems #125 is popular. I already top out near 40mph and I just want more grunt. Seems like this will work for me. Thanks for sharing the good the bad and the ugly.

[toomanytoys2]

I would be very leary about putting a larger carb on the motor that you have now. A rule of thumb is that the larger carb will give you more top end, but losing a litttle bit of torque and responce down low. The smaller carb will give better torque and responce down low, but limit your top end. Right now I am running a 170cc BBK, PnP Big valve Head, A12 Cam (got from Tom), Uni Filter, Custom Exhaust with a modified TTR125 muffler, 10G rollers, 1500 Contra Spring, 2000 Clutch Springs. I am still running the stock carb though.

I built this engine to be as bullet proof and as user friendly as possible. When we go camping, approx. 10 or so familys go (mostly dirt bikes). I wanted a motor that could handle kids learning how to drive and just be sort of a who ever wants to drive it buggy (i did fab up a throttle limiter).

In testing it I have put the buggy in some pretty wierd situations, climbing hills without a running start. Driving down into canals (dry) stopping at the bottom, then climbing out from a dead stop. I tried to copy what a new driver or one less experienced might do to the buggy. It passed all of these tests with my 220lb carcass and my 12 year old son aboard. Also, it is still faster then the suspension can handle in the rough stuff.

I would highly recommend the A12 cam for good power in all a round driving conditions. However, I can only speak for the cam that I got from Tom. I have a suspision that not all cam makers use the same grind or quality.

Almost forgot, this engine is in a 2005 HH150. The other mods that I have done is to add "real" 4-point belts (3" lap, 2" shoulder), a passanger grab bar near the dash and Yamaha Blaster shocks on the rear (big improvement).

Good luck and happy motoring

[SLESTAK75]

That sounds great as my plans are to make a low to mid rpm powerband and go a few teeth smaller on the drive sprocket and set the CVT to shift slow.So more torque on bottom to mid is just what Im looking for. Thanks for the reply.

[SLESTAK75]

Just curious. If you keep stock carb with 24mm outlet do you really benefit from upgraded intake. I could see if it was just smoother inside but most I've seen are 30mm intakes. Wouldn't you still be limited by the 24mm outlet of the carb?

[toomanytoys2]

Yes, in fact that is sort of what you want. It would be great if everything on the intake track (port, manifold, carb) flowed the same. However, in a carb, the flow is relatively stable. It doesn't have to go around curves, or be split in half by the valve stem. So it is the porters job to try and balance out the whole system and not just to hog out the ports. If the ports in the head or manifold get too big, it can hurt the low end performance. That is why I stayed with the stock manifold and ported it. I did not want to use the 30mm manifold and end up with reduced intake velocity.

The really good head porters (I'm not) have spent years learning the dos and don'ts of porting and they get the big bucks for their work. I have just been lucky to know a couple who have taught me what to look out for and to understand what is happening within the head (intake, exhaust and combustion chamber). When I port, I don't try to get the maximum I can get out of the head, but rather improving the flow without doing more harm then good. In most cases, bigger is not always better.

[SLESTAK75]

I see. Port and polish the stock intake. Great idea and much cheaper than buying a new high performance. My wife LOVES this forum.......talkin me outa buyin all sorts of stuff.

[Johnny 5]

I had great success with my home port job on the stock dune 150 head. Christmas 2010 I borrowed my brother in laws dremill with a long bit a little bigger than a pencil lead in size. I removed the valves by putting a rag in the combustion chamber and using a socket to push the retainer down with a magnet in the center of the socket to remove the keepers. Wear safety goggles because a retainer keeper can take your eye out if it flys. I put duct tape strips on the valve seats to be safe. The intake spacer was offset from the head port so that was matched up first by opening the spacer to the head. The rough edges in the ports were cleaned up. Basically any bumps or flaws from the casting were removed. I left the intake port rough and polished the exhaust and the combustion chamber. To polish the port I used small pieces of red scotchbright pad on the dremill cut off wheel atachment. The scothbright pieces would not last long but got the job done. I didnt open the port diameters just removed the rough spots and smoothed out the transition and the back side of the valve area that was cut out and looked unfinished due to mass production of these heads. Lapped the valves with some compound by using my cordless drill and a piece of vacume hose on the valve. Not too much just enough to reseat the valves.
The first trip it made a huge top end difference and would pull all the way to max rpm.
Before the engine would flatten out at mid to high rpm.
I tried a 120 jet from a stock 114 and it bogged. Went to a 117.5 and ran perfect, with a uni filter and stock modified muffler with a little bigger tail pipe tip,3/4 inch.
I was willing to give it a shot because if the head got damaged it can be replaced for 50 bucks stock or get a performance head for about 100 bucks or more.

When we put the 39t rear sprocket on the blue dune it hurt the top end pull but would climb with 2 riders alot better.

If you dont feel confident dont mess with the head. I have been messing with small block chevys and dirt bikes for 23 years, the buggies for 8 years and have broken bent scracthed stripped cracked NOS melted pistons over built under built broken rocker arms and have had a blast doing it.

I cant leave a perfect running motor alone without modifying it for more power, or at least trying to get more power. My Dad would tell me that it was engineered by the manufacture and all I was doing was messing it up. Some times he was right, but not always.

Merry Christmas all you buggy builders and Jesus loves you.

[SLESTAK75]

I am the same way with guitar amps and CBs and appearently buggies now too. Dont know if Ill attempt my own P&P or not. My brother is a mechanic and I may get his help or i may take it to the vocational school and let up and coming machinist have a stab at it. Also shave off 10 thousandths for a bit more compression. Do you think that the 58.5mm bore kit will make a noticable difference??

[Johnny 5]

You can get a 58.5 kit with a higher copmpression piston . I put this kit on my red buggy and cranking compression went from stock 125psi to 145psi. Valve lash at .003intake and .005 exhaust. Made a good improvement but the port job was probally the most noticable. Also I tend to do more than one change at a time so the results are mixed together.
Before you do the piston kit I would get the 1500rpm torque spring and some 10 or 11 gram rollers. Scooter elements has a roller kit by oko with 12 different sets for 35 bucks!
That would be a great tuning tool for the money. Also if you like top speed keep the gearing stock and run 11 gram rollers. I have run 12 gram sliders and 11 gram sliders and keep going back to the 10 on the blue buggy. My red buggy has dr2 variator with 8/9 gram rollers and it hauls but but top speed is 31mph. I also got a A9 cam and am waiting for my stiffer valve springs before it goes in.
When you do the bigger bore kit measure the case opening because some 60mm kits will fit without boring, but the lower part of the sleeve is thin so beware.
I bored the case on the blue buggy this summer with a ncy boring tool and I will say it was not that easy because the tool would not line up the same every time and the power gain is worth it but a 58.5 or 60mm kit will work pretty good also.
Also remeber if you mill the head it will retard the cam timming a bit and could hurt the bottom end. Also the valves are closer to the piston. I had to shave off 15 thousandsth from the head on the 3mm stroker build becaust the timming chain was so tight the cam would not sit flush. I used a 1.6mm base spacer with 2 gaskest to get the piston to sit
.025 down the hole. And the first 62mm kit I got the piston was crooked, measured .015 on the chain side of the piston a .035 on the other side. I found a piston for 35 bucks on ebay and fixed the problem. The compression was 155psi and was slow to crank over.
So every major mod can have its problems. I Put a A12 cam in it and opend the combustion chamber a little more for the 62mm bore and the compression is now 145psi.
Now the motor runs strong compared to the stock cam. Just waiting for the valve springs for both buggys before we test them in the desert. Will find out if they stay together next month. I can only test drive down my street that is only about 50 yards or less. I have run it down the main street but am worried about getting run over.

[SLESTAK75]

I actually just got my 1500 contra spring yesterday and I had planned on getting the a12 cam. So maybe ill skip the shaving on the head. Mine came stock with the 58.5mm head on it so i figured the matching bore would be nice. I know alot of people do the larger bores but I really dont want to bore the block. Although 180-190cc's would definitly be sweet. Thanks for the replies. Ill probably get my clutch and cvt back together later today. Then just waiting on my chain to get here. Then ill test it with my Garmin.

[toomanytoys2]

If you feel confident at all with a dremel and sanding drums, I would match port and polish the intakes and exhaust. I am stealing some quotes from johnny 5, bur a little out of order.

"The intake spacer was offset from the head port so that was matched up first by opening the spacer to the head. The rough edges in the ports were cleaned up. Basically any bumps or flaws from the casting were removed. "

You can use a dremel with various sizes sanding drums for this.

" I didnt open the port diameters just removed the rough spots and smoothed out the transition and the back side of the valve area that was cut out and looked unfinished due to mass production of these heads."

This alone can make a huge difference. There are usually a lot of flash and casting inperfections that can mess up flow.

"I put duct tape strips on the valve seats to be safe." You really want to do this. sometimes the dremel will try and get away from you or chatter. The sanding drums will not usually go through the duct tape, so it protects the seats really well.

Have fun

[SLESTAK75]

I watched a video on it earlier and think I might just give it a try at some point in the future. I can see where this could be a great benefit.

[SLESTAK75]

So I got my new chain and all is back together and tested with the Garmin today. I only have a short flat area and was able to get up tO 30mph there. 27 up a slight uphill and 39 coming back down and held at 37 on the flat. Orderd my a12 cam and should have it in by the end of the week. I have a 1p57qmj engine but it came with the 58.5mm head on it and i think they put the regular height head on it. Ill make sure when I put the cam in. Then Ill do more testing.

[SLESTAK75]

My concern with the p engine is if the head is taller will standard valve springs work on it. I would like to better springs on it and maybe stainless valves.

[Johnny 5]

I dont know about the p motors but just make sure it turns smooth by hand after cam installation.
I put a A9 cam in the red buggy with the ncy 11k rpm springs and the inner spring would
bottom out causing it to bind. I was rotating it by hand and noticed it was binding at max lift on the intake and the exhaust. The a12 cam works fine in the blue buggy with the same ncy valve springs.

What I found was the A9 cam I got is ground 1mm smaller than the A12 when you measure the width of the cam lobe, The A9 is 20.47mm on the intake and 20.12 on the exhaust when you measure the smaller profile of the cam. The A12 is 21.50 intake and 21.03 exhaust. Almost a mm narower causing the max lift to be more on the A9 due to the rocker arm following closer to the cam.

The cam lobe on the A12 I got is 27.30mm intake and 27.00mm exhaust. The A9 is 26.90mm intake and 26.80mm exhaust when measuring the widest ponts.

I was confused why the a9 was maxing out the spring being a smaller cam. But when I put it in the rocker arms had to be adjusted almost a full turn in to come in contact with the cam. So after measuring the cam lobes I found the 1mm smaller diameter put the rocker arm at a different angle causing more leverage I guess. I was able to send it back and am waiting for another A12, should be here on Friday the night before we go to the desert.

I always wait till the last minute to get stuff ready for off roading.

[SLESTAK75]

Thanks Johnny. I had planned on spinning the crank and checking for bind before replacing the valve cover. Ill have to run the stock springs for a while. I was looking at the posted set of springs and valves but noticed they wouldnt work on the "p" engine. Makes sense if the head is taller the valves would be longer. Again though I think the 160cc head that came on this buggy is the standard size. Ill have to check when changing the cam so I make sure to order springs and valves that work. Ive seen some posts on other forums that said the spring seats needed ground down a little on the p engine in order for anything more than a stock lift cam to avoid coil binding. Don't know how true this is but would love to know. Im just going to test and see. If I dont like the test results Ill pull the a12 till I figure something out. Thanks for the reply and hope you get your cam in time. Hate for you to have to go stock to the desert.

http://item.mobileweb.ebay.com/viewi...id=61957468747

[SLESTAK75]

Alrighty then. I got my a12 this afternoon and got it in and ran it for a few minutes. Still gotta get the shroud buckled down and get the fan back on before I can drive it. But just taking quick jabs at the throttle and slowly increasing rev to top rev the engine REALLY seems to like that cam. It revs higher and the throttle response is a major improvement. This is with stock springs. I didnt want a high rev engine anyways so I will stick with stock springs unless they need replaced for some reason. Save some wear and tear on the val es and seats. Ill get it together tomorrow and take it for a ride. Cant wait.

[Johnny 5]

Good job, I noticed a big performance gain at take off and mid range acceleration. I also have a mini tach/ hour meter that my wife got for 30 bucks it is a TTO brand. I found the 183 stroker motor would run best below 7200 rpms. This trip we will find out how the A12 cams work in both buggys, we will keep the rpms below 7500 if possible.

The first thing we noticed when we started the buggy was the chop sound and valve noise. The chop sound is from the exhaust and the valve noise is the steeper cam angle I think.

If you dont rev your motor to the moon the springs will work, for me its hard when your hauling and dont want to get out throttle thats why we got the ncy springs.

You could get titanium retainers to lighten up the valve assembly.They are about 45 bucks and I was going to get them but got 2 sets of springs for 36 bucks instead.With two buggys to feed it made more dollar sense to get springs. Work is a little slow so got to watch the cash flow.

I am not sure if your valve retainers are the same as (157qmj) but this might be a good for your situation. The lighter retainers will make up for the stock spring a bit.

Have fun.

[SLESTAK75]

Thats a good idea. Also gives a bit more security. Mine came with a 58.5 head and bore. They called it a 163cc. All of the 58.5 heads I have found were "racing" heads and had the stainless oversized valves in them. And my buggy was called the "racing" go kart. So I've been wondering about what I really have in there. Granted I didnt have it under load but I slowly increased the throttle to WOT and it got to screaming without missing a beat. I want to look at P&P the head so Ill find out for sure at that point. Ill post later how she does today.

[bear]

All indication from my tax account lady are that I will be getting a "very nice" return this year! If so I'm gonna divert some of that college money into at least one awesome buggy engine upgrade!!! boh-hahaha

[SLESTAK75]

@bear. TURBO....FUEL INJECTION....BLOWER....?? What what do tell!!!!!!
@johnny. I did get some backfire out the carb at WOT with the airbox off. Will test a bit later with all back together. Ive got a 117 jet stock in it and it always seemed to run rich so maybe it will be good now or I may need a larger jet.

[bear]

My blue one is all stock, so its my canidate! maybe the stage one kit and a p&p head with different cam and exhaust, nothing too crazy! then possibly a cvt upgrade? this one is the one my daughter rides the most and if someone goes riding with me they usually take it, I'm Partial to my red one, it has a little more low end grunt to it, but that could all change!?

[SLESTAK75]

I should be getting my 11g sliders today so all in all I will have 1500rpm contra,11g sliders,drilled out muffler, drilled out stock airbox, 117 jet, a12 cam for now. I will in time get pod filter and pvc velocity tube, cdi and coil, not sure of gearing in transmission but the sprockets are 16t/32t so I have speed and not much grunt. Will soon p&p and stainless valves titanium retainers and nyc springs, 58.5mm bore with high comp piston. With that Im hoping it will make enough power to satisfy me with no regearing. Although Im going to see if vocational school machine shop can make me a 13t and a 19t drive sprocket so they can be changed out pretty easily for hills or flats. Then I have 3 gears to choose from.

[bear]

Both of mine seem to have plenty of low end to them, I've yet to have been anywhere that has overly"challenged" them! although one area I go to has some pretty deeep sand and that definitly takes the power away from them! I just want to start doodling with them like the rest of y"all. I know my red one has a aftermarket exhaust and rejetted carb, but other than that they are pure stock and all I've done so far is change rings in them both!

[SLESTAK75]

The way mine is geared right now it has very little low end. But it gets up to around 40mph. Feels faster with a12 cam but havnt checked with Garmin yet. Waiting to put 11g sliders in. Just got them today and its raining. The short ride I took yesterday showed me that the a12 really made a difference from low end to top speed. Im quite happy with it.

[jmansracerocket]

I have the a-11 cam and like it, I use 10 gram rollers with it topping out at 35-36mph still have to port my own head I think im going to mill it .030 also

[xlint89]

Originally Posted by jmansracerocket

I have the a-11 cam and like it, I use 10 gram rollers with it topping out at 35-36mph still have to port my own head I think im going to mill it .030 also

Be REAL carefull with doing this.

The ex valve comes pretty close to the piston with the A11. Shaving the head will only make it that much closer to contacting it.

And with light weight rollers (I say 10's are light because my yerf came with 14g stock) your WOT RPM will most likely be higher if you're using a CDI with raised or no rev limit.

Couple that with weak stock valve springs, and you have pretty good chances of floating a valve on a WOT run and causing damage.

Just giving you a heads up......

[SLESTAK75]

I thought about shaving the head at one point but I am now leaning more toward a lighter high compression piston.

[jmansracerocket]

thanks for the advice xlint89 im trying to look for titanium valve springs and stainless steel valves that way i can port the head then and mill it and be safe then

[SLESTAK75]

I did get to measure the height of my head and it is not the tall head. It is standard height so the titanium retainers and stainless valves will work. I am getting backfire at WOT so I see I need to get a larger main jet. Seems like the pilot is just fine but hard to say because I cant really ride enough to get an accurate read on the plug.

[SLESTAK75]

Originally Posted by Johnny 5

Good job, I noticed a big performance gain at take off and mid range acceleration. I also have a mini tach/ hour meter that my wife got for 30 bucks it is a TTO brand. I found the 183 stroker motor would run best below 7200 rpms. This trip we will find out how the A12 cams work in both buggys, we will keep the rpms below 7500 if possible.

The first thing we noticed when we started the buggy was the chop sound and valve noise. The chop sound is from the exhaust and the valve noise is the steeper cam angle I think.

If you dont rev your motor to the moon the springs will work, for me its hard when your hauling and dont want to get out throttle thats why we got the ncy springs.

You could get titanium retainers to lighten up the valve assembly.They are about 45 bucks and I was going to get them but got 2 sets of springs for 36 bucks instead.With two buggys to feed it made more dollar sense to get springs. Work is a little slow so got to watch the cash flow.

I am not sure if your valve retainers are the same as (157qmj) but this might be a good for your situation. The lighter retainers will make up for the stock spring a bit.

Have fun.

So I see from the album you are back from the desert. How did the a12 cams work for you? Ive not gotten to do much with mine. Rain and even snow here for better than a week now.

[SLESTAK75]

Obviously the a12 didnt get you up that one hill. But I see it created enough torque to flip the buggy over.

[Johnny 5]

We didnt go yet, those are old pictures from trips over the years. I wanted to post a picture of the chain tensioner for bear, and put up some old pics.

We are planning to go this next weekend the 26/27/28 if the weather is good.
Last weekend it got down to 28 at night and a high of 55 with a possibility of high winds.
Not being wimps because of the weather but my son who has downs/autism dosnt do well in the wind and cold.

I did swap out the 39t sprockets on both buggys for the stock 31t. They feel slow on take off but will help our top speed and possibly keep the motors a bit cooler.

The 39t is like my 68 chevelle with 4.10 gears and a 8 inch 4200rpm racing converter.
Great for take off and seat of the pants acceleration but cant keep up on the freeway.

The 31t slowed the hole shot but will help our cruising speed.

With a small engine you give and take, I love the results with all the changes because it dosnt cost a arm and a leg like parts for my chevelle.

Will give results with a12 cam and ncy11k springs after trip. (GOD willing)

[SLESTAK75]

I can understand about your son. I have a cousin with autism and my neighbors son has the most extreme case of autism. He can be violent at times. That being said you are close to my setup now. I have a 32t sprocket and 16t drive from the reverse. I think the sand is going to eat up alot more of your power now. I thought of putting higher rev clutch springs in mine to help the takeoff a bit. I can say the a12 helped the bottom end quite a bit on mine. Still need to rejet the carb. The weather here in Virginia has been down right pleasant. We just had our first taste of winter a few days ago. Snow and cold and then right back up in the 60's yesterday.

[bear]

Well winter temps "kicked the door in" here 2day!!! brrrrr