Not enough power for hills and trails
 

Been trying to hit the trails, which in my area have quite a bit of steeper hills. My buggies just bog out and can barely make these long stretches and feel like I am going to overheat it and blow it up. Many times either have to turn back or have the other person get out and push. Smelling clutch.

The pistons and heads are stock.

Added aftermarket see through exhaust

Koso clutch and air vented bell with ridges

Stock carb with 125 jets

Irridium spark plug, orange coil, no rev limit cdi, redneck style intake

New performance chain

Clutch details: 1500 larger contra spring (yellow), 3 red clutch springs 2000

Variator: Had 12g sliders, now have 12g rollers.

Any advice would be appreciated. Would a big bore 61mm ncy, matching head and a 3mm stroke make that much of a difference? Is there anything above that you would suggest changing.

Considering the a12 cam as well.

Cam... all day long. A12-A14 depending on whether you still want a high top speed.

I run a A13, has great low end and MASSIVE midrange to help me climb. It accelerates to 25 very rapidly then slowly pulls to 30 in the first 100 yards or so. Haven't done a top speed run because going more than 30 isn't important. I need the power for hills, getting through deep mud and hauling lots of weight. While it seems to run kind of higher RPMs at low speed compared to stock, it doesn't have the power to keep pulling at high speed so it kind of settles at comfortable medium at speed. I'm running a 1500 torque spring, stock clutch springs, 12g sliders, unifilter, afternarket muffler, rejetted carb.

Also, your clutch springs being 2000s may be causing a lot of engaging/disengaging if your doing a lot of on/off throttle. I do a lot of tooling around at low speed so it wouldn't match with my driving style. I'd be slipping the clutch constantly. If your smelling the clutch/seeing smoke come from your CVT vent, it's a possibility. I recently replaced my belt and noticed the new belt was substantially tighter than the old one, despite then being the same size and might be worth inspecting.

I had 13g rollers stock and went with 12g sliders as a single mod so I could feel just the one change. I thought it helped hold me in low better than the roller by a large amount. I don't know if a slider would give superior performance to a roller given the same weight. Some things I read made it sound like it could improve both low and high end.

In recap, A12-14 cam, possibly open your CVT and check the clutch and belt condition. Read your plug again. Im a touch lean running a 130 near sea level. Cams are cheap and easy compared to the other stuff you mentioned. Try that definitely before you go further.

Thanks Charles,

My name is Charles as well. :)

I was thinking before an a12 cam as well. It will be interesting to see how much it changes over stock. Do you know what is the typical stock cam in a buggy?

it will be interesting to see the difference. Is it difficult to change with the timing and all?

I had the 12g sliders but blew them up when my belt was destroyed after a big climb. However, it did seem much better at climbing than 12g rollers. Should have put 10g rollers I think if was going to do rollers.

My belt (Kevlar) did seem tight. Seemed to work properly but not go up the ramps all the way.

When using sliders, is it ok to use them with lets say a Koso variator or does it need to be Dr. Pulley?

I am building another engine that has NCY 61mm (need boring) ceramic coated and 60mm ncy heads. Will be interesting to see how much it gains.

Considering with that build a 2.5 or 3mm stroke as well.

Charles

Not knowledgeable about the difference in variators, but so long as the weights are the right size, they'll fit and they're not brand specific.

I don't have links available, but there are a few very detailed links on the web showing the difference in the A8-A14 cams and the stock, to include their lift, duration and power over their RPM range. You'll see where the A13 specifically has some guts at low RPM but is 1-2 HP less at higher RPMs than some others, owing to why my buggy won't keep pulling. It doesn't have the power to pull for high speed. I may try an A12 one of these days... I've only been running the A13 for a couple months.

Plenty of vids for the change. Honestly, for me it took me longer to pop my seat loose for more room to work and take the plastic covers off the motor than do everything regarding taking the valve cover off, loosening the bolts on the rocker, loosening the tensioner and swapping the cam. YouTube has a few very good videos. Just check your timing and as an idiot check, I always bar an engine over to make sure valves/pistons aren't hitting. You can turn these just from turning the engine fan easily enough. Do it cold so your valve lash is set perfectly on the way out.

Found a link... has some good info.

http://www.dansgaragetalk.com/topic/...gy6-camshafts/

I read somewhere changing to a good uni air intake, make a big difference for them, in the climb area. Not sure what you got.
I ran a A12 for years. I don't know if made much difference, but run the hills just fine.
If your going up and down hills a lot. 10G rollers, will give you best low end power, and keep you there. Wont affect the top end, but will take a little bit, to get there. What I've been running for years.

I recommend 10 gram rollers if ur looking for more climbing

Big valve head with big ports and a camshaft will wake the buggy up big time.

Thanks.
I have an ncy 61mm big bore and 60mm ncy head that I have not built yet. However was getting doubtfull I could ever get descent power out of gy6150 as I already put on better muffler, coil, cdi, irridium plug, redneck air, 12g sliders, koso clutch and variator and jetted 125.

Was so discouraged having to turn back from hills. Sounds though that I need to toss the 2000 springs for the 3 1500rpm. Install the a12 cam and do the big bore.

Do you all think if I did the 61 ncy bore in cyl. 60 ncy head, a12 cam, port and polished head and a 3mm stroke will drastically make a difference?

Do you recommend stroke, no stroke, 2.2mm, 2.5mm or 3mm?

Do you believe in changing out the 24mm carb? If so for what?

Our riding has lots of hills, powder dirt, mud and we average 300 to 325 human weight as we ride double.

Thanks

The cam will make a difference. I can't speak forgoing big bore as I'm still running 150cc, but it should. I was given the recommendation when I needed to do my rings from.some smoking that, since I wasnt looking to spend a lot, to just do rings/piston assuming my cylinder was good and do a cam. That's all I did to great effect.

Going bigger carb will generally lose low end slightly to gain high end slightly, more flow at a lower velocity. Again, I'd verify you're not lean running the 125. It may help if you have more displacement but 24mm seems fine for 150cc. The head work would probably make the most difference, from all I've read.

Those must be some big hills... Ive got some big retention pond hills around and mine will just chug up them w/no problems and zoom up them if I goose the throttle. For the money, I'd still check your jetting, go with an A12 and maybe step down a gram or two in your rollers. Running a larger sprocket will lower your gearing as well and provide an instant improvement in torque while sacrificing some top speed. I've run 500+ lbs between people and cargo and it struggled and had to be revved out a bit and struggled up some moderate hills. Done the same running around weight-wise post new piston/rings, belt and cam and it was easy going. I have to believe it's mostly cam w/a small bump from higher compression. I can do what I did before without having to really rev out the motor.

Does your engine seem to running right otherwise?

Yep, to my surprise all the riding in our areas have alot of hills. I would say 15% grade for long stretches.

I have two of these buggies identical and they run pretty much the same. However, one of them when I had the 12g sliders did much better than the stock buggy until I changed to 12g rollers.

I am going to get the a12 cam , put in 12g sliders and change the 3 clutch springs to 1500 from 2000. I will post what the outcome is.

Good deal. Will be looking forward to the outcome. I've got the 12g sliders now. I actually got ahold of some cheap 14g sliders thinking the next time I go in the CVT I may try those to see if I lower my crusing RPM a bit since power isn't an issue. I've resisted the urge... I'm so close to perfect for what I do right now, I think changing things will be diminishing returns. I do think an A12 is in my future... as I think it might be worth losing a touch of low end to gain back ~1 hp and the desire to pull another 1000 RPM at the top. Based on the power curves, my power drops after around 7000 RPM or so. On the flip side, I don't think I could practically ever blow my motor though, as long as I'm in gear.

By most of my research it seems that buggies do best with cam of a11 or a12 with most being a12 for all around power. It is the one thing I have not changed.

One thing I did and suggest for cooler cvt is to cut the rubber snorkle backk and attach vacuum hose to it with a hose clamp and run the other end higher up for cleaner fresh air. You can then put a filter on the end. Perhaps a scotch brite pad cut to fit.

like i said before try the 10 gram rollers. it wont add power or tq but it will help. the 2 seater buggies are heavy for a 150cc, unless its a spiderbox frame lightest of them all. Do the head and cam with the 10 gram rollers. Ride that for a while if still not enough then try for a big bore with a stroker. If that's still not enough then do a engine swap lol.

jmansracerocket

I agree. The 10g roller and the 12g slider I understand are similar in performance. I had the 12g slider and it did better but just not able to hit these hills.

I think I am going to stroke it with either the 2.5 hoca or a 3mm. The big bore I have is the 61mm and 60mm head.

If after this big bore and stroke, it does not make this come alive with power to climb and get some real offroad fun, I have to bite the bullet and start looking at the trail rzr.

They make lighter sliders too... 10gs might be worth a try. If you look at the charts, those cams add upwards of 1-2 hp towards through much of the RPM range, favoring either the top or bottom depending on what is picked. You've still got your actual sprocket as an option to change to lower your overall gearing. That'll absolutely raise the torque going to your wheels.

Charles,

I do have a Chinese a12 cam that I am going to put in and see how it performs.

I have three of these buggies. Being I already have most of the parts to build up an engine, I will install them and see what it can do. If it gains me enjoyable power to do all that I would like it to do, I will build all three the same way. If after this first one still does not perform, I guess I best consider selling these off and going with two rzr trail utvs. Hope the buggies can fit my need.

So, I will update you when I put the cam in.

Next state is to put in a 2.5 Hoca stroker
61mm ncy cyl
60mm ncy head
Have the heads ported and polished.