Downright Embarrassed!

[Immokalee]

I need some advice/opinions for setting up my Hammerhead GL150 (same GY6 as the GT model). I bought it new a few months ago and so far I have mostly ridden slow going rocky trails and hard pack dirt tracks. This past weekend I went to ride at the Red River just across the OK and TX border and was downright embarrassed! I didn’t get 50 ft out of the parking area and got stuck in the sand. I got pushed out and figured I would get a good run at it and try again. I probably made a good 100 ft for the next run and had to get pushed out again. I got turned around and headed back to hard ground, only to get stuck again before I got back to hard pack. I’ve read tons of info on changing weights, rollers vs. sliders, etc.. Instead of piece milling it I want to buy a kit. These are the kits I’ve found. Anyone have any experience with riding heavy sand after making CVT mods? What are the pros and cons of these kits? Any other good kits out there I missed?
KidNME Kit 150cc "CVT Upgrade Series" Level 2 - $123.49
DR2 Variator Kit, 1500rpm Main Torque Spring, 1500rpm Clutch spring set

MRP Kit - $99
MRP racing variator, weights, drive face plate with fan, high tension clutch spring.

Dr. Pulley Kit - $149
GTC Superfly Racing Variator
Dr. Pulley Sliders
Clutch Main Torque Spring, Red
Kevlar Belt (Optional)

Thks, Pat

[edroden]

I think you would be better served to get a spare set of sand treads to go on your ride!

[Immokalee]

I thought about getting sand tires, but was afraid my buggy wouldn't have enough umpf to make it worth the money.

[T3beatz]

The 1500 main torque spring and some lighter weight rollers are sliders will help.
If you already have a 39T sprocket installed, you will want to up the internal gear ratio... you can buy kits for them.
You will loose speed with these mods but you will gain low end power.
Also you will want to get a 1.5" Uni filter and ditch the stock airbox, you will gain a little extra Hp and will have to re-jet the carb (stock jet size is usually 115, you will have to go up to at least a 125).
Changing the CDI to a performance one will also get you a little more power on the top end, and get rid of the rev limit from the sock CDI.

All of these mods will cost you some $$ if you want them to.

[GX150]

Sand will easily take a third of your engine away from you. You need as much torque as you can create.

Gearing:
There are only two places you can adjust gearing. The drive gears in the final transmission and the sprockets. The 13/40 gear set was the best ratio that came with some buggies - SycArms may have an even better ratio for you to swap in to drop gearing. If you have an external reverse you will have 15-17t drive sprocket and you want the smallest sprocket you can fit. If your reverse is to the left of the sprocket, you will be able to use a 13t sprocket. Stock axle sprockets vary from 27-39t - The largest the sprocket that will fit without modification is usually a 39t, but some swing arm configurations allow a 42t to clear.

Engine Breathing:
Remove the restrictions in your intake and exhaust to make the engine flow better. Changing the cam to a long duration torque model A11 or A12 will help get the motor moving under load.

CVT Tuning:
You want get the engine to stay in it's peak horsepower curve by lightening the variator and stiffing the main torque spring. 12g slider weights will give the variator full range while keeping the engine in it's peak RPM. Using a red torque spring will drop the the variator to lower gearing quicker when you let off the throttle plus it will keep more tension on the drive belt. Running other clutches or variators in sand will not help you. Also changing over to heavier clutch arm springs will stress your CVT too much and result in component failures.

Tires:
The 150cc GY6 does not have much power, so paddles will hurt performance since it will have too much bite not be able to spin them. You are better off a pattern like the AMS Zipper or even a turf tread that float on top of the sand. Try to keep the rear diameter short, but the footprint wide. Our buggies are not like rails with light front ends - You want a tall and fat tire up front so it does not drag you down.

Ignition:
High powered coils and CDI's will not make much of a difference until you do the other modifications to allow the the engine to spool up more.

[Immokalee]

I appreciateall the responses. I will took look at the sprocket to see if its a 39t. I found some exhauset, cdI and other performace kits that seem to be reasonalbe in the $100 range. From what I read, it seems I will get the best bang for my buck with a cvt upgrade.. Does anyone know much about the Dr2 KidNME is selling? The concept sounds good.I want my buggie to be hill sand shredding mahchine.

[GX150]

I don't like the DR2 because it is a vented pulley. When the belt slips under load, it will shred on the vents.

[T3beatz]

In sand, with the 150 the low end is where it's at... so the DR2 won't make much difference over the stock with the correct size weights. I doubt that you will be getting up to speed with it... It's a great concept but price vs performance you might only gain a couple MPH on the top end (which you rarely see when trail riding).

[Immokalee]

Thanks guys, this is the kind of feedback I was hoping to get. Anyone have feedback on MRP vs the Dr. Pulley kits?

[GX150]

I don't have a high opinion of MRP mostly due to the the owner's personality and attitude. But because they rebrand many parts with their name without doing thorough testing or they over rate the parts they do sell without any proof, I do not recommend their products unless you can get them cheaply. I see MRP looking out for profit margin more than growing the sport which means using the least expensive parts at the highest markup with greatest advertizing hype.

[Immokalee]

I bought the Slider Weight 18x14x12.5G, and a 1500 rpm main spring for my 150cc Hammerhead and installed them today. I was sorely dissapointed when my wife took off in hers (same buggy) and left me in the dust on the take off. I could pretty much tell when I backed it off the trailer that I was going to get smoked, it bogged so bad coming out of the hole that I was ready to load it on the trailer and drag it home wih my tail between my legs. I plan on a ride this weekend and I don't want to be the one holding up the party. I followed the KNM you tube video and everything seemed pretty easy.

I weighed the stock rollers, which were 14g, the sliders I purchasd were 12.5g. My stock rollers are 14g. I marked the nut on the clutch when I took it off to install the main spring but I went passed that mark by about an 1/8" when I torqued it back down. Could this be part of the problem?

[roysheepdog]

IDK what kind of tires you have,but if they are chevron type you can swap sides and run them backwards.This will make it hook up much better in sand because it will act more like a scoop.

[Immokalee]

Well, I got it fixed. the belt wasn'r riding up when I rev'd he engine. I sent a video to tom at KNM and he was very helpfull. Tom gave me a few tips to check, which I ended up taking th cvt again and reinstalled the parts. I can definitly feel that it is faster out of the whole shot. I'll get to reallly test it out saturday morning.

[xlint89]

If you bought sliders, make sure they are oriented correctly. if not, that will affect perfromance drastically.

[Tosser]

Bigger sprocket