strange noises from gear box on 150cc

[mr.b]

well i got bit by the buggy bug hard bought a 1502r maxxam made a ton of repairs got it running great was out riding today an was trying out new hillclimb way tosteep i might add 75yds. 35 to 45 deg. slope an short attack run made a couple attemps an then a loud grinding noise fron gear box motor revs. up i let off revs die down an the clunk it goes back into gear i put it in rev. get off hill ride it round everthing seems ok go back to hillclimb make it this time barely go round track up steeper hillclimb 50 to 55 deg. slope but can hit bottom at 3/4 of top speed make it spinning all the way up go round to new hill an it pops outta gear an grinds again let off clunk it goes back in an drives like nothing happened whats up with that iam new to this type drive train also when pulling hills as buggy bogs down i hear a loud clunk will do it several times on longer hills like its trying to down shift i run stock varitor with 11g sliders stock clutch with stock springs kevlar belt home made red neck uni an stock exhaust i am very impressed with this things ablity to carry my 6'2 190lbs butt up these hills an go 30 mph on flat ground if anybody can help i would be very thankful an i know i will post video asap lol thanks

[mr.b]

also running no rev limit c.d.i. an hotter coil

[tmsandk11]

Do you have reverse?
Your cable maybe out of adjustment.

[GX150]

Snap a picture of your reverse unit. You may need an additional keeper spring to hold it in gear.

[mr.b]

yes it has reverse an yes it is adjusted an its a new cable everything has been working great as far as the gearing goes up till yesterday when i tried to go up new hillclimb it was like it popped outta gear or stripped a gear had that happen in reverse before when cable was out of adjustment but not ever happened before going forward

[tmsandk11]

if it is an external gearbox there is a 23mm nut in the middle mine came loose and caused this problem. if there is any gap between the outside cover and the engine this can cause the same problem, Climbing hills.

[mr.b]

thanks tmsand i'll go check that

[mr.b]

checked nut it is tight i dunno i changed back to 14g rollers took out 11g sliders an it seems to pull better went up new hillclimb half dozen times today an it never popped out of forward gear an shifting on clutch is more quite an smoother

[x-bird]

sounds like the change in the range of the power transfer with the sliders is more than the gearbox can handle --- helper spring like GX mentioned may solve it and let you use the parts you paid for.

[SYCARMS]

The 11gr sliders in a stock variator compares to 9gr rollers. But this is not your problem. You will need to pull the rev box and inspect the splines on the final drive shaft, if good then if not done already disassemble the rev box and clean out all the hardened grease, inspect the fork spring, sun gears, check that the bolts holding sprocket to rev box have nor sheared. Pack rev box with a good quality moly/lithium grease. If the fork spring is weak or broken the gears will disengage under heavy loads, or if the grease has hardened it may not be letting the gears mesh completely, bad gears will cause this as well. If the bolts have sheared in the sprocket you should know for sure after a couple more rides for this just happened to my son's buggy. He would climb and it seemed to pop out of drive, let off the gas and everything was normal. He rode it the next 2 days on flat ground and even drag races a half dozen times. It started poping when we drove it on the trailer. The next time he drove it it went into neutral, towed it home and found all the bolts sheared 1/4" from the threads.

TOM

[mr.b]

thanks sycarms but thats not what i wanted to hear lol sounds expensive but i need to pull it anyway buggy sat outside for a year or so without running so it needs to be cleaned an greased but as far as rollers vs. sliders can u tell me why an 11.5g slider acts like an 9.5g roller an why would my buggy pull better with the 14g rollers vs. the 11.5 slider from what i been reading lighter weights mean better acc. an more pulling power don't know why this is not the case for me thanks again

[SYCARMS]

The only thing that would be expensive is if the rev box gear is tore up. The planitary gear can be replaced, but if the stationary gear is bad you will need the complete rev box. Nothing else besides that is too expensive. You need to tear it all down and inspect before more damage if any is done.

As far as rollers vs. sliders go. Here is the readers digest version. On a stock variator and even some performance it requires less energy to slide as compared to rolling, this is why if you have 12gm. rollers and replace with 12 gm. slidders the slidders will climb the ramp quicker then the rollers thus acting like 10gm rollers. The cvt can be tricky to tune to the beginner for several factors are figured when tunning. If your engine is stock your 11.5 slidders will act like 9.5 rollers. Since it taked more rpm and energy to move the lighter weights up the ramp your engine will peak its power much sooner. To move a lighter roller up the ramps requires more power from the engine. The maximum output power of a stock GY6 engine is 7500 rpm, after 7500 rpm the engine will not make anymore power. Also if your torque spring is worn it will allow the belt to fall too quickly in the clutch pulley. This is why most will when tunning the cvt replace both weights and torque spring. To pinpoint your power loss is difficult since there are several variables to take into account. Now one thing you will need to check depending on what year buggy you have is: Carter in 2004, 2005 and some 2006 buggies come with a final drive gear ratio of 2:70. This made for a fast buggy on strait flat ground but on any terrain performance went to h@ll. It did not matter what cvt upgrades you done. Sometime in 2006 they replaced the final drive gears to 3:08 ratio. Its worth checking this out as you do your inspection. When you pull the clutch there will be about 6 8mm bolts to remove, to remove the final drive cover. What you will do next is count the teeth on the most rearward gear, it will slide on a splined shaft, and also count the small gear that rides against it. Divide the small gear into the large gear and this will give you the ratio. If the numbers are smaller then 3:08 you will need to replace those gears to increase your performance. About a month or so ago I had a customer check his gears on an older Carter and he had a 2:15 ratio. I sold him a set of 3:08 gears which he was reluctant to purchase until I told him I would return all his money if it did not improve the performance. Well I did not have to refund the money since he could not believe the difference the gears had made. So check out those gears while you have everything apart.

TOM

[mr.b]

thanks tom now i undrerstand better will tear rev. ass. down this weekend an also count those teeth on the drive buggy has not popped outta gear since changeing back to 14g rollers but i still wanna find out why it did with the 11.5g sliders i liked running them the acc. was much better with them but i need pulling power lots of steep hills here thanks again. Bryant