Hustler 950 running slow

[Dino]

I have a hustler 950 with a 20 hp Briggs engine and t20 trans. Top speed is about 7 mph. Belt is fine, chains are tight, spark plugs are new. It seems to be choppy turning as well. It also seems to run smoother and faster in reverse. Anyone have any suggestions or have had similar issues? Thanks

[Dino]

One more thing - the RPM's are getting up. In other words at full throttle and the rpm's up it is still only going about 7 mph. Belt is relatively new and has the typicaly 1" to 1 1/2" deflection midway between. Could this be a clutch issue? Previous owner replaced an 18hp Briggs with this 20hp I/C twin engine. I don't think it ever did run correctly since he installed it. Any feedback would be greatly appreciated. Thanks.

[racerone3]

I would start out with a band adjustment. do a search for "band adjustment" and start reading posts till you have an understanding of how its done

[Dino]

Thanks for the info! I read up on adjusting the bands and received some info regarding the plungers. I noticed the top/bottom plunger on the right side were sticking out about 1/2 inch and they were not responding to pushing or pulling on the right lever. I took the U bracket pins off and was able to push the top and bottom right plungers in with my finger. I adjusted the bands as instructed with an in/ft torque wrench and homemade adjustment tools. I just used two finish nails that were about 5/16" thick and held them and spaced them together with duct tape. It seems to me the purpose of the adjuster tool is to keep the 5/16" space between the t20 and the u bracket bars and also to give you the clearance needed to maintain the socket on the bolt head. I am not sure, there may be more to it than that. Anyway, when I was done the right top/bottom plunges and lever seemed to work in line with the left counterparts. Top/bottom right plungers were recessing about flush with the openings and responding to push and pulls on the right lever. So I thought I was onto something. However, when I started it up I noticed that even thought the right side plungers were moving in and out, the vehicle did not move, it actually moved very little with the lever pushed all the way forward. However, pushing just the left lever forward caused the vehicle to move forward. So now I am thinking there is more to it than the adjustment. I reviewed the t20 rebuild in the "how to section" of this site. It seems very detailed. I consider myself a pretty handy guy, but I also know a little knowledge can be dangerous. If I crack this thing open how much work can I expect? Will I be replacing bands or can I assume I will be replacing drums and bearings and whatever else? will I need to purchase any "specialty" tools. The left side of the transmission seems to be working fine. Can I just take the right side apart and diagnose and fix this side? or do I need to take the left side apart as well?

[racerone3]

now that you know the procedure, it's time to cheat. run each bottom plunger bolt in 2 turns and try it again. don't put too much stock into how far plungers stick out of the case relative to each other. also look over all your linkages and make sure nothing is keeping the bands from fully engaging. does everything work in reverse? if it all works in reverse, then bands aren't broken.

[Dino]

That worked! Thank you! Both levers work forward and back. I still can't figure out why speed is maxed out at around 7 mph. I say 7 because I am just a bit faster than my son's 5 mph ride on. Engine rpms are up, belt is tight enough. Maybe there are some issues or adjustments that can be done to the 20 hp Briggs and stratton I/c engine?

[ARGOJIM]

What is up?

What size tires.

[hydromike]

Also, are you sure the clutches are cycling through their ranges under load (when you drive it versus watching them when the machine is at a standstill)? You could have a sticky primary or secondary or issues with the rollers in the primary.

[Dino]

I see the clutch (attached to the t20 with the spring) closing as I give it more gas while driving. however I don't see any difference in the chain speed coming off the t20? I think I need to learn how the clutch works. Do you know of any online literature or videos? Must be the clutch. Engine runs fine, I just put new plugs in. Also, reverse seems to be a little faster than forward. Thanks for all the info.

[TravisW]

I'm not 100% sure but the spring inside the driven clutch might be worn, as far as I know those clutches are torque-sensing, so if the spring is worn it might not be engaging all the way. Or like hydromike said it could be an issue with the rollers in the primary. Unfortunately your guess is as good as mine when it comes to finding literature, knowing the model of your clutch(es) would help a lot.

[hydromike]

Take a look at the video Buggyman shot of his CVTs cycling through their range on his big Max II. http://www.6x6world.com/forums/transmissions/25160-cvt-test-run.html

The drive belt should run all the way up the shoulder on the primary clutch when the vehicle reaches top speed. If you can't safely watch it while driving, take a black marker and draw a line on one of the drive clutch sheaves from the top of the belt to the outside of the clutch. The belt will wear away the marker (or at least some of it) during its cycling. If you still have a lot of line on the clutch sheave after a test drive, it's likely that the drive clutch is restricted in some way. If you're only running 2 out of 3 rollers for example, the clutch won't cycle through its range.

[Dino]

That is it. The primary clutch is only closing about a half inch at most. after looking at it more carefully the secondary clutch isn't really moving either. I believe the secondary clutch is triggered by the primary? Seems like the rpms are high enough So I don't think that is an issue. The primary clutch is a Comet Duster. Any advice would be greatly appreciated.
thanks.

[hydromike]

Advice? Take the primary clutch off and disassemble it to find out what's wrong. It might be that somebody just threw that clutch on the machine and it's not calibrated for this application whatsoever. The Duster doesn't use rollers, just weights/pucks and a spring. Take a look at the clutch's innards. That's the starting point.

[racerone3]

...also if the secondary is stuck, it won't allow the primary to work. lube the shaft area inside of the spring with some dry graphite spray.

[Dino]

You read my mind. I was pondering this on my way to work this morning. My plan is to take the primary and belt off and check the secondary to see if I can work it closed. If that closes up ok, I'll take a look at the primary. I'm assuming I need to take the belt off to be able to see if it will close manually. thanks.