Yerf Dog Brake Band problems
 

Hi all. I just purchased a Yerf Dog 30033 for my son. It is in pretty good shape, but when we purchased it the brakes were non-functional. The brake band was hanging lose. It appears that the only part missing was the bolt holding it to the frame. I have gone through a carriage bolt (which appears to be whatt was originally on the cart-the largest that would fit) and a grade 8 bolt. Both bend within a few applications of the brake and once they bend the brake work poorly. After carefully studying the poorly scanned diagram in the online manual it appears that I may have the brake rod installed backwards (inserted to the band outboard rather than inboard) could this be the cause of my problems? Seems insignificant but perhaps not. Also, there is very little pedal movement to apply the brakes, but appears to be no adjustment. Any ideas here would be appreciated. I have scoured the internet for pictures of our paticular brake set-up but have found none.

Welcome- post pic's of your brake set-up for us to see and to help advise. Band brakes are a very simple set-up- it's possible you have the rod on the wrong end of the band.

trying to post pictures

http://www.buggymasters.com/forum/al...pictureid=1692

I have posted pictures in an album on the board, but I cannot figure out how to post them in the thread. The URL are:

http://www.buggymasters.com/forum/al...pictureid=1692
http://www.buggymasters.com/forum/al...pictureid=1691
http://www.buggymasters.com/forum/al...pictureid=1690

The bolt that is in there now is a Grade 8. Originally, I had a carriage bolt (as shown in the schematic for the cart) but it bent so I tried a grade 8. This was the closest one I could find length wise, but it is too long, but not rubbing anything. I'm really beginning to believe that the rod from the brake pedal should be inserted into the band from the other side. Any thoughts on this are greatly appreciated. Thanks!

I'd try hooking the top of the band into the frame connection and running the rod down to the other end-reverse what you have. The rod laying on the drum isn't right, the clearance on the drum is too tight from your pic's, there should be a 1/4"+ gap most of the way around it to keep from over-heating the drum.

I tried that... the rod runs through a hole in the frame and won't bend down that far. The parts schematic from the owner's manual shows it running through the top. The rod is not actually making contact with the drum. I see what you meen about it being to tight. In my brief test drive I got the sens that the brake was beginning to overheat and fade. I was worried about that, but the rod is extended as far out as it will go. I wonder if it is the wrong brake band. I think they make a 4.5" which would allow the band to have more slack. I need to take another look at it...I wonder if the drum can be moved farther inboard on the axle. seems like it is a long way from the frame, also. Thanks for your help. Any other thoughts. I still think the the rod is flipped around backwards. I may try flipping it around and see if that helps.

Sorry- thought it might work!!! I'm not aware of a band that's 4.5". The drum can be moved with the set bolts,but doesn't look to be out of alignment The grade 8 bolt being too long may be an issue, letting the band slide over off the drum over time or letting the band get cock-eyed. Flipping the brake rod probably won't make much difference. Does the brake rod run straight into the pedal? I don't see anything that would make it not work(other than overheating)

I appreciate your input! The Rod does run straight from the pedal, through a hole in the frame under the seat directly into the band. I have it adjusted as far out as it will go, so I don't see any way to give the band more clearance. I originally used a correct sized carriage bolt as shown in the parts breakdown in the owners manual, but it bent as well.

I had a similar problem with my Manco Critter. It needed new brakes so I got the brake band and drum from Northern Tool and it was too tight. Just like yours. No adjustments available for that type of setup. I thought all 4” brakes were the same but when I ordered another one online made for my model kart it fit perfect. I compared the drums and bands and they were just a little different in size but that made a big difference in fit and band clearance. They were both listed as 4”. Maybe you just have the wrong band or drum.

Thanks Bryce. I wondered about that. I may give that a try...I still wonder why it is bending the bolt that mounts the band to the cart frame.

is it bending in towards the drum? if so it's likely because the band is grabbing so quickly and so close to the bolt that it pulls the bolt in rather than clamping evenly around the drum and distributing the force. I'd say bryce has your issue figured, mismatch in the diameters. the braking "action" is probably only occuring in the first inch or so of band right next to the bolt. if you take the band off, you should be able to see this... even put some permanent marker or machinist blue dye on it, reinstall, do a couple braking runs and check again.

Thank you all for your advice. This gives me a few things to work on later this week.

Anybody have any suggestions on the best place to buy a new brake band? The cart is a Yerfdog 30033.

******** may have your part... http://www.*************/category/Bra...ries-297/rec/0

The band looks to have been rewelded and is now too short. As metal had said there should be 1/4" gap or more between band and drum. From what I see in the pics when you apply the brake the band will first contact the drum on top which will put a pull on the band due to the uneven pressure thus bending the bolt. If the band is proper when you apply the brake the band will contact the drum on its back side then as the pedal is pressed the band will contact the drum equally at top and bottom eliminatong the eneven pull. Hope I did not confuse things. Run into this on an old Manco. The band had broken several times and rewelded. Due to the material lost the band was too short on top. Installing a new band solved the problem.

Just get gokart disk set up

i have a basically brand new band sitting on my bench, measure your drum diameter--if it's a match to the yerf drum that i had, the band is yours for the shipping cost.

So I ordered a new band and put it on the go cart. The new band made contact with the drum on the front side. I bent the ends of the band and removed about 1/2" of brake material and that seems to have helped. The bolt still bent when I applied the brakes only not as bad. It still doesn't feel like there is much holding power, but I am unable to test it until I get the other problem resolved.

The other problem: The go cart will not idle down. It can sit for a week and start on the first pull. I have taken the carb apart and cleaned everything. I have checked for vacuum leaks on the intake manifold at both the card and the engine. It will only idle slow enough to not take off if it is on full choke. at helf choke or no choke it just revs up to a very fast idle. I have attempted to adjust the butterfly. It has a sweet spot where it doesn't idle as fast (but still fast enough for the cart to take off) But actually if I turn it down more then it idles up. I don't understand it. I'm thinking about just buying a new carb, but, I'm not convinced that is the problem. Any other thoughts? I have disconeected the throttle linkage so I know that is not part of the problem.

Thanks.

Idle issue- have you tried to make small adjustments on the govenor spring/linkage? In the past I've found that if the springs aren't JUST RIGHT!! there's some un-wanted issue.
Sorry you haven't nailed down the braking issue- as Zapper suggested- a disk brake set-up may be the solution if you're wanting really good stopping power.

Thanks for the response. I have completey disconnected all linkages from the carb in an effort to isolate the problem. With everything disconnected the ony thing that impacts the engine speed is to manually move the springloaded linkage on top of the carb and I still have the same problem. I checked for vacuum leaks on teh intake and found none. So that doesn't appear to be the problem. I can buy a new carb for $40, but I don't want to do taht until I know it is not a vacuum leak. I would also hate to do that if there is an easy solution with the equipment I had. It's funny I just rejetted the card and adjusted the timing and dwell on a K-code 289 in my 67 Mustang today. That went off without a hitch, but I can't seem to make this little 6.6 HP engine idle.

As for the brakes if money were no object I would convert to disk in a heartbeat, but I am trying to keep the cost down. It seems strange that using the exact same equipment that the cart came with it would be so hard to make it work properly. It just doesn't seem like it should bend the mounting bolt so easily. I have scoured the internet for pictures, but I have never found a picture of this brake set-up on the same model cart anywhere. That would probably help. Tons of pictures of light additions, seat belts, etc. but nothing on the brakes.

I feel your pain!!!A simple go-kart shouldn't kick our butt's!!!! I've had TEC's that appeared to have zero mod's or tinkering done on them and had your same issues till I changed out to the manual choke version carb. Your braking issue could have an acummilation of small wear factors- slightly bent frame,axle,brake pedal,brake rod,warped brake drum,warped/bent wheels,ect... I've made some real junkers work again and ran across all these contributing factors on what appeared to be a nice go kart. A mechanical disk brake caliper and rotor aren't very expensive to buy new, as I'm the biggest cheap-skate around!!! I always make sure my stuff (kid driven) will stop without any issue before anything else I fix or modify!!! it doesn't matter how fast it goes or how well it steers if it won't stop quickly when avoiding something.I know you understand my statement and wish we could help fix these issues for you- it's just alot harder to do over the internet without physically touching or seeing it.

If you take a look at the brake setup below, I have a complete ready-to-install (it's even fully bled) exact same set (including rotor) with the exception of an axle hub to mount the rotor on. You can get those from BMI pretty cheaply. You would have to add a mount tube for the master bracket and either a pair of caliper mount arms or a mounting bracket for it. So much better than messing with the band brakes. $40 shipped and it's yours. Very little use on them.

As far as the engine idle, check to see if the nut and bolt that hold the governor arm to the shaft going into the engine are loose, maybe the governor's slipping on it and it's creeping open. The tec's can be a pain, but also can be very reliable and make good power when dialed in. My daughter's mini shark is lighter than the yerf the tec was in. Its power to weight ratio is better than my 150 buggy and it'll smoke it out of the hole if i adjust the throttle stop on the gas out to let it have full throttle.

Even though you have a new band if the drum is warped or out of round the braking will not be 100% until the shoe material wears in to the drum. The bolt could be bending due to the pressure applied. Remember these are designed for kids, an adult is capable of applying more pressure. If the drum is not trashed the break should wear into it in short time. As far as the idle, spray some WD40 or carb cleanner around the base and manifold to check for an idle change just remember to control the spray so that the overspray is not sucked into the carb inlet for this will give you a false reading. Also check your spark plug for color. If your vacume leak is that bad to keep the idle up that high, 1 it should surge at top end 2 the plug should be white. I still think along with metalstudman that your problem is in the govenor.

Thanks again for your response. I'm not mashing the brake that hard just enough to stop it so it still seems like it shouldn't bend. I wish it was cable operate. It seems like the brake bands that are pulled equally from both ends would work better.

On the idle issue. I have completely disconnected the carb from the governor and I have the same problem...so I think it must be in the carb. I have tried the vacuum trick using carb cleaner around the intake manifold and have not found anything...

I'm open to any suggestions. Thanks again for everybody's help.

I'll ook into the disc brake thing. I'm beginning to run short on time to work on this so a complete mod at this time seems like more work than I have time for...however stopping is very important so I may have to just make the time somehow.

It is a manual choke carb without a primer bulb. The thing can sit for a week and start on the first or second pull. Runs like a champ...it just won't idle down even without anything hooked up to the carb at all. If I turn the idle screw back it starts to idle down, but before it gets to the right idle it actually starts increasing again...very strange.

I really do appreciate everybody's help on here. This is a great forum!

Yerf dog running and stopping great - Thanks to all
 

Hi all. Just though that I would post an update since so many on here offered advice. I ordered a new brake band for the cart and it was still too tight. I wound up bending the band intself more at the mounting points (towards the center) and removing about 1/2" of brake material from the leading edge of the brake band. Now it does not make contact with the drum until the brakes are applied and it is stopping well. The new bolt bent slightly, but seems to have"settled in" I will probably do a disc brake conversion eventually, but until then it is stopping well.

I took the carb and intake back off. Disassembled the carb again and really concentrated on cleaning the idle passage (which is apparently problematic on the Tecumseh carbs). Put it all back together with new gaskets on the intake and it is running and idling great.

I replace the seat belts (which were shot) with new three-point belts with inertia locking retractors (out of a Humvee). Built a new seat (the back was fine) the bottom was a board, alignment, packed all the bearings and added a keyed kill switch (left the original kill switch for east shut down) to prevent unauthrized joy rides. We paid $350 the cart and I have spent an additional $75. So we are into this thing for less then $450.

Thanks again for everybody's advice.

Couple of questions. Does anybody have any ideas on improving the turning radius (it has the turning radius of a battle ship) I realize it will increase the possibilty of a rollover, but it would be easier to manuever if it just turned a bit tighter. There is an electrical plug coming off of the engine that is showing 4 volts AC at idle. Does anybody know what this is for? I need to check but I am sure it makes more voltage at engine speed. I'm thinking of adding a rectifier and a 6 volt voltage regulator and adding some 6 volt lights. Any thoughts on this? I'm also thinking of replacing the muffler with a straight pipe. Has anybody done this? Is their still enough back pressure? It is a Tecumseh OH195EA 6.5 HP.

I doubt there is much you can do to increase turn radious without major fab work but if you will post some pics to give us a better idea, also pics of the plug your talking about. Someone may be more versed on your type of engine but on the average atv, scooter or cycle engine it would have a negative effect running just a strait pipe, but on that type I'm not so sure since my mower's muffler is totally gone and it runs fine and they run strait pipes on the Jr. Dragsters but although basically 5hp Briggs they are worked to the max.

Steering mod
 

I will try to post some pictures, but it looks like I could pick up some steering angle if I notched the portion of the spindle that attaches to the outer tie rod end. Clearly, I would need to reinforce that portion of the spindle if I remove material, but I have a welder so I'm not too worried about that...I'm just wondering if anybody else has done this and if so if it wreaked havoc at all with the steering geometry. It doesn't seem like difference would be dramatic...

curious about the wire coming off the engine, never knew that there was a version with a stator ...