Heim Joint A-arms

[Masteryota]

Hello, I have a Yerfi GX150 that I want to convert the A-arm bushing design to Heim joints. I just fitted this one with the BD HD balljoint kit, and if and when they fail, I will look at heims for them as well. For now I want to trash the bushing design currently in use for something better. I read metalstud's thread on his suspension build, and although I love the travel and geometry engineered into it, I don't have the tools or resources available for that type of fabrication, yet.. What I would like to do is brace the control arms approx. 1/2" out from the stock bushing tube and lopp the tube off and insert bungs for 5/8" heims. Doing some rough math, I come up with the arms being from 1/2-1" longer, and would give me the camber and caster adjustments I'm seeking as well. With this plan, I am also looking for some 11 or 12" shocks up front prior to the major fabrication as I know this will dictate just how much I will need to do. I'm not looking to pull down houses with this rig, and not likely to hit any real mud or water holes with the current CVT/Howhit engine installed, but I might change my mind once I swap in an RM80 engine later on down the road. I'm looking for stability, reliability, adjustability, and cost effective.

Buggy info:
'04 YD GX150 in stock form
Equal length A-ams
3rd Gen spindles, already braced for impact
Wish list:
18-20" front tires
11-12" front shocks

[Masteryota]

WOW! 5 days and no responses. Guess I'm on my own then.... I'll let you know how they turn out.

[Ryeguy]

im looking to do the same thing. i think people get tired of this same topioc being asked since it seems to be so repetitive. they should have a whole area dedicated to articles on the yerf dog front end rebuilds. Im not looking forward to making the holes for the bungs.. i would just rebrace the "ears"/tabs coming off the a arms but there are no ball joints left when i purchased this a few days ago, instead there are just regular bolts stuck in there loosly... and the "ears" have been welded several times it looks to repair the damage done by just having bolts in there banging around instead of ball joints.. also the spindles have been welded.. and bent.... looks like i got a full rebuild ahead of me but at least the kids can go for a ride or two on their xmas present for now until i rip it apart asap! I should have paid less for this ha.. picked it up for $500 but prob needs $200 in the front end in parts. yeah well.. it will be worth it once its done.

[xlint89]

Don't know many guys that have elimintaed the bushings for heims, so i can't comment on those.

Yerf however, did away with the bushings and went with a 5/8" bolt bushingless A arm design.

If you're going to remake your A arms, I've got nothing for ya. Maybe send Metalstudman a PM and see if he can help you out? (although I haven't seen a post from him in a long time)

[Masteryota]

When I had the arms off to fix the ball joints, I studied the bushing design, and of course being me, I shook my head in amazement at the flaws of the design, with or without bushings. The fact that they did not use a full shouldered bolt all the way through the bushing tube appalls me, no way you can get those arms perfectly aligned and keep them that way when riding with that design.

I'm not looking to build new arms, just fix what I like to call 'the friday afternoon' design yerf decided to run with. It should be pretty straight forward really, thinking about it, I think the toughest part will be making sure all the holes are true all the way through the bulkhead when I add the inside support tabs. What concerns me is that heims are kinda open to the elements unless you buy the boot kits with them(almost as much as the joint itself), and not many have zerk fittings.

I like the way metalstudman built his suspension, I'm just not that into these buggies to that point, at least not yet! I have been gathering tools and supplies to do the job, and after the holidays I will be tearing into the front end, but till then, a simple rack drop down plate will get me moving, if that dang carb will cooperate!

Good luck guys, and happy holidays.

[bear]

I'd like to suggest that when you do get into redoing your frontend you video it! it could help someone else later?

[x-bird]

It's been a little quiet lately. lot of yerf info on the site, just takes a bit of time using the forum search function and you'll have days worth of reading material. metal, myself and others have kicked around the idea of chopping off the cross tubes and sticking bungs in the inside ends of the a-arms and going with heims instead of thru bolts. as far as maintenance goes, they're surprisingly forgiving. because the tolerances are so tight, not much gets in. i routinely spray mine with light penetrating oil.

[Masteryota]

Originally Posted by bear

I'd like to suggest that when you do get into redoing your frontend you video it! it could help someone else later?

Although I feel it would help out, I hate video'ing anything I do, because I routinely have mega brain farts, but will do my best to snap and post pics as I make progress and any snags along the way. Look for a build thread in the next several weeks if someone else doesn't do it first.

Originally Posted by x-bird

It's been a little quiet lately. lot of yerf info on the site, just takes a bit of time using the forum search function and you'll have days worth of reading material. metal, myself and others have kicked around the idea of chopping off the cross tubes and sticking bungs in the inside ends of the a-arms and going with heims instead of thru bolts. as far as maintenance goes, they're surprisingly forgiving. because the tolerances are so tight, not much gets in. i routinely spray mine with light penetrating oil.

Yeah, I read alot of your stuff, along with a ton of metalstud's posts about front end work. I see where it was mentioned a few times, but nothing ever came of it that I saw, so thats why I tried a new thread. Believe me, I lurked here for weeks before signing up, and still routinely search and bookmark anything I think might help.

[Masteryota]

After flip flopping on whether to do the heims, I've decided to go through with it in place of the bushings. This will be a full front end upgrade, including more teeth on rack, replacing the sheet metal tabs for the ball joints with 1/4 plate, bulking up the bulkhead, and going with 12" shocks, either from a blaster or Harley sportster. The blaster might have longer travel, but I think the sporty's shocks might ride better and support the added weights.

Concerns: clearance of the the heim to bulkhead, should I cut reliefs into the bulkhead plate, or extend the mounting locations when I beef it up? Keep in mind, I will be placing the rack on the floor of the kart for various reasons, mainly to help with bumpsteer, but also foot-to-gas-pedal clearance. I was anticipating the heims to extend the length of the arms by 3/4-1" anyway, so another 1/2" shouldn't be too much trouble, Right??

[x-bird]

i sort of think i get your question about the reliefs, but pics would help. Take a look at Ckau's thread on the build of his narrowed yerf for the part when it comes to a-arm length and pivot point and rack location and tie-rod length so you don't encounter the same issue he ran into... that and don't create a polish buggy like i did ))))).

[Masteryota]

Originally Posted by x-bird

i sort of think i get your question about the reliefs, but pics would help. Take a look at Ckau's thread on the build of his narrowed yerf for the part when it comes to a-arm length and pivot point and rack location and tie-rod length so you don't encounter the same issue he ran into... that and don't create a polish buggy like i did ))))).

I know I want to center the rack in the chassis after adding more teeth, that way it takes some of the math away compensating for the offset. I know the inner tie rod pivot HAS to be inline with the pivots of the control arms, which is fairly simple with equal length arms and the simple mounting points Yerf used, and that will have to be addressed after the arms are done and rack mounted, but it is a fairly simple fix if it does need to be extended.

I can't take any pics atm, but to give you a mental pic, the bushing tube has very little clearance to the side wall of the bulk head, the heims are by nature thicker around the pivot section, therefor I know they won't fit in there in stock form. I could take a hole saw and cut out a circle(maybe 5/8") directly behind where the heim will bolt up. This will allow the heims to bolt in the factory location but not hit the bulkhead, I would think the hole would only be minimal, but till I have them in hand and partially fabbed, will I be able to know the exact size. The more I think about it, I think I will just cut the factory tabs and make my reinforcement bars longer to accommodate them, seems alot easier and looking at the bulkhead mounts, it will be close to the frame mounts, and I don't want to gamble with those stress points.

I was also considering modifying the spindle-tie rod mounting point as MSM pointed out in his front end build to incorporate some ackerman angle. Ok, last question for today, anyone considered if its possible to put a zerk fitting in the rack?

[xlint89]

Not too sure how the Sportster shocks would hold up to off road riding. Hell, my Works shocks for the Sporty doesn't even like bumpy roads....

I don't think you're going to like the Blaster shocks up front either. They're kinda stiff IMO and are usually used on the rear. Yerf front ends are very light. I doubt you'll get much dampening from them.

[Masteryota]

Originally Posted by xlint89

Not too sure how the Sportster shocks would hold up to off road riding. Hell, my Works shocks for the Sporty doesn't even like bumpy roads....

I don't think you're going to like the Blaster shocks up front either. They're kinda stiff IMO and are usually used on the rear. Yerf front ends are very light. I doubt you'll get much dampening from them.

Thanks for the heads up, I was looking for economical alternatives to the BD shocks, looking at 11-12" shocks for the front, and all the rest hinges on the shocks. In theory, if the arms are longer, it would spread out the mounting points, which would amplify the spring tension, maybe I will relocate the lower mount in some to soften it up. I am also taking into account my weight and the fact I will be relocating a medium size battery in front of the pass. foot rest to even out the weight some. I'm a big dude(~315lbs) and want to be able to carry passengers through decent terrain to scare the sh!t out of them too.

[x-bird]

when i comes to rack lubrication, packing grease in and cycling it repeatedly with the dust boots of, while sloppy, should give a grease job to it that'll last for about a year or 2. Otherwise, i see no issue with drilling and tapping for a zerk right above the rack teeth. just have to dismantle the rack for the job. install the zerk, check how much hangs out the inside of the rack tube and grind it down so its flush.
when it comes to shocks, snowmobile shocks seem to be a better match than quad shocks. I'm running fox shocks from a 91 arctic cat ext 550 and a 95 polaris. (model unknown--they have pink springs and white bodies)

[Masteryota]

Originally Posted by x-bird

when i comes to rack lubrication, packing grease in and cycling it repeatedly with the dust boots of, while sloppy, should give a grease job to it that'll last for about a year or 2. Otherwise, i see no issue with drilling and tapping for a zerk right above the rack teeth. just have to dismantle the rack for the job. install the zerk, check how much hangs out the inside of the rack tube and grind it down so its flush.
when it comes to shocks, snowmobile shocks seem to be a better match than quad shocks. I'm running fox shocks from a 91 arctic cat ext 550 and a 95 polaris. (model unknown--they have pink springs and white bodies)

What are the lengths of those sled shocks?
I disassembled the entire front end down to the frame, and see some serious room for improvement already. Aside from the A-arm tabs, where else should I beef up the bulkhead? I was looking at the side mounts, and also thinking of beefing up the frame tabs as well, along with finish welding the rest of the frame they felt didn't need to be finished off. Also considering adding a gusset from the tube frame to the bulkhead mount plate on the frame, something tells me there will be lotsa stress there too.

Has anyone used the BD shocks yet? I have an issue paying that much without some first or second hand accounts on how they operate.

*sigh* I might as well take the engine/swingarm off now, so I can flip the frame and see what else yerf decided not to finish welding. This hobby is getting serious, and fast.

Also, while examining the rack, I noticed the rack itself has what seems to be alot of rotational movement inside the housing, and when twisting, it binds rather harshly when cycling it back and forth. This concerns me a bit, as I don't want it to bind under any kind of articulation, and don't want to waste time cutting teeth and money replacing the boots and outers if the rack is trashed.

[bear]

Once u start looking at way to improve ur buggy it goes on & on to the end of ur imagination, thought it can get tedious at times, once done & you see what you've acomplished it turns out to be half the fun!

[Masteryota]

Welp, attempted to mod my rack, and screwed the pooch in the process, I could use it, except it has a bit of bind on the teeth I cut today, and don't want to chance a roll over if I don't have to, anyone got a coupon for BD?

And wouldn't you know it, they are back ordered............

[x-bird]

all may not be lost. clean the rack and pinion of all grease and use machinist's blue, or even just a sharpie marker on the rack teeth. rotate it until it hits the bind then take out a file, remove a little material where the bind is indicated by a mark in the dye. repeat until it clears. when i did mine, i got a bit off after a couple teeth and spent a looong evening getting it to work. FWIW, even when unmodded, the racks will feel a little notchy when not attached to anything and the rack is turned a bit. Mine felt horrible after i modded it until i had it lubed and installed and test ran it a few times. i had the same worries and it never became an issue. I'm not saying you're home free yet, but i'd set it all up first before ditching it and starting over.

"This hobby is getting serious, and fast" LMAO, welcome to the club my friend. I started out with just a simple no cost rear swingarm pivot upgrade and ended up in the 4 figure zone while working on a junkyard/scrap pile budget ... and 2 more running buggies ..... and another scrapyard project pile. )))))

[Masteryota]

Thanks for the words of inspiration, I was ok with it till I noticed alot more rotational play than on the rest of it. If you turn it by the rods ends, it feels terrible, but when turned by the pinion, it seemed better, but not great. I will take a look at it tomorrow, started removing the tabs from the A-arms, but remembered I need a new regulator for my welder. Parts came in for another project, so I will put this one hold for a few days.

I also found out there is a HUGE offset in the rack itself concerning trying to center it in the frame, I cut 5 teeth on the long side already and looks like I will need to cut another 5 to get even close to the same lengths. This may be more in depth than I originally thought.

[x-bird]

if you dig around in "my yerf upgrade" thread, you'll find how many i cut into mine to center it. i think it was 11 total, maybe 3 and 8. a lot of it has to do with the angle of your steering arm off the spindle centerline and how long it is in order to get the tire turning angle you want. my entire front front end was scratch-built so i can't give you an idea of what to expect in that regard if your working with stock yerf spindles etc.

[Masteryota]

Originally Posted by x-bird

if you dig around in "my yerf upgrade" thread, you'll find how many i cut into mine to center it. i think it was 11 total, maybe 3 and 8. a lot of it has to do with the angle of your steering arm off the spindle centerline and how long it is in order to get the tire turning angle you want. my entire front front end was scratch-built so i can't give you an idea of what to expect in that regard if your working with stock yerf spindles etc.

I read in that thread about the cuts, I would have liked to see the finished product though. I looked at mine again and realized I had cut the teeth increasingly off center, producing a threaded rod of sorts. That was my binding.....

A little digging and I was able to find a sand rail company out in AZ that has a new, almost drop in unit, all centered up and everything. A little more digging and I found a guy about 3 hours down the road that put one on a spiderbox, essentially doing what I wanted, and the best part, they are in stock and $50 less than BD. Only 1 concern though, these racks only list 4-4.5" of travel, lock to lock. Stock racks were in the range of 6". Now I'm stuck....

[x-bird]

If your one teeth are "turning" on the shaft, i think you still may be able to correct them. if you put up a pic of yours to show what youv'e done, might still be worth a shot to level the top of the pinion on the correct plane and depth and finish the teeth off where needed to fix the turn

A couple of these pics were in my thread. When i did mine, it went well until I test it and it bound up. Then i was up til about 4 am getting it to work, and the end result while not pretty, worked. Its pretty apparent inthe pics where i went wrong, first cuts were made with hacksaw and dremel and it slipped on the metal during the cut a couple times--that was enough to throw it all off. at one point i thought i didn't have enough depth. so i cut deeper ---turns out i just got off that bit on the tooth spacing and the pinion gear tooth would hit the face of one and the back of another. I ended up narrowing a couple down way more than i liked to fix it.

One of the keys to doing the teeth imo is to really carefully mark the continuation of flat run the existing teeth make on the top of the pinion shaft on both sides, and lightly grind the file to make the flat continue to where the teeth will end. After that mark tooth and valley centers and a pair of lines below the flat on either side for the depth of the cut.

BTW, belt sander worked really good making that flat top run. last shot is pretty close to final.

[Masteryota]

Thanks, those look great compared to mine, I did mine 1 tooth at a time and made sure it rolled into the new one before moving on. I will snap a pic monday when I'm back at work. I also was using a air cut off wheel, which might be the reason it got away from me.