Dirt Devil go kart progress

[tpage]

Hi folks,
I'm new here so I thought I would share some info on the progress of my Dirt Devil go kart build progress.

My friend Mike and I are building the kart as per the plans. We started the project back in October last year but had to put it off since we don't have a heated garage in the winter.

I've built 2 planes in the past so I have lots of metal working experience and thought this project would be a good introduction for Mike in welding, cutting etc... Plus it's a *lot* cheaper than building an airplane!!

This past weekend we finished the front suspension welding. Right now we have the frame, front wish bones and rear swing arm finished. We made all the brackets this past weekend with nothing more than a grinding wheel and a bench grinder on 1/8" steel using my old and trusted method of printing the CAD drawings on paper and gluing them to the steel and cutting them out. I was thinking of getting them all laser cut and thought we should try making them ourselves first since it's cheaper. They turned out just fine and almost as good as laser cutting

We have all the parts to finish the project (wheel, steering, brakes, tires etc... from BMI karts) and a new 6.5HP clone engine (from Princess Auto). We only need a chain and some shocks to finish it.

This past weekend we had to put the rear swing arm on hold due to an issue with trying to mount the bearings. Since we are building 100% to plans the bearing retainers I got as part of the BMI kit are not amenable to using them on the plans swing arm. I'm trying to figure out a way to either make them work or go another route. Anyone else run into this?

I wanted to ask anyone else located in Canada, specifically in Ontario, where we could buy some UHMW rods to make the bushings. I can get the stuff from mcmaster.com in the US since they ship very quickly and the parts are cheap but I like to buy locally if I can. Also, any good suppliers for the shocks? I bought all my stuff from BMI karts and had it all shipped to my parent's place in Florida a couple of months ago so they could bring them back on their way home up here but I totally forgot about ordering the shocks from them! Duh...

My album can be found here:
http://www.diygokarts.com/vb/album.php?albumid=206

 

[anderkart]

Nice, looking good man!

 

[landuse]

Hi there Tpage. There are a few guys here from Canada, and i think Toystory is from Ontario if I remember correctly. He will probably be on soon and help you out.

Welcome to the forums. You build is looking really good so far

 

[gokart14]

sweet the dirt devil kart looks awesome!!!!!
i built this kart last year without plans just pictures and it wasnt the best (good idea to buy plans) so i have sence modifed it with roll cage and the motor on the swing arm

check my thread out http://www.diygokarts.com/vb/showthread.php?t=11644

 

[mikem]

Im tpage's buddy, and we are having a blast doin this kart

 

[gokart14]

Im tpage's buddy, and we are having a blast doin this kart

Sweet. thst is mst important thing to have when building go karts.......FUN..... just have fun!!!!

 

[mikem]

dirt devil

We are having a lot of fun doing the kart, as tpage said, however we are stumped as to that darn bearing thing...since we have em, why build another mount? any ideas would be appreciated!
Like t.p. said, in this build, i am learning to weld, and am trying not to burn holes..any tips are greatfully accepted!

 

[gokart14]

as for the welding.. i have been welding for a while and still burn through dome times. just do small circles and turn heat down untill u dont burn through.

 

[mikem]

usuing a flux core wire welder, i think i need to work more on my aim...

 

[tpage]

I think Mike suffers from the welding flash. We have an auto darkening helmet but I think he's having a tough time actually seeing the weld puddle and the surrounding shadows so he can get his bearings so to speak. He's really good at grinding though!

 

[tpage]

Maybe I'm over thinking the bearings thing too much. Do we really need the bearing retainers to be adjustable? What if I just welded the bearing retainers to the swing arm tube and hope the chain length ends up right?
This is not the usual way for me to operate since building planes means little to no deviation because of safety (and my life at stake). I like to build things as intended but I don't relish making bearing retainers as per the plans since they require cutting out some rather large holes to which I have no tools to do (I wish I had a lathe!!)

 

[mikem]

I can grind, and cut like a madman i even almost set fire to my coat with the shower of sparks
...must be the flash..maybe darken the tint or increase the shutter (?) speed on the mask I plan on grinding the welds tomorrow after I take care of the lawn

 

[mikem]

Maybe I'm over thinking the bearings thing too much. Do we really need the bearing retainers to be adjustable? What if I just welded the bearing retainers to the swing arm tube and hope the chain length ends up right?
This is not the usual way for me to operate since building planes means little to no deviation because of safety (and my life at stake). I like to build things as intended but I don't relish making bearing retainers as per the plans since they require cutting out some rather large holes to which I have no tools to do (I wish I had a lathe!!)

could we move and adjust the attachment of the swingarm?

 

[tpage]

Mike, not on the frame side. The swing arm has to be inline with then engine drive shaft so we don't have to deal with chain tensioning issues due to an offset cam action.

Questions for others: what length of shock do we need for the swing arm? Can we use the same 12" length as the fronts or should be we go with a 16" one? Big difference In price!

 

[gokart14]

Mike, not on the frame side. The swing arm has to be inline with then engine drive shaft so we don't have to deal with chain tensioning issues due to an offset cam action.

Questions for others: what length of shock do we need for the swing arm? Can we use the same 12" length as the fronts or should be we go with a 16" one? Big difference In price!

it really depends on how much travel you want with a 12 inch you wont have a ton of movment the bigger sjhock will alow for more movment really your choice. i have 12 inch on back of mine

 

[gokart14]

usuing a flux core wire welder, i think i need to work more on my aim...

when i first started i had the same problem i kept going of the weld. just make sure you can see the entire weld dont let your hand gett in the way. it will come with practice

 

[tpage]

I think I might have come up with another solution to the bearing adjustment issue. I just placed an order for the shocks from BMI karts and I also ordered a couple of their clearance bearing hangers. This will give us a place to mount the bearings in their cages and give us a flat surface to weld onto the swing arm.

Instead of making the bearings plates adjustable, we'll fab a chain tension idler onto the swing arm. This will be a lot easier and allow us to keep the bearing cages we already have and make chain tensioning easier as well.
Sometimes I just have to sleep on things and it comes to me

 

[gokart14]

i am confused on why you need to make the bearing hangers adjustable. All you have to do is make sure that the engine shaft is aligned with the pivot point and you wont need a chain tensoner all throw a pic up of mine. all i did was weld the hangers at the end of the square tubing at a angle. WHAT I DID WRONG WAS NOT MAKE SURE THE SHAFT OF THE ENGINE WAS ALIGNED WITH THE PIVOT POINT. let me tell you a chain tensoner wont work! i bought one and put it on there and there still was a ton of movment and chain fall of on bumbs. That is whay if you look at my thread you will see i modified the back end to have the swingarm on the A arm.

maby you have this figured out, but i am confused

 

[tpage]

I have some engineering background so I already know you have the have the engine PTO inline with the swing arm pivot. What I'm worried about is the potential slack in the chain. I don't know at this point how long the chain is going to be once I install the sprockets on the engine and rear shaft. Hence we might need a way to take out a bit of slack if removing links will make it too tight.
Instead of over complicating things with adjusting at the bearing location, I'd rather just add a floating tensioner.

 

[gokart14]

ohhhhh yes A TENSIONER WILL DEFENITLY FIX THAT PROBLEM because the chain wont wont have that much slack