2017 - Model 285 Restoration and Upgrade

[Slackjumper]

So I have been checking CL every so often for the past 3 years for a go kart project. I grew up modifying a racing kart, and just loved it. In college I had a Roketa GK-44 that I purchased for the frame, CVT and motor. I eventually had it reliable after several ATV parts. Though I liked the gk-44, it was heavy and really left me wanting to go back to a simpler/elegant design. Something small, light, with decent power & clearance too. I don't have time for all it takes to learn to fab a good frame and steering, at least one that I would approve of (like Theo's kart) so I decided to start with a good pre-manufactured frame again.

I found an older Dingo (Baja?) model 285 with a non-working Tecumseh 8hp on Portland-CL for $160. Not a steal but I was loosing time to procrastination.

It came with a 30 series driven pulley and jackshaft. Also came with an older non-working 8hp Tecumseh. He had purchased new pedal springs and a throttle cable, but apparently lost interest or the time for it. The red peeling paint had been applied over the original black powder coat. The front cage bars are also custom; galvanized conduit, welded in what I can say is the worst weld joints I have ever seen. And I'm not a good welder at all. The band brake is ok, but had some poor modification done which makes the pad not aligned properly with the drum. The seat is ok, but needs a new board as the original has rotted. The gas tank mount is crap, and location, ...hmmmmm, we'll see about that. Front tires are nearly bald, rears are in good shape. The engine mount had been modded at some point, with layered weld joints that look like crap but are strong.

 

[Slackjumper]

Engines

I found a pair of engines for $100 on CL in Montana not far from me. The GX390 (verified Honda not clone) is in excellent condition. It came off a power washer that had a pump failure a year or two into its life. The flathead 8hp is either brand new (sat in warehouse somewhere), or completely refurbished inside and out. The valves are still shiney, not a speck of carbon down there! Both motors have like new compression. The model 185 originally had a 5hp and is a bit shorter than its 8hp big brother model 388, so some motor-mount and jackshaft mods are required to fit a bigger motor. I think the flathead 8hp would go nicely with this short frame; it's significantly lighter than the GX, and I have steep hills it'll be going up so I want to keep the front wheels down. I'll save the GX for when I come across a 388 frame or something. And, I can use the less expensive 30 series TAV2 which I have part of already. Also the new Manco 8252 throttle cable that came with the kart fits the flathead perfectly if I get the Briggs 692316 linkage kit. Stock cable assy is PN 1496, a bit longer but the 60" 8252 should do fine.

I actually like the idea of having the power of a model 388 with the short length of the 285. The flathead is not as conducive to this upgrade as the new OHVs since the cylinder is centered directly above the mount holes, putting the gas tank at an interference with the back of the seat. I see now that I will need to mount the tank on the roll cage, but I'm thinking behind the headrest, not way up where the previous owner had it.

 

[Slackjumper]

TAV2 (30 series) drive shaft length problem.

I found a new GTC TAV2 (30 series) kit on CL for $40, score! Here's my first problem: see pic. I need additional spacer to make the pulleys line up, after which there isn't much shaft left to engage the splined hub driver. The 1" crankshaft PTO is about 2-7/8" from the cover and 2.75" usable length. I did some research and lots of Briggs shafts 5hp to 8hp are the same. I can't be the only one with this issue? I really want to use this backplate for several reasons. The engine is a 190402-6015-01.

 

[Slackjumper]

Front pic of GTC tav2

Note: i do plan to install a larger 4th bolt on the backplate which is apart from the shaft bolt circle.

 

[OzFab]

... & now for the bad news...

Sorry to rain on your parade but, a 30 series is rated UP TO 8hp; as you're using an 8hp engine (which is a minimum rating), you need a 40 series TC, otherwise, you'll be shredding belts every time you ride it...

lots of Briggs shafts 5hp to 8hp are the same.

That's not exactly true; they may be the same length but, in my experience, a 5hp engine has a 3/4" diameter shaft whereas an 8hp engine has a 1" diameter shaft...

 

[Slackjumper]

... & now for the bad news...

Sorry to rain on your parade but, a 30 series is rated UP TO 8hp; as you're using an 8hp engine (which is a minimum rating), you need a 40 series TC, otherwise, you'll be shredding belts every time you ride it...



That's not exactly true; they may be the same length but, in my experience, a 5hp engine has a 3/4" diameter shaft whereas an 8hp engine has a 1" diameter shaft...

Yes I know but I'm talking about the same short 2.75" to 2.9" length. GTC claims 5-13hp for this kit #1004.
I looked at gopowersports 40 series with backplate, and I think I would have the same problem with this engines short shaft.

 

[Slackjumper]

Got the GTC TAV on.

I made a custom 0.8" shaft spacer for the driver pulley, and a custom pilot washer for the 7/16 end bolt. It all fits fine now; the 8-spline hub's keyway only extends half it's length so I got all of the keyway onto the shaft. I also installed the large 1/2" bolt into the crank cover for better backplate security. I'm curious as to what that hole is for. I see it a lot on these older motors. I'm willing to run this 30 series on the old 8hp as somewhat an experiment and just see how long belts last. If I'm not happy ill upgrade to the 40 series with a steel backplate.

 

[Slackjumper]

Frame torn down

I removed everything from the frame including the bolt-on roll bars. I plan to sandblast it, but first need to get all of the modifications requiring welding done. I'll start with the engine mount. Since I have the jackshaft on the TAV backplate, I can keep the engine low, which I like because I plan to use a bit larger tires, raising the center of gravity a bit.

I'll also need to mount the master and slave brake cylinders. I scavenged them off a parted-out 1999 polaris sport 500 that a friend of mine so generously donated to the cause.

I'd also like to upgrade to a polyethylene highback race seat, so I'll need to move/redesign the steering column support to fit the seat in.

 

[Slackjumper]

Angle iron engine mounts

I removed the original 5hp mount plate and used angle iron for the new 8hp engine mount.

 

[mckutzy]

Well regardless of what GTC says...A number people here have experience with that model, and if Oz says it'll likely burn... It mostlikely will...
Oz isn't in the business of selling belts/TC's (yet), GTC is...

 

[Slackjumper]

Well regardless of what GTC says...A number people here have experience with that model, and if Oz says it'll likely burn... It mostlikely will...
Oz isn't in the business of selling belts/TC's (yet), GTC is...

Yea I read some other threads that agreed it will wear out fast, but there are some out there that had good results on the 8hp. I think it also depends on drive train ratios, and maybe it'll be fast enough for me while still geared low? Oz is probably right that it will burn them up too fast for my liking, but im gonna try it anyway since I got it so cheap. I'll post results or document the 40 series upgrade in this thread either way.

 

[Kartorbust]

What you plan on doing with the galvanized roll cage? I'd keep it off as conduit isn't known for taking abuse. If you want a cage that'll take the abuse like a roll over, 1" round 0.95 thick steel.

 

[Slackjumper]

What you plan on doing with the galvanized roll cage? I'd keep it off as conduit isn't known for taking abuse. If you want a cage that'll take the abuse like a roll over, 1" round 0.95 thick steel.

It's already in the recycle bin. I don't want the front bars, the frame will look somewhat original.

 

[the Go Kart noob]

hey slackjumper just was looking at your go kart build and i noted that in the original pics of yo build the gas tank was above to head. you probably know this but it there is a mounting plate for it up there remove it cus its not gona do you much good up there

 

[Slackjumper]

hey slackjumper just was looking at your go kart build and i noted that in the original pics of yo build the gas tank was above to head. you probably know this but it there is a mounting plate for it up there remove it cus its not gona do you much good up there

Yup, I'm gonna use that plate to mount the tank lower or fab a new one.

 

[Kentucky Boy]

I found a new GTC TAV2 (30 series) kit on CL for $40, score! Here's my first problem: see pic. I need additional spacer to make the pulleys line up, after which there isn't much shaft left to engage the splined hub driver. The 1" crankshaft PTO is about 2-7/8" from the cover and 2.75" usable length. I did some research and lots of Briggs shafts 5hp to 8hp are the same. I can't be the only one with this issue? I really want to use this backplate for several reasons. The engine is a 190402-6015-01.

Your torque converter looks fine. The shaft isn't that short. You don't have to have much to lock that piece on. That's how most peoples are.

---------- Post added at 07:15 PM ---------- Previous post was at 07:09 PM ----------

And that torque converter should be just fine on the 8hp Briggs. It will burn belts if your sprocket is too small or the tires are too big. Your tires look fine as far as the size.

 

[Slackjumper]

Master brake cylinder mount and linkage

I finally got around to mounting the polaris master cylinder. I had to fabricate a little bracket and a linkage bar. The linkage rod was made from the original brake rod. The hardware isn't yet what I want but it's close. I got a small urethane spacer/bushing for inside the return spring too.

 

[Hellion]

...I found an older Dingo (Baja?) model 285 with a non-working Tecumseh 8hp on Portland-CL for $160. Not a steal but I was loosing time to procrastination.

Pffft, around my AO $160 is a crazy good steal. What you got would run $250+ and up where I live and that's usually just for a rolling frame, no engine.

 

[Slackjumper]

Pffft, around my AO $160 is a crazy good steal. What you got would run $250+ and up where I live and that's usually just for a rolling frame, no engine.

Yea I think it was a good price I suppose. I have heard and seen some go for $50-75 without functional motors though. Pffft, love the bassmaster

I often see complete ones in good shape go for ~$500-700 which is a good deal considering all the parts & work to get mine to that point, but I enjoy it and it'll be exactly what I want. It's like fort building, all about the process.

 

[Hellion]

Well I guess it really is indeed a regional thing (go kart values), that's why some members here really harp on users filling out their location in their profile because it's all about where you live.

An engine-less rolling frame in good/very good condition is at the most worth a Benjamin to me. $100 just isn't a lot of money in 2017.