Venturing into Duromax electric start 7hp

#1
I just found a new Baja Warrior. The guy bought it, thought he would use it, and didn't.
It has but a couple hours on it, then sat in his garage, until he sold it to me.
It looks showroom. I bought it for my wife, and passed hers on down to my daughter.

My wife has been having shoulder problems, and pull starting just adds to them, so I decided to get her something with an electric start. The duromax looked like a good contender, and a friend has one on his kart and likes it. I removed the Baja engine.

So here we go....

I'm keeping this engine stock for now, and not removing the gov or anything. The wife doesn't need to go 55 mph on dirt roads.
The first thing I had to address was throttle control. Instead of trying to reconfigure springs throttle rods and the likes, I found a Rotaderp throttle plate bolts right on. Easy peasy with one spring moved to another location.

I put a TC on it with no probs except the normal cut I have found needed at the bottom of the TC backplate to fit correctly on a baja.

I'm going to have to make a small battery holder for it, which looks like it will be mounted in front of the engine on the double bar frame.
Having electric start is going to be awesome for her.

After getting the engine mounted, and drive in place, my first major concern appeared.
The Duromax is almost 99% the same cast as a clone, except for one thing; the tank.

The mount is completely different than the clones, or even the rotaderps. I'm finding this is where they may have made things slightly different to call them their own. The rotaderps tank is also different than a clone.
The first BIG problem with the tank, is that the fuel cap is dead center on the tank, which puts it directly under the top bar of the frame, as well as the fake tank/glove box.
Also, the cap comes off with about 1/2 inch to spare.

On the first run, we filled the tank, but had to use one of those bendy snorkel type funnels. there was no way to monitor the level, and it got filled til it spilled.
This engine is KA commie compliant, and has the breather hose off of the tank to a charcoal filter that then leads back to the airbox.
The engine started fine, and ran good. Upon bumping and sloshing the liquid fuel made it down the tank vapor return, filled the charcoal filter, and choked/flooded the engine out.
Gas came pouring out the filter.

First redo will be to pull the engine, remove the epa tubing, block the feeds into the airbox, and address putting on a clone tank. I'm going to have to make some sort of bracket to make this adaption.
I'm thinking it shouldn't be too difficult.

Another small area of concern, is that the duro tank has a nice built-in petcock, which might mean there is no fuel shut off on the carb like the clones.
If I can't figure a way to fill the tank as it is, I'm going to have to look at the carb closer, and might have to switch it to a clone carb, which will also mean switching air boxes, because the duro's airbox is also different than a clone's.

The next issue looks like it will be a complete relocation of the starter switch, which ends up being awfully close to the footpeg on the right side, just begging to have the key kicked and broken off in the switch.
I ordered a momentary push button handlebar switch that will work as a start button, using the normal handlebar switch for the kill.

I'll try to take some pics today of the differences, and any mods I may make to adjust for them.
 
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#2
Might look at a Coleman 200 tank, they have an offset fuel filler on their tanks. As for the vent, similar on the Predator, I just rerouted the hose up to the top bar, and inserted a small fuel filter in it to keep the bugs out.

As for battery, maybe inside the fake tank, or something like I did on my CT200U, recipe box from Wally World, holds an AGM motorcycle battery.
 

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#4
I found that many parts off of the new Baja engine were needed in order to get the Duromax where I wanted.
I was able to mount the clone tank on the DM fairly easily. The rear bolt on the clone tank lined up with the DM. I made a bracket to hold one of the front bolts. The tank is going nowhere soon. The was no uncomplicated way to mount the third tank bolt.
You'll see that the front mounts on the DM come nowhere close to the tank mounts on the DM.

The DM uses a petcock mounted into the tank, and the DM's carb doesn't have a fuel shut off.
I ended up putting the clone carb and airbox on it. I also switched the intake studs to the longer clone ones to get it all to fit so there would be a proper fuel shut off.

Replacing the engine back in, I noticed a few things out of line, and was able to get it all back together nice and straight.
I used the chain tensioner from the clone jackshaft plate, made a bracket, and installed it on the frame as I have now done with all 3 of my Baja's.

Tomorrow the battery will be placed, and all the electrical components from the switch box will be relocated, and a starter button mounted on the handle bars.

I removed all of the EPA plumbing.
 

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cfh

Well-Known Member
#5
I'm using a duramax electric start on my Ruttman. I was wondering about the epa tubing. So you just remove it all? what about the value cover hose? There's three tubes if i remember right. One from the small black filter box to the air filter. one from the gas tank to the small black filter box. and one from the value cover to (i forget.)
 
#6
I'm using a duramax electric start on my Ruttman. I was wondering about the epa tubing. So you just remove it all? what about the value cover hose? There's three tubes if i remember right. One from the small black filter box to the air filter. one from the gas tank to the small black filter box. and one from the value cover to (i forget.)
Valve cover hose stays, and goes to the airbox.

I ended up using the throttle plate from a predator, and am leaving the governor intact for now.
The fuel tank was a no go as it sat too high, and the caps placement was in the middle, and directly under the top of the frame.
I replaced it with a clone tank, which needed a bracket made to make it work.

As these things go, one thing led to another.
The DM has a petcock on the tank, but not one on the carb. I prefer to have a fuel shut off, so I replaced the DM carb with a clone carb, which then led to me replacing the DM airbox, with a standard predator or clone airbox, which in turn led me to not having a hose from the tank to the carbon filter to the airbox.

I removed the starter switch box which ended up being to close for comfort to the foot pegs.
I then wired a pushbutton momentary handlebar switch to the starter, and also wired in the normal handlebar kill switch that comes with the bike.
I mounted the voltage regulator on the outside of the engine, just as some clones with lighting come.
I wired the headlight directly to an AGM battery that I mounted in front of the engine.

I have yet to find a suitable box for the wiring junctions, so for now the wiring is just wrapped.
I mounted a torque converter on the engine.

The engine runs great, and has lots of power.
I presented the bike to my wife, who cracked the throttle, as she used to do with her old bike, only to find herself on her butt, with the bike on it's side.
She has a few sore ribs, but is quite pleased with the outcome of the project.
 

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