2020 - GEGcorp "Dirt Bobber Trike"

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Video of a couple more miles of testing.


Ended up breaking the right anti-sway bar link on a full bump drop. Looks like the the outside tab (first picture) was too close and popped the plastic.
20200903_140511.jpg20200903_160733.jpg20200903_160823.jpg20200903_160856.jpg
Now shopping for aluminum links with misalignment bushings to give extra clearance between the mounting tabs.
 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Got the replacement links. These are made of steel and adjustable length. They will allow me to turn the lower mount 90 degrees so the 45 degrees of suspension travel will go around the bolt rather than all that motion going side to side into the swivel part of the link.
20200912_123223.jpg
I will have to do some grinding and cutting to remove the lower mounting tabs, then see if I can re-use them.


This is a good opportunity to check my welds. I ground into the fillet and used some large pillars to flex the mounting tab until it broke loose, and each one took considerable effort when I didn't cut most of the way through.

The tabs cleaned up ok, so I can re-use them....
 
Last edited:

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
I cleaned up the tabs and ground the welds off the tops of the mounting plates l Next I did some trial fitting at ride height and full droop.


20200918_200604.jpg20200918_225247.jpg
First photo is at ride height with the heim joints in their happy place.

Second photo is at full droop and there is interference against the sway bar because the mount plate is too far in as the suspension moves down.

So... the mounting plates on top of the control arms are not in the right place for the new heim joint links. Bummer. More rework due to the parts change.

I like having the bottom of the link rotated 90* from the top one, but to get that to work, I will have to grind the mounting plates off and re-position them to fit the travel limits of the Heim joints.

I'm sure I can make it look a tad better when I do them a second time, but really hate drilling holes.

<edit> Got the upper control arms cleaned up and used some flat stock to make new mounting plates for the sway bar links.
20200921_162614.jpg20200921_171243.jpg

You can see in the second picture how the sway bar end is angled at less than 90*...

That is to clear the front tires when turning from lock to lock. Will continue with the stock sway bar and hope the adjustable links can be set to match the sway bar angle to give proper clearances at full bump and full droop.

... so here's how the new mounts turned out:
20201010_184047.jpg
 
Last edited:

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
How time flies.... I have had the new heim joints for the sway bar a month but dont have them mounted yet due to other line-jumping projects.


In the mean time, I had found a DIY style ignition upgrade is available for the CBR1000F engine, so I ordered the used parts to get that going.

The tip on this was found on the CBR Forum and titled something like "How To: Stick Coils"
20200909_220916.jpg
The idea is to replace the (2) stock coils near the top of the picture and high tension plug wires with (4) stick type coils that fit directly on the plug seen inside the red circle. The stick coils are half the impedance of a stock coil, so the stick coils will be wired in series and will be triggered waste spark (CBR1000F) rather than sequential fire (CBR 1000RR).

True to form, I was able to find a wiring loom and a set of stick coils from a donor bike for about 45 bucks.

I stripped the stock CBR1000RR ignition loom and sorted the wires and connectors on a cardboard template. Also cut myself, but no stitches were required, so theres no pics of the wound.

20200904_213806.jpg 20200912_085913.jpg 20200912_091337.jpg
The DIY wiring loom is made from a trailer wiring connector and pigtail. I used the trailer wiring because it is heavier gauge to carry two coils in series and minimize any voltage drop.


Then over on the bike, I took off the stock coil packs and wires, and put in a fresh set of NGK plugs while I was at it.

20201019_202658.jpg 20201108_161557.jpg
I connected the 4 wires from the bike harness to the DIY stick coil harness.

Then I cut the waterproof caps off the original spark plug wires and fit them on the stick coils.

Time for more test and tune...
 
Last edited:

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
@landuse - Its definitely easier to "control" off the line or ripping straight through the yard. I was hoping I could muscle it to the inside of a turn for some dirt track style power slides but the weight and geometry is not right to lay get the rear to kick out for a good powerslide. (could try using the rear brake to set up a drift, I guess)

I am about ready to try a baseline lap time in my yard track.

I kinda doubt it will beat my 2019 Yard Kart build on the yard track, but the trike will roast the rear tire on pavement and wil be much faster where conditons permit as it has the big motor and a 6 speed gear box.

However, on the mechanical side, there is something going on with the engine during a cold start. It seems like it is taking a while to build up compression (?) to make power.

I put in new NGK plugs and upgraded the ignition coils to see if that would fix it, no joy yet.

It's a bit smoother and it will kick over immediately and warm up pretty quick if I use a shot of starting fluid in each of the carbs.

I did some searching around on the CBR Forum and a couple of folks there have said valve adjustment fixed their hard start issue, while others have no problems with cold start and they run theirs up to 25k miles with no service issues. This engine has just 17k miles on it, so it seems the PO may have not had it serviced before it got dumped.
20200320_133014.jpg


We all had a mower or tractor
that would not start until the valves were set to spec, right ?

I will be checking the valves and cleaning up the hoses under the tank, will try a compression check before and after. Then try to balance the carbs.

Maybe then it will start and purr (or growl) like I want it to...
 
Last edited:

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Got most of my yard work done for the end of summer, and took the trike out to burn some freshly cut grass.

20201017_161831.jpg

I was having diffuculty trying to use my GPS speed app because several times I knew I had a good rip through 3rd gear, but the app was stoped or asleep and not recording the speed or distance. I was really rushed using the handlebar clutch, throttle and steering while trying to get the phone in my pocket once I was sure it was recording.

The short story is on my yard track the best mph I can show today is 30.75 and that's pretty fast around the chicken pen and all.

Screenshot_20201017-161002.jpg

20201017_162432.jpg

And here's how it ended...
20201017_162309.jpg

A broken bolt on my shifter.

I did verify the anti sway bar link ends are good. No issue with them this time out.

Also found the cooling fan kicks on automatically when the temp gets hot enough, so that's good too.

Now into the ride-break-fix phase
 
Last edited:

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Easy fix on the shifter bolt, It spun on through when I tried drilling it out. I got a longer stainless steel bolt to replace the stock one so that if it breaks again, I can grab it and turn it out.

I hooked up a USB power box to the battery to power a dash cam and hope to produce a riding video later today.
20201017_222020.jpg 20201017_222244.jpg
Also tried a GPS mapping app today to show the oval section of my yard track. This tome out I was hitting 28. About the same uphill or downhill, it's a matter of being able to slow drastically or creep to near stall speed for the 180* turn each way.

Screenshot_20201018-160855.jpg
The gear set is too tall for yard work, but hey, I'm riding!

20201018_150800.jpg
 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Thanks guys.

I made a quick ride video today using a dash camera.
Its awkward to watch compared to some of big name YT channels, but I'm trying.

 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
I had a visitor today, my neighbor just bought a Honda 4Trax 450 4wd, so we talked and took turns leading a few laps around the yard track.

20201023_143655.jpg

So the 4x4 quad was definitely better through the turns, but no contest anywhere there was room to use the throttle and another gear.

I saw him get on 3 wheels in a corner, but the Dirt Bobber trike gets up on 2 wheels a lot easier than the quad would lift a tire.

... so I am convinced the build is NOT COMPLETE.

I will be making the trike lean to hopefully help in the corners where I hope to peel off some dirt track style powerslides.

Screenshot_20201023-140544.jpg
 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
I've been thinking about how to do the most practical mods to make this work as a reverse leaning trike.

After a few sessions on the search engine and oggling through CAD drawings, Pinterest YT and a few GB of images on the topic, I have a plan...

I have decided to chop out the upper shock mounts and insert an articulating upper shock mount based on a pillow block bearing.

20201023_170713.jpg

Just a matter of minutes with a Sharpe, the cutoff wheel and sawzall and I have committed myself to a few more hours/days/weeks of building.

20201023_170741.jpg 20201023_171652.jpg

Now to rebuild this part like a triangle:
20201023_173539.jpg

...that will fit in this space:
20201023_173448.jpg
 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
This is the stock upper shock mount and the pullow block bearing.
20201023_233745.jpg

Here is a cardboard assisted design template. I am keeping the stock shock width and ride height +- a few mm. The caliper was used to get the measurement from the shock mount to the center of the bearing pivot.
20201023_193802.jpg

Here is how the template looks in the frame:
20201023_204423.jpg

Next, I cut out the triangle brackets from 1/8" plate and tacked them together for shaping and drilling two pieces at the same time.
20201023_222431.jpg

Trying out some brand new drill bits and motor oil to make 'em last. See how the new bits spit out a nice spiral when cutting the hole. Wish they would stay sharp like that forever.
20201023_230613.jpg

For the connection of the bearing to the plate, I need a short piece of pipe or axle shaft that would slip inside the inner race. Did not have anything the correct diameter, but this pipe is close enough.
20201023_194040.jpg
I had to use my redneck lathe since I don't have a real one. Started with a piece of rebar in the vice. It spins ok, but was jittery.
20201023_195003.jpg

I found a socket that was closer to the ID of the pipe and a tad longer, and chucked it up in the vice for smoothing with a flap disk.
20201023_201441.jpg

Here is the fit after a ride on the redneck lathe.
20201023_234113.jpg

And here is another trial fit.I noticed that I need to take some off the bottom edges of the brackets to give more clearance for the coilover spring cups.
20201023_235333.jpg
 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
I marked and trimmed the triangle brackets.
20201024_124959.jpg

Added some nuts inside the axle tube where the pivot bolt threads into. Squared up the tube and welded it to one of the triangle plates. The other plate just bolts on.
20201024_152000.jpg

Here's how the new shock mount is looking in place. The trike is still supported by the jack.
20201024_155420.jpg

Now I need to add strength where I made cuts in the frame so the weight and stresses get carried properly. I will start at the small tubes that the pillow block bearing is sitting on.
20201024_155331.jpg

The steering shaft has a pretty beefy bracket that I will tie to the upper and lower frame tubes.
20201024_155509.jpg
Looking for some 1" angle iron.
 
Last edited:

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Rainy Saturday during quarantine season continued....

I scarfed some angle iron off my home made bending brake.

20201024_202738.jpg

Made some 1/2" studs by cutting the heads off bolts and ground tight fitting holes with the cutoff wheel.
20201024_204723.jpg

Used the max heat setting to weld the bolts to the angle brackets.
20201024_210007.jpg

20201024_210204.jpg

Made some holes for rosette welds on the "inside" edges.
20201024_222605.jpg

Brackets in place for welding.
20201024_222651.jpg

Running out of welding gas, but got both sides tacked up.
20201024_224624.jpg

Standing on its own now....

20201024_225126.jpg

We have a LEANER !
20201024_225241.jpg
20201024_225227.jpg

Seems to be working as intended.
 
Last edited:

Functional Artist

Active member
Messages
2,591
Reaction score
12
Location
Toledo, Ohio
Nice work! :thumbsup:
Are you gonna have/use some kinda sway bar, to help control the "lean"?
...& to help keep 'er "centered", when you don't want 'er to lean?
 

gegcorp2012

Member
Messages
398
Reaction score
17
Location
Alabama
Nice work! :thumbsup:
Are you gonna have/use some kinda sway bar, to help control the "lean"?
I have an anti-sway bar on it, and it worked well for what it does. The biggest problem is my front track width is only 41 inches outside to outside, making It too narrow for the height of the center of gravity, so when faced with a turn (even at low speed) it wanted to tip or bring one of the front wheels up.

The sway bar would act kind of like "training wheels" to prevent lean, so I will be taking it off for the next series of test drives.
...& to help keep 'er "centered", when you don't want 'er to lean?
That's something I have seen on some high end prototypes. A lean lock, if you will.

I could try a solenoid pin or a short linear actuator some mating holes in between the shock mounts on the top of that triangle bracket. I think an actuator may be better to conserve the battery, as a solenoid would have to be powered to hold the lock.

Thanks for the comment and idea. It's kind of funny.... I was thinking about how much you like to drill holes in your stuff !

Having a "lean lock" would be much better than a hoakey kickstand.
 
Top