Build a Fun 4-wheel Buggy on Your Own!

Go on a Ground !
01/12/2003 Updated

Seeking a Place for Test Run

Side of S River

This is a place that I found close to a bridge of the river. Upon a recommendation given by a friend of mine living around the place, I went to there to see if I could enjoy driving my buggy in that place.
The ground basically consists of small stones, but in flat evenly. I did not find any area where I could enjoy going up and down hills and tight cornering, but it looks pretty good for the first run.
It must be noted that, as shown in the photos, number of people enjoying barbecue and camping around the bridge. I am sure that my buggy will get number of eyes of them open if I will drive around...

Went on a groundI

I had a day in October 2002 with friends of mine celebrating the 1st run of my buggy on a ground at the same time of holding a barbecue party at the place shown in the above photos.
Unfortunately I could not take any photos of the buggy running at all. I however expect some movies will be uploaded to the web site of a friend of mine sometime soon.
Photos below are that I took right before the run. These are also the first photos I took out of my home after I got it complete.

Few people behind the buggy are friends of mine in preparation of barbecue.

A Short Movie of the 1st Run !

A short movie of the 1st run has been uploaded to a website of my friend.
Click the below image to view the movie in a new window.

From time to time, as a nature of the place, I had to talk a brief history of my buggy build several times to some people that I did not know who came around.
I probably need to prepare some printed reference introducing the whole story for this kind of people next time.

Fortunately or unfortunately, any fantastic failure such as crumble of the frame in the first seconds or having engine flying away did not happen.
As expected, however, a couple of minor problem happened.

(1) Difficulty in starting engine
Although I had the carburetor overhauled and certainly confirmed at home that it can be easily started, the engine seemed not in the mood of turning. I had to put the carburetor off from the engine, tore down, and re-assembled. Engine then could be started.
Throughout the day, restarting was a difficult job.
It may be due to some dust remaining inside that I could not flush completely when I had it overhauled last time. I will do it again at home later.
Another thing I have to do is to replace the spark plug which has been in place for more than 8 years with a new one. The original owner of the XLR says that he had not replaced the spark plug for more than 2 times in his total milage 30,000km.

(2) Front axle failure
After I cautiously met the clutch to start, and accelerated gradually, it happened. Axle shafts in front were bent in the first seconds when I tried to enjoy drifting the rear wheels.
The only thing to say is a mischoice of the material for the axles. See below for some photos and plan for the repair.

(3) Less performance of brake
I was convinced that a brake hose, that has spent over 10 years associated with an another one connected for extension purpose, will no longer work efficiently.
I will simply replace it with a new one. Hopefully the replacement could be a stainless-meshed one as long as I can get it in less expensive price somewhere.

Repair & Improvement

Bent axle shaft at the right-front side. Oil seal has been completely destroyed by a metal collar, placed in between the wheel bearing and suspension structure, which was drifted due to the axle shaft bent.

The complete mistake I made was the choice of the material. I used stainless steel for them that I had to anticipate high stress.

However, stronger bolts in such length are not easy to find around my home, even at DIY shops.
I found 3 different alternatives in my stock as shown in the photo above.
From top to bottom...
(1) Bolts for cylinder head of Nissan L20 engine. These are already used.
(2) Front axle shaft for scooters. Higher strength would be expected, and it needs to be cut into length.
(3) Drop forged 4T bolts. Strength would not be enough.
I will test starting from (1), then move onto the next one if I see failure.

Stopper for Steering Angle

I thought that the excess angle of steering control may have contributed failure of the front axle shaft in combination of the weakness of the material.
I cut a metal sheet into pieces and welded onto the frame to create a restriction of the angle of steering control.
The photo shows the stopper that I placed at the right side. I painted it later.

Brake Performance Improvement

I got a pair of brake hoses for motorcycles in length of 1m, protected with stainless braid.
They should provide some improvement for braking performance.

Whoops, drive shafts have been...

Splined portion of the right side shaft appears... twisted!

Left side does as well.

I thought only the critical portion was front shaft, but now I see another significant issue also on rear shafts.
Splined portion had been twisted due to an excess torque. The part is relatively in smaller diameter compared to the rest portion of the shaft and I was concerned if some failure would happen, then it happened.
The only good thing was that I noticed it before it would completely collapse.
On the other hand, I was convinced that the welding I did around this portion was strong enough against the twisting torque.

So, how should I have them repaired...
I initially thought to purchase a set of universal joints in larger size for new shafts that I would need to order, but I also thought that I did not want to pay anymore for machined shafts that is costly.
I therefore decided to take the easiest but bold approach that I cover up by welding all around the portion where I see twisted failure.
Upon taking this way, I will get one negative element that the shafts I initially designed serviceable will become un-serviceable.

Became un-serviceable...

As planned, I got all jointing portion of universal joints and shafts welded for more strength supported by larger diameter.
Strength will be probably achieved, however the drive shafts have become un-serviceable as a barter.
For any further modification potentially necessary on the shaft, the absolute thing to do will be to cut the shaft (which means need of fabricating the complete shafts again).

I put off the drive shaft assembly from the frame to get the two splined portions at inboard side welded first.
No photo was taken during the welding operation.

Then I put the whole drive shaft assembly back in place on the frame and welded the rest.
Through the welding work, I used several clamps (in red in the photo) to protect rubber boots of universal joints against the heat coming from the welding.

... To be continued.

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