Dirt and Trail September 2019


SA's adventure magazine

no mechanical knowledge whatsoever

carried on trying start the bike. The motor

was cranked repeatedly resulting in lots of

damage on the piston crown and head.

I decided that we should do a 692

Big Bore conversion and due to the

damage, also do a big cylinder head valve

conversion at the same time.

Apart from the Cam chain, valve and

head damage I found out that the previous

owner had never re-tensioned the Balancer

chain tensioner (Commonly know as the

Doohickey in the KLR circles). This resulted

in the Balancer chain stretching to its limits.

I decided to go through the engine with a

fine tooth comb after all this neglect.

All the normal carb mods that get carried

out after increasing the CC and airflow were

done. I decided to fit an FCR 44m carb from

a Yamaha WR450 on to this one. I know

it works because I’ve had one on my bike

for the past 10 years and have loved the

crazy response that one gets. To fit the FCR

carb the frame needs a small notch cut out

of it. I build an aluminium spacer that goes

between the carb and the rubber intake

boot. The throttle response is remarkable

and the fuel economy is only very slightly


I decided to use the complete Gen2 frame

and just fit some of the Gen1 cosmetics to

it. The Gen2 has superior braking due to

the fact that it has dual pot brakes front and

back. The rear shock has a wider range of

rebound settings then the Gen1.

I upgraded the rear spring so that Collin

could load up his wife and lots of kit, ride

off-road and not worry of bottoming out.

The front suspension needed to be worked

on as it is a bit weak. The Gen2’s forks

are 50mm shorter than the Gen1’s forks

although they have a 4mm bigger diameter.

The other bad thing about the Gen2 forks

for off-road is the length of the spring. I built

a set of 50mm Stainless steel caps that

screw into the top of the fork, replacing the

fork cap. This lifts the stance in the front

moving weight back which greatly improves

the off-road capability. The fork springs are

replaced with Wilber Progressive springs.

These mods put the bikes off-road

capability way above the standard Gen1.

There were quite a number changes

that I had to make on the frame so that

the Gen1 plastics would fit. The only Gen2

body parts that were retained were the 2

side covers. I had to use the Gen1 radiator

- the Gen2 radiator is mounted differently.

I welded tabs onto the frame to be able to

hold the Gen1 radiator.

How engine came out. New crank, piston, bigger

valves and inners.

The engine casings get some TLC

This how the engine started out...

The valve heads had actually snapped.

New chains, guides and gaskets.

Umm Houston we have a problem...

Big bore kit. Big valves, ready to run.


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