Honda S90 - Test drives

This page documents the first test drives of the Honda and the initial problems that were found.

The Honda on its first drive - June 2008









The video clips below show the very first road test on the Honda


 Large format video, Broadband users (7MB)


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The first test run uncovered a few problems.

  • The bike smoked more than it should (white smoke).
  • There was intermittent performance in second gear, the gear slipping maybe or the clutch ?
  • There was a loud clanging noise from the chain or rear wheel.
  • It cut-out at the end.
  • The idle wasn't steady.
  • It was difficult to find neutral and sometimes the neutral light was on, but the bike was still in gear.

On the positive side the bike suspension, tyres, wheels and brakes all performed well.









The loud clanging noise was the chain (which was a bit loose) touching the chain guard which had a dent in it. The dent was pulled out and the chain tightened to correct this.

A second test run confirmed that the chain drive was much better but the bike actually stopped on this test and wouldn't re-start, there was also back firing.









Back at the garage the timing was checked and was found to be out. The cause was that the bolt on the end of the camshaft which held the breaker-point cam in place was not tight and the pin on the camshaft was not engaged with the cam.









At the same time it was noticed that the camshaft sprocket bolts were also loose.

With all the bolts tightened correctly the bike started first time.









The slipping second gear needed closer inspection, so the engine and gearbox assembly was removed from the bike, this work is detailed here.









3rd Test run

This run proved the gearbox to be fixed, engagement of second gear was reliable and without slipping.

The engine was much less smoky.

A few problems were uncovered, a leak from the carburettor which require a float adjustment and an oil leak from the gearbox which turned out to be a loose sump nut.

I was noticed at the end of the run that the rear brake drum was quite warm. This could be the brakes just bedding in or something more serious like a wheel bearing.

Test run 3, completed in the rain.









Overall performance was good although the engine didn't pull so well in the higher gears. However, it was still missing the air box pipe so the tuning could probably be improved. There was also a good degree of engine vibration at certain revs - more than expected. The ride was very bouncy but brakes and road holding were good.

Road Worthiness test.

At the local garage the bike was booked in for a road worthiness check (a legal requirement in the UK to make sure the vehicle is safe to ride).


The bike failed on a number of points which are shown below.

There was also an advisory notice

With the exception of the rear tyre fitting - all the other issues were essentially parts that were too loose. The item of most concern was the front forks one of which seemed very loose when the wheel was clamped and the handlebars turned.

The loose handlebars were caused by a short thread on the mounting bolts, which meant the nut was tightening against the shoulder on the bolt instead of clamping the rubber washers. This was fixed by adding an additional washer under each nut.

There was a similar problem with the rear, brake, torque arm which also needed an additional washer to help the nut pull tight.

Both bolts for the rear torque arm were drilled to accept split pins as this was a requirement for the test.

The rear swinging arm pivot bolt was only finger tight ! This was tightened to the specified torque.

The tyre was just deflated, re-seated on the rim and inflated again to get the valve on the inner tube to sit correctly within the tyre.

Headlamp adjustment would be left for the garage to adjust, as would the advisory to align the wheels.

The loose front fork was a safety concern and could also have been expensive to fix if the internals of the forks needed to be repaired. However tightening all the associated bolts made a huge difference.

The bolts tightened are shown on the right. In particular the mudguard bolts significantly increased rigidity at the front as did the main pinch bolt which clamped the fork to the steering yoke.

The loose headlamp was fixed by modifying the upper mounting. This was a metal tag which was supposed to sit between two plastic edges inside the housing. The problem was that the metal tag had rounded corners which didn't locate in the housing very well so a brass plate with sharper corners was soldered in place.

This located the lamp assembly more positively in the housing and removed the sideways play found in the test.

Finally the bike was roadworthy.

This film shows some footage of the bike in action.

Click for a movie of the S90

(Sorry about the sound quality)