Twisted front forks? – 29 Sep 2016.

Well folks, this could be a long post! Ever since I have owned The Fire Bike the handlebars have been turned slightly to the right when riding in a straight line. I’ve always thought that the handlebar mounts were a bit bent and just lived with it. As I’ve said before, I’m no riding god and pretty much just ride what I’m presented with. When I took the bike for its MOT test last week the tester commented on this trait and suggested the forks could be twisted in their yokes. I thought that I had better take a look.

The first thing I did was to clamp some timber to each side of the rear wheel. I then clamped the front wheel in straight-ahead alignment using some thin pieces of plywood on each side as shims.



I could now see how far out the alignment of the ‘bars were.


It doesn’t look much but, what you might just be able to make out is that the instrument binnacle is turned to the right as well, meaning the top fork yoke is the same.

I decide that I would undo the pinch bolts on the lower yoke to see if everything would spring back into alignment but, I found that to do this I needed to remove the screen/fairing first. The pinch bolt is actually a through bolt so I needed to be able to get to the nut on the back of it as well.


Due to the way the indicators are fitted, these had to come off before the fairing. It was easy enough to go into the headlamp and disconnect the wires but the connectors had to be cut off as they won’t pass through the headlamp mountings.


That was the easy bit! The indicators have rubber stalks with a square drive fitted up against the fairing. They are screwed into the fixings for the headlamp. Turning these square drives is pretty well impossible without causing damage to the fairing. I found that I could loosen the headlamp nut between the fairing and headlamp bracket. Then hold the indicator stem still with a spanner on the square while tightening the headlamp mounting up again. This gradually wound the indicator and stalk off and I managed to keep the headlamp in alignment.



With the indicators removed I temporarily put the headlamp back together. I decided that I would remove the fairing leaving the chrome brackets fitted to the handlebar clamps and the short black brackets attached to the fairing by undoing the two nuts and bolts at each side.



Now I could get back to releasing those fork pinch bolts. I slackened them completely. Lots of flakes of red paint were shed from the nuts and bolts. I’d noticed before that the front end of the bike seems to have been given a coat of paint while assembled.

I had already removed all the timber and bounced the forks a few times. Then, with the front wheel between my knees, I tried to force the handlebars from side to side. I re-clamped the wheels and took another look at the alignment.


I’d say that’s a significant improvement. I re-tightened the pinch bolts and was pleased to see this hadn’t changed. I put some wood between the fuel tank and handlebar mounts to see if the gaps were the same on each side. Not very accurate I know.


Front fork oil change.

At this point I decided I would change the oil in the forks. The original oil specified was 160ml of Shell Tellux 33, whatever that was. I did some research on the web and found a number of suggestions. Some people use 20W50 engine oil and others use 30W fork oil. There are also suggestions about increasing the amount of oil used. Some say 200ml and some 8oz (225ml). I decided to get hold of some 30W fork oil and to stay with the factory specified amount. My local shop expressed surprise at me wanting such heavyweight oil but sold me the one and only 1litre bottle of the stuff they had on their shelf.

So, with all my temporary timber work removed, I undid the four allen screws holding the instrument binnacle/bezel/whatever to the top fork plate. I could ease it up enough and block it out of the way to allow me to get to the plugs in the top of each fork leg. More red paint was shed as I undid these but I was careful not to get any inside the fork tubes.


I removed any remaining paint when the plug and its washer were on the bench.


Then the drain screws were undone. They are just a couple of Cheese-head screws with a fibre washer.


I put a bowl under the first leg and watched as what looked like a 2-inch long black slug slowly oozed from the drain hole. This was then followed by cleaner oil. The same happened when I drained the other side. I’m guilty here as I haven’t changed the oil before. I had assumed it was OK!


After draining the oil, the screws were replaced along with new fibre washers and I added 160ml of 30W fork oil to each leg before replacing the top plugs. The washers under the plugs look like they are too big until you realise that they match the ring profile of the underside of the plugs. I checked the wiring connections under the instrument binnacle before screwing it back in place.

All that remained now was to put the fairing back. Initially I held the fairing in position with some screws and washers in place of the indicators.


I could then turn my attention to the upper mountings to the handlebar brackets. I loosened the screws in the top of the ‘bar clamps and loosely refitted everything before going round and tightening the lot. The aim of this was to minimise the stresses on the fairing.


Getting those indicators back on and facing the correct way was a bit of a rigmarole. With the headlamp off again, I fed their wires into the shell. I added a washer between the square drive on the stalks and the fairing and then just kept fiddling with them until they were right.


I then had to crimp replacement connectors to the wires and link them back up. With the headlamp back on I checked that everything worked as it should before going for a ride.

The test ride confirmed that the ‘bars are now straight. I can’t feel any improvement in handling but am reassured by knowing the alignment is now correct. However, even I could notice a huge improvement in the action of the forks. Compression damping is improved and there is less dive under braking. As I found with the V7Sport, less dive seems to improve braking performance.



4 thoughts on “Twisted front forks? – 29 Sep 2016.

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