Suzuki blowing bubbles

 I had an issue with the 2 stroke oil injection on the Suzuki where there were intermittent bubbles inside the pipes on the left hand cylinder. There was obviously a leak somewhere and on investigating I could see there was some oil weeping out at the pump end of the pipe assembly.

To get to the pipe banjo on the oil pump the right hand carb has to be removed, in fact it's easier to remove both carbs. I removed the carbs and tried tightening the banjo bolts, all 3 bolts (the RH pipe outlet, LH pipe outlet and pump inlet pipe) could be tightened so I carefully tightened all 3.

I then reassembled everything and started the bike. Sadly the bubbling on the Left hand pipe assembly was worse then before as was the oil leak! So I took it all apart again and removed the left hand pipe assembly to investigate.

After removing the end of the banjo fell off and it was obvious that the banjo bolt had fractured, this was the source of the oil leak and air coming in to form the bubbling.

Fortunately the banjo on the input end that had fractured is just a plain banjo rather than the more expensive and harder to obtain (Suzuki or Kawasaki part) ones at the engine end which have check valves. 

I purchased a new banjo from ebay, some 4mm id oil/fuel pipe that was a tight fit on the banjo and the original pipe and some clear adhesive lined heatshrink tube to seal the joint. 

I assembled the new banjo, pipe and heatshrink to the end of the oil pipe assembly. 

After reassembling and starting the bike, it was apparent that the bubbling and oil leak issue had been successfully cured. Job Done!

CV Driveshaft upgrade for the GT6

 I recently had an advisory at an MOT test that the Rubber Rotoflex couplings (Donuts) were starting to deteriorate. 

The genuine Rotoflex couplings (made by metalastic) are now very expensive (over £200 each) and the pattern ones like most  rubber components on our cars don't last very long. However, there is now and alternative, an upgraded driveshaft set up which replaces the rotoflex coupling and UJ for  more modern CV joints. This is the set up used in modern rear wheel drive cars like BMWs. I know from covering 125,000 miles in my recently sold BMW 3 series that I'd owned from new that a CV joint solution is very durable as I'd never had to replace them. The CV upgrade to GT6 and Vitesse Rotoflex drive shafts is made by Classic Driving developments. It is quite expensive but will work out cheaper in the long run. It also changes the drive shaft nut on the end of the shaft to a meatier 20mm x 1.5mm from the puny 5/8 unf  (c16mm) diameter on the original which is a weak point and prone to stripped threads.

I therefore decided to take the plunge and buy a CV driveshaft kit, unusually Rimemrs was the cheapest place to buy them as they had a sale on and the kit cost me £714 vs the normal price of £780

The new CV driveshafts

The old driveshafts were removed from the car and the bub/vertical link assembly pulled off the shafts with a hub puller.

Using a puller to remove the hub/upright assembly from the old shaft

My bearings were in good condition so I didn't change them but did clean them and re-pack with grease.

 The bearings on GT6/Vitesse rotoflex suspension are adjusted with shims and if I had changed the bearings then I'd have had to measure the end float and reshim them which is a tricky operation. So with the existing bearings I just had to remove the shims and distance pices from the old shafts and reuse on the new shafts.

Distance Piece on new shaft, this side had no shims

I fitted the new shafts to the car without the uprights and hubs, one small issue I found is that the standard spring lifting tool got in the way and prevented the shafts from being pushed into place due to the inner CV joint being larger than the old UJ set up. So I had to jack up the end of the spring without the spring lifter just to get it into place.

Getting the bolts that hold the CV joint to the diff flanges into place was a little bit fiddly but once in place all was good. The bolts are 3/8 unf x 3/4 and they use a special lockwasher called a schnor washer.

Attaching the inner CV joint to the diff flange

I then added the upright/hub assembly (after fitting the shims/distance piece) and tightened the axle nut on the end. On one side of my car the adjustment of the bearing was correct with just a distance piece which is the one shown in the picture.

Once I had reassembled everything and connected/adjusted the handbrake I put the hand brake on and torqued the axle nut up fully to 105 ft/lb with a torque wrench. The nut is a special flange nut and once tightened the flange is distorted into a groove in the shaft to lock it into place. 

Axle Nut locked into place

The nut is a 20mm x 1.5mm pitch thread, 30mm across flats and 20mm high. I found that several Ford and VW cars use a similar nut so I bought a couple for my spares stash as they will need to be replaced for any jobs where the hub nut is removed in the future.