Featured 1964 Tiger 90 Restoration

Spent some time cleaning the Concentric which wasn't too bad given it hadn't been used for years. Fitted it, tickled it and she fired up first time. The spec is 190 main jet, 25 pilot, air screw one turn out, 106 needle jet and the needle in the leanest position. No air filter. Went for a ride and all seemed good and lively. Stopped to adjust the idle and air screw and she conked out. Much kicking and nothing. Tickled in desperation and she started again. Managed to find a sweetish spot for the air screw and idle. A bit fluffy and snatchy at slow speed but I have a fix for that I'll do later. Back home got the air filter on so will need to test that next.

 

Added a 160k resistor in the main beam warning light wire which gives a dim blue glow as opposed to the garish blue dazzle I got on my test run last night.

 

Alys wanted a ride on the bike so I suggested a 10 mile trip to Old Warden airfield but no. She's a veteran of Brit Butt rallies and European touring so wanted to go on a decent run to the Super Sausage cafe up the A5, an 80 mile round trip. But we're still in shakedown! Anything could happen!
So we set off and all was good. The idle was a bit lumpy/clunky and low speed running was hesitant but once on the open road everything smoothed out and she ran like a dream at 4000rpm which must be 56 mph because we followed lorries most of the time. I did take her up to 5000 rpm for a while and she ran well. Got to the Sausage and Alys's boot was covered in oil. It looked like there was some seepage from the rubber oil return pipe/ rocker feed pipe. Luckily I had a mini socket set in my pocket and was able to tighten the clips up. These are the clips you get from Halfords and I think they are tightening oval and distorting the rubber tube. I will change them for different ones soon when I change the oil. The idle cut out once on the way home in the traffic jam town of Hockliffe but she fired up again easily. The photo shows the spaghetti junction of oil pipes leading from oil tank to pump and back through the under seat oil filter and rocker feed.

 

Took the carb slide out and applied my modification which you can see in the photo. It's a radius filed into the flat base of the slide just 1mm deep. This forms a micro venturi between the two tiny holes that provide fuel from the pilot jet circuit. This mod improves slow running dramatically and cures fluffing and stalling when opening the throttle from idle. Before this mod I was only able to run down to 2500 rpm in top gear to avoid fluffing and snatching so was using 3rd gear in 30 mph zones. After modifying the slide I can run smoothly at 2000 rpm in top gear which coincides with 28 mph according to my local green smiley face speedo (my bike's speedo doesn't work). It will pull away smoothly from those low revs too. If you have a bike that is fussy at low rpm it's worth a try.

 

Decided to change the oil and filter. These bikes are not oil change friendly so I set up a syphon to drain the oil tank. It was very slow so I left it and went to buy some Halfords Classic 20/50. I already had a spare filter. Remarkably it drained the tank almost completely. I unscrewed the sump plug which was clean and the magnet I left in there had no metal parts stuck to it. All good so far. Tried to unscrew the oil filter by hand. Way too tight. I had to take the oil filter fitting off the bike and use Fat Max pipe grips and a filter adaptor on a socket set ratchet to unscrew the thing. Once off I drained it and the oil that came out still had the tint of the Halfords green colour. I consider the bike broken in now and running nicely.

 

I've got my brother's T140D on the ramp now. It hasn't run for 10+ years so needs a full service and cleanup. Drained the oil which looked black but with no sparkles. The clutch is firmly stuck and has always needed freeing up before starting so I got the plates out and will replace them.
Rode the T90 to Halfords for some carb cleaner. She's going really well so I took the long way home up the A1(M) for a blast. Cruises lovely at 4500rpm and even sings along at 5000 which gets me past the lorries. No idea how fast that is as the speedo doesn't work. Which brings me on to the speedo gearbox which arrived today. The eBay advert was
"FOR BSA NORTON TRIUMPH SMITH SPEEDO CABLE 64" INCHES AND METAL DRIVE BOX" £29.40 (too good to be true?)
which would seem to suggest it will fit. It's come from India so I presumed that it's for their Royal Enfield and it would be compatible. The first thing is that the hole in the middle was too small so I bored it out to 3/4" on my lathe. Then the outside diameter was different, the pegs don't fit in the slots and it's the wrong way around. Beware when buying cheap parts!

 

I got the speedo working. I had to do a bit more machining on the gearbox and make a couple of spacers to elongate the cable outer. The speedo over reads by about 10% but doesn't flicker about like it used to. Result!

 

A note about my carb modification. For the last week I've been getting my brother's T140D back on the road after many years. He stopped riding it partly due to the frustration of it stalling pulling away from traffic lights. I cleaned up the Amal MK 2 concentrics and filed a 1mm deep crescent in the slides as in the photo above. The MK 2s slides have thicker walls so there's a bit more filing to do. The result is the same though. Smooth slow running and perfect pickup from idle. Hopefully he will ride it to the Fleet Classic Rideout on 6th May.

 

Went for an 80 mile round trip to my little grandson's birthday party. The ride started well enough with a 60 mph cruise along the A1(M). Enjoying myself immensely and congratulating myself heartily on my rebuilding skills I opened her up to 65 which equated to a nice 4500 rpm. Suddenly the engine cut! Nothing, nada! I glided to a stop on the hard shoulder. Empty fuel line. Switched to reserve but nothing came through. Looked in the tank. Some fuel in the bottom. Leaned the bike over to move fuel from right half to left half. It worked! Rode a bit further and she cut again this time at the top of the slope down to the Welwyn Garden City exit so I glided down there and tried reserve again. A flood of brown rusty fuel polluted the clear fuel line and bottle filter but it worked! I made my way to the BP garage just up the Old North Road and filed the tank with E5. The shakedown then moved on to the next problem. The brand new fuel cap was not sealing and at 40 mph, fuel sprayed out all over the tank and all over me. One spark and I'd have gone down a "flamer". I stopped in a convenient layby and tried wiping the tank with some dry leaves which then got stuck in the tank's lacquer coating which the petrol had somehow melted into a sticky goo. I had to get rid of some fuel so I leaned the bike over and poured some out. I continued along the country lanes without incident then along the M25 with all working well. Was a bit late for the party but my three year old thinks I'm a cool biker so it's all worth it. I've attached a photo of the gooey tank. The leaves have come unstuck.

 

I've cleaned the bit of paint and rust off the filler neck and fitted a rubber seal. Hopefully that will be better. Planning another shakedown this weekend with my brother on his T140D that I've got running.

 

If the rubber fuel cap seal doesn't work I'll make one from cork/nitrile. Thanks for that darkman.
Been riding my brother's T140D around today and apart from it being a lot faster it is much smoother. "Rubbery" I'd describe it as. My T90 feels snatchy but the drive train is the same so mine should feel similarly elastic. I suspect my 60 year old cush drive rubbers have hardened so I've ordered a new set.

 

So we had a shakedown run, me on my T90 and brother Pete on his T140D. We filled up with fuel then rode off. Pretty soon fuel started leaking out of my cap.again despite the new rubber seal. We stopped and swapped caps and the problem moved to his bike. We rode slowly back to my house where I borrowed the fuel cap from my T150V. No more fuel leaks so the (Wassel branded) fuel cap is no good. We rode 10 miles up the A1(M) at 60 mph to the services at junction 10 and had a McDonald's then back to Stevenage along the country lanes. All was good except Pete's rear disk was sticking. My T90 runs well but is not as smooth as the T140D.

 

The cush drive rubbers arrived today so I took the primary drive and clutch cush drive covers off. I was expecting to have to wrestle the old rubbers out but they hooked out easily. Getting the new ones in was a whole different ball game. I pressed the 3 big ones in first which was easy but there was no way the smaller ones would go in to the spaces available without compressing the big ones a lot.
I tried tyre levers but could not get nearly enough compression so I made a "pusher" from a 7/16 nut and bolt (see photo). Winding the nut out compressed the big rubbers quite effectively and I got two of the small rubbers in with a bit of manipulation. I was expecting the last rubber to be difficult but it went in ok with some persuasion. I'm optimistic it will improve engine smoothness and will test ride tomorrow.

 

Went for a test run and the transmission with the new cush drive rubbers is definitely smoother with less snatching at low speeds. I'm pretty confident she'll be ok on the 200 mile trip to the Fleet classic show and ride out. We're staying in Fleet the night before so I've fitted some throw over panniers and made a booster cushion for Alys.