Tiger Cub Top Tube Oil Tank

[mik60ish]

Hi All I was thinking of making a Tiger Cub Top Tube Oil Tank for my trials Cub I did contact Sammy Miller for a price to ship to New Zealand, but didn't get a reply so has anyone made one themselves or if some one could post a simple diagram of the layout of an oil tank which I could adapt to suit my Cub Cheers Mike

[gii]

My Cub has an unusual top tank oil tube arrangement, made by the previous owner.

PM me if you need more details

Edited November 9, 2009 by GII

[gii]

The finished article

[mik60ish]

Thanks for the pics Gordon bike looks really good I was thinking of making one out of alloy to fit between the top and middle brace, as I have an alloy petrol tank which is fitted front and back not like yours with the bolt through it. I see you have an oil filter as well. And I need to move my foot pegs like yours. Did you get the geometry from your 4RT, as I was thinking of copying my GasGas TXT Pro set up!

[gii]

The photos are of the bike the way it was when I bought it, and I've not substantially changed it since other than to lower the pegs about an inch.

The forks are Cerianis and are a bit long, I guess they were off a scrambler, I'm investigating a pair of parallel yokes instead of standard Cub ones to try and steepen them up a little

[alan]

Compared to parallel yolkes, The offset on the cub yolkes reduces the trail (much in the same way as leading axle fork on all modern bikes), parallel yokes will increase the trail and make it want to go in a straight line. to reduce your trail you need to steepen the head angle on the frame.

[mik60ish]

Hey Gordon

I fitted MZ 150 forks to my Cub on recommendation from Brian Trott Totnes, they work quite well, I bought a complete bike just for the forks when I was in the UK.

[triton]

Hi G11

Is that a Mikuni VM22 carb in the close up shots of your cub, if so what jets and slide are you running, I noticed you have an Amal concentric in the completed photo which carb was most effective?

Any info appreciated,

rgds Roy

[gii]

Aargh, carburation

I've not got it sorted yet, not nearly

The engine is reputedly 246cc. I don't know the extent or detail of the modifications, but it is powerful, and in the mid range, very powerful.

There seems an awful lot of secrecy about pre 65 bikes and for me it has made improving things rather difficult

When I acquired it it had an Amal mk1 concentric, 25 pilot jet, 106 needle jet, needle middle groove, No 3.1/2 slide, 120 main, and PVL ignition firing an NGK B7HS plug, which was always sooty black

It went well but had a horrible hesitation if you cracked the throttle open quickly, you could stop the engine dead by opening the throttle wide open close to tickover

I bought a No 3 slide and a 110 main. This improved things in that instead of stopping dead when you cracked the throttle open, the engine gulped, then went, revved nicely too. Not too sure if just stopping wouldn't have been better. As a crap rider I tend to ride right up to obstacles before tackling them. The gulp means you can hit them pretty hard when you expected to lift over them. It really sooted the plug up (new plug every 2 laps) so I've changed to a BP4

I borrowed a Dellorto off a mate's 199 cub, it was great on his, jets were Pilot 35, Slide 40, Emulsion BZ260, Needle D40 middle then top groove, main 100. It was absolutely terrible, wouldn't take any quick throttle, moving the needle didn't make any difference

I tried the Mikuni VM22 in the pics, haven't made a note of the settings but it's no better than the Amal, I just can't shift the hesitation.

I have a new Amal and I've tried it too in case the slide was slack in the body. Running the same as above but a number 107 needle jet and needle raised as high as possible improved things but only slightly.

I kinda feel that a 2.1/2 slide might sort out the hesitation, but not sure if the plug could take the richness

Edited November 13, 2009 by GII

[triton]

Hi G11

Carburation keeps me awake at night,

Started off with Amal mk 1 big hesitation off idle, bought a new one as I thought bore was worn on old one, New one has 110 main, 105 n/j, 3,1/2 slide 25 p/j cracking throttle wide open kills engine, slightly better if idle is at max richness and needle is in bottom groove, had 7 fives last trial because of this, so frustrating

Bit the bullet, bought a new Mikinu VM22, starting is better due choke, but still coughs and dies if throttle cracked open, have yet to try it in a trial. I'm just going to remove head/ barrel give it a decoke and new rings and see if that helps. Engine is still 199cc by the way.

Sorry to hijack original thread guys.

Roy

[superhondaman]

I have been running a new Mk1 on my 199cc cub and found it runs better than the dellorto. I have a 2.5 slide and feel this stops a lot of spitting etc. I have also found its worth sleeving the enging side of the carb down to about 20mm which improves the bottom end but then takes a bit of setting up on the main jet. This is just what i have found but i am no expert just like to tinker a bit!