The fabrication of a café racer – ThunderDUCK!

It all started off one day when I decided that I wanted to build a café racer kit on the Thunderbird. I had planned on the direction I would be taking with this project and finalized (at least in my mind) as to how the bike would finally look. This project took a step towards reality when over a session of beer and mindless doodling on Scottish Pub’s tissue paper; Prashanth told me that he had a café racer tank with him.

He told me that I could take a look at it if needed. This, as most other things that are usually discussed over beers, was forgotten for a long time to come.

March 2005, a fellow biker Anand, floated a wonderful idea about hiring the track at Coimbatore to create a track weekend for ourselves. To read more about that event and see pictures from there click here.

When I discussed with Yousuf, (my mechanic, tuner, and friend in Bangalore), as to which bike I would like to take along with me to Coimbatore, I was torn between his offer to take his race spec RX135 and my Thunderbird. All the work that was needed on the RX135 to bring it to track specs would have been a new bore kit with milder porting as the existing one was ported out to drag racing specs and probably wouldn’t last the grueling heat and extended distances. But the challenge in building the Thunderbird for the track was immense and very interesting.

I spoke to Yousuf and it was clear that he needed at least 25 days to build everything from scratch. Many things happened between this discussion and the actual start process of the fabrication, most of them personal. But peripheral work didn’t start till about a couple of weeks before the event and work on the bike itself till about 4 days from the weekend.

Prashanth who was coming to the event too had a few tanks in his place and offered to let me try these on the bike to cut down work. None of these fit and the only way out was the tank that he had spoken about, the café racer tank from the Jawa racing team factory. This was lying with a tinker who had disappeared and finally when he managed to trace him did a fine job with the conversion to fit on the bullet. It was a long and arduous task and many man hours later the tank was ready. Only the top half of the tank was from the original tank and the rest fabricated.
Countdown to the weekend, 7 days.

This had been the main bottleneck in the plans to race the Bullet. Thanks to Prashanth this was done. The rest I was confident we could manage to fabricate in the garage. The only constraint was time.

Sunday 08 May, we had a small meet of people who were planning to head out to the track, and I was beginning to get pretty apprehensive whether the bike could be built as Thursday night it had to be ready.
Countdown to the weekend, 4 days.

Monday morning I went and dropped off the bike at the garage and told them to go ahead and strip the bike. The main thing I told them was to avoid reusing any of the stock Thunderbird’s part because all of it would have to go back on it. I dropped the tank off also at the same time. Evening when I went back, the bike was stripped and bare. We had quite a few tasks on hand.

We just painted the tank with a can of touch up paint. No time for detailed work on the bike. I just created a few stickers in my free time and printed them out and pasted them on the tank. The name ThunderDUCK was originally a derogatory name for my bike, given by Dods, one of the guys in the Bullet club. I loved the name actually and decided to retain that name for this!

The front fork tubes had to be shortened by quite a bit as the thunderbird front tubes were longer than the normal ones. We got new tubes of varying lengths and checked them all. Finally having found the perfect ones we replaced it.

18-inch wheels were what I had initially planned on putting on the bike. But this seemed impossible within the short span of time. This was because of the 40 spoke 19-inch wheels that they would have had to replace. Not happening and I decided to leave it as it was.

The seat, we decided would not experiment too much with and go along with a tried and trusted design. This was one that I had designed a long time ago when I had made a café racer kit of sorts for the RD 350. The only difference being that, I never managed to get foam on it. I just rode out the weekend on the metal base.
To read more about the seat, go here.

Clip-ons were found at another mechanics place. The ones that we tried initially didn’t stand a chance in front of the fit and finish of this set of clip-ons. It was from a CZ and after a bit of grinding and cutting, it was just perfect on the bike.

The bike was given a 28mm Dellorto carburetor instead of the normal CV carburetor that comes stock on this model. This warranted a change in cables for the throttle and we had to resolve that issue too. While we were at it, I got one of the boys in the shop to cut the control levers on the handlebars to a comfortable length.

The 17 tooth sprocket that I had put on the bike to test it out wasn’t satisfactory. Too sluggish coming out of corners etc. No bump up in the top speed, but a very lazy feel to an already lazy engine. Back to the 16 tooth sprocket.

Thursday was here and the rear sets still not ready. I was beginning to get really jumpy and tried out quite a few things on the bike. Not happening.

The shifter side rear set was created by welding a nut into a spark plug spanner and tightening the nut onto the shaft that was created which in turn went into the rear foot peg’s original mounting slot on the frame. The shifter itself was cut from the OEM shifter and the parts used accordingly. The heel shift was the only part that was discarded from the unit.

We got a rear set with a brake lever from an old CZ and had to do a lot of cutting and welding to get it to work the way we needed it to. The reason being, the thunderbird has the brake lever on the right, but the rear drum is on the left side of the bike. I don’t think I’ve seen these many welds on any brake unit till date. 😀 Well, I had to give in and a few of the OEM parts from the Thunderbird were cut and welded. But the brake never worked the way I wanted it to and still doesn’t. Note to self: must try a completely different method next time around.

Finally, at about 11.45 Thursday night, we kind of put it all together. The bike was started up and I did a test run on it. It just bogged down. Darn jetting. After quite a few runs and quite a bit of drilling, finally, it seemed to be okay. But then we decided to go one step further and check, still just okay. Jetting can be such a pain. This was accentuated by the fact that it was running no air-filter. Called it a day at about 12:30 am and went home with a not perfect but satisfactory setting.

The next day morning was when the bikes needed to be loaded up into the truck at Anand’s house, which is a good 20+ km run from mine. Realized when running on the ring road that the jetting wasn’t enough at the top end and decided to pick more jets and take them with me to Coimbatore. But that never materialized and ended up doing the weekend with the same jets. Luckily nothing untoward happened at the track and the ThunderDUCK did what it had to; put a smile on my face!

I’ve only a few snaps during the final build as ASk who shot these photos when we were building it had to leave early.

(Edit: Images have not yet been moved to the new system, please check back later.)

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