greetings fellow travelers!

i am talking as much of the evolution of my mind and opinions as my rd.

at the onset, let me make it clear that i have no intentions of keeping my bike stock. As i say, there are a lot of great people around doing a top notch job of keeping theirs stock.

The story start with a great RDD rebuild.
I already had an eliminator disk installed and the so called 'ace' handlebar.
After a month of riding around, the brain gets a twitch one morning that i want to make the bike better in the handling aspect.


so i spend a coupla months working on rearsets, two miserably failed attempts and then i finally get it right. and they work brilliantly! they are lighter than stock and bloody strong.




the brake arm had to be lengthened as the brake pedal had to be shortned in order to maintain braking effectiveness.

this pic is an old one where you can see my trial and error of getting the linkage length just right. it looks much better now.


ride around for a month on this setup.

then cought the weight reduction bug. had done a post here as slingshot but couldnt find it now. (can anyone who stumbles on it please post a link of it here)
the concept is lower weight improves speed, handling, braking... everything. the rd manual says the rd weighs something like 138 kgs. but i weighed it mine as stock and weighs 154 kg. now thats a lot!
so after the weight reduction i got the weight down to 134 kg. and it was still street legal.






then the last incarnation was small...



trust me... the pulsar tank was actually a bid to keep my stock tank unmolested. i was facing fuel starvation issues at full throttle, high rpms. so went for the big momma solution and got a low pressure lpg tap. to save the stock tank from the cutting, welding used this tank i had lying around. this setup flows 2 liters per minute from both the outlets with filters on compared to 400ml / minute from the stock tap.
annother advantade of the pulsar tank is it makes the bike get lost in a public parking so less chance of idiots playing with it.




the cowl was a pain... literally as i cut and bent the cold rolled steel by hand. my hands were bleeding and sore at the end of it. it works as a bum-stop and also hides the battery. i have grown to like bikes you can see through.



NOW!


i go like... this is not enough...
i want even better handling!

so i spend months going through dozens of sbk workshop manuals to see how the technology has progressed in the 40 years since the rd was designed.

[dont know if putting up links like this is allowed here, so please let me know so i will remove it if its frowned upon or you can remove it yourself.
]Bike Chat Forums : Workshop/Service manuals !!

i started trying to figure out how i can make the frame better by identifying the frame's weak points. but then realized a few things:

weaknesses of the rd chassis: (or most indian bikes for that matter)
1. forks
they are ancient. i can elaborate on that later but unless you have a metal guide bushes in them, they will behave like pigs during trail braking... if you know what i mean.

2. swingarm
its too short. but the wheelbase cannot be lengthened. it will be counter productive.
also, its too flexy. the axle to swingarm junction is hopeless. even a pulsar's rectangular swingarm is much better in that aspect.

3. steering stem bearings.
rd uses horizontal ball bearings race. the world is using taper roller bearings or angular contact ball bearings for donkey years.

4. swingarm pivot
most indian bikes use rubber bushes there. in the 80s bronze bushings became popular. now, everuone is on needle roller bearings. so we are two generations behind.

5. rake angle of the steering head
rd is 27 deg. its now being proven thats too much. most bikes use 23 to 25 deg rake. more the rake, harder it is to turn and survive a tank-slapper...


these are just a few of my observations in brief.
if you really want to know what i am talking about, please read "motorcycle handling and chassis design" by Tony Foale. its a easy to read book and very informative. highly recommended.


the conclusion i derived from this is that the rd chassis is hopeless and awesome at the same time. it is hopeless because it fails miserably when critically analyzed in the 2009 context. but because i see no significant advantage in any 'band aid' modifications to it, its a well rounded and adequate frame for 1970's. mind you, most current bikes are no better.

and by band aid mods, i mean sbk forks and stuff. you can put a rs250 fork on it, but whats the point if the frame will flex like a noodle.


Now i cant live with it and i love the sensory involvement of the rd engine.
so...





working on it.

dont measure anything in the pics cos the pipe is arbitrary.

as you can see, i intend to make a new frame which can in principle accept any engine... upto say 600 cc.
would probably use some 600 sbk USD forks and rear suspension unit. going to make my own swingarm.


fabrication starts in december.
the aim it to have a stiff frame in torsion and under longitudinal loading. and the operational weight under 120kgs. the chunk of blue you see at the seat is actually the fuel tank which i intend to make structural. that means the bodywork shown is purely indicative and i would much appreciate if the discussion will stay away from the cosmetics and appearance of it.

comfort is not my priority. that said, what sets high quality suspension apart from the old units we currently run is not hardness. its response time and damping quality. a sbk suspension will react much faster to all the tiny bumps in the road. the main motive is road holding but the same quality also improves the ride quality. the frame i am going to make has absolutely no rubber in it.

i think enough rant for today...
i am open to constructive criticism and i have put this up on this site basically to judge public reaction and some knowledgeable inputs as well.
would love to discuss anything i have mentioned in greater detail.

cheers
abhi