I would request all Suzuki GS-150 owners to discuss typical performance issues with their bikes and how they resolved them. this way, we'll have a collection of information here for the benefit of newbies such as myself and hopefully, other bike owners will also profit from it.
Following problems/issues has been identified so far:
1. Less than ideal performance of the ignition system
2. High tendency of the bike to break speedometer and rpm cables.
3. Loud (Tuck!) noise from rear wheel and less than ideal gear shifting.
4. Faulty/Finicky fuse.
Poor performance of the ignition system:
The factory /EM coil provided with GS-150 is not up to mark. I replaced it with Honda Deluxe's ignition coil (DENSO) and the quality of the spark improved. then I installed a platinum spark plug (NKG CR8EGP) and instantly experienced better throttle response and stable idling. on top of all that the bike's cold starting ability also improved significantly.
Then I read an article where the author was recommending spark plug indexing in a bid to aim the open end of the spark plug's tip somewhere in between the intake and exhaust valve of the engine for better performance. BOY! it was some exercise but the results made it all the worth while. the throttle feels much lighter than before, the bikes accelerates better than before and the idling is as stable as the heart beat of a monk.
now someone might ask why not Iradium? well....contrary to popular belief, Iradiums do not offer any performance benefits over Platinums. they just offer increased/longer life. so why spend three times as much when you can get the same benefits from Platinum plugs?
high tendency of the bike to break speedometer and rpm cables:
I was getting kinda tired of casual breaking of the speedometer and RPM cables. I know one is supposed to lubricate them with WD40 but somehow I was never convinced that a simple CLP (cleaner, lubricant, protectant) would be good enough for the job. the problem with oil is that it eventually migrates from the place where it is applied. Then I stumbled upon this:
NASA Liquid Grease
Its a solvent based lithium grease packed in a pressurized container. which means that it can penetrate to the desire spot then solvent evaporates leaving behind a uniform film of lithium grease. pretty neat concept. I bought one and sprayed down the RPM and speedometer cables. I was instantly sold. Now I use it on clutch and throttle cables as well. Guess what? the Speedometer and RPM cables haven't broken since then and clutch and throttle stay lubricated longer.
Loud (Tuck!) noise from rear wheel and less than ideal gear shifting:
Loud noise as it turned out was from rear drum as the drum rubber was not a tight fit. just for the sake of killing a few million brain cells solving this problem I approached a guy who makes custom drum rubbers and voila! no more sound and the gear shifting is now as smooth as silk. I don't know how it made the gear shifting smooth but it did. now shifting the gear up and down do not produce any jerk or noise.
The OEM ignition fuse provided with the bike is nothing more than an outdated piece of cheap contraption. I learned that the hard way. I was on my way (to nowhere) and the bike suddenly totally went dead on me. nothing would work. luckily, Suzuki Center was near and I took the bike there and it started without a hiccup. I moved on then one fine day it happened again. I took the bike to the same guys and the bike started again without any problem. then the mechanic told me that I should get the fuse replaced with a car fuse of equal ampere. I took the the bike to a car electrician who installed a proper car fuse and charged me just Rs. 100 (including the price of the fuse box and wiring) no trouble since then.
Anyhow, thats how I went about solving some of the issues with my bike. if you guys have identified any other issue and successfully resolved it, kindly do share with all of us.