did you make any changes to the crankcases? they are diffrent.

Thanks to all the con mechanics otherwise I would've been satisfied & would've not joined this wonderful community & made some awesome friends here

Crankshaft, piston & rings are is of 135; the previous mech took care of that & I took care of this even this time including the primary gear drive.

Yap; that's the way to go about it, however, sorry to say , I'm not having money for that now. I'm looking to buy some good riding gears. So may be about 3-6 months down the lane, I might buy a stock carb.

Err...Yamdoot, let me explain to you as well as others here a little on the background.

Aug-01 - is the time when I bought this Rx as third hand with over several questions as we'd also been hearing that Govt is banning all 2S & people will be forced to sell their 2S for scrap to Govt . This was a stock Rx100 & had lots of issues with clutch (I know it only now), oil leaks. Next day I too it upto my regular mech, spent about 3K (call me stupid) & fixed things.

Jul-02 - is the time when I did a complete overhauling including paint job through my regular mechanic. No engine work, but replaced parts as & when necessary. Huge bill though.

Oct-07 - is the time when I changed things completely; there were 5 changes totally. Cylinder to 135, 5 speed gearbox, quick throttle, front disc & TM28 carbs. He said the bike would speed up so mad that on initials it would beat even a stock RD (haha...I never took up his word for that). It costed a little more than a huge bomb!!!

Sep-09 - is the time where I learned that the cylinder lost its compression; by then the vehicle had done only about 8K. I completely lost trust with the regular mechanic & took it to a new guy. The new guy said that the cylinder is a sleeved one. So much to have paid in the previous build for buying a new cylinder!!! Since I couldn't get hold Rx100's, I settled for Rx135 brand new OE cylinder through Y.A.S.S with bill

So you see, by now, I have a stock cylinder, TM28 & disc setup. I ditched the quick throttle & decided to keep the 5 speed setup. So that's how I landed up with TM28.

During Oct/Nov-09 a friend of mine introduced to RDD & was eyeing upon the CDI as well as 90/100 kit. I got hold of a CDI sometimes during Dec 09 & 90/100 during May 10. I'm little skeptical on fitting CDI & 90/100 as I might land up blowing out something. Anyway, I'm little confident with 90/100, but only thing is I don't have a magnet puller & cannot change it myself. I need to take SriramEFunds's help to get the 90/100 as well as CDI's help.

Let me assure you - after the last experiementation, there's no problem with idling now. The bike can idle beautifully, just that the something is causing the back fire/beat when the throttle is closed. But again not at high speeds, may be upto 60/70.

Man i really admire your patience on the bike.. since i believe its a new rebuild you should be able to get some answers after you plonk a stock carb.
If the bike is running a 90/100 kit, did you check the timing?

Is it? Then I don't know what the problem is with mine. Before the sprock change, I could touch 40 Kmph in 1st gear, but now only 35. Anyway, give me time till Sunday morning; I'll get it tested thorougly as I would be hitting the good highway.

Also I'm servicing it now before a long ride; I'll post some pics on clutch damper bushes too, they seem to have worn out in a weird way. Not sure how this happened.

Bigbore's stock RX on 15/34 crosses 110 on the speedo easily. Most of them do.

Whew!!! Issue fixed finally today without taking ANY help of ANY mechanic. Had taken to a mech day before & sorry to say, he's the dumbest ass of the lot. He's never seen a TM28 ever in his life & over & above he comments saying this is a fantastic carb

Anyway, the backfiring or sputtering or whatever was there previously is still there. I cannot use the 165 mains because either the fuel or air is not mixing properly, but with 180 there're no such issues.; I need to plonk even bigger jet than 180 & hopefully that should resolve the problem.

Anyway, I'm not done with experimenting; will try more & post here. And yes, Yamdoot. do you wannt hear about the 15/34 sprockets? Just one word - its as good as empty vessel making much noise ; I'm sure its not going to cross 90 Kmph mark I guess; will try on Sunday morning & post an update here.

Anyone wants to know what the issue was? Its going to turn all your theories to dust for sure

Boss, why are you using a TM28 for a stock 4-speed RX? If you are stockish kind of a guy then revert to stock settings. Just by plonking a TM28 on a stock barrel (which is hardly making 12BHP), you wont achieve anything. The very definition of stock is to be as per factory setting.

As Yamdoot has pointed out try for somebody else's OEM 4-speed carb & check it on your bike, i am 110% sure your problem will be solved. Try this stuff out & let us know of the results.

As for your TM28, if you are not able to get it right, then let the experts do the job for you. Don't tell me there any no good race mechanics in Chennai, i assume there are many in Coimbatore atleast.

Man i am sorry to say this, but you are really screwing big time with your bike. Even i had severe jetting issue with my VM26, but my guy has been into 2-Ts for the last 20Yrs, so he was sucessfull in tuning it as per my needs & now, no matter what i dont screw around with my bikes. Tune & Forget, thats how it should be.

I really don't want to start another argument here, but please stop screwing your bike. Revert to factory settings & i am sure you will have the desired result.

Peace.

you better try a stock carb asap. else you'd be beating arnd the bush. like psycho said, its difficult to trouble shoot online.

I'm running on 180 mains which is stock for TM28; 2 days ago I tried 165 mains which is stock for Rx. After changing to 165, all this issue started (check the video) main thing is the engine refuses to raise after certain RPM & beyond raising the throttle, the engine gasps for air or fuel & then dies.

So I thought 165 is wrong choice & replaced with 180, but to my surprise, the same issue happens with 180 which was not the case earlier.

What could've conked off?

tell me what is stock jet in flat side carb .i strongly suggest u, u have to check filter bcz these kind carb doesnt support stock filter

But Aalop, I tried even without air filters & the engine stalls after reaching certain RPM, may be lack of fuel or air or both, not sure what's going inside!!!

I'm using stock airfilter; no matter which gear it is, idle or running, the engine begins to stall after reaching certain RPM.

by the way which air filter r u using generally in flat side carb air fillter is not necessary .If u go for air filter than u should try uni or something else,the sound of u r bike little harsh that's means it flutters, if u pulling in second gear or in final gear with steady throttle the sound is continuous not in stroke form .

Then you have to go for 16. although it wont matter that much with a 15.

The point is, at stand still, it doesn't stay at the same RPM & keep sputtering. Same case when riding too; after a certain RPM (don't have the meter) the sputtering increases & engine shuts off unless I start random throttling. Got the point?

Nope it was 16/34 & now its 15/34, though I've 37 & 39 with me . Let me know if I need to change the rear sprocks too; I wish to have a top speed than pickup.