[yamaniac]

Hey Guys,

I have a Yamaha rx-100 a 1993 Model in completely stock condition. She rides good. No problem until you hit the 90 Mark. But once you reach there the engine shuts off, and loses steam and again powers up while it gets down to the 70 mark. She runs on a brand new stock, Bore/Piston/Crank.

The mechanic said he has tuned her up. But nothing has changed. I have no idea whats going on? and the same trend continues. She behaves really well otherwise, between 0 - 80Km.

I mix 30 Ml oil with a liter of petrol, and do not use the Oil Pump. Because I Just cannot take any chances, suppose if the oil pump fails. May this be the issue?

Here she is:

[wolfy]

Hey there.
No, It's not coz you are running premix.
While it is very difficult to sort this out online, as a starting point I'd say see if you are running too big a main jet(?). At what throttle position does it bog down?

[Ajaybiz]

You are running lean, check the plug reading if its showing the sign of lean mixture, immediately up-jet the bike else your block, piston, ring and crank will be soon gone case.
A good 25 ml of 2T is enough for 1 liter of fuel and 20 ml of fully synthetic 2T is enough to run the bike with optimum lubrication.

[yamaniac]

Originally Posted by Ajaybiz

You are running lean, check the plug reading if its showing the sign of lean mixture, immediately up-jet the bike else your block, piston, ring and crank will be soon gone case.
A good 25 ml of 2T is enough for 1 liter of fuel and 20 ml of fully synthetic 2T is enough to run the bike with optimum lubrication.

Thanks for the suggestion bro. Up jet to what size?

I initially thought this would be a CDI problem. I changed the CDI to another rx100's. But it started to misfire even before I reached 40. So i changed it back to my original one. I have adjusted the needle. The oomph of the RX seems to be missing as well, I am not getting the rx torque in the power band area as well, She is not behaving like she used to.

[ku69rd]

Originally Posted by yamaniac

Thanks for the suggestion bro. Up jet to what size?
.

Why not upgrading the rear wheel to 18 Inches (Stock)?

From the pictures it appears to be a 16 Inches (Yezdi) wheel?

Yes please look at the tire after you have confirmed that the correct Jet is used!!!

[yamaniac]

Originally Posted by ku69rd

Why not upgrading the rear wheel to 18 Inches (Stock)?

From the pictures it appears to be a 16 Inches (Yezdi) wheel?

Yes please look at the tire after you have confirmed that the correct Jet is used!!!

Honestly, I feel the RX looks better with a smaller rear wheel of the yezdi's. No Plans to change it as of now. Feels, it gives me a better handling.

I did check the spark plug just now. It was of a muddy brown colour . Got the points cleaned. Still behaves the same. Also I did take a look at this guide

http://www.ngksparkplugs.com/tech_su...qs/faqread.asp

It didn't have any of the characteristics as mentioned in this guide.

Also Read on a forum elsewhere that a muddy brown (Not Rust), Means the spark Plugs are in good condition.

[adrian]

Originally Posted by yamaniac

I did check the spark plug just now. It was of a muddy brown colour . Got the points cleaned. Still behaves the same. Also I did take a look at this guide


Also Read on a forum elsewhere that a muddy brown (Not Rust), Means the spark Plugs are in good condition.

Hi yamaniac, Did you do the plug chop with throttle at WOT so that the mixture strength through the main jet can be assessed?
regards adrian

[yamaniac]

I finally found out what the problem was and rectified it myself. There was a problem with the spark-plug adapter plug wire. I chopped an inch off of it and re attached the adapter and connected it back. And Voila, problem solved. I am guessing there was no proper connectivity to the adapter and hence if wasn't sending the current to the spark plug properly as it should have .

Kinda weird really. None of the mechanics in the entire city could identify what the problem was.

But alas, she runs beautifully as she should. Thank you for all your inputs guys.

Mods, I guess this thread can be closed as it has served its purpose. Cheers.

[--9--]

My Honda Unicorn VBSport Edition - purchased in 2008 is giving me a unique problem.
While riding - if at any given point of time RPM exceeds 4K - Bike loses power and starts knocking. I have to deaccelerate or upshift to ensure that it does not stall.
Problems get worse when I am going up a slope - minor ones at that.
Bike which used to go up to 110 kmph earlier now refuses to go above 60 - 70 kmph.
I tried getting it serviced at Castrol Bike Zone but problem reappeared 10 days after getting it serviced.
Can someone provide me with information as to what might be root cause of problem faced and pointers to good service center in Pune?
Thanks in advance for your help!

[The Great]

Originally Posted by --9--

My Honda Unicorn VBSport Edition - purchased in 2008 is giving me a unique problem.
While riding - if at any given point of time RPM exceeds 4K - Bike loses power and starts knocking. I have to deaccelerate or upshift to ensure that it does not stall.
Problems get worse when I am going up a slope - minor ones at that.
Bike which used to go up to 110 kmph earlier now refuses to go above 60 - 70 kmph.
I tried getting it serviced at Castrol Bike Zone but problem reappeared 10 days after getting it serviced.
Can someone provide me with information as to what might be root cause of problem faced and pointers to good service center in Pune?
Thanks in advance for your help!

This happened with my bike (Yamaha Rx 135 5speed). I tried all possible solutions but the answer came from the clogged fuel tank.

In regards to my bike it so happened that the epoxy coating which was done a while ago and a lot of carbon settlement inside the tank narrowed the outlet hole. Hence the carb wasn't getting proper fuel at high speeds and I faced the same problem that after 50 kmph the bike suddenly felt powerless, only after the bike came down to 30 kmph or so it would regain power.

I would suggest you to get the tank cleaned and also the fuel outlet hole cleaned along with a new fuel filter change. After this get your carb opened and clean it with "carb clean" solution. Lastly go to any IOC petrol kiosk and pour 2 sachets of "Petrol Addon" when you fill the tank.

(PS : Kindly note that I am in no way endorsing these products, I am recommending you only with my personal experience that these worked for me)

Hope this works for you too. Cheers !!

[Nilay]

Originally Posted by yamaniac

Hey Guys,

I have a Yamaha rx-100 a 1993 Model in completely stock condition. She rides good. No problem until you hit the 90 Mark. But once you reach there the engine shuts off, and loses steam and again powers up while it gets down to the 70 mark. She runs on a brand new stock, Bore/Piston/Crank.

The mechanic said he has tuned her up. But nothing has changed. I have no idea whats going on? and the same trend continues. She behaves really well otherwise, between 0 - 80Km.


Here she is:

Hello Yamaniac
I have yamaha RX-135 4S 2000 Model clocked at 105000 KM on stock engine. Then i rebuilt it in year 2012 with new Bore/Piston/Crank. My bore is YP-2 3KA20. The original one is 4TL00. I have somewhat similar problem as you mentioned. Bike runs good in first two gears with max 60 kmph in second gear and pickup is amazing but then shifted to 3rd gear and it behave likes Diesel DI engine and picks up speed and acceleration very slowly (like sudden RPM loss) and shifted to 4th gear shows even worst speed and acceleration progress and max out at 75 kmph. Mechanic said everything is OK but agreed that it is not rocket-pocket in 3rd and 4th gear. He says run it till 1000 km and you will see the improvement. I have used it only 300 km after the rebuilt. Also i have to constantly open the throttle to keep in its power band otherwise it will not accelerate. Don't know what is the problem but mechanic with 30+ experience on RX model has no clue.

Any Advise would be very useful to me.

[--9--]

Originally Posted by Nilay

Hello Yamaniac
I have yamaha RX-135 4S 2000 Model clocked at 105000 KM on stock engine. Then i rebuilt it in year 2012 with new Bore/Piston/Crank. My bore is YP-2 3KA20. The original one is 4TL00. I have somewhat similar problem as you mentioned. Bike runs good in first two gears with max 60 kmph in second gear and pickup is amazing but then shifted to 3rd gear and it behave likes Diesel DI engine and picks up speed and acceleration very slowly (like sudden RPM loss) and shifted to 4th gear shows even worst speed and acceleration progress and max out at 75 kmph. Mechanic said everything is OK but agreed that it is not rocket-pocket in 3rd and 4th gear. He says run it till 1000 km and you will see the improvement. I have used it only 300 km after the rebuilt. Also i have to constantly open the throttle to keep in its power band otherwise it will not accelerate. Don't know what is the problem but mechanic with 30+ experience on RX model has no clue.

Any Advise would be very useful to me.

Hi!

Problem with my bike was clogged air filter. Having it changed helped my bike to get its steam back.

[Horizon]

Originally Posted by Ajaybiz

You are running lean, check the plug reading if its showing the sign of lean mixture, immediately up-jet the bike else your block, piston, ring and crank will be soon gone case.
A good 25 ml of 2T is enough for 1 liter of fuel and 20 ml of fully synthetic 2T is enough to run the bike with optimum lubrication.

Hello Ajay, I was looking for some help with my Rx100 and I came across this post. I am new here so please forgive and guide me if this not the appropriate way to seek advise.
My Rx100 is currently running on a standard bore (sleeved) after being bored twice in the past year. And again, there is an unusual sound in the engine with compression loss. As if the piston drags against the cylinder. So this is the third time i am having this issue and here are the details about the work that was done all three times:
I always add 40 ml oil to a liter of petrol as suggested by the mechanic. (shell 2t)
I have not been harsh on the throttle for at least 500 kms once the engine was fixed.
The cylinder bore, new piston, rings and all bearings (crank,connecting rod) were replaced, connecting rod was changed. The crank was checked for anty play/out. This was done all three times.
The carburetor is stock mikuni with no changes.

I am really frustrated as I am not able to find the cause and somehow I dont want to give up on this bike. I have had another rx100 in the past that I used really rough but never had issues.
Any help/advise will be appreciated.