Yamaha YB-100 Alterations For Incredible Pick, Incuding Boring

[drabdullahorth]

Salam Alikum bhaioyoun.

Yamaha Yb 100's are available for extremely low prices, if one searches for the right place. For example, I found two for 18k-16k, each.

So, I really want to make this bike a monster through even more mods.

Let me list them.

1. Suzuki GS 150 used carb. 2200 rs.

2. Front sprocket 12t, or if more power is available, 10t/45t! Yes, I am going crazy. Around 300-700 rs.

3. Engine boring! Some really hard boring.

So, I got quite a few questions. First if all, is engine boring possible on 2-stroke engines? I heard their structure is different inside. And if possible, by how much? In mm. And finally, how to?

And my aim is to make this bike, for under 28k, (broke af) a competitor to civics. Yes. Civics. Even if the top speed is only around a 100 kmph. I won't mind that.

Soo, any other really effective mods, with them being cheap. Such as a better clutch box, better carburetor jets, and so on? Oh, and a better air filter?

Remember, fast and cheap is my goal.

[Hassan1991]

Wailaikum Assalam.
There's nothing cheap when it comes to modification.
You know the difference of 2stroke and 4 stroke?
First project?

[drabdullahorth]

Why not? Used and intelligent purchases tend to be cheap. Found many. Take a look:

https://www.olx.com.pk/item/yamaha-100c-iid-1053127724

And, yeah, got a basic idea of differences between 2 and 4 stroke, read much about Pakistani motorcycles.

So, brother Hassan, any idea of how to ideally bore the yb 100 to much better displacement? Aiming for 150cc. Needs 52->62 mm boring. Is it ideal? Or even posssible?

First ever motorcycle and project.

[Hassan1991]

Better to stay away you or will end up spending double the amount you would spend on cheap purchase. Because of inexperience.
No, you can only bore 1-2mm more that Is if cylinder is oem not sleeved. Buying a new cylinder will cost you similar to the price of bike.
Or buy an old cd70 and start with it.

[drabdullahorth]

Really? Is that so? The thing is, that 2 stroke power of such old bikes, does wonders. The cd 70 is much more expensive, and weaker.

But still, lets hypothesise for a moment. If I buy a 70, and bore it up to 61mm, upgrading the carb, exhaust, and changing the sprocket ratio to more torque, then will it be able to match the yb 100 (with its carb and sprocket mods done)?

Looking forward for your answer

[Hassan1991]

Yep.
Get an old cd70. Install a pridor or quinchi 100cc piston in it. Again in new cylinder. Get hero RF 70 Pz22 carb and head with runner.
Your good to go. Fun little ride.
No can't compare with 2t's.

[drabdullahorth]

But the bore won't go to 120cc or more then. It will only stick at 100cc. That is stock yb 100 displacement. And even with the mods, it will struggle to compete with its faster yb 100 counterpart.

Thanks for the input. Thought could make the yb 100 a lion through the boring. But turns out that you can't have the whole cake, can you

Then better to opt for the yb 100.

Also, even if I go overboard my budget, and decide to buy a new cylinder, and all that; What is the max performance boost and displacement that I can hope to achieve?

[r1]

Why would you need a big bore for a 100cc 2 stroke? This bike is already a little monster, a fully maintained and well tuned stock YB100 can smoke any 100/125/150 category local assembled bike.

[drabdullahorth]

Problem is, I am hungry for more. More power, to compete better. I have raced Priuses and Corollas, Civics and Hiluxes, and I have a familiar sense of high power. Iwish for that satisfaction, that adrenaline.

[sohailabdullah26]

Hassan bhai, is there a way to increase it's average with same power.

[Hassan1991]

No.