My first 2 Stroke 70cc Yamaha 2005 BWs Build

[Fatskie]

 

Hello there!!

So this is my first scooter and my first time Building a 2 Stoke motor! It is a 2005 Yamaha BWs 50cc. It has 24080 Km's.

I'm a Bigger Dude (6'1 300 pounds) and this isn't my daily driver, Its just my run around/play time ride! (usually go out for 2-5 hours a go when I do!) I live on Vancouver Island in the Pacific Coast (British Columbia, Canada) so I'm pretty much at par with Sea Level (Not sure if the changes much or not but I thought I'd throw it in) I'm not looking to race this thing, I just want to be able to 70 Km/h and maintain my 60 km/h when going up slight hills (its an island, Not flat by any means)

So far I have bought the Malossi Silent Pro 70cc kit and a Malossi X-Special Minarelli Long (Not 100% sure it is actually the right belt)

I've also bought some seal/gasket kits for the Carburettor and case! Got a new Petcock Valve (as my scooter leaks a tiny bit of gas while sitting) and all gas lines to replace the old stock ones and New rear brake kit (pads and the holders) (still waiting for these to come in)

I have installed a Tech on it now, and have bought a Temp Gauge for the Spark plug, which I will install once I actually start this build!

I also bought and installed a new tire for it (was hoping to find a match for front & back but I couldn't so I ended up throwing the one I bought on the Front (130/90R10 Anlas Wintergrip2)(amazing tire so far) and I also put a new front Rotor and Pads on it as when I got it it was Metal on Metal (and then I rode it for 1500km's Was to much fun not to)

I also took the panels off and gave it a fresh coat of paint as I couldn't stand the faded Orange and hurting flames!

I do have some basic mechanical skills with Vehicles, But this will be my first time jumping into a Small motor (Specially a 2 stroke)

Is there any tips or tricks I should know before I Dive into this build? Should I be pulling the motor right out of the scooter when changing the Heads over or is this Malossi Kit something I can do while its still in the scooter?

Currently I don't have any specific questions on this (as I haven't started this yet) I know I will have tons of questions when I jump into all this and am excited to have such an epic scooter community like this to help me through this build!

Thanks in advance and I will be updating this thread along my build!

[aeroxbud]

That should be a good kit together.
The rollers might be a bit heavy though. It's the standard rollers in the kit. Designed for a stock engine.
You can fit cylinder kits while on the bike. But it's quite easy to remove the engine. Making it much easier, especially as it's your first kit.
I would probably get a set of three different strength clutch springs as well.
Check the ports and squish as you assemble the kit.

This might be worth a read through. 49ccscoot.proboards.com/thread/556

[chadbullet]

I would agree with aeroxbud, pulling the motor is like an extra 5 minutes once you have the bike ready to pull the cylinder anyways.

The belt is correct. I like searching the part numbers on Malossi's website and then you can check the applications.
6118140
www.malossistore.eu/x-special-belt-for-scooter-16x8x751-mm-28-6118140-P

[90GTVert]

Welcome to 49ccScoot! It looks like you are well prepared to meet your goals. One of the best tips IMO is one of the simplest... Take your time, pay attention and ask for help if you aren't sure. The how-to that aeroxbud linked you to should cover most things.

[milly]

A nice bit of kit you have there.

[Zino]

The malossi cylinder and silent pro exhaust is a solid build you should push over 75 kph and possibly break 80 .

I have found with that set up
Small up jet in the carb ,notch stiffer clutch springs and 5.5-6 gram weights in the variator really wakes it up .

The tach will help alot in tuning the set the weights in the variator so when you hit the throttle wide open it jumps to 8200 -9000 rpms and holds and then rises .

Temp gauge 
Will protect your hard work and help prevent tuning mistakes 

[Fatskie]

Hello again!

Great guys thanks for the help already! Thank you aeroxbud for that info and linking me to that epic build thread!

I'm looking at getting the Polini 3G 107mm Minarelli Clutch & Polini Speed 107mm Minarelli Clutch Bell with the Polini Sport Clutch Springs set (Not sure if its over or under kill but I figured it be good to put a fresh one in there)



I'm also looking at grabbing the Variator Roller weights adjustment set from Stage6 Size 16x13mm 5.50g 6.00g 6.50g 7.00g


And chadbullet & aeroxbud sounds like pulling the motor maybe the route I go, also gives me easier access to fully cleaning the motor off for probably the first time in 15 years

Thanks for the idea chadbullet for actually going to the manufactures website (cant believe I didn't think of that before!)

90GTVert Thanks for that! I'm very excited I found this site/community!! and that is great advise though! One thing I constantly forget and end up screwing myself somehow!


I do have a question about the front brake, I changed it out with new stock Rotor and Pads, and I cant help but notice the the pads don't use the whole Rotor? Is there a different pad & caliper setup that uses the whole brake? (Or did I do something wrong?)

[Fatskie]

Should have refreshed before posting my post! Zino Thank you for that info!! With the Jets they have sent me the Polini Dellorto 6mm Main Jet Set 80-98. Do you have an idea on what one I should be starting with?

[Zino]

The polini clutch and bell is a nice upgrade.
I have used it .

I have not used those jets .
I usually just start pig rich and work my way down till it cleans up and rev clean.
Taking the richest jet that gives me the best top speed .

Here is a good way to give you a baseline comparison on those jets to stock.

With your temp gauge .
Run down the road wide open for a couple miles with your current jetting .
Note what tempature you peak and level off at .
Throw the 90 in and see if the temp is higher or lower .
If higher go up 2 jets sizes if lower go down a jet at the time .
Running rich or too cool of a jet just hurts performance .
A leaner jets is dangerous .

With your temp gauge alot of us use 350 degrees as the upper limit on what we see temps level off on long wide open runs .