Crankshaft replacement By sdverona (Read 914 times)

[sdverona]

Hey all! I need to make a list of tools and parts to purchase so I can replace my crankshaft. Can I get some help? I asked on scootdawg and I got completely ignored. (I know, boo who right?)

Any help would be appreciated!

[jct842]

When bash comes back on in the morning I am sure he can list all of them. He made a thread some time back where he totally rebuilt a 150cc and has pictures and text covering every thing. I am sure if you search or possibly he can give you the link for it.

Most of us here don't care for dawg, I sure don't. I am sure you will find this forum a lot more personable. john

[Alleyoop]

By the Way which motor is in there? 157QMJ short case or long case or some other motor?

Two Special tools you will need and they are the FLYWHEEL PULLER and the STARTER CLUTCH SOCKET: Other than that just your basic Metric Socket sets. And of course a full set of Gaskets.
Alleyoop
Here is the the COMPLETE Teardown and Rebuild of a 150 GY6 motor:
www.scooterdoc.proboards.com/index.cgi?board=techtips&action=display&thread=6884&page=1

And here are the two special tools you will need:

Flywheel Puller:


Starter Clutch Socket:

[sdverona]

Alleyoop - oh it's a 157qmj shortcase. YOU are AWESOME. That's just what I needed... thank you!

[Alleyoop]

Your welcome Sdverona, My Trike also has the 157QMJ short case, But I have it all modded had the case halves bored and had a 62mm and a 2+2 Stroker Crank which added 30 more ccs to the motor from stock 149.6ccs to 182ccs plus a taller gears and everything else is performance stuff. The GY6 157QMJ there are parts galore. Since your going to tear it down you can add a little more MOJO to the motor without having the halves bored out and stick in 60mm and a 2+2 Stroker Crank and you will bring it up to 170ccs. Then put in a Free Flow Filter and Upjet the Carb. I am running with 38 Pilot Jet and 122.5 Main Jet.
Alleyoop

[Bashan]

Alley is right, you should get a starter clutch wrench. I used a BF screwdriver but it's a PITA and you can easily ruin the nut. Also, I would strongly urge you to get a gear puller to get the kick start gear off of the left side of the crank. Get the two arm type because the three arm won't fit into the recess in front of the gear. I got this at Advance Auto:

It's still a little tricky because there's a bevel on the inside of the gear that makes the arms want to slide up and off. After a couple tries I got it to stay on. Other than that just standard tools with a lot of 8mm and 10mm nuts and bolts. A wood hammer helps get the case apart.

[sdverona]

Jan 15, 2013 1:12:26 GMT -6 Alleyoop said:

Your welcome Sdverona, My Trike also has the 157QMJ short case, But I have it all modded had the case halves bored and had a 62mm and a 2+2 Stroker Crank which added 30 more ccs to the motor from stock 149.6ccs to 182ccs plus a taller gears and everything else is performance stuff. The GY6 157QMJ there are parts galore. Since your going to tear it down you can add a little more MOJO to the motor without having the halves bored out and stick in 60mm and a 2+2 Stroker Crank and you will bring it up to 170ccs. Then put in a Free Flow Filter and Upjet the Carb. I am running with 38 Pilot Jet and 122.5 Main Jet.
Alleyoop

Awesome stuff! I actually just installed a 61mm NCY BBK and 61mm head, A9 cam, and a 30mm carb. What crank should I get? OEM or performance?

Does the valve lash change with our BBK installed?

[Alleyoop]

Well if you want or need more toque say you have a lot of hills that you have to go up then a 2+2 Stroker Crank will give you more low end torque and a little less rpms. If you want a more high reving motor then stay with an OEM.
The Valve Lash is the same .004 inchs on the INTAKE and either .004 or .005 inchs on the Exhuast. I set both to .004 inchs. If you get a good head it will not change much at all because of the good metal and will hold its lash.
Alleyoop

[Gti]

sdverona
Alley and Bashan are the men when it comes to getting help with your scoot. They are patient and willing to answer questions that you MIGHT think are stupid. Ask these guys and there will be an answer. If you have a motorcycle shop in your town you can get that gear pulled at a repetitively low price. The project you are about to undertake is not overly difficult but it is a hard, it does require your full attention and focus, I will reiterate ASK QUESTIONS, READ POSTS, LOOK AT PICS, LABEL your nuts, bolts, and misc parts, TAKE PLENTY (TOMS) of PICS. Good Luck!!!

[sdverona]

Jan 15, 2013 21:40:32 GMT -6 Gti said:

sdverona
Alley and Bashan are the men when it comes to getting help with your scoot. They are patient and willing to answer questions that you MIGHT think are stupid. Ask these guys and there will be an answer. If you have a motorcycle shop in your town you can get that gear pulled at a repetitively low price. The project you are about to undertake is not overly difficult but it is a hard, it does require your full attention and focus, I will reiterate ASK QUESTIONS, READ POSTS, LOOK AT PICS, LABEL your nuts, bolts, and misc parts, TAKE PLENTY (TOMS) of PICS. Good Luck!!!

Fantastic! I am up for the challenge. I did the top end pretty well, so I'm pretty confident that I can do this repair. It doesn't hurt that I grew up around tools because my dad is a mechanic either.

I'm lucky when it comes to that. ;D

[sdverona]

Jan 15, 2013 20:52:02 GMT -6 Alleyoop said:

Well if you want or need more toque say you have a lot of hills that you have to go up then a 2+2 Stroker Crank will give you more low end torque and a little less rpms. If you want a more high reving motor then stay with an OEM.
The Valve Lash is the same .004 inchs on the INTAKE and either .004 or .005 inchs on the Exhuast. I set both to .004 inchs. If you get a good head it will not change much at all because of the good metal and will hold its lash.
Alleyoop

awesome. I'll take a look at that. I got a 62mm head from scooter elements, I hope it's a good quality head. Could you point me in the right direction for a 2.2mm crankshaft? If I'm going to split the case, I might as well upgrade it.

[sdverona]

Nevermind... I just googled it lol ;D