Rebuilding a motor...

saber63 · May 1st, 2011, 12:14 PM

so this is my first go at rebuilding a ex250 motor (ive done some small diesles a plenty) i kinda ate a conrod-crank bearing... i havent gone in there to look at all the damage.... but ive got some spare parts (mainly the crank and conrods)

so if im doing a full rebuild, which gaskets do i have to replace, if none, which ones am i most likeley going to muff up and need to replace?

also with the bearings, whats the nifty color code to size chart thingy (its been awhile )

much thanks guys!

-levi

p.s. any advice from experience would be great!

Dangler Action · May 14th, 2011, 08:03 PM

Hi Saber,

You should replace the head gasket and cylinder gasket

You'll also need to replace the piston rings if their worn badly. I didn't do it when I rebuilt my engine and my compression is still fine.

And if you're going to split the cases you'll also need Kawabond or some other liquid gasket like Yamabond or Hondabond. Don't get the cheap liquid gasket you would find at your local auto parts store.

You might be able to reuse the gaskets for the clutch cover and stator if they don't break. But if they do and you are doing this rebuild on a budget, you can always use the Hondabond liquid gasket for that.

Head Gasket
Cylinder Gasket
Piston rings
Side cover gaskets

Can anyone else think of something?

Good luck with the rebuild.

road_rascal · May 15th, 2011, 06:39 AM

I personally would get all new gaskets if you're going through the trouble of rebuilding. Servicehonda.com has great prices on Kawa parts. I've used them many times for Honda and Kawasaki parts.

speedgsx98 · May 16th, 2011, 11:42 AM

There are usually plenty of complete motors around on Ebay for $500 or so...maybe less. Haven't checked in a while. Or look for a non-running bike locally that hasn't been parked too long, but long enough to kill the battery and clog the carbs. You can then use the motor and sell off the good parts =) Rebuild will cost you time and more trouble than you want to endure...trust me. Only reason to rebuild something is if you have to or want to. I can't see anyone wanting the braggin rights to rebuilding a 250 ninja motor =) Rebuiling some obscure 60's or 70's collectible bike yes.

May 1st, 2011, 12:14 PM	#1
saber63 ninjette.org member Name: F Location: seattle Wa Join Date: Dec 2009 Motorcycle(s): '90 250 project, '03 250r, '14 STR,12 STR, '01 R6 Posts: 84	Rebuilding a motor... so this is my first go at rebuilding a ex250 motor (ive done some small diesles a plenty) i kinda ate a conrod-crank bearing... i havent gone in there to look at all the damage.... but ive got some spare parts (mainly the crank and conrods) so if im doing a full rebuild, which gaskets do i have to replace, if none, which ones am i most likeley going to muff up and need to replace? also with the bearings, whats the nifty color code to size chart thingy (its been awhile ) much thanks guys! -levi p.s. any advice from experience would be great!

May 16th, 2011, 11:42 AM	#4
speedgsx98 ninjette.org member Name: Dave Location: San Diego Join Date: Apr 2009 Motorcycle(s): 250 ninja 2002, 2008 ZX10-R Posts: 149	There are usually plenty of complete motors around on Ebay for $500 or so...maybe less. Haven't checked in a while. Or look for a non-running bike locally that hasn't been parked too long, but long enough to kill the battery and clog the carbs. You can then use the motor and sell off the good parts =) Rebuild will cost you time and more trouble than you want to endure...trust me. Only reason to rebuild something is if you have to or want to. I can't see anyone wanting the braggin rights to rebuilding a 250 ninja motor =) Rebuiling some obscure 60's or 70's collectible bike yes. __________________________________________________ 90 EX250 Ninja, 92 FZR600, 86 CR125, 77 GS750, 73 RD350, 86 CR250, RD350 in SRX250 frame, 75 RD350, 99 RM125, 99 GSXR750, 07 Reflex, 02 250 Ninja, 02 GSXR1k, 08 ZX10R, 07 250 Ninja, 05 250 ninja

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May 14th, 2011, 08:03 PM	#2
Dangler Action ninjette.org newbie Name: Rick Location: Sacramento Join Date: May 2011 Motorcycle(s): 07 Ninja 250 Posts: 2	Hi Saber, You should replace the head gasket and cylinder gasket You'll also need to replace the piston rings if their worn badly. I didn't do it when I rebuilt my engine and my compression is still fine. And if you're going to split the cases you'll also need Kawabond or some other liquid gasket like Yamabond or Hondabond. Don't get the cheap liquid gasket you would find at your local auto parts store. You might be able to reuse the gaskets for the clutch cover and stator if they don't break. But if they do and you are doing this rebuild on a budget, you can always use the Hondabond liquid gasket for that. Head Gasket Cylinder Gasket Piston rings Side cover gaskets Can anyone else think of something? Good luck with the rebuild.

May 15th, 2011, 06:39 AM	#3
road_rascal ninjette.org member Name: ___ Location: ___ Join Date: Jul 2010 Motorcycle(s): ___ Posts: 160	I personally would get all new gaskets if you're going through the trouble of rebuilding. Servicehonda.com has great prices on Kawa parts. I've used them many times for Honda and Kawasaki parts.