Register Community Calendar Today's Posts Search

Go Back   GZ 250 Forums > GZ250-Specific > General Maintenance

Reply
 
Thread Tools Display Modes
Old 04-26-2011, 03:57 AM   #11
Water Warrior 2
Senior Member
 
Join Date: Dec 2006
Location: Squamish B.C Canada
Posts: 11,409
Re: Time for an engine overhaul?

5th bike, it is normal to have tools you will never use. I have lots of them. I even have a half inch torque wrench still sitting in the original packaging for the last 16 years. I have no idea how it works.



Login or Register to Remove Ads
Water Warrior 2 is offline  
Reply With Quote
Old 04-27-2011, 11:42 PM   #12
anjames
Junior Member
 
Join Date: Sep 2010
Location: San Diego, CA
Posts: 12
Re: Time for an engine overhaul?

Damage report!

I got it all apart today and to my surprise only ONE of the rings was broken, into five pieces. For those of you curious, it is possible to take the head apart without removing the engine, but just barely.

Unfortunately, the cylinder is pretty scored from the broken ring bits jabbering around during my ride home, and a new cylinder is $300! Doh! Anyone know where I can pick up a cheaper used cylinder?

I took photos too, and will post them.
anjames is offline  
Reply With Quote
Old 04-28-2011, 12:55 PM   #13
anjames
Junior Member
 
Join Date: Sep 2010
Location: San Diego, CA
Posts: 12
Re: Time for an engine overhaul?

Found a new cylinder on ebay for $40! I talked to the seller and they said it still has smooth gasket and cylinder surfaces. Score! :rawk:



Login or Register to Remove Ads
anjames is offline  
Reply With Quote
Old 04-28-2011, 03:24 PM   #14
anjames
Junior Member
 
Join Date: Sep 2010
Location: San Diego, CA
Posts: 12
Re: Time for an engine overhaul?

For the curious, here are the photos.
anjames is offline  
Reply With Quote
Old 04-28-2011, 05:15 PM   #15
Water Warrior 2
Senior Member
 
Join Date: Dec 2006
Location: Squamish B.C Canada
Posts: 11,409
Re: Time for an engine overhaul?

Just curious. Are the cylinder walls to badly scuffed that trying to hone out the marks would be a waste of time ?



Login or Register to Remove Ads
Water Warrior 2 is offline  
Reply With Quote
Old 04-28-2011, 06:39 PM   #16
anjames
Junior Member
 
Join Date: Sep 2010
Location: San Diego, CA
Posts: 12
Re: Time for an engine overhaul?

Unfortunately, I think they are. The scuffs are smooth, but since I had to ride it almost 5mi home after the rings blew, they are quite deep. Also, since the rings were broken into several bits, the gouges are not axisymmetric, so new rings wouldn't be able to seal against the cylinder. I think they may be even more than 1mm deep in some places.
anjames is offline  
Reply With Quote
Old 04-28-2011, 07:44 PM   #17
blaine
Senior Member
 
blaine's Avatar
 
Join Date: Feb 2010
Location: P.E.I. Canada
Posts: 3,784
Re: Time for an engine overhaul?

That cylinder is toast.You were lucky to find one on e-bay.Good luck.
:cool:
__________________
If at first you do succeed, try not to look surprised.


blaine is offline  
Reply With Quote
Old 06-10-2011, 02:36 AM   #18
anjames
Junior Member
 
Join Date: Sep 2010
Location: San Diego, CA
Posts: 12
Re: Time for an engine overhaul?

Hey hey, at least two bits of good news this week: it's back together and actually running today and I finally finished my PhD. Hell yes! In hindsight, both of these things are clearly possible to do, but I wouldn't recommend starting either one because you will decide halfway through that it is way too much work for what you're getting but as soon as you're started it feels too late to quit.

I accidentally bought the wrong tappet adjuster, so I wasn't able to adjust the valves (which were tighter than spec after reassembly), and the spark plug is a little gunky due to burning all that oil, but it fired right up and ran fine this afternoon when I gave it a go. One new plug and one tappet adjuster set and it'll be running like a champ again.

Some words of wisdom:
The over-sized rings must be hand compressed while sliding the piston into the cylinder, otherwise they will (did) break, you will have to buy a new set, you'll have to fish bits of them out of the case, and you'll feel like an idiot at the same time. A telescoping magnet eases all of this pain if you do make this mistake. To avoid this problem, you should definitely have a clean rag immediately handy as you pull the cylinder out to wrap around the bottom of the piston before completely separating them so broken ring bits don't fall in the case, and you should leave it wrapped there until after you have the piston with fresh rings in the cylinder again.
anjames is offline  
Reply With Quote
Old 06-10-2011, 08:50 AM   #19
blaine
Senior Member
 
blaine's Avatar
 
Join Date: Feb 2010
Location: P.E.I. Canada
Posts: 3,784
Re: Time for an engine overhaul?

Quote:
Originally Posted by anjames

I accidentally bought the wrong tappet adjuster, so I wasn't able to adjust the valves (which were tighter than spec after reassembly), and the spark plug is a little gunky due to burning all that oil, but it fired right up and ran fine this afternoon when I gave it a go. One new plug and one tappet adjuster set and it'll be running like a champ again.
A Schrader Valve or a Phillips screw will fit the adjuster.I always liked using a schrader valve.A short one works better than the factory tool.The factory tool is too long for adjusting the valves on the intake side without moving the wiring harness out of the way.
:2tup:
__________________
If at first you do succeed, try not to look surprised.


blaine is offline  
Reply With Quote
Reply




Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:15 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.