Results 1 to 9 of 9
  1. #1

    New Top End - Easy...By Myself- No scrapes/scratches!

    Just finished putting a new top end on my '93 650. The last time was so frustrating...not enough hands! So....I came up with an easier way!

    1. I sat in my easy chair, put the rings on and slid the piston down from the top with just a little work to compress the rings! PUT FORWARD E-CLIP IN PLACE!
    2. Hooked two ties together (only because I didn't have real long ones) and put them thru two jug holes and then under piston skirt so the piston can not fall too low where the rings will pop out, but allows just enough room to insert the piston pin from beneath!
    3. cut a 2 x 4 with two notches to support the piston
    3. used one of my gluing clamps to hold the 2 x 4 in place!
    4. put wrist pin in rod
    5 Set jug on 2 x 4, turned crank by hand until piston pin alligned with rod, pushed in pin, all the way
    6. Took 2 x 4 out and carefully layed jug to one side ( making sure NOT TO raised or lower and allow rings to escape!
    7. Put rearward e-clip in most of the way
    8. Took old pin and with "light" hammer smack, set e-clip in place
    9. Used light and mirror to MAKE SURE THE E-CLIPS WERE PROPERLY SEATED!

    All 3 done in 21 minutes, no stress, no help needed, no bad words!

    Click image for larger version. 

Name:	DSCN4727RED.jpg 
Views:	55 
Size:	66.0 KB 
ID:	281629

    Click image for larger version. 

Name:	DSCN4731RED.jpg 
Views:	51 
Size:	109.8 KB 
ID:	281623
    Click image for larger version. 

Name:	DSCN4733RED.jpg 
Views:	51 
Size:	81.5 KB 
ID:	281627
    Click image for larger version. 

Name:	DSCN4735RED.jpg 
Views:	56 
Size:	101.0 KB 
ID:	281628


  2. #2
    I did remember the gaskets! just took the pictures first! HOWEVER, i still have to address the squish problem. Everything is stock (cyl are .5 over) and the squish is about .115?

  3. #3
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31
    Nice job LT.

    Are you sure you're getting the solder all the way against the cyl wall for squish test?

  4. #4
    Absolutely! At TDC, the tops of the pistons are exactly even with the top of the jug. There is a .125 head gab above the jug top surfacem, exactly the width of the piston. So, the only way to reduce the squish is to surface the head! Period. It's all stock!

  5. #5
    burtonrider10022's Avatar
    Join Date
    Jul 2012
    Location
    Orland Park, IL
    Posts
    396
    +1
    13
    What gaskets are you using? A thicker cyl base gasket or head gasket can effect squish IIRC

  6. #6
    I'm using a standard gasket. They are not thick by any means. I'm going to attach a pic of the head. As you will be able to see, because of the head configuration, the .090 you see at the "lip" area, unless the crank was lengthened, it is impossible to achieve LESS that the .090 Then, the additional squish (taking it to about .125) is due to the slight curvature of the piston at it's edge. Even with NO head gasket, it's impossible to decrease the .090 without milling the heads. I have my original 1993 manual and the word Squish or anything related to that value is non-existent! Is there any chance that squish was not an issue at that time?

    Click image for larger version. 

Name:	DSCN4644.jpg 
Views:	49 
Size:	49.8 KB 
ID:	281686

  7. #7
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31
    I wonder if we can get another 650 owner to check the heads on theirs? That just seems like an aweful lot.

  8. #8
    That would be nice. I can say that all the heads that I've seen on e-bay appear to be identical to what you see above! If decreasing the squish on my 650 would make it more reliable, I will have someone mill them. I thought I read that the proper squish (.065 or so) supposedly helps with the cylinder heat, etc, not just the combustion burn? The solder I used for the test is .125 and it barely get an imprint during the test. So little, in fact, that it actually just indicated a .125 squish!

  9. #9
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31
    I got confirmation that the old 650 heads had that much squish from the factory. No need to have them milled.

    Break the rings in and see what you get.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. FS polaris-700-cyl-new-top-end-kit
    By ZMANN in forum Polaris Classifieds
    Replies: 2
    Last Post: 12-16-2009, 01:53 PM
  2. FS F.S. NEW top end rebuild kit 750 pol 1mm over
    By john zigler in forum Polaris Classifieds
    Replies: 0
    Last Post: 11-30-2009, 10:34 AM
  3. Troubleshoot New Top End - running rough 787 Engine
    By KCseadoo in forum 2-Stroke Performance
    Replies: 5
    Last Post: 09-05-2009, 10:54 AM
  4. new to doo looking @ 05 with new top end
    By firehawk in forum 4-Tec Performance
    Replies: 0
    Last Post: 04-16-2008, 08:58 PM
  5. HOLY COW!! New top-end SPEED!!
    By Pistonwash in forum Yamaha PWC Performance (2-stroke)
    Replies: 18
    Last Post: 03-26-2006, 10:06 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •