Anyone with a '99 do a top end yet?

9 replies to this topic
  • Dougie

Posted March 16, 2002 - 11:58 AM


Just wondering if it is something I should be thinking about. I'm coming up on 3 years and about 5000 or more miles on this thing.

I can check and replace valves myself but I don't have the time, tools or know how to do a complete top end (rings, piston if needed, etc.). So I'm wondering if I need to shell out the 500 to 600 bucks to get it done or should I wait until I see smoke?

What is going to be the performance benefit with a revamped top end?

  • MN_Kevin

Posted March 16, 2002 - 02:31 PM


New piston/rings are probably in order, Doug.

You will see increased compression, crisper response, more power everywhere.

The easiest way to find out your top end condition is to check your compression. Find out what a new top end compression is to compare it to. A low compression means either valve leakage or rings. If you pour a couple tablespoons of oil down your sparkplug hole, and kick her over a couple times w/ the compression tester installed, you can determine rings or valves. If compression goes up, it's your rings. If it stays the same, it's your valves.

Top ends are very easy to do, but you will have to remove your entire valve train (head), and cam chain. This WILL require you to align the cams ALL OVER AGAIN.

Find someone who has done 4 stroke tops ends before to help. Don't try it by yourself. You'll need someone to help compress the rings when you are slipping your cylinder over the piston.

Also, when your cylinder is off, you can inspect your cylinder walls. There should be no scoring. The finish should be uniform throughout.

The first time is always the hardest. It is time to break that top end hyman, Doug!! :)

  • Taffy

Posted March 17, 2002 - 12:11 AM


agree with kev.

i would say that you only need do the rings usually.

if you race it should get new rings for each season.



Posted March 17, 2002 - 03:27 AM


Change the Piston and Rings on a 4 Stroke at 5000 miles???? Dude Check your compression, If it is still within spec...Leave it alone... I race MX, Hare Scrambles and GNCC'...My top end is in great shape. This ain't no 2 Smoke....You do not have to re-ring every season. I'm on season #4 with just regular maintenance and valve adjustments. Man... I can Just see having to re-ring my Virago every year.....No Thanks

Bonzai :)

  • MOmilkman

Posted March 17, 2002 - 06:34 AM


Dougie, I dont have quite the mileage you do, but I have had my 99 since it was new and I can still outpull any of the new 01-02 426's. Some of that might have to do with the fact I weigh 230# (not as much wheel spin :) )

My point is, if it is still running good, then Im with Yamakaze, leave it.

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  • sbohanon

Posted March 18, 2002 - 03:51 AM


i did my top end at the end of last year. its a '99 with quite a few miles on it also. the reason i decided to do was twofold, it was smoking a little with the oil getting dirty faster and if i tried hard enough i could kick thru the compression stroke. i replaced the piston and rings however the piston was probably ok. no serious wear at all. in retrospect, if it runs good and the compression is still within spec, stay with it.

  • Mark_UK

Posted March 18, 2002 - 04:13 AM


mines a 98 and last year i did the top end , as it was a second hand bike i just wanted to for piece of mind.
i ordered the bits,,
took the top end off,,,
the piston and rings i took out where in pretty much perfect condition.

  • lewichris

Posted March 18, 2002 - 05:35 AM


if it aint broke dont fix it

  • MN_Kevin

Posted March 18, 2002 - 06:39 AM


I have been much influenced by 2 strokes. Racing MX, I put in one new piston a year and rings every half season.

Hence checking the compression first.

  • Dave_VanBrocklin

Posted March 18, 2002 - 07:06 PM


Guys, just remember that the cylinder is expensive!! A loose piston will hurt the cylinder, so make sure and do a compression check every couple months, when you see the compression start dropping replace the piston and rings. Also the crank pin on the 98 and 99 are smaller, and I have been hearing more and more of crank looseness at higher hour use. You don't want that to come apart, fix it first. My 2 cents


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