Rebuild or sell?



8 replies to this topic
  • ALLAN

Posted March 22, 2001 - 09:46 AM

#1

Background:
I have a 99WR with over 3000 race and dual sport miles on it. Physically, it's in pretty rough shape but runs very good. I also have 2001 YZ426.

Objective:
I'm looking for advice as to whether it's worth it to rebuild the engine on the WR and restore it from scratch. If yes, what actually NEEDS to be done on the engine. Or are the engine components used to an extent that can't be recovered.

Does anyone have experience with this sort of project? I'm willing to spend about $800 - $1000 if I can get it close to new. I'd also like to make it lighter and more responsive like my YZ.

Any ideas?

  • Taffy

Posted March 22, 2001 - 12:31 PM

#2

new rings, set the tappets, spend the rest on powder coating the frame & making it look like the bike didn't do a million miles!

camchain as well maybe, but that's all. it's japanese mate!!

Taffy

  • AZJeff_99WR400

Posted March 22, 2001 - 01:34 PM

#3

Hey Allan.

I just spent $555.00 to get my 99WR's top end done. Somehow my valves, etc. got all carboned up and stuck open, thereby losing all compression. Only within the last 8 months before the problem did I switch to YZ timing.

My mechanic is a well-known guy in Arizona (Piper Performance) yet he could not say exactly what caused the problem. He suspects some of the carboning was caused by my experimentation with race fuels, octane boosters, ect. The general rule from an engine builder is unless your bike is experiencing detonation, stick with 92 octane pump gas. The ignition system (not the timing) on WRs/YZs is designed to work with 92 octane by the way.

Parts-wise, they put in:
- new valve seals and guides
- new piston rings
- new compression release return spring (prone to breakage)

Labor-wise they:
- honed the cylinder for the new rings
- cleaned up the carb and head
- readjusted the valves
- installed a Scotts stainless oil filter
- changed the oil
- reassembled everything

That's my 2 cents worth. However, nothing feels quite like a new bike...

-Jeff

  • Mathew

Posted March 22, 2001 - 04:49 PM

#4

Does the thing use a lot of oil or something? You say it runs good - so why mess with it. I have 1500 off road only miles on my 98 and it seems just as perfect (power, compression, oil consumption) as it did new. The way I look at it - my friend has an FZR1000 street bike. 5 valve head, OK 250cc per cylinder but similar motor with a short stroke and such. His manual doesn't even recommend adjusting the valves until 20,000 miles!

My advice -

buy a YZ seat and tank (Clarke, IMS, Acerbis). Maybe some new shrouds if yours are hammered. While you are installing them, pull the valve cover and switch the cam to YZ specs. While doing that check the valve clearance. Oh yeah change the oil. Find a stock YZ pipe (or buy something else if you need a spark arrestor) to lighten weight and provide more power. Now you have spent ~$500 max, a small amount of time, and you get the lighter and more responsive feel of your YZ (although still a 400 vs 426) with a new seat, tank, and shrouds.

Why mess with a good running thing?

Mathew



------------------
98 WR400F, YZ'd cam, YZ muffler

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  • ALLAN

Posted March 22, 2001 - 06:08 PM

#5

I guess what I meant by "runs good" is that is starts pretty good and makes "ok" power. It doesn't seem to be burning oil like my old XR600 used that's for sure!

On the flip side, the compression feels mushy and I can tell it lacks power from when it was new. I don't expect it to pull like my YZ due to the flywheel and extra weight, but I suspect the rings, piston and valve seats are worn excessively.

I'm either going to restore the whole thing i.e. top end, new suspension linkage bearings, frame, etc or just sell it.

The front rim is in pretty bad shape as well after from some rock abuse after at least 20 desert races.

Does anyone know where to get used rims?
AL

  • Bryan Bosch

Posted March 23, 2001 - 04:48 AM

#6

Allan, if it runs "very good" why bother rebuilding it? I'd just ride the thing and have a great time. If it feels rough, put on a new set of grips, replace your throttle cable, and put on a new set of tires.

  • Guest_Guest_*

Posted March 23, 2001 - 05:01 AM

#7

I just got jammed with a big $$$$ bill on rebuilding my 99WR. All becuase of a little cam chain strecthing. If you raced it alot I'd at least check that out....(my 2 cents worth)

  • YZ400Court

Posted March 24, 2001 - 06:40 AM

#8

I also use Piper in Phoenix for my 98 YZ400 work. Unfortunatlly I have seen him a lot lately. A couple of months ago I broke the top end of the rod. It cracked straight down from the piston pin, and nuked the top end. We put it back together with no explination as to why the rod failed. Last weekend (only about 30 hours on the rebuild) I dropped an intake valve. Once again nukeing the top end. I called stroker, and explained what happened both times. They had no good reason for the valve, but said I should replace the rod occasionally. The reason being short rod*extreme rpm=short rod life expecxtancy. If your gonna pull the top end, spend the little extra and split the cases. Have stroker press in a new rod. It's cheap insurance.

  • YZ400Court

Posted March 24, 2001 - 06:41 AM

#9

I also use Piper in Phoenix for my 98 YZ400 work. Unfortunatlly I have seen him a lot lately. A couple of months ago I broke the top end of the rod. It cracked straight down from the piston pin, and nuked the top end. We put it back together with no explination as to why the rod failed. Last weekend (only about 30 hours on the rebuild) I dropped an intake valve. Once again nukeing the top end. I called stroker, and explained what happened both times. They had no good reason for the valve, but said I should replace the rod occasionally. The reason being short rod*extreme rpm=short rod life expecxtancy. If your gonna pull the top end, spend the little extra and split the cases. Have stroker press in a new rod. It's cheap insurance.

YZ400Court
Phoenix, AZ




 
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