How should I rebuild my WR400.. Or should i scrap it..

[AUSmoker]

I have a 99 WR400 that I paid $2600 for, it's in pretty good condition other than the engine..

It had a noise that got worse over time, to the point its in the shop now and they think its the bottom end. They have only pulled the engine and yet to open it. There rough estimate was $750 for labour and around $1000 for parts (cylinder, piston, crank and bearings seals etc.)

My options are to cut my losses and try and sell it now before they open it, and I wont get much, or, rebuild.

The main question is if I chose to rebuild, while its open what are the must do things to get done. I've heard back cutting the gears (dont know what that is) and what about going a bigger piston, higher comp etc.

I've read about 426 parts working but dont know enough about it. I believe the 426 cylinder can go to a 444cc where as the 400 only to 420. More power makes scence if its only going to cost a few hundred more.

What are other things to check, such as valves and carb slide etc. If I fork out 2 odd k I want this thing to be super reliable and not drop a valve or some other $50 part thats 16 years old and take out the engine.

Its basically stock other than some exhaust pipe on it and a cam to make it start easier. My plans if I keep it would be to deck it out in SM rims and basically check every other bolt and make it custom and upgraded where I can, over time.

Buying used has really made me wery, especially something so old. There is an 04 Wr450 for $3500 and a 06 WR450 with SM rims for $6000 near me. I could spend $3500 for the engine and rims, and have a fresh engine with fresh rubber and brakes for about the same as the 06. Id hate to fork out for a new bike only to have the engine flake after 6 month to a year, even 2 years!

Is a newer 450 that much better? Can I mod suspension to compare fairly? I dont mind the kick start so thats no biggy. Any areas the 450 just wins?

Long post I know, tough decision to make.

Cheers

[AUSmoker]

And when I say newer 450, i mean up to 06, and thats a bit out of my range.

[underground-mpyre]

I can tell you from experiance a big bore doesn't necessarily more power unless you add upgraded camshafts to help it breathe better. Still may not make a lot to even see a difference after the ton of money you will spend.

[AUSmoker]

Its hard though, spend nearly what I paid on the bike just to fix it.

If I spend the money and it doesn't run much better that would be worse.

Edited January 30, 2015 by AUSmoker

[Big Ron L]

if hes a good Mechanic get it rebuilt. you could buy a newer WR 450 "which are better bikes" but the engine could still go so your taking a chance. it you get your 400 rebuilt at least you'll have a new engine. i have a 400 i love it. make sure you put the YZ cam in it. it makes it start easier.

[FORMA MOTO]

Dump it

Buy a newer model, 2004 or later

 

ESTART

BETTER CARB

BETTER TRANS

[AUSmoker]

Dump it

Buy a newer model, 2004 or later

 

ESTART

BETTER CARB

BETTER TRANS

How much difference is the power delivery?

What's the advantages with the carb, and also the trans?

[AUSmoker]

if hes a good Mechanic get it rebuilt. you could buy a newer WR 450 "which are better bikes" but the engine could still go so your taking a chance. it you get your 400 rebuilt at least you'll have a new engine. i have a 400 i love it. make sure you put the YZ cam in it. it makes it start easier.

It has a "decomp camshaft" fitted, i believe its the exhaust cam. Would this be inplace of the yz cam?

Should I put in a new intake cam, maybe from the yz?

It starts really easy, first kick.

[Big Ron L]

It has a "decomp camshaft" fitted, i believe its the exhaust cam. Would this be inplace of the yz cam?

Should I put in a new intake cam, maybe from the yz?

It starts really easy, first kick.

Yes, the decomp camshaft is what im talking about. to be honest with you i dont know if the intake cam is the same as the YZ im sure some of the more mechanicaly inclined could chime in about that.  btw i rode my friends 12 wr 450. its a better bike then the 400 but IMO not so much better that i would spend the $$$ on a new one. my WR works great. 

[Big Ron L]

Yes, the decomp camshaft is what im talking about. to be honest with you i dont know if the intake cam is the same as the YZ im sure some of the more mechanicaly inclined could chime in about that.  btw i rode my friends 12 wr 450. its a better bike then the 400 but IMO not so much better that i would spend the $$$ on a new one. my WR works great. my friend put a heavier spring on and the stock front forks work well.

Edited February 2, 2015 by elrontx

[underground-mpyre]

This might help.

 

http://www.supermotojunkie.com/showthread.php?139534-WR400-Street-Legal-Conversion-Project-quot-Where-it-all-Began-quot&s=ff7573aeb7152c2a686960b473a35348

[AUSmoker]

I just test rode the 04 WR450, the guy couldnt start it with the eletric start, had to use spray in the intake to start it, and took like 50 kicks then wouldnt idle. It was backfiring alot on decel. It had also been ridden in the salt and let sit so the frame was rusted and the linkage bolts seized.

But riding it, was pretty awesome. Not used to 3rd gear wheelies on command with throttle only. Only rode it for a short time but did feel really good.

I dont think my 400 would be that good even with a fresh engine. Really considering going with a 450, wish this one started first time and didnt have rust..

[AUSmoker]

This might help.

 

http://www.supermotojunkie.com/showthread.php?139534-WR400-Street-Legal-Conversion-Project-quot-Where-it-all-Began-quot

Nice link, cheers

[underground-mpyre]

I am starting to think you just don't have faith in the 50cc difference in the old and newer. Virtually the same power and easy to modernize your 400 to up to date components. Yes, you will need to drop some money to rebuild your current motor, but in the long run be wasting money by getting a new one and selling your 400 basket case for pennies on the dollar. Just only my opinion. But if you lived closer I would by your basket case, like $200 bucks. I doubt you would get more than that non running.

[bobpara]

AU Smoker: You have bad luck with bikes, In that price range you should be getting a 'no excuses' bike. Walk in the guys garage, press the lady button and boom! it starts

I'd suggest you expand your search. There are plenty of 06-ish WR450s out there for $3k

 

On that 426  once the engine is dead There are not too many good items except for the forks, the speedo & the plastic on that bike that will be worth much

Rims are gobs of work & packaging for 50 maybe 75 bucks

Bottom line is if you part out I think you'll be lucky to net $500

[FORMA MOTO]

Pouring money into a worn out bike is never a good idea, unless you have a strong emotional attachement

[AUSmoker]

AU Smoker: You have bad luck with bikes, In that price range you should be getting a 'no excuses' bike. Walk in the guys garage, press the lady button and boom! it starts

I'd suggest you expand your search. There are plenty of 06-ish WR450s out there for $3k

 

On that 426  once the engine is dead There are not too many good items except for the forks, the speedo & the plastic on that bike that will be worth much

Rims are gobs of work & packaging for 50 maybe 75 bucks

Bottom line is if you part out I think you'll be lucky to net $500

I think prices are cheaper where you are, nothing like that around me.

This guys wr that he couldn't start ran really well. Could it be a simple carby or valve issue.

He has lowered the price and i was impressed how easy it lifted the front in 3rd. Gearbox was nice and tight with not much engine noise.

There was alot of rust on it, the voice in my head is saying no but its getting cheaper and i loved how it rode.

[AUSmoker]

Well i bit the bullet, 426 to 444cc cylinder, piston to suit, 426 crank and rod, new crank gear, kibblewhite valves and new springs and seals, main bearings, 3rd and 5th gear in and out shafts, new oil pump and circlips, middle selector fork, gasket kit, seal kit,timing chain,hd clutch springs and new clutch. Possibly new trans bearings, maybe switching to hc piston and getting port and polosh and valve seats cut while im at it (this far).

I believe this should be close to the new 450s.

Also with time a yz400 seat and tank, new plastics in particular the ugly rear light will be replaced with yz400 fender and tail tidy. Set of motards would be nice too.

Yes its costing alot, but im getting a much more powerful bike, thats fresh

It is somewhat sentimental, and my cost is around half due To help.

Will the stock wr400 inyake cam and decomp exhaust need any different timing (cam chain position)

Wish me luck

[AUSmoker]

Some parts

[xr 350 kinglake]

Good thing you didn't buy that other one mate, sounds like it had issues. You in aussie? I just brought a wr400f 2000 model, it pulls 3rd gear wheelies on throttle so id go with the rebuild, keep posting if you can im keen to see what you do with the 426 stuff

Cheers