WR400 connecting rod

[TallBoysWRF]

You guys that have rebuilt you 400 motors, where did you get a connecting rod? All I have found is one for the YZ400 from Pro X. I am assuming that the two are the same (WR-YZ) but can someone confirm this for me? Where did you find a unit for a WR, and how much did it cost?

[Oasis_Flame]

There is a difference in the rods. The small end on the WR is larger than the YZ's. I use stock rods with no problems. If you do use a YZ rod I'll sell ya a YZ piston for it. ?

[TallBoysWRF]

Oasis, Do you just get your rod(s) from yamaha then? Does anyone know Yamaha's price. The price I found on the Pro X YZ rod kit wad around $146 w/o thrust washers.

[SXP]

When I bored out my 400 (to 426 cc - 95 mm piston), I sent the crank to Eric Gorr (www.eric-gorr.com) and he pressed in a new 426 crank with the 19 mm small end and replaced the bearings for just about $150.

[greg-wr400]

go to a website called yamahaaccy.com select your year make model, look through the pics and order it there. or go to your dealer? g

[SmallMonkey]

DGY.com they do OEM replacements as well

[matt_patton]

ok, what's the deal with DGY? they're 30mi from me and I used to live within 5mi. Are they like the dirtbike Yamaha equivalent to Ron Ayers?

[Oasis_Flame]

Converting to a YZ rod is another option. For racing, the Yamy OEM rod may not hold up. In my case, desert running, OEM is plenty strong. ?

[TallBoysWRF]

Ok, so what are the pros and cons of converting to a yz rod? I would think the WR would be more reliable, is the YZ rod supposed to have any other advantage than being lighter?

[Oasis_Flame]

The YZ rod is a little lighter which makes for a faster rev. Faster rev., more track speed. WR can be made into a dual sport which means road use so a beefier rod is needed. Wiseco has a 426 13 to 1 piston that makes a ton of power, easy to jet and runs on pump gas that is in my 00' WR 400/426 right now. It was very easy to bump up to a 426. Were not building Space Shuttles here. ?

[TallBoysWRF]

I know Wiseco makes a 13:1 WR piston too. So do you have a 400 with a big bore kit or something?

Is the difference between the 400 and 426 just the cylinder diameter, or is the stroke also different?

[Oasis_Flame]

Same stroke, just a bigger slug. Now I did not use a 400 cyl. I bought an 01' 426 cyl. bolts on with no mods. Then used a 426 gasket set.

I rode last Sun. with this new Kenda Millville tire, great bite in mud, snow and ice. It's not the same cheap Kenda that I used to buy in the late 70's when I was a punk with no money. Much better tire. ?

[Rich_Rohrich]

Ok, so what are the pros and cons of converting to a yz rod? I would think the WR would be more reliable, is the YZ rod supposed to have any other advantage than being lighter?

The WR400 and YZF400 use the exact same connecting rod. The WR426 and the YZF426 use the same rod. When Yamaha went to the 426 they updated the rod with a bigger pin and small end bearing surface. The 426 rod is the better choice and can be used on the 400 crankshaft without any issues. Just keep in mind if you use a 426 rod on the 400 crank that you need to use a 426 style piston so the wrist pin is the correct size.

[GPS Dual Sport]

What year is your WR400? The piston pin diameter changed after the 98 model year. This is the reason for the different part numbers on the connecting rod. I owned a 98 WR400 and sold it when I found out that Yamaha quit making pistons for the bike.

[Rich_Rohrich]

The 1998 and 1999 400s (WR & YZF) all use the same connecting rods. The rod didn't change to the larger pin diameter till 2000 when the YZF426 was introduced.

Yamaha still makes a piston for the 1998 model it's part # 5BE-11631-02-A0 . Wiseco and JE also make standard sized pistons for these bikes.

[TallBoysWRF]

I have a 99 WR400. In 2000, was it just the YZ (being a 426) that the pin dia. was changed. I was looking at the pro X kits in the TT store and it says the same rod fits the YZ400 98-99 and WR400 98-2000. Does this sound correct?

I think I will stay with the 400 components though, as much as I would love to make it a 426, The wallet says otherwise. ??

[Oasis_Flame]

Tall, my bust. I think the p/n on the 2000 WR through me off as far as my info. It seems that the 2000 WR rod may be the only rod with the larger small end. After doing a p/n education check at Ronnies.com, I guess I was confusing myself. I'm still not finding the actual wrist pin sizes for the rods. Anybody? ?

[SXP]

Tall, my bust. I think the p/n on the 2000 WR through me off as far as my info. It seems that the 2000 WR rod may be the only rod with the larger small end. After doing a p/n education check at Ronnies.com, I guess I was confusing myself. I'm still not finding the actual wrist pin sizes for the rods. Anybody? ?

18 mm for the 400s and 19 mm for the 426s.

[Rich_Rohrich]

18 mm for the 400s and 19 mm for the 426s.

Exactly. ?

ALL 400s and all 426s follow this. There is no difference between a WRF and YZF connecting rod for the same year.

[Oasis_Flame]

So I guess my Wiseco piston is a special order made to fit a 00' rod but also be 95mm. Right?