Amsoil V Motul 300 v Motorex

Hi Guys,

I have done some searching but havent found quite what im looking for...I have rebuilt my YZ426 2001 (due to 3rd gear dog tooth wearing off) and want to run the best possible oil. Usually ride trails/forest 30-40degree celcius.

Since 2001 when i bought the bike i have used Motul 300 (fully synthetic $$$) and my engine builder said it was the cleanest engine he had ever seen considering the use its had. The only sign of wear was in the top of the rod from when it had first ever been started.

But lately i can get motorex cross power 4T 10w-50 fully synthetic at wholesale prices so i changed to that, however I have noticed more oil that usual coming from the engine breather and seems to be thinner than the Motul. I change it more regularly (usually 5 to 10 hours or if its been sitting in the shed for a while) as i dont really trust it as much.

I read great things about Amsoil and have read the tests, but I dont know which Amsoil product is right for me? No retailers stock it near me so will have to buy from ebay australia. MCV or MCF?

will this work? http://cgi.ebay.com.au/AMSOIL-20-50-MOTORCYCLE-ENGINE-OIL-/280532099358?pt=AU_Motorcycle_Parts_Accessories&hash=item415104211e

or this one?

http://cgi.ebay.com.au/Amsoil-10w40-Synthetic-Motorcycle-Engine-Oil-motul-/120538818808?pt=AU_Motorcycle_Parts_Accessories&hash=item1c10ac68f8

thanks

Do you really believe an oil test marketed by themselves? Not a fan of the multi level marketing either.

Look for an oil that is derived from a group V oil or polyol ester.

There are a few oils that use polyol ester as the base oil. I use Redline , but there are a few others. Maxima has one version that uses this base stock also.

I have an 09 yz450 with 388 hours on it and has not been opened up for a rebuild or even a timing chain. This bike is ridden by a pretty fast 20year old B rider. My son in-law. I understand oil is a personal thing but at least educate yourself on hard facts and not marketing hype.

I am in no way trying to downplay Amsoil oil because it is at least a " true" synthetic. It's a group IV. Redline just happens to be a Group V and that's what I feel is best for myself based on many many hours of research.

Edited by Gunner354
Do you really believe an oil test marketed by themselves? Not a fan of the multi level marketing either.

Look for an oil that is derived from a group V oil or polyol ester.

Multi-level marketing is only significant to you if you are a seller. Amsoil's oil test was done by an independent lab and certified by a notary public. The information published in the test is accurate.

I run MCF (10w-40) almost all year long here while the ambient temps remain below about 95 ℉. (35 ℃) For the warmest 3 months or so when I ride in temps consistently above or very near that hot, I run MCV (20w-50) instead. The product you linked to in the eBay ad is MCV.

Amsoil can be purchased directly from the website at Amsoil.com. If you think that you will use enough of it during a year to offset the fee, you can become a Preferred Customer for $20, and save 20-35% on product.

As for the transmission in the long run no oil will solve the 3rd gear issue thats why they went to a 4sp with wider gears in the 450s in 04. if you look at the part #s on the 426 gears you see they go back to the 2 strokes in the mid 90s and are not up to the out put of the new engines.

As for the transmission in the long run no oil will solve the 3rd gear issue thats why they went to a 4sp with wider gears in the 450s in 04. if you look at the part #s on the 426 gears you see they go back to the 2 strokes in the mid 90s and are not up to the out put of the new engines.

Pretty bold statement. Information to back that up please?

As for the transmission in the long run no oil will solve the 3rd gear issue thats why they went to a 4sp with wider gears in the 450s in 04. if you look at the part #s on the 426 gears you see they go back to the 2 strokes in the mid 90s and are not up to the out put of the new engines.
It's both bold and inaccurate. The YZ400F and YZ426 transmissions are the same physical size as the ~1999 and later YZ250, but the part numbers on the earlier 250's are not the same. The 3rd, 4th, and fifth pinions, the gears involved in the typical 4th and fifth gear pop-out problem in the YZ426, are directly from and interchangeable with the 1998 YZ400F (5BE...) These were also used in the 1999 YZ250, but the 1998 YZ250 had a whole different gear set (4JX..., 4MX...and 4XL... mostly).

Furthermore, the problem has nothing specifically to do with the load bearing capacity of the gears, so it is unrelated to the gears' widths. The trouble is more a combination of materials and rider technique. The lugs on the gears are a bit softer than they might have been, and "lazy" shifting can aggravate the matter by causing more than the necessary amount of clashing of the lugs as they mesh. Oil can provide some protection from this, but only to the extent that the lugs are worn away, rather than hammered round.

Incidentally, the 4 speed was introduced for its own sake, because it was decided that the bike should be a 4 speed, not to make the trans stronger. Kawasaki did the same thing at first with their 450F. Also interesting is that many of the 4 speeds have developed the same exact problem with 3rd and 4th, and are in fact apparently more prone to actually break third gear than the older 5 speed was.

98 yz250 and 98 99 400f are pretty much all 5BE gears and all the way through the 5sp 426 they interchange 5BE. except for the 1st gear you can use WR or YZ gear sets to get a pretty custom ratio trans.

the fact is that the 3rd gear ratios of the 5sp and the 4sp are the same and with the same engine( 04-05 450's), same tracks , same rider,same oil, same final ratio, the 3rd (and to some extent) 4th gears (teeth) in the 5sp version chow out. the 4sp ones don't. Our local Yamaha dealer still stocks 3rd and 4th gear pairs for the 426 and they still sell, they don't find a need to stock the 4sp gears.

All I was saying is that from personal experiance with the 4sp and the 5sp in 05 450's no amount of surface treatment or coating seems to prevent the teeth in the 5sp from failing ( non standard HP supermoto use). The newer bikes have the same ratios as the early 5 speeds and when you lay them out on the bench most of the extra width of the trans pack has been added to the 3-4 gears.

98 yz250 and 98 99 400f are pretty much all 5BE gears and all the way through the 5sp 426 they interchange 5BE.

This info is from the Yamaha parts manual. The list is partial for brevity, and I've edited out clips and washers:

1998 YZ250K:

1 4JX-17411-00-00 AXLE, MAIN

2 93306-20540-00 BEARING

3 4MX-17151-00-00 GEAR, 5TH PINION

4 90201-22555-00 WASHER, PLATE

6 4XL-17131-00-00 GEAR, 3RD PINION

8 4XL-17141-00-00 GEAR, 4TH PINION

9 4JX-17121-00-00 GEAR, 2ND PINION

11 93311-41734-00 BEARING, CYLINDER 11

12 93311-62035-00 BEARING, CYLINDRICAL

13 2VM-17421-01-00 AXLE, DRIVE

16 4MX-17211-00-00 GEAR, 1ST WHEEL

17 4XL-17251-01-00 GEAR, 5TH WHEEL

1998 YZ400K:

1 5BE-17411-00-00 AXLE, MAIN (14T)

2 93306-20532-00 BEARING

3 5BE-17151-00-00 GEAR, 5TH PINION (21T)

6 5BE-17131-00-00 GEAR, 3RD PINION

7 5BE-17141-00-00 GEAR, 4TH PINION

9 5BE-17121-00-00 GEAR, 2ND PINION (16T)

11 93306-00431-00 BEARING

12 93306-00426-00 BEARING

13 5BE-17421-00-00 AXLE, DRIVE

14 5BE-17211-00-00 GEAR, 1ST WHEEL (27T)

15 5BE-17251-00-00 GEAR, 5TH WHEEL

1999 YZ250L:

1 5BE-17411-00-00 AXLE, MAIN (14T)

2 93306-20540-00 BEARING

3 5BE-17151-00-00 GEAR, 5TH PINION (21T)

6 5CU-17131-00-00 GEAR, 3RD PINION (18T)

7 5BE-17141-10-00 GEAR, 4TH PINION

9 5BE-17121-00-00 GEAR, 2ND PINION (16T)

11 93306-00442-00 BEARING

12 93306-00426-00 BEARING

13 5BE-17421-00-00 AXLE, DRIVE

14 5BE-17211-00-00 GEAR, 1ST WHEEL (27T)

15 5BE-17251-00-00 GEAR, 5TH WHEEL

Note that not only the gears but the bearings differ in the earlier 250. The fact is that the YZ250 got an upgraded gearbox from the 400F in 1999, a year after the four-stroke came out.

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