skyshot44

Member
May 6, 2003
18
0
I'm trying to figure out what model and year this bike is. I was told it was a YZ490.
The frame is a 1982 serial number 4V6-012856.
The engine number is 5X6-001476.
I'm starting to wonder if the engine was from a different year, or even a different model.

I would appreciate any help..

Thanks!!
 

Yogurt

~SPONSOR~
Dec 25, 1999
218
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Call your local Yamaha dealer. They can look up the VIN # and the engine # and tell you exactly what it is. On the side of the cylinder there should be a marking showing was displacement it is in cc's. If it's a 490 it'll probably be something like 488cc or 489cc or so.
 

snb73

Member
Nov 30, 2003
770
0
If I'm not mistaken, your Vin should be 17 characters. Try plugging your VIN into these sites. They worked for me.
Hope this helps, Steve.

http://www.analogx.com/cgi-bin/cgivin.exe?Mode=Decode&VIN=JS1RJ16A6P2101661&Submit=Decode

http://www.autocheck.com/autocheck/1_autocheck/jsp/home.jsp?&_209=8&_414=0040252696qIa2P8GKuAS7AmY1GDud

http://auto.consumerguide.com/vhr/index.cfm/act/freereport
 

skyshot44

Member
May 6, 2003
18
0
The Yamaha dealer is the one that got me confused.
He said the engine serial number was an '82 IT465, but the clutch arm seal that he had to find to fit it, was from an '83 IT490.
I know the cylinder is a 490, it has an 87mm bore. The carb is a 38mm, which the '82 YZ490 had. It's a four speed, which the YZ's had. The IT's had five speeds. Those things lead me to believe it is an '82 YZ490, but I just want to be sure.
I'll take another look at the VIN#, but I was pretty sure that I listed the correct numbers.
 

jmics19067

LIFETIME SPONSOR
Jan 22, 2002
2,097
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the 4v6 and the 5x6 should be able to tell you what the models are.

the it/yz 465 and 490 are so close that a lot of the parts are directly interchangeable. the seal you are talking about should fit quite a few different models.

the 465 should be a 5 speed and the 490 should be a 4 speed but the transmisions will swap out. and the engines are a direct bolt on except for the exhaust port being out to the side on earlier models and out the center of the jug for later 490's. Basicly the crank/ and crankcase are the same as with a lot of incidentals and any difference in jugs or transmisions are direct bolt in assemblies.

I will see if I can remember to get the info for you when I go to work's Christmas party today.
 

jmics19067

LIFETIME SPONSOR
Jan 22, 2002
2,097
0
serial #'s 4v6 is an IT 465 000101 is year 81 010101 is year 82

5x6 is an 82 yz490 so it sounds like to me you have an 82 yz 490 engine in an 82 IT 465 frame.

the clutch arm seal fits 74-79 yz-dt-it 250/360/400 ...80 -84 it/yz 425/465/490 RD 350's and all Banshee quads plus other models so it will fit an 83 it490 but I wonder why he picked that particular model.
 

skyshot44

Member
May 6, 2003
18
0
Thanks for the help with that. So a YZ490 engine in an IT465 frame, weird..
He had initially ordered a seal for an '82 YZ490, but it was too big. Maybe he ordered the wrong one??

Merry Christmas!!
 

snb73

Member
Nov 30, 2003
770
0
If you have any parts questions, check here. The exploded drawings can be helpfull with identification. Good luck.

http://www.bikebandit.com/partsbandit/OEM.asp

Steve
 

skyshot44

Member
May 6, 2003
18
0
Yeah, I've been using that website as a reference. Just to make sure I have all the washers and stuff in the right places.
Thanks!!
Merry Christmas!
 

jmics19067

LIFETIME SPONSOR
Jan 22, 2002
2,097
0
let's see if I can explain this well but I am going to try and brak down what Yamaha part #'s mean.

all Yamaha part numbers are 12 digits but they can be grouped into 2 different ways. lets look at a 1998 wr/yz 400f top end

Piston 5BE-11631-00-00
base gasket 5BE 11351-00-00
piston pin circlips 93420-18082-00
rings 5BE-11603-00-00


1999 yz/wr 400

piston 5GR 11631 00 00
base gasket 5BE 11351 00 00
piston pin clips 93420 18082 00
rings 5BE 11603 00 00

now lets look at the numbers themselves for the piston. All Yahama pistons are ???-11631-??-?? the 1st 3 ??? denotes the model/s the 5BE being specific to the 98 and 5GR being specific to the 99. Now all other surrounding part's numbers are the same so I tend to believe that the pistons are interchangeable but something like the designed weight denotes the difference between the two model years. The last 4 ??-?? would be 00-00,10-00,20-00 for the different sized pistons for cylinders with boreable liners OR
01-0A,01-0B,01-0C,01-0D.... the 01 saying something important is following and the 0a,0b for the a,b,c,d cylinders. There is no o's in yamaha part numbers only zeros. The base gasket and rings are the same sothey keep the original model designation that they where produced for .

parts such as bearings,bolts etc follow a different grouping of numbers as the piston pin circlips- 93420-18082-00 93420 says it is a special type of circlip.18082 says its sizes. Snap rings will have a different 1st five numbers as do different circlips if they have the little ears you can grab on etc etc.

all roller ball bearings start with 93306 all needle bearings start with93310. and here is something that can be very useful with nuts and bolts.
91317-06014-00 is an allen head bolt
98706-04012-00 is a countersunk flat head,the 1st 5 numbers saying what kind of bolt it is and the following 5 stating its size If it is a standardized hardware 06014 is a 6mm bolt 14 mm long 04012 is a 4 mm bolt 12 mm long.Bolt # 90105-104A7-00 and bolt#90105-10323-00 are both 90105 washer based bolts both are 10mm diameter bolts the next digit says that it is special, the A7 being a lenght that is not standard the 23 is a standard length.

this is something that I am still observing /learning so it is not 100% accurate but I am heading down the right path understanding them.
 
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