Greeting from Fort Worth, Texas

Hello, I am a long time rider and basic builder. My current daily ride is a Triumph Thunderbird 900 cafe.

I have been wanting to build an older Yamaha or Honda and landed on this one. Couldn't beat the price. This was left at one of my buddies rent houses a while back. He had plans for it but lost interest after he unloaded it.

I just picked up this '81. It is in sad shape. This will be a full restomod. The plan is for my wife to ride it. After I got it home Sunday I checked oil levels and the checked compression. #3 cylinder is low so the head will have to come off.
I have yet to read through the stickies, but I have already found a tremendous amount of information.

 

Do not pull the head just yet. Oftentimes the combination of stuck rings and out-of-spec valves cause initial low compression numbers.
Check and correctly set valve clearances.
Put a tablespoon of 50% Automatic Transmission Fluid and 50% Acetone (or diesel) down each spark plug hole and let it set for a week.
Spin the motor over by hand several times, then recheck compression. If it's a runner, run it till warm and recheck after the ATF treatment.
Stuck rings are very common on an engine that has sat for long periods of time.

 

check your inbox
I see you listed your shorty vin number do you have the white tag with full vin on it?
located on the frame at headstock behind head light

 

Negative on the long vin. Shorty is all I have.

 

I have plenty of time Kmoe, so I'll give that sticky ring treatment a shot. The last time it was registered was 2009. I am fully prepared for the fuel and brake systems to be junk. I am hoping the engine is solid.

My triumph sat in a garage for about 8 years, but had fuel stabilizer in a full tank and the fuel was turned off. The carbs were very manageable when rebuilding. I can already tell that the throttle valves are sticky and the cars will need new rubber everything.

 

can you register the bike with just that.
your serial number shows it is an early 81 possible under the exemption yamaha had for 9 months

list of threads by Bigfitz
http://www.xjbikes.com/forums/search/662489/?q=Bigfitz52&o=date&c[node]=21&c[user][0]=3404

 

From what I've read , it's an early 81 and Yamaha did not have the full 17 digit VIN until late 81 or 82. This should be all I need.

 

I have a feb 81 maxim with the full vin tag but you are correct and it is exempt for the first 9 months of production run for 81

 

Any idea where my production falls based off of the short vin?

 

601 is the serial number your bike was one of the first 500 built. the 500th unit built most likely built in 1980 for 81 model year
it is also a seca 4u8

is the vin from head stock or motor see if they match as far as the 4u8
5k5 is maxim

MODEL NAME: XJ550RH Seca
STREET NAME: 1981 XJ550 Seca
MODEL ID CODE: 4U8
FRAME ID: 4U8
SERIAL NUMBER STARTS AT: 000101
USA MSRP PRICE: $ 2,529.00

I would advise you to check at dmv about being able to register it as I do not know Texas requirments

your long vin would be JYA4U800?BA000601

the ? would be the check digit which is unknown until some math is done.

if my math is correct your check is 6

making your long vin JYA4U8006BA000601

TECH TOPIC: Model ID and VIN's

 

10-4 good info. Once I get back to it I will check the engine vin for comparison. It looks as though it had a VIN tag at one time. The whole bike was spray painted black by a methhead i'm sure.

 

white tag has a clear sticker on it but i do not know how you would clean it off. it also has the dat of mfg on it

the reason to check engine number is to make sure it is a seca motor 4u8 the serial number part should match frame but does not have to match, because you register the frame