2h7020491

[yamahansolo]

i never paid attention before but according to my vin this was #491 built in 70 right??? so it should be an early 79 model. i would guess any ideas?

[DiverRay]

With that VIN, it was probably built in August of 1978 as a 1979 model Standard. The white tag on the left side of the steering stem will give the month and year of manufacture, if it's still there.

[yamahansolo]

i'll look... it's still there

[rover]

2h7020491

My 79 special has the number 3h3000343. The tag on the fork is not readable. The dealer I bought it from said the very early specials were a bit hopped up. He miked the cams, and they are quite different from the standard or the specs in the book. He also said he and his mechanic ran it against a later special, and it easily beat the other, then they switched bikes, and my special again easily outran the other one. He contacted the factory in Japan, and they say none of the experimental specials were sold anywhere. I wonder.........................

[yamahansolo]

what were the specs on the cam? also the 79's had more advance than the 80's and newer. also i suspect that maybe the early 79's may have still had the 78 timing plate. maybe???

[rover]

2h7020491

I don't remember the specs, as that happened some 27 years ago. I do remember he said the valves opened faster and stayed open longer. This motor always had a bit of a loping at idle, that is what led to him checking out the cams. We could not get it to idle as did the other XS11's at his shop.

[yamahansolo]

3h3000343. ........................

well i just looked at my label and it said april 78 not august. i have blasted quite a few 600 cc bikes and could have easily pulled away from tc and i did pull away from earl... and i was behind both of them when we took off!

[Dragon Tamer]

Rover is probably correct here (he usually is), my Fire Dragon has the same loping idle symptom. I was once told by an old Yamaha mechanic that some of the earlier '79 Specials had (if my remembry is correct) 78E cams in them and the semi rough idle was a characteristic of that marriage. Never paid any attention to whether or not the timing plate is a '78 or not, next time I have the cover off I will check it out if I remember.

[yamahansolo]

news flash 78 and 79 had the same cams!

[rover]

news flash

news flash 78 and 79 had the same cams!

If you will read back to my original post, you should be able to determine that my dealer miked the cams of the present year cams in 1979, and found that the specs were different from the cams of the PRESENT ERA. I guess the bottom line is that everyone is right, and everyone is wrong at the same tiome. Makes me wonder what the good of a discission is in the first place.

[yamahansolo]

the part numbers for the 78 and 79 were the same.

this was already discussed alot in the past about the differences of the bikes. it looks like the only thing that was changed about the 79 was one of the jet sizes was different and the timing plate advanced to 35 not 36* or something along those lines...

sorry if i sounded jerky i was ran off the road the day before yesterday and it pissed me off alot!


plus you gave me a thumbs down. i was excited because i had a very early number 79 bike one of the first built and after looking at the plate on the frame it was built in april 78 so more than likely it has the 36* advance not 35??? maybe. all i know is it screams!

i have owned several 600cc rockets and this one has more power. plus it's no where near stock either.