(Video!) how much top end noise is too much?

[Tombo]

Just another example of backyard mechanics being too enthusiastic! We've all been there. We get the bike, we can't put down the wrench, and if it runs, we run it hard. For me, it took a solid couple of months plus for my excitement to subside, at which point I got real and had to go back and fix some things I missed, and fix some things I did wrong, I may be 30 now (I know that isn't old), but I am, and we are all, still just excited little boys when it comes the things that growl when twisted :ride:

 

[Recreateme]

I know those feels brah

When i get something i know i can fix i have a compulsion to work on it until its done, getting my bike in the fall has not allowed me this since winter came in harder then normal this year...


Back on topic, i THINK your bike runs a bit noisier then mine. Although i haven't heard mine in a while, but when it was running i do not remember hearing that tiny clatter i noticed right away on your video.. However, your engine has a better sound then mine does lol its more consistent and sounds stronger.

In summary - It makes noise, but sounds strong so if it was my bike i would call it a day because the chances of screwing up something good are higher then fixing that last little tiny detail that doesn't seem to effect the performance...

 

[Scorpio1963]

When I adjusted my valve train I made sure the bike was tdc and held the wrench in place by wedging another one to hold it in place being carefull that it didn't slip backwards.I double checked my work after adjusting each valve.When it was done I couldn't hear my engine cause of the straight pipes and turnouts I had on the bike at the time.I changed the mufflers which had a hole about an inch around in diameter for the cats that are supposed to hook up there.Even though I capped it off with a copper fitting that fit on tight I cut off too much of the pipe where the copper fitting goes so I had an exhaust leak on both sides.I could feel it the air escaping from these spots so I used some Jb weld to seal them off till I can braze them.I then synced the carbs and went on several test rides.The bike pulled good and strong and had lots of power.Then winter came and she got put into hibernation mode.So like I said closer to spring time and when its warm enough to start it up I`ll make another sound clip and you can give me your opinion and go from there.I have also read that its better to have a little looseness in the valve train than not enough.

 

[Tombo]

You are spot on about wanting to be in spec instead of too tight. It seems with these motors, the looser
you go the louder the Clatter gets. ask me how know. My other Yamaha, xs650 is actually louder at top end than the 400 as far as Clatter, but the cam chain seems to be louder on the 400. Older bikes could be louder, now there are restrictions. Nothing is quite as loud, though, as an older ducati at idle. Nothing is quite as magnificent either

 

[Scorpio1963]

Tombo on your bike are you running pod filters<
?I ask this cause I kinda here wine noise when you give her throttle.I wasn't sure if the noise Im hearis your carbs sucking air or if its coming from something else like too tight of intake valve adjustmentThe first time I adjust my valves oh way back when my bike made a similar noise when I gave it a twist.It doesn't make the noise anymore except when im cruising along at 60mph or above that because my filters suck a lot of air.

 

[Tombo]

No pods. All this talk of valve clearance got me to check this morning, still in spec.

 

[Orlen]

Here is a little info I found. Excellent book to get if you like to learn about the evolution of Yahama over the years - as well as bike styles themselves evolve in the Crotch rockets and Cruisers that are omnipresent on the roads today. Interestingly the Yahama Specials were the Grandfathers of the Cruisers we all see today. Just grabbed the camera instead of dragging out the scanner....

Please note there is reference to a lot of valve train noise in these engines. Very common among the Yahama twins at that time. Hope this is helpful!

.

 

[Tombo]

@orlen thanks for sharing! Seems like this would be a nice book got the commode. Cheers

 

[xschris]

Good read I have seen a lot of books say the xs400 had a 392cc motor but all the motors that I have and have seen, none of which where stamped 392 but all are 391