A LESSON LEARNED
 

Well, this probably isn't too big a deal or even new to many of you but, to me, it is. So I wanted to share in hopes it might help someone else.

BACKSTORY: Like many of you, I have done a ton of mods to my VTR. And like many of you, I have been inside my airbox and carbs more times that I ever want to go again. So a few months ago, my last carb mod was to thoroughly check and replace all Vacuum tubes and to turn the fuel mixture screws DOWN to F-1.50 and R-1.75 turns. That mod went without a hitch needless to say cause that's the easy part. The hard part was seeing if the mixture screw setting agreed with info I learned from another website in Europe. So, to make a long story short, the mixture setting worked and the bike ran way better down low and up top. So, the next day, I go for a ride to thoroughly ring out the bike through the gears and rpm range and all was PERFECT! The only problem was that damned 4000-4500 rpm range upon DECELERATION. I was getting some slight hesitation when I eased very gently off the throttle at this rpm range. But I refused to make anymore damned carb changes.....lol!

So now, moving forward with this story, when I replaced my rear tire recently, I had previously tightened my chain due to EXCESSIVE sag as this was the first chain lube since the new tire. After getting everything nice and tight, I was ready to lube the chain while I had the bike on the rear stand. I had remembered that while at the tire shop, the tech told me that I had a pretty tight, TIGHT SPOT in my chain. So as I rotated the tire while holding a rag on the chain with my left hand, I noticed the tire would lock up and become pretty hard to rotate. At first, I thought the bike had somehow slipped out of neutral and into gear. I then pushed a little harder and the wheel spun then spun pretty freely. I was like, "WTF"? So I loosened the chain slightly. WHen I rode the bike though, I got very little chain noise but I did notice the bike would sputter while decelerating as though something was amuck in the carb settings.

So fast forwarding another month and a half................

Yesterday, I purchased a new front tire and also a new chain. The Tech remembered me and I asked him if a "TOO TIGHT" of a chain would cause my bike to sputter upon deceleration. He said that it could in theory cause when you decelerate, you are removing the load (acceleration) off the bike and that tight spot if too tight could cause the bike to jerk every time that spot rotates around. His reply was..........YOU WILL FIND OUT VERY SOON.......lol!

TODAY: Well, I rode the bike to work with the new chain and tire and OMG! The bike is sooooooo smooth now at acceleration and deceleration and I get no hesitation. WELL, OKAY, JUST A LITTLE BIT WHEN THE BIKE IS AT ITS HOTTEST TEMP (rich?). And even then, I have to find it in the throttle. And THAT is probably something in the carb settings but its not worth messing with cause its so slight.

The old OEM chain that had the tight spot definitely affected the bikes performance and it was a good lesson learned. I was almost ready to go back into the carbs before the chain swap and mess with everything again cause I simply associated the "HICCUP" thingy at deceleration with the carbs and the jetting and it was the damned tight chain.:p;):D

Did you even look at sprocket wear?

Its important to set the chain to spec at the tightest part of the chain as well as doing it while the bike is on the side stand! The chain has a different tightness when its on the side stand as opposed to on a rear stand and the manual calls for it to be on the side stand when adjusted

Wow, thats a lot of.........words.

The moral of the story is a beat chain can feel wierd.(?).

I didnt know about adjusting the chain on the sidestand. Good info.

And tofaz, its not like you put diesel in the tank or something. Now THAT would be a heckuva story.

Next time I tune carbs will start with the chain

My bike is not playing up at all and my original chain has a tight spot.

I have new chain sprockets and Cush rubbers ready to go.

I too have been into my carbs more than once.

I hope that a new chain etc does not do the reverse and cause problems!

That would be my luck.

Also do you have a rear shock spacer? If you do that throws the whole chain adjustment thing out the window.

I have one and trial and error on the back stand has resulted in correct chain tension for me.

Good news for you, glad it worked out.

My original chain and sprockets are still serviceable, but my bike has always had a vibration around 4500 revs and I am hoping that the driveline refurb takes care of it.

By the way , don't trust the marks on on the chain tensioners, I always use a laser aligner!

Peace of mind, and use it on the Duc and Aprilia as well, and they run sweet.

THETOPHATFLASH: The rear sprocket is brand new. I had the tire tech look at both sprockets and they are in tip top shape. The front shows very LITTLE signs of wear according to the tech (who owns the motorcycle tire shop that I frequent).

JSCOBEY: Yeah, I read that in the manual. But I've talked it over with the tire shop guys and I've found no real difference either way. The chain was OEM and I bought the bike used. Its had a tight spot since before I bought it. Its just gotten progressively worse. Next adjustment, I will do it on the side stand.

SMOKINJOE: Not really sure about your comment and sorry it wasn't interesting enough for you so, I will just say.........OKAY?! Oh yeah, and I will not be putting diesel in my tank anytime soon. I'm 44 years old and have gone this long without doing it to any vehicle I own and im quite sure it will NEVER happen...........lol!

Jerry: Cool

KENMORE: Great response. I do have a 6mm shock spacer and I use the same method all the tire guys use. They adjust my chain upright and I've NEVER EVER had a chain issue due to adjusting other than the way the manual sais too. The tight spot just got progressively worse and the chain has been up for replacement since I bought the bike....lol! It was rusted too much for my liking but the tire techs told me that it was in good shape at the time and replacing it is just burning 150 bucks. But the tight spot got worse and it was time to go. And I use a set of calipers to adjust the chain down to .001". Yes, i'm a perfectionist in my own mind when it comes to getting both side of the adjuster tits. And like your laser aligner, the calipers help to get the everything all even and the bike runs great. the new chain though made a HUGE difference in the way the bike runs......period. Its as noticeable as gaining 10 HP across the rev range.....lol

what have you found in regards to chain tension with a spacer?

also i think all the VTR's have that vibration. its not that bad but its a bit lumpy from a low RPM and at about 4500 it starts to smooth out. just the nature of the twin

the ducati is REALLY lumpy till about 4000