Hi gang......took CanD for a good run today....and found some deserted stretches where I was able to really open her up.......wow.......I don't think I have taken the tach this high before..........was reeeeeaallyyy coooooooool........but something happened that has caught my attention and I am hoping someone knows what it is........ I hit 2nd gear at about 6500 revs....I really opened it up....and she took off.......at about 9500.....there was a flat spot(like a spit....or pop) so I shifted into third ......again rolled it up and as soon as I hit 9500....hit the same flat spot....it only lasted for a second and the power came back on with a jump.......and again I shifted........into 4th....... On another stretch I went through the same procedure...but instead of shifting this time ...I continued up to 10500......revs........it popped again....but when she came back she really jumped and I had to hold on. Now I know it was not the clutch as I upgraded the clutch with Barnett discs plates and springs last year..... .....there was zero slide to it at all....no.......this was a power issue.....so I began to wonder how the boost and vacuum hose works...........it almost felt like the vacuum hose lost its vacuum.......I am only theorizing
Kev
rev limiter cutting in maybe
Quote from: fj11.5 on May 12, 2012, 07:13:39 PM
rev limiter cutting in maybe
I don't think our FJ's have a rev limiter, Kookaloo till Kaboom.
does anyone understand how and when the boost works.....what's supposed to happen.....?
Kev
:empathy3: Boost? As in forced induction?
The tach on the FJ is notoriously slow.... I would bet money you were bouncing off the rev limiter.
KOokaloo!
Frank
Quote from: racerman_27410 on May 12, 2012, 09:50:16 PM
The tach on the FJ is notoriously slow.... I would bet money you were bouncing off the rev limiter.
KOokaloo!
Frank
I have a rev limiter, but it is my shitty second gear issue...
Quote from: Pat Conlon on May 12, 2012, 09:00:01 PM
:empathy3: Boost? As in forced induction?
Hey Pat....good to see you ....hope all is well.........well actually when I was taking my girl apart...I looked at my shop Manual(service) and got to the section 7-48 where it shows the boost control hose routing.....I asked a few shops and apparently there is a boost hose running into no.2 carb that is a vacuum hose and somehow does something to ignition timing and opens something up and gives the FJ a little bit more in the upper revs....I think it was a precuser to the now popular V-BOOST found in the V-MAX. I read Bob Shamas's write up on his turbo project and he does mention the boost hose and how it becomes "unusable" after he threw his turbo on his bike......so I was hoping that some of the more experienced FJ er's would know more about it....
Kev
(http://i1071.photobucket.com/albums/u517/photocandman/FJboost.jpg)
Quote from: racerman_27410 on May 12, 2012, 09:50:16 PM
The tach on the FJ is notoriously slow.... I would bet money you were bouncing off the rev limiter.
KOokaloo!
Frank
Hi Fankie........is there a remedy for that........is it possible that it could be a vacuum pressure jet?
thanks everybody for all your great comments......looks like there isn't a problem at all.....
Kev
Yamaha calls it "boost", but all it is is a vacuum advance. V-boost is a heck of a lot different..... It lets the V-Max breathe thru 2 carbs per cylinder, over ~5k RPM, via a flap in the airbox.
Thought it was 6k? The fun trick there is to change the trigger to see both coils firing, which makes it come on at half the rpm. Or just use a switch to trigger it manually... makes the idle sound like you've got really big cams in the motor. :)
Could be, I'm just going by memory from 20+ years ago.... A couple friends had 'em. 1 was an '85, the 1st & fastest of 'em all.