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boost or bust?

Started by CanDman, May 12, 2012, 04:37:43 PM

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CanDman

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   
Never regret your choices in life ! There is no way to go back to do it again and compare. Make the most and do your best with every decision you make

fj11.5

rev limiter cutting in maybe
unless you ride bikes, I mean really ride bikes, then you just won't get it

84 Fj1100  effie , with mods
( 88 ) Fj 1200  fairly standard , + blue spots
84 Fj1100 absolutely stock standard, now more stock , fitted with Fj12 twin system , no rusted headers for this felicity jayne

FJmonkey

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.
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

CanDman

does anyone understand how and when the boost  works.....what's supposed to happen.....?
Kev
Never regret your choices in life ! There is no way to go back to do it again and compare. Make the most and do your best with every decision you make

Pat Conlon

 :empathy3: Boost? As in forced induction?
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

racerman_27410

The tach on the FJ is notoriously slow.... I would bet money you were bouncing off the rev limiter.


KOokaloo!


Frank

FJmonkey

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...
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

CanDman

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
Never regret your choices in life ! There is no way to go back to do it again and compare. Make the most and do your best with every decision you make

CanDman

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?
Never regret your choices in life ! There is no way to go back to do it again and compare. Make the most and do your best with every decision you make

CanDman

thanks everybody for all your great comments......looks like there isn't a problem at all.....
Kev
Never regret your choices in life ! There is no way to go back to do it again and compare. Make the most and do your best with every decision you make

RichBaker

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.
Rich Baker - NRA Life, AZCDL, Trail Riders of S. AZ. , AMA Life, BRC, HEAT Dirt Riders, SAMA....
Tennessee Squire
90 FJ1200, 03 WR450F ;8^P

andyb

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.  :)

RichBaker

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.
Rich Baker - NRA Life, AZCDL, Trail Riders of S. AZ. , AMA Life, BRC, HEAT Dirt Riders, SAMA....
Tennessee Squire
90 FJ1200, 03 WR450F ;8^P