Major power loss over 3/4 Throttle

[TheNicestPeople]

Hey there, Long time reader. First time poster

I baught a 1999 vs1400 last year for 800$ that a guy had leaning on a tree for years. Every single part of the bike was modified horribly and ive been slowly trying to fix it up.

I put a chopper front end on it. completely chopped it out. Built a custom wire harness, Added baffled mufflers, cone filters, Stage 3 jet kit. and 40 jugs of metal polish.

Long story short it runs now and pulls hard untill halfish to 3/4 throttle and it falls flat on its face. Just bogs out, no backfiring. If you back off the throttle it starts pulling again untill you throttle up and it bogs again.

The choke is not stuck on
The carbs are very clean
The cone filters i restricted untill it ran better
The fuel pump is new
The coils, plugs, and wires are new
No Vacuume leaks
The boost sensor is hooked up
The decompression is not stuck on
The stator charges 14.2 volts
The carb diaphrams are not leaking
The carbs are synced enough that the butterflys open at the exact same time and with the idle screw
It has brand new 87octane fuel
Grounds are all clean and battery connections
Good clean engine oil

Any ideas on how to fix this issue?

Thank you
-Pat

[sgtcall]

Welcome!
I can't be much help for your issue but we can try and bring in some of the experts.
In the mean time, here are a couple of things to check out.

POSTING PICTURES ON INTRUDERS ALERT
viewtopic.php?f=19&t=13992

INTRUDER MANUALS AND INFORMATION
viewtopic.php?f=19&t=14168


Here are some of the guys that may be able to help you out.

[Herb]

Is this under load on the road, or when it is sitting still reving it up or both.

The only thing I ever saw like that was a 389 pontiac that ran fine in the yard but bogged out on the road. come to find out the hood insulation was getting sucked into the air filter intake.

[sgtcall]

Check out this thread. The end result was the carbs were not clean enough but there is good info before that on other possible causes.

viewtopic.php?f=13&t=14241&hilit=Power+Loss

[Lechy]

Try a couple of socks on the pods, use air filter foam, it worked for me:



For what it costs, make up and fit a new battery earth cable, solder the ends.

[hillsy v2]

Most of those cone filters have a massive lip on them that can restrict flow to the air jets and the ports to the diaphrams. If you still have the air boxes maybe try running the OEM rubbers by themselves and see if that helps?

Or just run them without the filters (temporarily) and see if it solves the issue.

[TheNicestPeople]

Welcome!
I can't be much help for your issue but we can try and bring in some of the experts.
In the mean time, here are a couple of things to check out.

POSTING PICTURES ON INTRUDERS ALERT
viewtopic.php?f=19&t=13992

INTRUDER MANUALS AND INFORMATION
viewtopic.php?f=19&t=14168


Here are some of the guys that may be able to help you out.

[TheNicestPeople]

Alright so here is a proper update

Thanks to everone who posted! And in other threads ive googled on here in the last 14 months.

So since the last post the bike now runs 95% and considering its history iam very pleased.


So it turns out my cones were blocking the port for the bellows in the carbs.

I changed cones and it got worse, i oiled them and it got worse. i wrapped them with material and it got worse.

I cleaned the carbs and installed a carb rebuild kit. Slightly better! i dropped the front needle valve clip to 4 and the rear to 5 and slightly better! Then i found a crack in the rear carb leading into the bowl but above the floats, i sanded and patched that with fuel tank compound and it was a little better again.

Then out of desperation i removed the material from the cones and bam! 160kmh wide open pull from first gear to top gear!

Damn it feels good! i will never buy or work on another vs1400 again but iam happy this one works! My super magna 4 cylinder wasnt even close to this hard to tune


Thanks again to all you gentleman!

[TheNicestPeople]

i cant figure out posting pictures with my phone but thats a video of it when it ran poorly, atleast you can see what it looks like