srv 540 help

R

RBBH540

New member
Joined
Jan 10, 2011
Messages
7
Age
46
Location
Illinois
I came across an 1987 SRV 540. I messed around and got it running pretty good. I got one problem.....

It starts easy....Idles fine. When you punch it (WOT) it runs excellent for a couple seconds then falls to 5000 rpms or so and wont go any faster. If I stop for a couple seconds then hit it it does the exact same thing.

Is this a fuel issue? Is the float bowl running out of gas....pump not keeping up?

ANy body had experience with this I could use your help.

Thanks



P.S.
It has the stock keihin carb.
I have taken apart and cleaned the carb.
No airbox....looks like a K&N filter.
I disabled the oiling system.....I run premix.
 

Many possibilities. Does it rev past 5000 and then drop back or only rev up to 5000?

If it's reving up to 5000, check your clutches. Possibly a broke primary spring. I recommend a good cleaning and go through to see what's what in the clutches.

I'd also double check your main jet to make sure it's clean.
 
It runs up to 7k...pulls good then bogs down to 5k....if u stay in it then it will backfire.
 
i have a 84 srv 540 it did the same thing i got a can of gumout carb&parts cleaner from the auto parts store and soaked the carb for an hour runs great now.
make sure to tear down the carb. before you soak it !!! it is a very mild acid and will eat gaskets and some plastic. run startron in your gas to keep it from doing it again . well i hope this helps you
 
thanks,,,i will try anything at this point.

ive cleaned and recleaned the carb
changed fuel pumps
changed coil
new pickup in the tank
new fuel line


I have thought about changing cdi box. Just not sure how.

Do these things have exhaust reeds? I know nothing about em but would that do anything.

I have also heard that these things had a TORS system? somwthing to do with a stuck throttle safety.....anyhow... there are no wires to the carb...so I guess its unhooked.

Thanks for the replies.
 
Looking at the diagram it shows some intake reed valves?

Would can these malfunction where they would cause the problems I have?

BTW...thanks for the diagrams.
 
hay any time and yes bad reeds can cause problems check them out to see if there broke or bent and check your compression in both cylinders
 
There are known issues for bad grounds on the srv's, try running a ground strap from motor to frame.
 
srv540 said:
There are known issues for bad grounds on the srv's, try running a ground strap from motor to frame.
Click to expand...
i wonder if that is the problem with mine when i hit the brakes my oil light comes on and my lights go dim :o|
 
My 93 VK 540 ate the pto piston gradually over possibly the last 2 yrs
which is only about 50 miles...used as a tow truck and ski track setter in
our back yard...It never quit , would miss at idle and would start on 1 cyl.
Never saw WOT , normally under 20mph..
It would appear to have caused by pto side crank seal. .
After pulling the ign off to rebuild crank seals and maybe brgs,,,discovered
a lot of oil in mag side which would also be a poor seal....
Bad seal on mag side results in bad crankcase suction and the impulse line
on my VK is on mag side....a cracked vacc line or one that can collapse
made from thin fuel line will lower the fuel pump capacity and behave
as you mention....I didn't see the impulse line on your list of replaced parts.
Plugged up exhaust pipe can be similar...mine has had a C section done on
it at some point in its life.
good luck
Ron
 
Ill try that...Ive looked at the vaccum line ...it seemed ok but I will still replace it...jsut in case.
 
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