Rebuilding 94 gs500e

[chbix]

Hello everyone, ive been reading this site for about a week and finally decided to post.  My brother owns a 94 gs500e and got my onto this site.  He bought a 04 gsxr 600 when his gs started having problems.  Mainly it wont stay running.  He put a V & H exhaust, and then while he was in Iraq he recieved an ignition advancer and I installed that, I didnt really ride the bike but started it to keep everything nice and happy.  Well he gets back and it runs fine for a while but then decided to not want to stay running.  We changed the plugs and that did some good for a while but after about 6 months it happened again.  We rejetted and cleaned the carbs and that did not fix the problem.  We noticed that if you remove the carbs and turn the engine over that air is being pushed back out on one of the intakes (where the carb is connected to the engine).  

So we finally have time to work on it this week  (thur & fri), and having recently bought a 2001 gs 500 engine, are either going to tear open the old engine and see if we can rebuild it, or put the new one in and see how it goes (maybe both options).  

Any ideas on what else the problem may be?  Any advice on rebuilding the old or installing the new (anything to make sure or be careful of? )

We are also going to install clip ons, and a full fairing kit that is sitting in the garage for abotu a year, paint, and hopefully some custom tail work and LEDS, but we only have two days so we will see.  Im going to document the whole thing and hopefully have a website up to show everyone.  

Great website and I love the GS.

[werase643]

start by doing a compression test before you break it apart
around ...155-170 PSI ans lass than 15% diff between the two
throttle WFO or carbs removed when testing

[The Buddha]

Yea I am guessing its shitty fuel and gummed up carbs ... run cleaner and ride it till you run out of gas, then fill up with premium and couple shots of that outlaw crap and ride it till you run out of fuel again... by then the problem might have disappeared. BTW a rejet might be useful, Advancer and pipe ... rejet to 40/125/1 wahser/3 turns out... and repeat the first 2 steps.
Cool.
Srinath.

[Bob Broussard]

Blowing back out of the intake manifold is a valve that's not seating.
Could be burnt or bent

[Kerry]

Blowing back out of the intake manifold is a valve that's not seating.

So, at the very least check the clearance on that valve.  It sounds like it may be way too tight, leaving the valve open too long (which may have resulted in "burning" the valve).  If you're really lucky you might get away with swapping the shim out for a thinner one.

But like Bob said, there are other possible causes which would explain the "blow back" just as well.  It's just that they're all considerably less desirable....  

[chbix]

we did rejet, it does have an advancer and a V&H exhaust.  we did a basic, thumb over the hole as you turn it over compression test and it seemed ok, but we will get a tester and try as well as check those valves.  Thanks guys, the more input the better

[chbix]

my bad its a 95 not a 94 but it shouldnt make a difference

[JBix]

Hey guys, long time no see. This is my bike that we're talking about here. We've had the carbs out three times and cleaned them each time, they weren't dirty to begin with, which surprised me. They are full of fuel each time we take them off. When we jetted it, we put in 40 pilots and 140 mains. This bike is intended to be a track bike when we get it running, so economy and driveability aren't our main concerns at the moment. We just wanna get it running. It will be thanksgiving, so nobody's gonna be open in our local area, all we're gonna have is the two engines, tools, and some gasket maker. Thanks for your advice so far, hopefully this info helps to narrow it down, but we'll post to update and let y'all know what we find. We also just won a shock on ebay from a katana 600 which we'll be doing when we get it, but everybody knows how to install that. I'll put all the pics and walkthrough in detail on my website. Once we get it all together I'll post the website in this topic.

[The Buddha]

OK 140 mains... too big for airbox K&N and too small for K&N lunch box ... 150 if linch box and 127.5 if airbox K&N... why you have 140 in there...
If DJ 140, ok still too big, they give you 132 or 134 right.
Cool.
Srinath.

[chbix]

we have pod airpod filters.

[The Buddha]

POD - as in one pod that covers both carbs and goes in place of the airbox ... aka no air box .. Then use 150 mains.
Or that K&N that goes in side the airbox just like stock filter ... use 127.5.
Problems when hot = rich, too rich, only way you get over rich with 140 is if you have the K&N in the airbox ...
Cool.
Srinath.

[chbix]

we have individual pod filters one for each pod, they are not K&N

[The Buddha]

Then 150 mains ... they are the metal mesh and gauze inside type right... then yes 150. If they are the UNI type which is foam that shuld be ~145 or so.
Cool.
Srinath.

[dgyver]

150 was too rich for me. Running 145 with the built motor. Nice tan plugs.

[JBix]

Okay, here goes. We took the head covers off to check the valves, manually cranking the engine, everything rises and seats.  On manual power, we did a compression test, and registered about 50 psi through about four compression cycles. (Manually as in by hand, can you even measure compression in such a manner?)  We put it all back together to do a compression test under its own power, but had to hook it up to another vehicle as the battery is doa. Since we had to jump it, we decided to just see if it would fire. After about five minutes of cranking, it fired up.  Runs strong, but HIGH (about 7k rpm. or more) Throttle and choke are not stuck, we checked, played with the idle screw to no avail, we are yet to adjust idle air mixture screw on the bottom of each carb.  Any ideas on why it would run so sky high?

Thanks

[JBix]

And btw, we have individual pod, uni type foam air filters, 1 for each carb.

[werase643]

leave the engine alone
send the carbs to buda...Srinath

congrats on starting it...what is the compression reading
by hand.....ya'll that bored...really?

[chbix]

the compression reading when we cranked it over manually was lie 50 psi

[werase643]

yeah i know.... how about when you do it the right way.....

not being a duck
actually trying to help
but need valid info
to help troubleshoot

[chbix]

as soon as we finish it ill post