GStwin.com GS500 Message Forum

Main Area => General GS500 Discussion => Topic started by: Paulmuphesto on March 29, 2007, 08:11:10 AM

Title: 1998 gs500, Finding hard to start
Post by: Paulmuphesto on March 29, 2007, 08:11:10 AM
Hi there, i have been reading through the forums and found lots of useful information.  However i dont know if all applys to me.  So here is my problem and i would be greatful for any replys:

Recently purchased a 1998 Gs500.  The person i purchased it from rode it to me house with apparently no problems.  Since having it i have put in a new battery, done and oil filter change and oil change.  After oil, and filter, change the bike seemed to be starting fine with no problems.  It would idle ~ok~ ish and rode up and down my street fine.  So i booked in to get my M.O.T done.  However i decided to wash the bike so it was clean for the M.O.T, so if it passed i could take it out to play.  After washing the bike it became very reluctant to start - so i took out the battery and stuck it on charge using and Oxford oximiser.  Battery was charged and back in bike.  Still having problems getting it started unless i set the fuel tap to PRI.  Once the bike was started i took it (or at least tryed) for a quick spin up and down my street.  This is where the problem started.  It was backfiring ALOT, and stuttering to a halt and staling, unless i reved it up very high.  So i took it back to my driveway and put it on the centre stand.  Still having the same problem - Starts up relectently, Back fires alot, White smoke from exhaust, Stutters (throttle doesnt appear to do much until high revs) and stalls.

I have checked the air filter, which seems ok, as i though perhaps the carbs were flooding?

Would water in the fuel (from washing) cause these problems?

My Haynes manual suggests that these kind of problems are related to the carbs, and that they need to be taking out and inspected and repaired.  I would however like to know of any other things i could try before doing this.

Thanks for reading, and thanks in advance for any replys

Paul
Title: Re: 1998 gs500, Finding hard to start
Post by: Stephen072774 on March 29, 2007, 09:05:43 AM
You may have just flooded the bike and fouled the plugs.  I'd try new plugs first and see if that solves your problem. 

I fouled my plugs after I got my gs... I quickly learned no gas, choke on for starts, unless it was really warm out.
Title: Re: 1998 gs500, Finding hard to start
Post by: TobyR on March 29, 2007, 10:39:07 AM
You accidentally knocked the vacuum hose off of the fuel petcock? If it is acting like there is no fuel from ON or RES this is most likely it.

"Vacuum Hose to Left Carb"

(http://cgi.stanford.edu/~sanjayd/gs500/uploads/Main/hoserouting.jpg)
Title: Re: 1998 gs500, Finding hard to start
Post by: Paulmuphesto on March 29, 2007, 11:01:25 AM
i did notice when looking through the haynes manual that 3 pipes came out the bottom of the fuel tank.  When i took mine off it only had two pipes (the two from the fuel switch under the tank) but the ?water removal pipe? was not connected?

Also, i dont really understand that diagram, could you explain it more please?  (Would that cause the back firing etc if the PRI is set)
Title: Re: 1998 gs500, Finding hard to start
Post by: Paulmuphesto on March 29, 2007, 11:30:33 AM
also i checked the spark plugs for spacing etc and the spacing was fine. however , for those of you with a haynes manual they had the carbon fouling problem (picture 3 down on left, back page of haynes)

Carbon fouling - Dry, black sooty deposits leading to misfire and weak spark.  Caused by an over-rich fuel/air mixture, faulty choke operation or blocked air filter
Title: Re: 1998 gs500, Finding hard to start
Post by: scratch on March 29, 2007, 12:10:28 PM
Welcome!

Make sure the choke cable has not hung up outside its housing on the left carb.

Link soon. http://gstwins.com/gsboard/index.php?topic=8756
Title: Re: 1998 gs500, Finding hard to start
Post by: Paulmuphesto on March 30, 2007, 07:29:52 AM
Ok so i took the bike apart a bit more today and got some pictures for yous all to look at and tell me what yous think

Firstly the air filter - theres no rips in it or holes, but i still think it would need replaced?

(http://img405.imageshack.us/img405/5236/airfilteruf1.th.jpg) (http://img405.imageshack.us/my.php?image=airfilteruf1.jpg)

Secondly some pipes from the carbs:

(http://img142.imageshack.us/img142/7991/pipeskj9.th.jpg) (http://img142.imageshack.us/my.php?image=pipeskj9.jpg)

I know that C and D go into the fuel tank (normal and reserve), but i am unsure as to what A and B are.  According to my haynes manual they are the AIR VENT HOSE and VACUUM HOSE.  Should these be joined to anything as they wernt when i took the tank off?  Also C and D are joined onto the frame mounted petcock

Thirdly a pipe that was sitting down below the engine (clutch perhaps?) on the right side of the bike, is this the AIRBOX DRAIN HOSE, and if so does it matter that there is a wee hole at the bottom and it was leaking when i blew down pipe B?

(http://img105.imageshack.us/img105/8200/drainhoseuc6.th.jpg) (http://img105.imageshack.us/my.php?image=drainhoseuc6.jpg)

Fourth is the colour of the petrol that came out of pipe D when i blew down pipe B (also from when i drained the carbs).  The petrol that comes out of the main tank seems to be fine though.

(http://img259.imageshack.us/img259/3738/petrolhz3.th.jpg) (http://img259.imageshack.us/my.php?image=petrolhz3.jpg)

Lastly is some pictures of the inside of the air box, looking onto the carbs.  What do you think of these?

(http://img259.imageshack.us/img259/770/carb1th0.th.jpg) (http://img259.imageshack.us/my.php?image=carb1th0.jpg)
(http://img378.imageshack.us/img378/583/carb2aq8.th.jpg) (http://img378.imageshack.us/my.php?image=carb2aq8.jpg)
(http://img264.imageshack.us/img264/3913/carb3io7.th.jpg) (http://img264.imageshack.us/my.php?image=carb3io7.jpg)
(http://img378.imageshack.us/img378/4701/carb4af4.th.jpg) (http://img378.imageshack.us/my.php?image=carb4af4.jpg)


Thanks for looking and thanks in advance for any replys :)
Title: Re: 1998 gs500, Finding hard to start
Post by: salad on March 30, 2007, 08:16:01 AM
Quote from: Paulmuphesto on March 30, 2007, 07:29:52 AM


Thirdly a pipe that was sitting down below the engine (clutch perhaps?) on the right side of the bike, is this the AIRBOX DRAIN HOSE, and if so does it matter that there is a wee hole at the bottom and it was leaking when i blew down pipe B?

(http://img105.imageshack.us/img105/8200/drainhoseuc6.th.jpg) (http://img105.imageshack.us/my.php?image=drainhoseuc6.jpg)



yeah, thats the airbox drain hose. follow it up to see what its connected to. (or isnt connected to.) its probably 'pipe b'.

the airbox drain hose connects to the bottom of the airbox... on the left side, i think. and im pretty sure the slit on the cap is supposed to be there.
Title: Re: 1998 gs500, Finding hard to start
Post by: Paulmuphesto on March 30, 2007, 08:25:07 AM
Thanks for the reply.  Pipe B goes into the carbs, well it goes inbetween them then splits into two and goes into the top of each carb.
Do you know if pipe A and B should be connected to anything at the end you can see, or should they just be left as a sort of air intake/output type thing?
Title: Re: 1998 gs500, Finding hard to start
Post by: salad on March 30, 2007, 08:42:04 AM
hose b splits and goes into the bottom of the carbs?

then its supposed to connect to the top of the charcoal canister... if your bike has it. (its below the battery) im not sure where itd go if yours isnt a california model.
nowhere, maybe?  :dunno_white:

check out 3.16 in the haynes manual.