Hi. I've been having a couple of issues with my 1985 GPZ600R recently.

Firstly, occasionally the engine does a wierd thing. After starting
the bike (which goes as planned) the engine will run as normal. Then
shortly afterwards it may bog down and won't rev past about 3k rpm, no
matter how much you twist the throttle or play with the choke. It runs
like this for quite a while and then seems to clear itself (it also
fixes itself if you leave it off for a few minutes). When it does
clear out it gives some smoke out the back as it revs, then it will
run fine for a long time. I have checked the spark plugs (new set in
now) which were quite sooted up. I believe she is running quite rich
at the moment. Does anyone have any ideas what might be causing this?
The next step I'm taking is to replace the air filter and then re-tune
the carbs to be leaner.

Secondly, I am having an issue with the handling of the bike. I'm not
sure how best to describe it. If your travelling along in a straight
line at about 70mph the problem is noticeable. It feels almost like
the rear is moving slightly from side to side (or it could be an issue
from the front). It's like it's trying to track in a straight line but
doesn't. It doesn't seem to oscillate and get out of hand. I think it
occurs at all speeds and when cornering but it is definitely worse the
faster you go. I have recently replaced the swingarm bearings, shock
lingage bushes, rear bearings (including sprocket), chain and both
sprockets. I have a fairly recent pair of BT45s on and the tyre
pressures are correct. I am at a loss for what could be causing this,
I was thinking it might be an alignment issue somewhere or maybe the
shock and forks are shot. Does anyone have any suggestions? I don't
really enjoy riding the bike at the moment.

Cheers

Rabbit

On Aug 14, 1:38*pm, Rabbit <dylanw...@yahoo.com> wrote:

> Firstly, occasionally the engine does a wierd thing. After starting
> the bike (which goes as planned) the engine will run as normal. Then
> shortly afterwards it may bog down and won't rev past about 3k rpm, no
> matter how much you twist the throttle or play with the choke. It runs
> like this for quite a while and then seems to clear itself (it also
> fixes itself if you leave it off for a few minutes).

The fuel system may be dirty, all the way from the fuel tank into the
float bowls and into the idle mixture system.

When the idle jets and idle ports really gets plugged up with gum and
varnish and little bits of rust from inside the gas tank, the engine
will not respond to the throttle but will still run on the "choke".

The "choke" is not actally a plate type choke at all, it's an air
bypass passage built into the side of each carburetter. When the
"choke" lever is moved, a small air valve is opened and fuel is sucked
up from the float bowls through a small brass tube.

> When it does
> clear out it gives some smoke out the back as it revs, then it will
> run fine for a long time. I have checked the spark plugs (new set in
> now) which were quite sooted up. I believe she is running quite rich
> at the moment.

Well, actually, the "choke" system will supply an air/fuel mixture of
about 1:2 or 1:3 in dorder to start the engine, as compared to a 1:14
mixture for cruising operation, so the indications you'll see on the
spark plugs give the correct impression that "she is running quite
rich."

But if you're running the engine on the choke to avoid fixing a dirty
fuel system problem, whose fault is that?

> Does anyone have any ideas what might be causing this?

See above.

> The next step I'm taking is to replace the air filter and then re-tune
> the carbs to be leaner.

No, clean out the fuel system first. You can drain most of the
gasoline out of the gas tank and remove the two little screws holding
the fuel selector lever onto the
automatic fuel petcock.

If there is a bunch of rust particles in any of the four fuel ports
you see facing you, you should remove the petcock completely and clean
the fuel filter screen and flush out the fuel tank.

Also, be sure to check that the small vacuum hose on the backside of
the fuel petcock doesn't have a split end, causing a vacuum leak and
intermittent fuel supply.

If the fuel tank doesn't appear to have water, rust and other debris
in it, you can try cleaning out the carburetors without dismantling
them by adding about 4 ounces of CLEAR carburetor cleaner to a fuel
tank of gas and riding until the engine begins to run better.

It's a good idea to know where the master idle adjustment knob on the
carburetors is located before you set out on a ride with carburetor
cleaner in the gas tank, because you will need to turn the idle RPM
down at some point.

>
> Secondly, I am having an issue with the handling of the bike. I'm not
> sure how best to describe it. If your travelling along in a straight
> line at about 70mph the problem is noticeable. It feels almost like
> the rear is moving slightly from side to side (or it could be an issue
> from the front).

A motorcycle is ALWAYS trying to fall over to one side or the other,
and the front steering geometry is ALWAYS trying to push it back
upright.

To the observant rider, it feels like the motorcycle is rocking
slightly from side to side.

> It's like it's trying to track in a straight line but
> doesn't. It doesn't seem to oscillate and get out of hand. I think it
> occurs at all speeds and when cornering but it is definitely worse the
> faster you go. I have recently replaced the swingarm bearings, shock
> lingage bushes, rear bearings (including sprocket), chain and both
> sprockets.

Well, save your money until you figure out what motorcycle do
NORMALLY.

You'll waste a lot of hard-earned ca$h chasing imaginary handling
problems.

> I have a fairly recent pair of BT45s on and the tyre
> pressures are correct. I am at a loss for what could be causing this,
> I was thinking it might be an alignment issue somewhere or maybe the
> shock and forks are shot. Does anyone have any suggestions? I don't
> really enjoy riding the bike at the moment.

BT45's are a dual tread compound tire. I have a set on my old GSXR-750
and I don't like them.

You might just be feeling the difference between the center compound
and the side compound as the motorcycle normally rocks a little from
side to side.

This rocking is exaggerated with 16-inch wheels...

On Aug 14, 4:18*pm, schwarzesonne <schwarze.so...@rocketmail.com>
wrote:

Oh **** off you pervert...Thanks to reading what you cut and paste
you've finally learned to relay it by rote. As for the BT45's they are
fine and how would you know? You do not own the motorcycle you claim
to own and for that matter you've never ridden a motorcycle in you
geritric lying life.

On Aug 14, 2:38*pm, Rabbit <dylanw...@yahoo.com> wrote:

Drain the fuel tank and refill with fresh CLEAN fuel. That means put
it on reserve and let it sit...tilt it to the side where the petcock
is. Then put in a quality fuel system cleaner. In the states the
prefered stuff is called SEAFOAM, not sure what is available where you
live but whatever the guys at a marina use can't hurt.

If that doesn't help you will either end up rebuilding the carbs or
having it done.

As for handling I'd check ALL the bushing the headstock bearing etc
for excessive wear. There are some good tutorials on the web for
checking these things. Unless your tyres are worn it isn't the
tyres...no matter what that fraud 'schwarzesonne' aka krusty kritter
says, he is an unskilled fraud that parrots what he reads and usually
gets compleately wrong.

On Aug 14, 8:04*pm, "S'mee" <stevenkei...@hotmail.com> wrote:

> Then put in a quality fuel system cleaner. In the states the
> prefered stuff is called SEAFOAM, not sure what is available where you
> live but whatever the guys at a marina use can't hurt.

SeaFoam is just about worthless for cleaning out motorcycle fuel
systems because it's just a light, straw-colored oil to free up seized
pistons from rusty cylinders and isopropyl alcohol that will absorb
water.

The hot mix for cleaning motorcycle fuel systems in the USA is
Berryman B-12 Choke and Carburetor Cleaner which is a powerful mixture
of methyl alcohol, toulene, xylene, and acetone which will cut right
through gum and varnish.

B-12 comes in liquid form and in an aerosol can for about $3.50 a
Wal*Mart.

> As for handling I'd check ALL the bushing the headstock bearing etc
> for excessive wear.

You can spent hours and hours looking for mechanical problems and
discover in the end it's just a matter of suspension setting and tire
pressure *adjustment*.

schwarzesonne <(E-Mail Removed)> wrote:

> BT45's are a dual tread compound tire. I have a set on my old GSXR-750
> and I don't like them.
>
> You might just be feeling the difference between the center compound
> and the side compound as the motorcycle normally rocks a little from
> side to side.

Absolute nonsense. And why have you morphed again?


--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ER GN250 Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

Rabbit <(E-Mail Removed)> wrote:

> Hi. I've been having a couple of issues with my 1985 GPZ600R recently.
>
> Firstly, occasionally the engine does a wierd thing. After starting
> the bike (which goes as planned) the engine will run as normal. Then
> shortly afterwards it may bog down and won't rev past about 3k rpm, no
> matter how much you twist the throttle or play with the choke. It runs
> like this for quite a while and then seems to clear itself (it also
> fixes itself if you leave it off for a few minutes). When it does
> clear out it gives some smoke out the back as it revs, then it will
> run fine for a long time. I have checked the spark plugs (new set in
> now) which were quite sooted up. I believe she is running quite rich
> at the moment. Does anyone have any ideas what might be causing this?
> The next step I'm taking is to replace the air filter and then re-tune
> the carbs to be leaner.

Yes, it's running rich. Gunged up carbs: very common. Has the bike been
standing for long? I suspect so. You could try carb cleaner but if
they're reall bad, ulrasound cleaning is the best way.

>
> Secondly, I am having an issue with the handling of the bike. I'm not
> sure how best to describe it. If your travelling along in a straight
> line at about 70mph the problem is noticeable. It feels almost like
> the rear is moving slightly from side to side (or it could be an issue
> from the front). It's like it's trying to track in a straight line but
> doesn't. It doesn't seem to oscillate and get out of hand. I think it
> occurs at all speeds and when cornering but it is definitely worse the
> faster you go. I have recently replaced the swingarm bearings, shock
> lingage bushes, rear bearings (including sprocket), chain and both
> sprockets. I have a fairly recent pair of BT45s on and the tyre
> pressures are correct. I am at a loss for what could be causing this,
> I was thinking it might be an alignment issue somewhere or maybe the
> shock and forks are shot. Does anyone have any suggestions? I don't
> really enjoy riding the bike at the moment.
>
Check everything again. Check also the head races. Check you've actually
got the right size tyres fitted. Check the swingarm pivot hasn't been
under-rightened so is loose. The 600R has 16" wheels fore and aft and
does feel twitchy as stock.


--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ER GN250 Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

On Aug 14, 4:38*pm, Rabbit <dylanw...@yahoo.com> wrote:
> Hi. I've been having a couple of issues with my 1985 GPZ600R recently.
>
> Firstly, occasionally the engine does a wierd thing. After starting
> the bike (which goes as planned) the engine will run as normal. Then
> shortly afterwards it may bog down and won't rev past about 3k rpm, no
> matter how much you twist the throttle or play with the choke. It runs
> like this for quite a while and then seems to clear itself (it also
> fixes itself if you leave it off for a few minutes). When it does
> clear out it gives some smoke out the back as it revs, then it will
> run fine for a long time. I have checked the spark plugs (new set in
> now) which were quite sooted up. I believe she is running quite rich
> at the moment. Does anyone have any ideas what might be causing this?
> The next step I'm taking is to replace the air filter and then re-tune
> the carbs to be leaner.
>
> Secondly, I am having an issue with the handling of the bike. I'm not
> sure how best to describe it. If your travelling along in a straight
> line at about 70mph the problem is noticeable. It feels almost like
> the rear is moving slightly from side to side (or it could be an issue
> from the front). It's like it's trying to track in a straight line but
> doesn't. It doesn't seem to oscillate and get out of hand. I think it
> occurs at all speeds and when cornering but it is definitely worse the
> faster you go. I have recently replaced the swingarm bearings, shock
> lingage bushes, rear bearings (including sprocket), chain and both
> sprockets. I have a fairly recent pair of BT45s on and the tyre
> pressures are correct. I am at a loss for what could be causing this,
> I was thinking it might be an alignment issue somewhere or maybe the
> shock and forks are shot. Does anyone have any suggestions? I don't
> really enjoy riding the bike at the moment.
>
> Cheers
>
> Rabbit

Hi I have been riding bikes since I was 15 and am 76 now .
so I have a little experience.

I use Lucas fuel conditioner in my bike with each tankful of gas This
helps to keep the grunge out of the carbs and fuel lines as well as
any condensation in the tank.

I use the same Lucas fuel additive in my 2002 Camry -4 and havent ever
had a problem in either vehicle

For winter storage I fill up with FRESH gas and then add the Lucas and
FUEL STABILIZER , TWICE AS MUCH AS WHAT IT CALLS FOR .

And the bike is stored for almost 6 months here in Ontario Canada.
NEVER had a problem with spring start-up .except once when the battery
died , a new battery fixed that problem.

I FILL UP THE TANK AS FAR AS IT WILL GO LEAVING SOME ROOM FOR
EXPANSION.THIS ELIMINATES CONDENSATE WHEN THE TEMP CHANGES

Condensate will encourage the formation of gas line sludge , blocking
the fuel filter and possibly the gas lines.

Something else I have been doing when I go out for a ride is lubricate
the chain each time (2001 750 Shadow)

I also run the bike on RESERVE for several miles to make sure THAT
line isnt plugged and I have free gas flow when I need it.

Sounds to me that your fuel filter may be partially blocked and as
suggested on here a GOOD carb cleaner might help.

If you follow the procedure like I mentioned afterward ? when the bike
is running good you will NEVER have another fuel related problem

I have ridden everything from an Excelsiour two stroke CB 500
Honda ,to Intruder 1400, Goldwings and Venture Royales .

A bad back keeps me to the 750 Shadow now.
good luck

On Aug 15, 6:38*am, Mark Olson <ols...@tiny.invalid> wrote:
> mred wrote:

> I would check the condition of the steering head bearings, you may have
> notching which accounts for the wandering feeling. *Obviously tire
> condition and pressure have to be right, too. *If the bearings are fubar,
> replace them with the tapered roller type.

Might not hurt to also check the swingarm and maybe the
wheel bearings and just for laughs, dump the whole tank
of gas into your car's tank and refill the bike with new. I
usually figure any fuel problem will get well diluted in the
car's tank, especially if I top off afterward.

On Aug 14, 10:38*pm, schwarzesonne <schwarze.so...@rocketmail.com>
wrote:
> On Aug 14, 8:04*pm, "S'mee" <stevenkei...@hotmail.com> wrote:
>
> > Then put in a quality fuel system cleaner. In the states the
> > prefered stuff is called SEAFOAM, not sure what is available where you
> > live but whatever the guys at a marina use can't hurt.
>
> SeaFoam is just about worthless for cleaning out motorcycle fuel
> systems because it's just a light, straw-colored oil to free up seized
> pistons from rusty cylinders and isopropyl alcohol that will absorb
> water.

Yeah right this coming from you? HAHAAHAHAHAH you ****ing liar. The
difference betwee you adn I is that I DO things and tell people how
they worked and you just talk out your ignorant stupid eneducated ass.

> The hot mix for cleaning motorcycle fuel systems in the USA is
> Berryman B-12 Choke and Carburetor Cleaner which is a powerful mixture
> of methyl alcohol, toulene, xylene, and acetone which will cut right
> through gum and varnish.

Reading the web page again I see.

> B-12 comes in liquid form and in an aerosol can for about $3.50 a
> Wal*Mart.

In you infinate stupidity you ASSUME he lives in the states.

> > As for handling I'd check ALL the bushing the headstock bearing etc
> > for excessive wear.
>
> You can spent hours and hours looking for mechanical problems and
> discover in the end it's just a matter of suspension setting and tire
> pressure *adjustment*.

No you'd be wrong as **** yet again.