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GPZ resurrection


Leesey
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Hi All, I’m hoping that I’m in the final list of people to do the run this year, the noble steed that I will be using is a 1995 Kawasaki GPZ500S on an M plate. 
she has done around 11k miles from new and hasn’t been used or run since 2008. She was bought for the princely sum of £290.

I was then given a bike to do the run on from someone who had done it previously but I then got rid of it due to it having a rear suspension issue that was well beyond my skill set to fix and the person who Took it needed transport and stated they were able to fix it. 
 

the brakes are being rebuilt. And she now starts after I have cleaned the carbs numerous times. However the big issue is she will not rev over 6k when at idle. Does any one have any idea what may be causing this. 
 

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thanks

Jon
 

Edited by Leesey
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Hi Jon,

A sold choice of bike.

Do the carb slides move up and down smoothly?

 

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They seem to, I’ve never had cause to check the needles on bike carbs so could say otherwise, it revs freely until 6k then it seems to hit a wall. 

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Is the fuel getting through ok? Maybe a partially blocked filter, or maybe a coil breaking down at higher revs or reg/rec? 

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You say you have cleaned the carbs, so go back to the basics of an old bike.

Check the fuel tap flows as it should, strip and clean it. Try a run with the fuel cap off, see if the tank is causing a vacuum. Check how much the slides lift by hand, then confirm the throttle lifts them to the same height. Strip the twistgrip, clean and lube all the cables. Drop the float bowls and see if any new crud is in there, see if the tank is clean of debris. Confirm the fuel hoses are the right size, not broken down internally or blocked, and haven't been swapped by a previous owner for something daft. Fit new hoses for safety. Check your needles are set at the right height, if adjustable. Set the float heights to spec. Are they the right needles and jets? Any aftermarket fuel filter? Get rid of it whilst solving the issue. Can it breathe properly? Air filter blocked, broken down and feeding crap into the carbs? Dead mouse in an inlet?

Can it breathe out? Exhaust blocked, rusted and collapsed? Does it have a cat, is this blocked? Dead rat in the tail pipe?

After that move to the electrical side of the system. Plugs in good nick, the right ones and gapped correctly? Get a manual and test the coils. Gently look over the wiring. Don't move too much and look for corrosion or worn though sleeving causing higher resistance or earth issues. Then carefully separate the connectors, clean all the pins and plugs. Easy stuff that can cause issues. Battery good? fully charged? Is it getting a charge? The manual will have all the numbers need to check the stator/windings and reg/reg unit.

 

Sounds a lot, but it is all relatively easy and if this has sat for so long it would be of benefit anyway. 

Edited by zedsdead
Spellinks.
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@zedsdeadhas comprehensively covered the proper stuff so I'd just say welcome to the party and muchly hope you enjoy it!

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The magnets fall off the stator with these engines, i would look for a spare to rebuild. Cool fact the cranks spin backwards in them too like a MotoGP bike.

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13 hours ago, zedsdead said:

You say you have cleaned the carbs, so go back to the basics of an old bike.

Check the fuel tap flows as it should, strip and clean it. Try a run with the fuel cap off, see if the tank is causing a vacuum. Check how much the slides lift by hand, then confirm the throttle lifts them to the same height. Strip the twistgrip, clean and lube all the cables. Drop the float bowls and see if any new crud is in there, see if the tank is clean of debris. Confirm the fuel hoses are the right size, not broken down internally or blocked, and haven't been swapped by a previous owner for something daft. Fit new hoses for safety. Check your needles are set at the right height, if adjustable. Set the float heights to spec. Are they the right needles and jets? Any aftermarket fuel filter? Get rid of it whilst solving the issue. Can it breathe properly? Air filter blocked, broken down and feeding crap into the carbs? Dead mouse in an inlet?

Can it breathe out? Exhaust blocked, rusted and collapsed? Does it have a cat, is this blocked? Dead rat in the tail pipe?

After that move to the electrical side of the system. Plugs in good nick, the right ones and gapped correctly? Get a manual and test the coils. Gently look over the wiring. Don't move too much and look for corrosion or worn though sleeving causing higher resistance or earth issues. Then carefully separate the connectors, clean all the pins and plugs. Easy stuff that can cause issues. Battery good? fully charged? Is it getting a charge? The manual will have all the numbers need to check the stator/windings and reg/reg unit.

 

Sounds a lot, but it is all relatively easy and if this has sat for so long it would be of benefit anyway. 

The coils and condition of the connectors are next on the list. The carbs are all set up as per the manual and there is no further crud in the float bowl. The air filter is new as is the fuel line and there is sufficient fuel flowing. The floats are set to the right heights etc. 

It has new spark plugs and has been fully serviced before I even turned the engine. The battery is fully charged.

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Hmmmm  sounds like you are well on the way then. Yeah, time to move onto the electrics. With it being sat for so long corrosion in the system may be an issue. Slow and steady will get to the bottom of it. As mentioned, pop the generator cover off and check inside visually. After that the manual and a meter are your friends.

Keep at it, you look to have the measure if it one way or another. 

 

🤖 No idea about the robo head! The phone has a mind of it's own!

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  • 2 weeks later...

So she is back together and running. The carbs have been apart about 6 times. When they were apart for the last time I used a child’s medicine syringe and put the end of it into where the pilot jet was and blew air through it it appeared blocked at first and was then after the third blow of air it was clear. 
I had put in new jets etc during the rebuild but I put the original main jets back in. 
I then put everything back together and it now revs all around the clock (slower than I would like but I’m used to my R1 and 916. 
everything is now back together and I’m waiting for new flush front mount indicators. Then it’s going for new tyres and an mot next week!

Hopefully it passes but we shall see then it will be to ride it and fine tune the carbs. 

42C06E09-C30C-432B-A095-48D0BB392E0C.jpeg

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1 hour ago, Leesey said:

So she is back together and running. The carbs have been apart about 6 times. When they were apart for the last time I used a child’s medicine syringe and put the end of it into where the pilot jet was and blew air through it it appeared blocked at first and was then after the third blow of air it was clear. 
I had put in new jets etc during the rebuild but I put the original main jets back in. 
I then put everything back together and it now revs all around the clock (slower than I would like but I’m used to my R1 and 916. 
everything is now back together and I’m waiting for new flush front mount indicators. Then it’s going for new tyres and an mot next week!

Hopefully it passes but we shall see then it will be to ride it and fine tune the carbs. 

42C06E09-C30C-432B-A095-48D0BB392E0C.jpeg

Out of likes but well done indeed. That's dangerously close to a fully functioning bike well before any deadline! 

Something I'm determined to do this year - i simply ran out of time with the unklefukker bike. Got it running but couldn't sort the lights, indicators etc in time. Hoping to do that this month.

Have you decided which tyres to go for?

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1 hour ago, hawkati said:

Out of likes but well done indeed. That's dangerously close to a fully functioning bike well before any deadline! 

Something I'm determined to do this year - i simply ran out of time with the unklefukker bike. Got it running but couldn't sort the lights, indicators etc in time. Hoping to do that this month.

Have you decided which tyres to go for?

Thanks for the kind words, as for tyres I don’t know what they do that will fit anything with tyres as skinny as this. On my other two bikes I’m going for s22’s or something sticky as they when this is road legal will only be used on sunny days. 
the ‘side light’ doesn’t always work but I will sort that. 
My main concern is getting the carbs running sweetly but again I will do that with a bit of trial and error when she hopefully passes and mot. 
 

im open to advice and suggestions for what tyres to go for. 

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I've heard good things of the bridgestone bt46's and I've used and trusted Avon roadsides 2's on my old vfr750 - sizes were suitably skinny like yours...

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Went to fit the newly purchased flush fit led ones I have so I can get this ready for the mot and when fitted they don’t flash. I’m assuming that this is because there is not enough resistance as the old ones do flash when fitted.

I would refit these however I have no mounting brackets for them and they are virtually ruined.

 

does anyone have any ideas on how to cheaply sort this.

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Have you got them wired correctly? 

Leds only work one way, so your +12v should be on the right wire. 

If you swap them over they won't work, unlike regular bulbs. 

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So new indicators ordered from wemoto and fitted so the indicators are now working. 
I had tried using flush mount jobbies from Amazon but they didn’t work whatever I tried so I opted for some new originals which were ironically cheaper than so 2nd hand ones from Ebay.

I’ve spoken to my local motorbike garage and I have a chalice of tyres and unsure which to go for.

continental contigo pair at £215 fitted

bridgestone bt45 pair £245 fitted

metzeler roadtec 01’s pair £250 fitted

i had the metzeler a on my old 2014 BMW R1200GS and they were brilliant but I don’t know enough about the other tyres to see if they are worth the extra. 
 

they are going to be removing a snapped off pinch bolt which is stuck in the near side front fork leg.

once the tyres are on it is mot time. All of this will be done Monday 

all advice re the tyres is great fully appreciated.

thanks Jon

96556B2F-AB41-4003-AFB2-CA923761927A.jpeg

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If you can get roadtec 01's to fit then go for them! I had them on my hawk for the charity ride, commuting and trackdays - the level of wet grip is surreal and definitely confidence inspiring. No idea about the contis but the roadtecs are a metric fucktonne better than bt45's

Just get them. Trust me.

 

 

 

...you do trust me don't you?😈

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2 hours ago, hawkati said:

If you can get roadtec 01's to fit then go for them! I had them on my hawk for the charity ride, commuting and trackdays - the level of wet grip is surreal and definitely confidence inspiring. No idea about the contis but the roadtecs are a metric fucktonne better than bt45's

Just get them. Trust me.

 

 

 

...you do trust me don't you?😈

I had them on the GS and they were brilliant in the wet. Even touring round the south west of Scotland 2 up in the rain. 
 

I shall go for them then. 

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So she has had new metzeler roadtec 01’s fitted and an MOT. She only went and passed first time with no advisories. 
 

the wheels were corroded which the garage had to clean up and they had to remove the pinch bolt so the garage charged a bit more in labour than I would have liked but at least she is done and still well within budget.

picking her up tomorrow and will start putting miles on her and it will be the first time she has been ridden on the road since 2008!

2287D875-1353-43A8-9591-B489DCAC902B.png

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14 minutes ago, Leesey said:

So she has had new metzeler roadtec 01’s fitted and an MOT. She only went and passed first time with no advisories. 
 

the wheels were corroded which the garage had to clean up and they had to remove the pinch bolt so the garage charged a bit more in labour than I would have liked but at least she is done and still well within budget.

picking her up tomorrow and will start putting miles on her and it will be the first time she has been ridden on the road since 2008!

2287D875-1353-43A8-9591-B489DCAC902B.png

May the smug sense of satisfaction keep you warm for days

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1 hour ago, EXUPDEL said:

May the smug sense of satisfaction keep you warm for days

I’m hoping it will haha

if I’m honest I’ve never worked on a bike before and it was a voyage of discovery and there were many times I nearly threw it in the river Don! 

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4 minutes ago, Leesey said:

I’m hoping it will haha

if I’m honest I’ve never worked on a bike before and it was a voyage of discovery and there were many times I nearly threw it in the river Don! 

Are you local to Doncaster?

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17 hours ago, EXUPDEL said:

 

Are you local to Doncaster?

I live in Doncaster. Used to live in the dearne valley area, now Doncaster.

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The smugness died a bit today when I rode my mates gpz and he rode mine and it became very apparent that the main jets are not kicking in. 
many advice on how to rectify this issue

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1 hour ago, Leesey said:

The smugness died a bit today when I rode my mates gpz and he rode mine and it became very apparent that the main jets are not kicking in. 
many advice on how to rectify this issue

Check the slides are moving freely and fully, I'm looking for a graph that shows which jet works at which throttle opening 

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,cv,high_rpm_engines.html

 

This stuff worked on gummy CBR carbs without a stripdown 

https://www.google.com/amp/s/www.instructables.com/Homemade-Seafoam-Knockoff/%3famp_page=true

 

Edited by ssray
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If you take the carbs of the bike Ash at Swinton Motorcycles has an ultrasonic cleaner. he'll run them until they are clear. 

Its cheaper if you strip them down before you take them If you need any help give me a shout he's done a few sets for me.

Pilot jet does tick over and low rpm Then the mains do the midrange through to top end as the diaghram lifts the needle out out of the emulsion tube. its possible the circuit that creates the vacuum to lift the needles may be blocked. which is why it is struggling over 6k

 

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I’ve had the carbs off and the floats weren’t set right they were to low (at 11mm instead of 17mm) so they were letting too much fuel into the bowl. As a result the screws at the front of the carbs were wound nearly all of the way in (as to much fuel had been going into the engine resulting in some coming out where the end cans meet the exhaust tubing. They were about 1 turn out instead of 2 1/4
I am hoping this is going to help. 
everything moves as it should they are all clean inside. 
Ash did the carbs on my old 600 bandit a couple of years ago. I’m just trying to limit spending on the silly thing. 
 

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