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slowlydoesit |
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Posted: 22:44 - 11 Aug 2014 Post subject: |
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That's what I bought the first time. ____________________ Kawasaki KMX200 with broken fixed powervalves and a stutter |
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dangerousdave |
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Posted: 11:38 - 12 Aug 2014 Post subject: |
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slowlydoesit wrote: |
That's what I bought the first time. |
Nightmare. ____________________ 1988 Kawasaki KMX 200
Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50 |
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slowlydoesit |
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Posted: 21:03 - 09 Nov 2014 Post subject: |
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So, today I went and did some work on the KMX200 with the help of my long-suffering friend. To recap, the bike idles fine and runs well at small to medium throttle openings, but stutters and misses above around 6,000 rpm or at wide throttle openings.
We had agreed to whip the head off and that's what we did, probably took us 30 minutes, including rooting about for a container for the coolant and trying to find the right size spanners and sockets. Then we took out the KIPS valves.
https://i.imgur.com/JwHHOVJ.jpg
Now I'm left with a conundrum. As far as we can see, the KIPS valves were inserted properly and if you move the rod that is supposed to rotate the valves, the valves open and close. However, the cutouts in the valves seem the same, whereas the valves shown in the official Kawasaki service manual and the Haynes book have different shapes. Here's what the manual shows:
https://i.imgur.com/FmmArWK.jpg
Notice how the cutout is straight across in the valve on the left and diagonal across the valve on the right. And here's a random image plucked from elsewhere on the web - again, different cutouts:
https://i.imgur.com/KjFN2fo.jpg
Oddly, although my valves have the same cutout shape, they seem to come from different stock. Note that end of one of them is blunt and closed whereas the other has a bevel with a hole punched in the end. Also, look at the shape of the teeth of the cog - clearly different. So it looks as if they were made by different suppliers.
https://i.imgur.com/EJlQ3HB.jpg
What do I have here? A mismatched set of powervalves? But if you look at the site BDK Engineering, which makes and sells two-stroke parts, their valve kit looks like this - just like mine and both with the same shape cutout. Curiouser and curiouser.
https://i.imgur.com/2I9h8iJ.jpg
What's going on? ____________________ Kawasaki KMX200 with broken fixed powervalves and a stutter |
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dangerousdave |
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Posted: 00:08 - 10 Nov 2014 Post subject: |
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The BDK valves are an exact match of the Kawasaki KMX 200 Kips valves.
Your valves have the correct cutouts. However, if you look at your valves, they seem to be missing the piece of steel at the bottom which helps them locate in the cylinder? Or is it just the photo? ____________________ 1988 Kawasaki KMX 200
Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50 |
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slowlydoesit |
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stevo as b4 |
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stevo as b4 World Chat Champion
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dangerousdave |
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Posted: 17:50 - 10 Nov 2014 Post subject: |
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slowlydoesit wrote: |
So why does the manual show different cutouts - is this a difference between the KMX125 and the KMX200? |
KMX125 valves are very different to the 200 valves.
The 125 valves are much smaller in comparison, and the cutouts are different.
And, as Steve said, to add to the confusion, there are two types of valve for the KMX 200.
1. Early type, made of alloy, different profile.
https://www.ebay.co.uk/itm/kawasaki-kmx200-kmx-200-kips-governor-valve-kit-rod-guide-power-valve-exhaust-/121480339078?pt=Motorcycles_Parts_Accessories&clk_rvr_id=728556009733&hash=item1c48cade86&nma=true&si=uwOUy5Y5cedM5EtL8f2zCN1LJrg%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
2. Later type, 1989 on i think, made of steel, both sides very similar profiles. Profile can be seen on the BDK valves.
https://www.ebay.co.uk/itm/KAWASAKI-KMX200-KIPS-VALVE-KITS-NEW-STEEL-REPLACEMENT-ITEMS-WITH-BUSH-AND-SEAL-/381048664437?
Both types of valves will work fine, but the early ones were more prone to snapping due to being made of the weaker metal.
Your valves are of the later type. How the bottom has snapped off like that is really odd. Maybe somebody tried to modify them?
Is the remaining part stuck in the cylinder ? Or is it missing?
I don't suppose they would work too well like that, as I imagine they will tilt and possibly jam in position without being stabilised by the part on the bottom. I doubt they would be able to operate smoothly, although this would be easy to test with the valves in situ. ____________________ 1988 Kawasaki KMX 200
Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50 |
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Posted: 19:41 - 29 Jan 2015 Post subject: |
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slowlydoesit wrote: | To recap, the bike idles fine and runs well at small to medium throttle openings, but stutters and misses above around 6,000 rpm or at wide throttle openings.
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Have you checked the spark plug colour ? Although you are running what seems to be the correct size main jet, and clip position, I can't help thinking the fuel mixture could be off. ____________________ 1988 Kawasaki KMX 200
Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50 |
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Posted: 19:18 - 07 Jul 2015 Post subject: Plug is fine |
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dangerousdave wrote: | slowlydoesit wrote: | To recap, the bike idles fine and runs well at small to medium throttle openings, but stutters and misses above around 6,000 rpm or at wide throttle openings.
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Have you checked the spark plug colour ? Although you are running what seems to be the correct size main jet, and clip position, I can't help thinking the fuel mixture could be off. |
Sorry for silence, been having a busy year. Well, I bought the BDK kit and replaced the power valves, which has helped at the high end, it will rev freely now, but it still stutters under load at around 4-5,000.
We thought that the symptoms could be interpreted as a problem when the bike is coming off the pilot and on to the main jet (not for the first time). So we stripped the carb for the fourth time last weekend and it looks fine. Measured everything again, checked needle and pilot, all look OK. Most of the parts are new.
No obvious problems in the various ducts. Coil has been replaced. Plug is new and looks perfect.
I haven't tested compression - worth a go?
And perhaps the CDI?
All very frustrating. The bike runs fine, until 4,000 rpm. ____________________ Kawasaki KMX200 with broken fixed powervalves and a stutter |
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Posted: 23:25 - 08 Jul 2015 Post subject: Re: Plug is fine |
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slowlydoesit wrote: |
I haven't tested compression - worth a go?
And perhaps the CDI?
All very frustrating. The bike runs fine, until 4,000 rpm. |
Depends how bad the stuttering is. Remember it is a stroker so not the smoothest when out of the powerband.
You mentioned it stutters under load. Is this momentary, for example when throttle whacked wide open, or is it a permanent feature around 4,000rpm?
If you were to ride up a hill in a high gear, throttle wide open, around 4,000rpm range, would it continuously stutter. Or would it briefly stutter then clean up?
Stuttering can be an indication of running too rich. I had this at around 5,000rpm when I was using a main jet which was too large. It was very noticeable when the engine had not fully warmed up, less so when up to temp. The main jet is not just responsible for top-end behavior, it also overlaps other circuits in the carb, enriching them also. Worth checking the plug colour after a run at 4.000rpm. You are looking for a creamy coffee brown colour on the electrode. If it is not this colour, then your jetting is incorrect.
You have had fhe cylinder off for the KIPS replacement, so unless there was blow by, scoring to the piston or bore, I can't see an issue really. If you have access to a compression checker, then worth doing just to eliminate that completely. Minimum psi is 108 on these, mine had dropped to 110. At this stage the piston in my bike was worn, and the piston slap could be easily heard in a nasty rattle.
Good luck and us know how you get on? ____________________ 1988 Kawasaki KMX 200
Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50 |
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Old Thread Alert!
The last post was made 8 years, 344 days ago. Instead of replying here, would creating a new thread be more useful? |
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