Piston & Jug
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Piston & Jug
I just got a 99 Kdx 220. I have been doing a lot of reading & thinking (scared about what piston is in my bike). So I pulled it down, the piston looks to have a W in a circle on the bottom side of one of the wrist pin holders, Is this a Wiseco Piston? I thinks it all looks OK. What now new gaskets, & rings?
- Julien D
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Measure the piston at the bottom of the skirts and measure the cylinder. Make sure it's all within spec. If the piston is perfect, no scratches, scuffs, blowby, etc, put rings and a gasket set in and ride. The W on the wrist pin boss is Wiseco, yes.
Pictures would always be helpful!
Congrats on the bike too and welcome to the forum!
J.
Pictures would always be helpful!
Congrats on the bike too and welcome to the forum!
J.
- Julien D
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- fuzzy
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- Julien D
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- Varmint
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juliend wrote:Measure the piston at the bottom of the skirts and measure the cylinder. Make sure it's all within spec. If the piston is perfect, no scratches, scuffs, blowby, etc, put rings and a gasket set in and ride. The W on the wrist pin boss is Wiseco, yes.
Pictures would always be helpful!
Congrats on the bike too and welcome to the forum!
J.
- fuzzy
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Micrometers and a feeler guage son't even get close to the specs on these piston's / cylinders. IE just try to figure out if you need an A B C D E F piston with those tools. Wiseco is always sized like an E/F. You can certainely check to see if something is way out of wack.
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
- Julien D
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I'm sorry, I don't follow.
Using a micrometer you measure the cylinder bore at the skirts and you measure the piston size at it's skirts, and then you take the difference between these two measurements as your piston to cylinder clearance. You can check the bore in a few other places as well to make sure it's consistent, but the largest wear area is usually down toward the bottom so that's an ideal place to get your measurement. A,B,C,D,E piston sizes are all listed in millimeters, as are Wiseco pistons, so it's pretty easy to extrapolate the clearance you would have with a given piston using the measurements you take from your cylinder. So long as you can subtract, that is.
For ring end gap you push the rings into the cylinder before they are installed on the piston. Push the rings squarely down into the bore and measure the ring end gap with a feeler gauge.
You don't need anything more high tech than a micrometer and feeler gauge to get these measurements. If you can't get the measurements accurately, you're doing something wrong.
Using a micrometer you measure the cylinder bore at the skirts and you measure the piston size at it's skirts, and then you take the difference between these two measurements as your piston to cylinder clearance. You can check the bore in a few other places as well to make sure it's consistent, but the largest wear area is usually down toward the bottom so that's an ideal place to get your measurement. A,B,C,D,E piston sizes are all listed in millimeters, as are Wiseco pistons, so it's pretty easy to extrapolate the clearance you would have with a given piston using the measurements you take from your cylinder. So long as you can subtract, that is.
For ring end gap you push the rings into the cylinder before they are installed on the piston. Push the rings squarely down into the bore and measure the ring end gap with a feeler gauge.
You don't need anything more high tech than a micrometer and feeler gauge to get these measurements. If you can't get the measurements accurately, you're doing something wrong.
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I get by with a caliper, a set of telescoping gages and feeler gages. The cylinder measurement is 16 mm down from the top, so t-gages or an ID micrometer are needed. The caliper is good for the piston and measuring the t-gage. Feeler gages take care of the end gap measurment. Maybe $5 for the feeler gages, $25 for a used set of t-gages and $40-$50 for a caliper. If you are patient, you can aquire everything you need for less than $100. Figure 4 to 5 times this if you go top shelf and buy new.
- Julien D
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