1st things 1st?

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babo89
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1st things 1st?

Post by babo89 »

new to the forum and the kdx. i just bought a 1997 kdx 220. from original owner with less than 25miles on it. still has factory tires only thing thats been replaced is fuel line, filter , and air filter. what should i focus on as i get it ready for the season. i dont wanna drop a bunch of money into it right away but i will eventually do performance mods as my skills grow, for now i just want to get it tuned for my weight and size and make sure i dont have any catastrophic failures

i know the top end needs to be rebuilt due to the bad pistons on these. given the circumstances do you guys think i would be ok to put a few hours on the top end as is? are there any sounds ir things i can look for to see if i have one of the bad pistons.

aside from changing oil ,greasing axles bearings linkage.. new fork oil? the valves should be ok?

i would think new tires but its been in climate controlled garage its entire life and they dont have any signs of wear or cracking

the main thing ive been researching that im getting hung up on is suspension..this things almost too tall. what weight rider are these set up for from factory? guy i bought it from was 6'4 250... but said he never had any adjustments made not sure if i need to spring it before setting sag , or how to approach this ? im 5'11 170 without gear. what is my best option to making this fit better.?

sorry for the ramblings , just so many questions and ive spent entirely too much time going in circles on this forum and google withiut finding definitive answers, if i spend any more time im gonna end up sleeping with my kdx in the doghouse. appreciate any help i can get
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Re: 1st things 1st?

Post by SS109 »

babo89 wrote: 10:01 pm Apr 17 2024i know the top end needs to be rebuilt due to the bad pistons on these. given the circumstances do you guys think i would be ok to put a few hours on the top end as is? are there any sounds ir things i can look for to see if i have one of the bad pistons.
No, there is no safe amount of time on a 220 cast piston. It can be perfect one second and a grenade the next. Only run forged pistons in the KDX220. No exceptions.

babo89 wrote: 10:01 pm Apr 17 2024aside from changing oil ,greasing axles bearings linkage.. new fork oil? the valves should be ok?
It would probably be a really good idea to have the fork and shock oil serviced and have the proper springs for your weight installed at the same time.

babo89 wrote: 10:01 pm Apr 17 2024i would think new tires but its been in climate controlled garage its entire life and they dont have any signs of wear or cracking
Those tires are toast being that old. I notice degradation of dirt bike tires (they tend to get harder as they age) sometimes in less than a year.

Tires I have heard that work very good in almost any terrain is the Bridgestone X31 up front and the IRC VE33S Gekkota rear. Tire sizing plays a huge part in how a bike handles different things so read up on it and make an informed decision. I like the big front (90/100-21) tires and larger rears (120/90-18) and have run both in the tires mentioned above and love them.

I would also replace the inner tubes with a high quality one like Bridgestone UHD tubes. They are heavy, and not cheap, but they last longer than any other tubes I have run and they don't puncture or pinch flat like cheaper tubes. Well worth the investment IMO/IME.
babo89 wrote: 10:01 pm Apr 17 2024the main thing ive been researching that im getting hung up on is suspension..this things almost too tall. what weight rider are these set up for from factory? guy i bought it from was 6'4 250... but said he never had any adjustments made not sure if i need to spring it before setting sag , or how to approach this ? im 5'11 170 without gear. what is my best option to making this fit better.?
Too tall? I'm only 5'8" and can ride my KDX220 without issue and it is even taller than a stock suspended KDX. After a while you won't even notice the height as you gain experience and confidence on the bike.

No point in even trying to set the sag with the incorrect spring installed. You'll probably need to get stiffer fork springs and a lighter shock spring. KDX's were very out of balance from the factory for which no one knows why. Use RaceTechs online calculator (https://racetech.com/product-search/) to find your spring rate. Answer the questions as accurately as possible and you'll be set.

Other things you'll want to probably check is that your carburetor is in good working order and jetted correctly. Make sure the jet block gasket isn't leaking, that your float level is set to 18mm, the float needle is sealing, what size jets and needle (and needle clip position) you currently have installed, and then follow the jetting guide found here (viewtopic.php?f=105&t=1156) to really dial it in. Also a good idea to flush the coolant system and flush both brake systems and add DOT4 fluid to them.

Oh, last thing and the most important, get yourself a factory service manual.

Any more questions just ask away!
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Re: 1st things 1st?

Post by KDXGarage »

Best money is a service manual

What is your weight in full riding gear? 190?
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Re: 1st things 1st?

Post by babo89 »

KDXGarage wrote: 12:50 am Apr 19 2024 Best money is a service manual

What is your weight in full riding gear? 190?
service manual and wiseco piston top end kit is otw..
i honestly dont know my exact weight in gear , birthday suit is 167.. right now i only have a helmet gloves and goggles, trying to find a good pair of boots. (all of this is on a pretty tight budget just had a baby &work os slow) but ive always been told to add 20for gear. im 35 and 1st time back in the saddle in 15yrs so im not gonna risk getting hurt for something that silly , ill have full moto gear (-neck brace )just bought my son a crf125f and it got me itching to ride.

im more along the lines of just ride it and have fun( the bike has plenty of power for me at this point) as opposed to having the best kdx in the world. my main concerns are not destroying this beauty and having the most comfortable ride and not having to work the bike to death i just want an optimal setup for myself but also dont want have to do something twice (for instance while doing the top end , is there anything else i should do while its torn down, just trying to be as efficient with my time and money as possible.)

ive been stalking the forums pretty hard for the last few weeks leading up to my purchase so im familiar with a lot of stuff but my ocd adhd mind needs lists or else i just spon my wheels and get nothing done so was just hoping to get a few suggestions to do abc xyz type thing.. im slightly overwhelmed ..

thanks for taking time to read my post and reply any help is greatly appreciated

What is your weight in full riding gear? 190?
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Re: 1st things 1st?

Post by babo89 »

SS109 wrote: 02:47 am Apr 18 2024
babo89 wrote: 10:01 pm Apr 17 2024i know the top end needs to be rebuilt due to the bad pistons on these. given the circumstances do you guys think i would be ok to put a few hours on the top end as is? are there any sounds ir things i can look for to see if i have one of the bad pistons.
No, there is no safe amount of time on a 220 cast piston. It can be perfect one second and a grenade the next. Only run forged pistons in the KDX220. No exceptions.

babo89 wrote: 10:01 pm Apr 17 2024aside from changing oil ,greasing axles bearings linkage.. new fork oil? the valves should be ok?
It would probably be a really good idea to have the fork and shock oil serviced and have the proper springs for your weight installed at the same time.

babo89 wrote: 10:01 pm Apr 17 2024i would think new tires but its been in climate controlled garage its entire life and they dont have any signs of wear or cracking
Those tires are toast being that old. I notice degradation of dirt bike tires (they tend to get harder as they age) sometimes in less than a year.

Tires I have heard that work very good in almost any terrain is the Bridgestone X31 up front and the IRC VE33S Gekkota rear. Tire sizing plays a huge part in how a bike handles different things so read up on it and make an informed decision. I like the big front (90/100-21) tires and larger rears (120/90-18) and have run both in the tires mentioned above and love them.

I would also replace the inner tubes with a high quality one like Bridgestone UHD tubes. They are heavy, and not cheap, but they last longer than any other tubes I have run and they don't puncture or pinch flat like cheaper tubes. Well worth the investment IMO/IME.
babo89 wrote: 10:01 pm Apr 17 2024the main thing ive been researching that im getting hung up on is suspension..this things almost too tall. what weight rider are these set up for from factory? guy i bought it from was 6'4 250... but said he never had any adjustments made not sure if i need to spring it before setting sag , or how to approach this ? im 5'11 170 without gear. what is my best option to making this fit better.?
Too tall? I'm only 5'8" and can ride my KDX220 without issue and it is even taller than a stock suspended KDX. After a while you won't even notice the height as you gain experience and confidence on the bike.

No point in even trying to set the sag with the incorrect spring installed. You'll probably need to get stiffer fork springs and a lighter shock spring. KDX's were very out of balance from the factory for which no one knows why. Use RaceTechs online calculator (https://racetech.com/product-search/) to find your spring rate. Answer the questions as accurately as possible and you'll be set.

Other things you'll want to probably check is that your carburetor is in good working order and jetted correctly. Make sure the jet block gasket isn't leaking, that your float level is set to 18mm, the float needle is sealing, what size jets and needle (and needle clip position) you currently have installed, and then follow the jetting guide found here (viewtopic.php?f=105&t=1156) to really dial it in. Also a good idea to flush the coolant system and flush both brake systems and add DOT4 fluid to them.

Oh, last thing and the most important, get yourself a factory service manual.

Any more questions just ask away!
thanks for the detailed reply this was exactly type of info i was searching for just something to simplify things and get me started, i know i will keep this bike for a very long time and plan to upgrade as my skills progress.

in regards to your reply i have had trouble finding a definitive answer online. the kdx stock is set up for a 140lb rider. me being 170-190 with gear how can i expect the bike to behave differently if i change to stiffer fork springs? softer shock? also say i dont do any of that right now and just set the sag properly what differences can i expect? i would imagine if its set for a 140lb rider and im heavier it will increase the ride height? right now it already feels too tall will that increased ride height be offset by a more balanced feeling bike underneath me? i just dont wuite feel comfortable on it yet. which a lot of that will come witb time im just a litt confused by alot of the suspension talk..

as far as the carb and jetting im guessing i can find all that info on these forums? cus that all sounds prett foreign to me too
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Re: 1st things 1st?

Post by bufftester »

With the fork set for 140 lb rider, and the rear shock set for 170lb rider the fork will settle lower in its stroke, effectively raising the rear sag and pushing the CG forward. The bike will feel like it is pushing into turns and you end up understeering. In rapid successive bumps the fork will begin to stack, resulting in a harsh feel up front. Getting the right springs for your weight in both the front and rear is the best money you can spend on your bike IMO, and should be the first place you upgrade. Sag is intended to set the starting point of the fork or shock in it's travel, ideally you have about 2/3ds of your travel available with the correct weight springs which is the sweet spot for the suspension. Too light a spring and you're running in the bottom part of your travel with it feeling soft, too heavy a spring and you're running in the top part of your travel with it feeling stiff. At 5'11" you're right in the zone for the KDX, unless you have like a 26" inseam lol. You can certainly ride it the way it is, it will just feel way better once you spring it correctly.
As for the carb stuff, lots of info on here. The big thing with carb work is change only 1 thing at a time then ride it and see how it reacts. The PWK is a very reliable carb when properly cared for, and generally jetting issues can be traced back to either operator error, or a mechanical issue with the bike. That's why the first step in jetting is to make sure all of the intake and exhaust track is good (no air leaks, cracked boots, worn reads, bad gaskets, etc). Keep in mind that you should decide on a mixture ratio and fuel type (i.e.: 40:1 93 Octane, 32:1 87 Octane, etc) then jet to that and don't change it. Changing your mix ratio, or anything in the intake/exhaust (pipe, silencer, reeds) will require changing your jetting.

That's all a very wordy way of saying, IIWM, I'd change the piston first, then start riding. When funds allow upgrade the springs to the right weight.
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Re: 1st things 1st?

Post by SS109 »

What bufftester said is spot on.
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Re: 1st things 1st?

Post by KDXGarage »

The shock spring should be correct for your intended riding. If you are just putting around following a child, I would not spend the money on stiffer fork springs. If you keep at it and want to get into more spirited riding on a trail, then I would worry about it.

cleaning and greasing the linkage bearings and such would be a good idea
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Re: 1st things 1st?

Post by babo89 »

SS109 wrote: 02:47 am Apr 18 2024
babo89 wrote: 10:01 pm Apr 17 2024i know the top end needs to be rebuilt due to the bad pistons on these. given the circumstances do you guys think i would be ok to put a few hours on the top end as is? are there any sounds ir things i can look for to see if i have one of the bad pistons.
No, there is no safe amount of time on a 220 cast piston. It can be perfect one second and a grenade the next. Only run forged pistons in the KDX220. No exceptions.





babo89 wrote: 10:01 pm Apr 17 2024aside from changing oil ,greasing axles bearings linkage.. new fork oil? the valves should be ok?
It would probably be a really good idea to have the fork and shock oil serviced and have the proper springs for your weight installed at the same time.

babo89 wrote: 10:01 pm Apr 17 2024i would think new tires but its been in climate controlled garage its entire life and they dont have any signs of wear or cracking
Those tires are toast being that old. I notice degradation of dirt bike tires (they tend to get harder as they age) sometimes in less than a year.

Tires I have heard that work very good in almost any terrain is the Bridgestone X31 up front and the IRC VE33S Gekkota rear. Tire sizing plays a huge part in how a bike handles different things so read up on it and make an informed decision. I like the big front (90/100-21) tires and larger rears (120/90-18) and have run both in the tires mentioned above and love them.

I would also replace the inner tubes with a high quality one like Bridgestone UHD tubes. They are heavy, and not cheap, but they last longer than any other tubes I have run and they don't puncture or pinch flat like cheaper tubes. Well worth the investment IMO/IME.
babo89 wrote: 10:01 pm Apr 17 2024the main thing ive been researching that im getting hung up on is suspension..this things almost too tall. what weight rider are these set up for from factory? guy i bought it from was 6'4 250... but said he never had any adjustments made not sure if i need to spring it before setting sag , or how to approach this ? im 5'11 170 without gear. what is my best option to making this fit better.?
Too tall? I'm only 5'8" and can ride my KDX220 without issue and it is even taller than a stock suspended KDX. After a while you won't even notice the height as you gain experience and confidence on the bike.

No point in even trying to set the sag with the incorrect spring installed. You'll probably need to get stiffer fork springs and a lighter shock spring. KDX's were very out of balance from the factory for which no one knows why. Use RaceTechs online calculator (https://racetech.com/product-search/) to find your spring rate. Answer the questions as accurately as possible and you'll be set.

Other things you'll want to probably check is that your carburetor is in good working order and jetted correctly. Make sure the jet block gasket isn't leaking, that your float level is set to 18mm, the float needle is sealing, what size jets and needle (and needle clip position) you currently have installed, and then follow the jetting guide found here (viewtopic.php?f=105&t=1156) to really dial it in. Also a good idea to flush the coolant system and flush both brake systems and add DOT4 fluid to them.

Oh, last thing and the most important, get yourself a factory service manual.

Any more questions just ask away!
so the top end kit i originally found is on. ack order. will this kit work?


https://www.ebay.com/itm/234992141539?e ... R8SV7aDgYw


i want to replace as much as i can while i have the top end opened up.. are there any better options?
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Re: 1st things 1st?

Post by SS109 »

babo89 wrote: 02:13 pm Apr 21 2024so the top end kit i originally found is on. ack order. will this kit work?


https://www.ebay.com/itm/234992141539?e ... R8SV7aDgYw


i want to replace as much as i can while i have the top end opened up.. are there any better options?
Probably. Have you measured your cylinder or checked the piston to see what size was installed from the factory? There are A, B, C, and D size pistons with each getting a little bigger respectively. That kit is for a standard A size piston. Considering the low hours of the engine it will more than likely be good to go but it's always a good idea to measure it to be sure.

BTW, Amazon has that same kit available from Wiseco for $149.01 https://www.amazon.com/Wiseco-750M06900 ... VIK2S?th=1 and even on Ebay you can find it cheaper than the link you posted.
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Re: 1st things 1st?

Post by babo89 »

babo89 wrote: 02:13 pm Apr 21 2024 [quote=SS109 post_id=226889 time=<a href="tel:1713426467">1713426467</a> user_id=2608]
[quote=babo89 post_id=226887 time=<a href="tel:1713409269">1713409269</a> user_id=19316]i know the top end needs to be rebuilt due to the bad pistons on these. given the circumstances do you guys think i would be ok to put a few hours on the top end as is? are there any sounds ir things i can look for to see if i have one of the bad pistons.
No, there is no safe amount of time on a 220 cast piston. It can be perfect one second and a grenade the next. Only run forged pistons in the KDX220. No exceptions.






[quote=babo89 post_id=226887 time=<a href="tel:1713409269">1713409269</a> user_id=19316]aside from changing oil ,greasing axles bearings linkage.. new fork oil? the valves should be ok?[/quote]
It would probably be a really good idea to have the fork and shock oil serviced and have the proper springs for your weight installed at the same time.


[quote=babo89 post_id=226887 time=<a href="tel:1713409269">1713409269</a> user_id=19316]i would think new tires but its been in climate controlled garage its entire life and they dont have any signs of wear or cracking[/quote]
Those tires are toast being that old. I notice degradation of dirt bike tires (they tend to get harder as they age) sometimes in less than a year.

Tires I have heard that work very good in almost any terrain is the Bridgestone X31 up front and the IRC VE33S Gekkota rear. Tire sizing plays a huge part in how a bike handles different things so read up on it and make an informed decision. I like the big front (<a href="tel:90/100-21">90/100-21</a>) tires and larger rears (120/90-18) and have run both in the tires mentioned above and love them.

I would also replace the inner tubes with a high quality one like Bridgestone UHD tubes. They are heavy, and not cheap, but they last longer than any other tubes I have run and they don't puncture or pinch flat like cheaper tubes. Well worth the investment IMO/IME.

[quote=babo89 post_id=226887 time=<a href="tel:1713409269">1713409269</a> user_id=19316]the main thing ive been researching that im getting hung up on is suspension..this things almost too tall. what weight rider are these set up for from factory? guy i bought it from was 6'4 250... but said he never had any adjustments made not sure if i need to spring it before setting sag , or how to approach this ? im 5'11 170 without gear. what is my best option to making this fit better.?[/quote]
Too tall? I'm only 5'8" and can ride my KDX220 without issue and it is even taller than a stock suspended KDX. After a while you won't even notice the height as you gain experience and confidence on the bike.

No point in even trying to set the sag with the incorrect spring installed. You'll probably need to get stiffer fork springs and a lighter shock spring. KDX's were very out of balance from the factory for which no one knows why. Use RaceTechs online calculator (https://racetech.com/product-search/) to find your spring rate. Answer the questions as accurately as possible and you'll be set.

Other things you'll want to probably check is that your carburetor is in good working order and jetted correctly. Make sure the jet block gasket isn't leaking, that your float level is set to 18mm, the float needle is sealing, what size jets and needle (and needle clip position) you currently have installed, and then follow the jetting guide found here (viewtopic.php?f=105&t=1156) to really dial it in. Also a good idea to flush the coolant system and flush both brake systems and add DOT4 fluid to them.

Oh, last thing and the most important, get yourself a factory service manual.

Any more questions just ask away!
[/quote]

so the top end kit i originally found is on. ack order. will this kit work?


https://www.ebay.com/itm/234992141539?e ... R8SV7aDgYw


i want to replace as much as i can while i have the top end opened up.. are there any better options?
[/quote]
SS109 wrote: 04:31 pm Apr 21 2024
babo89 wrote: 02:13 pm Apr 21 2024so the top end kit i originally found is on. ack order. will this kit work?


https://www.ebay.com/itm/234992141539?e ... R8SV7aDgYw


i want to replace as much as i can while i have the top end opened up.. are there any better options?
Probably. Have you measured your cylinder or checked the piston to see what size was installed from the factory? There are A, B, C, and D size pistons with each getting a little bigger respectively. That kit is for a standard A size piston. Considering the low hours of the engine it will more than likely be good to go but it's always a good idea to measure it to be sure.

BTW, Amazon has that same kit available from Wiseco for $149.01 https://www.amazon.com/Wiseco-750M06900 ... VIK2S?th=1 and even on Ebay you can find it cheaper than the link you posted.
i have not measured cylinder or piston. i notice a lot of the top end kits say 98-05 . but looks like the 97 had a slightly smaller piston at 69mm instead of the 70mm the 98+ came with . so in order to find the correct kit i need to measure the factory piston or cylinder size?
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Re: 1st things 1st?

Post by SS109 »

There is no change in any KDX220 piston size from 1997 until they stopped making them in 2005. The only difference is the A, B, etc. sizing which is measured in hundredths of an inch.

Preferably, yes, you should get the cylinder measured. However, again due to your engine being very low hour, I would bet a standard "A" piston (ie; stock size piston) would work just fine. An "A" piston size is 68.94mm. A "B" would be 68.95mm and a "C" would be 68.96mm.
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Re: 1st things 1st?

Post by babo89 »

SS109 wrote: 10:47 pm Apr 21 2024 There is no change in any KDX220 piston size from 1997 until they stopped making them in 2005. The only difference is the A, B, etc. sizing which is measured in hundredths of an inch.

Preferably, yes, you should get the cylinder measured. However, again due to your engine being very low hour, I would bet a standard "A" piston (ie; stock size piston) would work just fine. An "A" piston size is 68.94mm. A "B" would be 68.95mm and a "C" would be 68.96mm.
so basically as i continue to ride and the cylinder starts to wear, thats when the other sized pistons come into play or jf its been bored?

also when ordering these top end kits i will need to order the wrist pin bearing as well?
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Re: 1st things 1st?

Post by MoonStomper »

Always replace the wrist pin bearing when doing a piston…

… add good knee braces to your list of gear to acquire and in the meantime keep your feet on those pegs!
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Re: 1st things 1st?

Post by SS109 »

babo89 wrote: 02:54 pm Apr 23 2024 so basically as i continue to ride and the cylinder starts to wear, thats when the other sized pistons come into play or jf its been bored?

also when ordering these top end kits i will need to order the wrist pin bearing as well?
Yes, the piston sizes are for normal wearing of the cylinder over time. Big bore pistons are specialty pieces.

Yes, always replace the wrist pin bearing. I've seen some pistons come with them and some don't. Make sure what comes with your piston and if it doesn't come with one then order it separately.
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