1991 Kdx 200 and Ken O’Connor racing
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1991 Kdx 200 and Ken O’Connor racing
So I’m getting ready to drop my 91 Kdx engine off to Ken O’Connor racing to be gone through. I am having trouble deciding if I should keep it a stock build or not. I really don’t want to create a headache by going all out. Anyone got any input? Are these e model bikes still plenty strong enough stock with a full fmf? Thank you
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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Re: 1991 Kdx 200 and Ken O’Connor racing
You don't have to get crazy to get really great performance from a KDX. Make sure it's in great mechanical condition and dialing in jetting is a huge step. Then, adding regular bolt ons will add even more. The only non-bolt on thing I would have done is to get the squish on the head corrected. It adds power everywhere and helps make jetting easier.
I've done about every mod that can be done short of porting and I'm very happy with the power my bike has. I'm running Boyeson RAD valve, FMF desert pipe with Turbine core silencer, RB carb and head mod, air box lid removed, and my own custom CDI ignition. The only other thing I did was to gasket match the crankcase to the cylinder and removed some minor casting flashing on the cylinder intake and exhaust being very careful not to change any of the ports to the cylinder at all. Notice that every mod other than the head squish mod gasket matching/flash removal is a straight bolt on. You can check out my vids to see and hear how my bike runs and sounds while riding with way more modern, and hugely more powerful, bikes.
I've done about every mod that can be done short of porting and I'm very happy with the power my bike has. I'm running Boyeson RAD valve, FMF desert pipe with Turbine core silencer, RB carb and head mod, air box lid removed, and my own custom CDI ignition. The only other thing I did was to gasket match the crankcase to the cylinder and removed some minor casting flashing on the cylinder intake and exhaust being very careful not to change any of the ports to the cylinder at all. Notice that every mod other than the head squish mod gasket matching/flash removal is a straight bolt on. You can check out my vids to see and hear how my bike runs and sounds while riding with way more modern, and hugely more powerful, bikes.
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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- Supporting Member II
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Re: 1991 Kdx 200 and Ken O’Connor racing
Thanks for your response I didn’t realize RB did the head mod for the e series. I didn’t like the rad valve very much on My 220 but I’ll give it a go on the 200. It’s looks like RB only offer their head mod for the 220 now. I think I’ll have KOR “set the squish to run safely on 93”... does that sound like an ok way to word it? Thanks again.SS109 wrote: ↑05:15 pm Oct 31 2022 You don't have to get crazy to get really great performance from a KDX. Make sure it's in great mechanical condition and dialing in jetting is a huge step. Then, adding regular bolt ons will add even more. The only non-bolt on thing I would have done is to get the squish on the head corrected. It adds power everywhere and helps make jetting easier.
I've done about every mod that can be done short of porting and I'm very happy with the power my bike has. I'm running Boyeson RAD valve, FMF desert pipe with Turbine core silencer, RB carb and head mod, air box lid removed, and my own custom CDI ignition. The only other thing I did was to gasket match the crankcase to the cylinder and removed some minor casting flashing on the cylinder intake and exhaust being very careful not to change any of the ports to the cylinder at all. Notice that every mod other than the head squish mod gasket matching/flash removal is a straight bolt on. You can check out my vids to see and hear how my bike runs and sounds while riding with way more modern, and hugely more powerful, bikes.
Last edited by JZ05220r on 04:53 pm Nov 01 2022, edited 1 time in total.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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Re: 1991 Kdx 200 and Ken O’Connor racing
RB still does the head as far as I know. However, he is semi-retired so he doesn't do as much as he used to. I would contact him if you want him to do it but Ken O'connor should be able to do the same service and is probably the better way to go since your engine is already going to be there. Yes, your wording explains exactly what you want done.
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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Re: 1991 Kdx 200 and Ken O’Connor racing
Look into an R1173N needle instead of the stock thickness. I can't remember the Keihin translated letters, but it is the next step thicker. (same length, same taper, just thicker for leaner at 1/8 - 1/4 throttle). My 1994 imroved after that suggestion from Fredette.
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Re: 1991 Kdx 200 and Ken O’Connor racing
That’s exactly then needle I plan to run. That’s what fmf recommends as well.KDXGarage wrote: ↑11:48 pm Oct 31 2022 Look into an R1173N needle instead of the stock thickness. I can't remember the Keihin translated letters, but it is the next step thicker. (same length, same taper, just thicker for leaner at 1/8 - 1/4 throttle). My 1994 imroved after that suggestion from Fredette.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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- Supporting Member II
- Posts: 569
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Re: 1991 Kdx 200 and Ken O’Connor racing
Thank you SS109 and KDXGARAGE for all the help with all of my questions and concerns. Their are others on here as well like John S for example. You guys are always coming through when I have questions and it is definitely appreciated.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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Re: 1991 Kdx 200 and Ken O’Connor racing
All the people on here pitching in is really quite amazing.
Thanks to all of you!
Thanks to all of you!
Thank you for participating on kdxrider.net.
To post pictures from a device: viewtopic.php?f=88&t=24128
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Re: 1991 Kdx 200 and Ken O’Connor racing
I’m going a very similar route as you in terms of engine mods but I’ll be using a 36mm carb. Although I know it’s personal preference did you stick with 32:1 on your mix ratio? I know frp recommends 50:1 for the e series.SS109 wrote: ↑05:15 pm Oct 31 2022 You don't have to get crazy to get really great performance from a KDX. Make sure it's in great mechanical condition and dialing in jetting is a huge step. Then, adding regular bolt ons will add even more. The only non-bolt on thing I would have done is to get the squish on the head corrected. It adds power everywhere and helps make jetting easier.
I've done about every mod that can be done short of porting and I'm very happy with the power my bike has. I'm running Boyeson RAD valve, FMF desert pipe with Turbine core silencer, RB carb and head mod, air box lid removed, and my own custom CDI ignition. The only other thing I did was to gasket match the crankcase to the cylinder and removed some minor casting flashing on the cylinder intake and exhaust being very careful not to change any of the ports to the cylinder at all. Notice that every mod other than the head squish mod gasket matching/flash removal is a straight bolt on. You can check out my vids to see and hear how my bike runs and sounds while riding with way more modern, and hugely more powerful, bikes.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
- SS109
- KDXRider.net
- Posts: 5796
- Joined: 05:11 am Aug 23 2009
- Country: USA
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Re: 1991 Kdx 200 and Ken O’Connor racing
I run 40:1 in all my 2T bikes including my old E-series KDX I had. I run my bikes pretty hard for an old slow guy. A little extra oil doesn't hurt anything as long as you're jetted properly and can help ring, piston, and bearing life.
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R