low budget hybrid

Discussion for swapping a KDX motor in a MX frame...
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francis
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low budget hybrid

Post by francis »

A year and a half ago I bought a 2001 KDX 220 because the price was too good to pass up. $450. I just needed to clean the carb and replace a few knick knacks. I also bought a stock silencer off ebay for stealth factor. I have many dirt bikes but none compare to the 220 engine for low rpm hill climbing. Yesterday I bought a 2001 KX 125 rolling chassis off Craigslist. Complete without engine for $140. The 125 had been sitting outside for a while and the brakes had ceased. Realizing that this was going to be a pain to move around the garage I got right to it and disassembled it to the point where it's only a rolling suspension and frame. The sub frame is waisted, cracked, bent, and every nut is stripped. Other than that the bike seems pretty mint. After removing the brakes they seem to just need a little spray of wd-40. The rear master cylinder needs a new brake pad retainer pin. It's quite rusted and has a gouge almost halfway through it.

Now I'm trying to get together a parts list of the basics to mock this up. I've read quite a bit Here on the hybrids. Here's what I've come up with so far
1. New subframe
2. KX 250 silencer? Stock or aftermarket. Would like quiet but fit and costs are more important
3. Drilling the motor to receive swing arm bolt. When I'm ready I'm gonna try and contact the fellow here that loans them out for shipping costs.
4. ?
5. ?
6. ?
basically I'm wondering about the parts I need to start and suggestions about silencers. I found a stock one for a 01 kx 250 on ebay for $45 that looks almost new.
I want to try and put this together for as cheap as possible. Then I'll consider replacing bearings and painting the frame.

Thanks francis
francis
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low budget hybrid

Post by francis »

UPDATE


I couldn't resist and made my basic purchases on eBay.
1. Kdx,klf,kef,kxf,kxt,klx short petcock with reserve and adjustable (pressed in) fuel outlet $13.
2. 01 Kx 125 subframe $60. Shipped
3. 01 Kx 250 stock silencer $40. Shipped
4. Complete full hardware bolt kit from disassembling a 01 KX 125. Not including swing arm bolt, axles, motor mounts and bolts and probably more $17. Shipped

The KX didn't have the lower engine mount bolts but did have the upper head brackets and bolts. I'm assuming I'll be using the two KDX lower motor mount bolts so I don't think I need them from the KX. The KX I bought had a lot of metric hardware store bolts and we're missing many so I thought the kit might make things easier. I'm sure I could have used a lot of bolts from the KDX but once I get started spending on ebay I sort of get carried away. But I think I'm done spending for now.
I haven't removed the KDX 220 motor yet. The thought of ruining the motor for the kdx by drilling
it Kinda gives me trouble sleeping. It's hard to imagine ruining a perfectly good running bike.
Grand total so far
I put a hundred or so into the KDX the way it sits now.
Kdx $550.
Kx $140
Today's eBay purchases. $130.
Total $820. Ouch!!
This is going to hurt more than I thought. I hope I can stop the bleeding and this doesn't nickel and dime me to the poor house.







Francis
francis
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low budget hybrid

Post by francis »

Does anyone know if this hybrid will have weight savings over the Kdx. I plan on using a KTM headlight and a DRC tail light. Other than the kickstand it's hard to see where the KX can be lighter.

Dry weights listed
Kx 191 lbs
Kdx 222 lbs
31 pounds difference
Is this all in the engine, tail light, headlight and kickstand?
Does that sound right. Where might there be more weight savings if any? Every thing else look so similar besides the front end suspension and gas tank.

Francis
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bufftester
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Re: low budget hybrid

Post by bufftester »

You're through the toughest part. You could have just used the KDX silencer and saved a few bucks as well. You will use the KDX rear wheel with the KX axle and spacers. You will use the KX front wheel, but can use the KDX brakes on both ends. The hardest part comes next, motor mock up. Cutting the KX swingarm is easy enough, just take your time and only remove what you need to, don't just go by the measurements others have given, actually match it up to your bike and measure. You will use the KX front motor mount but will have to remove the KDX rear head mount. Once you drill the case, mock the motor up with the swingarm in place, and the front motor mount installed loosely. Then mount up the carb, airbox, exhaust. adjust as needed to get everything lined up, then and only then, measure and fabricate your lower engine mounts. If you just weld up mounts first you will run into issues with carb/exhaust alignment. Once the mounts are welded, put it all together and go ride! You should be out the door under $1K and have a bike that will do anything you throw at it. I know...I did it already!

As for weight savings, the bike will be slightly lighter, though not 30 pounds worth since the motor/exhaust make up some of that difference. However, it FEELS 50 pounds lighter, and carries the weight better. Once properly sprung for your weight the old KDX will feel like a tank.
francis
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low budget hybrid

Post by francis »

What The reason or difference for the KDX brakes ?
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bufftester
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Re: low budget hybrid

Post by bufftester »

no real reason or much difference other than you mentioned that the kx ones were not in great shape and I assume the kdx ones were. You can use either
francis
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low budget hybrid

Post by francis »

Good to know. thanks

The KX breaks we're locked up from sitting outside. I even tried squeezing the calipers with C clamps on both front and rear while everything was still mounted and nothing budged or loosened. Once I remove the calipers and gave a small shot of WD -40, the piston retracted smoothly with C clamps. I think the pads seized on the guide pins, then somebody squeeze the master cylinders on both front and rear, then the bike sat outside another year.

Another problem I might have related to sitting outside is the airbox boot seems to have taken a beating from the Sun. Maybe after I clean it with some of that magical stuff WD 40 it will regain some of its pliability and hopefully cracks won't appear and hope it's not dry rotted. Crossing my fingers. I'm anxious to know. Almost makes me wanna go out to the garage now but it's late. I'll clean it up tomorrow and see how useful it will be.
Oh wait, if I remember right I'll be using the KX air box with the KDX air boot. Well I think I'm getting a little ahead of myself.


Francis
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Post by francis »

Updates

Today I lucked out with the weather. It was 70 degrees, cloudy with a couple of light showers. Perfect for working in the garage with the door open. Barely broke a sweat. Much better than the past week 95' and high humidity.

Removed the engine today on the 220 and reassembled back to a rolling chassis. Fought with the air box for an hour and a half. Remove the whole rear suspension shock and swing arm and still couldn't get it out. Then and only then I saw the light. Man did I feel dim. How did I miss the fact that the subframe has a removale link.

Kinda lucky in two ways today. First while taking apart the KDX the Kickstarter had no nut or bolt holding it on. I'm sure I wouldn't have noticed before the next ride. Also, both exhaust pipe hangers were broke so the only thing holding the pipe on was the springs and the connection to the silencer.
Second The KX rubber chain guide on the front off the swing arm had just worn through and barely scratched the swing arm. So whatever happened to that KX motor it was just in time.

Got ahold of Skippypinecone this morning for the bits and reaming tool And I should be getting them soon. Man, how could you beat this service. Thanks a lot Darrell


Francis
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low budget hybrid

Post by francis »

Now that both bikes are disassembled to the same point (rolling chassis) the weight savings and size difference appear obvious.

Francis
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low budget hybrid

Post by francis »

Before I hack into the 01 kx125 I want to make sure it will fit my particular needs. My shortest trail rides is 50 miles so an oversized tank is a must. I also will not go back to a bike without a kickstand. Both are possible on the 01 chassis but not quite like the 03 and up chassis. So I was wondering if I can buy a complete 03 and up kx 125 and use the 03 motor in the 01 chassis. Then sell the 01 kx even steven keeping this build on track for a low budget. I posted in general discussion about "interchangeable engine" and receive some sound advice and good facts from bufftester. So if any more of you guys know more about this lets here


Francis

I only called this tread low budget because of the price I paid for both bikes but I definitely realize that most bike parts aren't cheap especially when you consider the price of just an air filter.
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Tedh98
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Re: low budget hybrid

Post by Tedh98 »

I went with an '04 because it was the most recent KX that was made. I also figured that my chances of finding parts (at least in the US) was better because there were two years of that model instead of just one like the '03.

I have an oversize tank and a kickstand on my '04, so you don't have to give anything up there.

If you find an '03+, I would just sell the motor to the kart guys or sell it on eBay. I wouldn't spend the time trying to get it in the '01.

Or another idea is while you are doing the work on the '03+, modify the '01 so that the KDX motor fits in it. Then sell it to a KDX owner who wants a hybrid but doesn't have the time or skills to do it. It then becomes a "bolt on" for that person. I did something similar with a frame and swingarm years ago.
francis
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low budget hybrid

Post by francis »

Those are some valid points and good suggestions.
Thanks Ted


Francis
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