1980 KZ250 Cafe Build

Back at it again. My rear brake light switch wasn't working the greatest due to the return spring being the wrong length and/or tension. I was thinking of ways to replace it since my sour cream container full of return springs didn't seem to have what I was after. Enter a father with a daughter whom has crazy hair. I took a length of 14ga stranded wire and stripped the insulation off of it. I then twisted 3 sets of 2 strands together and then braided them. A little bit of finessing through the holes and I twisted them together. Got the soldering iron out and soldered the twists, letting the wire get pretty hot to give it a nice look and to let the solder deep down. Totally functional and a slick little bit of detail.

Second, and most importantly; the battery. since the outset of this build I knew I wanted to avoid a big lead acid style battery. This left me with few options. LiIon was the obvious option but I refused to spend $200 on a battery. IMHO these companies are out to lunch with their pricing. LiIon batteries have been around for years, yet companies still feel the need to charge an arm and a leg for them. So, during the rebuild I was using one of my Makita 18v drill batteries for testing circuits (I actually did my first 2 test rides with it as well). Granted this was a bit of a roll of the dice with an extra 6V but it gave me the chance to test everything. My final solution was a DeWalt 12V-1.3AH battery. Measured with my voltmeter it comes out at about 13V at the leads, which compared to a standard bike batteries 12.8V is more than acceptable. I've started the bike a dozen times now without fault and it keeps up with the electrics just like a standard bike battery. I'm sure it would have the power to turn over a 750four or anything but for a little one lunger like this it is a perfect solution, especially at the $60 that Home Depot charges. Not to mention I don't have to buy a separate charger for it since I already have a full shed of DeWalt tools.
 

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Haven't posted in a while so I thought I'd send a little update. Took her on a couple rides last fall, cooked the battery and haven't got around to ordering a new one. Was thinking of the Antigravity 4 cell due to its size. Will likely order one of those as I think it's my only option.

I did up some stickers for my tank. My friend has a vinyl plotter so I did a few different renditions to see which I liked best. I'm quite happy with how it turned out.
 

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Well I broke down and ordered an Antigravity 4cell battery and it just arrived today. Fits nicely in my battery tray and it was packaged with a bunch of different pieces of sticky backed foam so I used that to make a pocket for the battery in my electrical tray. Checked voltages at idle and everything looked ok, same after taking it for a short 5km shakedown ride. Do any of you have any experience with running these Li-Ion batteries with your stock rectifier/regulator without issue? I know the literature recommends updating your charging system but if it's not entirely necessary I'd like to leave it.

As for my shakedown ride, all went well for the most part. Had a bit of a hiccup as I was approaching home, might have just been some cruddy fuel working it's way through, aside from that my guess would be that the carb needs a bit of cleaning (might have forgot to drain it for a month or so over the winter)

The other thing I noticed was that my hands were getting a little tingly even after 5km. I have about 30mm of height I can gain on my clipons so I might adjust those and go for another little ride and see if it's any better.

And finally the 5km ride gave me a better appreciation for how good the suspension is on my DRZ400sm

https://youtu.be/k_hAD9M3fE8
 
Disclaimer: Long post

This past week was a bit of a learning experience for me. I went on a couple more rides and each time the bike would fall on its face at mid-high revs. So I hopped on the forums and also consulted my father (he was a mechanic for years and built a few drag bikes in the past among other things)

Symptoms were
1. Idled fine but fell on its face at any revs beyond an idle or when snapping the throttle open
2. Air filter was wet with fuel after about 20 seconds of riding
3. Plug was fouled black after the same amount of riding.

So all the evidence pointed to a diagnosis that the bike was running rich and was likely not getting enough air as a result of the float level being too high. However the bike ran fine last fall after being tuned by my father and only started this 5 minutes into my first ride this season. I chocked it up to some crud in the carb from fuel that sat in it for a couple months over the winter before I remembered to drain it.

Last night I took the carb off, completely dismantled it and gave all the components a good cleaning. Put it back together, popped it back and and started the bike up to ensure the carb was all in good order after reassembly. It started up fine but I couldn't take it for a test ride because of a flash storm. I did however notice that the idle was very slow and it stalled a couple times. I figure I blew out some chunks of crap that might have messed with the idle (will adjust this later)

Fast forward to this afternoon and I took it out for a test. Still idling slowly but I pulled out onto the road and had the same symptoms as before. Only thing left to do was tune the float. Adjusted it about 6 times and on the last adjustment I turned the key on.....nothing, no power at all. I thought I cooked the battery somehow so I lifted the seat and went to check if I had a voltage and low and behold the ground connection was loose. Added some lock washers and put everything back together. Started it up and took it for the test ride an voila! Bike ran flawlessly.

So I'm still not sure if my float adjustment did the trick or if it was an issue with the loose connection at the battery. I'm quite positive the float is at or almost at its previous setting so I'm wondering if the bad connection would cause an ignition issue if the coil wasn't getting enough juice when the throttle was opened. If this was causing the bike to be missing would that cause the symptoms I was experiencing? Almost makes sense to me but I'm no mechanic.
 
As the bike moves (and starts to rev), more vibrations occur which probably started shaking the ground wire which might be why it seemed to run ok at idle. Multiple carb cleanings do not hurt. Now you need to set the mixture jet and idle speed.
 
I was thinking the same thing, the vibration while riding is pretty substantial with this little bike. Judging by how loose the terminal screw was I'm assuming it was making and breaking contact at will. At any rate, I've learned a lesson in using lock washers for the hundredth time.

I had a chance tonight to play around with the idle. It only took about 1/2deg turn in to get it back to a nice idle. I didn't want to touch the mixture screw because it is working well now that the float is adjusted and my battery is sorted out. Will have to take it out for a couple more shake down rides just to ensure it's all set properly but I think I'm there.

I'm thinking it would be a good idea to put together a little toolkit to throw under the seat incase I have to screw around on the road. I don't carry a toolkit on my DRZ but that thing is so reliable that the thought has never even crossed my mind.
 
I'm a pretty tall dude (6'4") so I already look like a circus monkey on this bike, which doesn't concern me but I always feel like my toes are going to hit the pavement while cornering. I've been considering replacing the shocks with something a bit longer. I've got 12.5" eye to eye now and I was thinking 13.5" would be a good shock height. I was tinkering in the shed tonight anyway so I mocked up a 13.5" shock with a piece of MDF I had laying around.

I took before and after pics and put them together so I could see if it looked any better and I think it does.kre importantly, sitting on the bike, it feels quite a bit more natural. I can't imagine an inch in the rear would have any negative effects on handling. I've done some reading about adding height to the rear end and alot of what I see is that a small change one way or the other usually won't make any difference in the handling characteristics. One fellow mentioned that 10-15% on top of the stock length is about the maximum you should go before you start to notice bad handling or speed wobble.

I did notice however that because of the greater angle of the swingarm it looks like the chain might have a tendency to bounce off of it. I'd have to wait until I have a new set of shocks to see if this would still be an issue with my weight on it. If it does happen to interfere it won't be by much and I can remedy that by putting an idler roller in the place of the chain guard mount. There was never a chain roller there as long as I've owned the bike and I'm not sure if one was ever there but it would be small, only about .500" diameter. Not sure I'll be able to find one this small but if I can't I will just grab some polypropylene and make my own.
 

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Looks like orig shocks ? so they are prob stuffed :)....get someone to help and measure your rear shock sag with you on the bike (google motorcycle suspension sag) ...or if no help get a small cable tie and rap it around one of the shocks internal plunger shaft (can be a pig to do depending on how tight wound the spring is) put the cable tie down so it rest on the shock bottom oil seal, sit on bike loaded up (helmet jacket ect) hands on bars with both feet of the deck.Then check were the cable tie has ended up...You want 30 to 35mm sag....you can raise the spring preload if to much sag....if you have preload max and still have 30mm or more sag, then springs are stuffed or to small for your weight....
 
Yes they are the original shocks. They are starting to leak a little bit too so it might not be a horrible idea to replace them anyway. I did a sag test just out of curiosity and I measured about 20mm sag with the preload set to maximum.

I've pretty well made up my mind to go with a 13.5" (340mm) shock to get that extra inch of height in the rear. I plan to keep my eyes peeled for a lightly used set. If I don't find any within the next couple weeks I will likely order some of the rfy shocks on Amazon.
 
My list of small items was building and building so I decided I'd tackle that this weekend. Basically, I had a bunch of little things to button up that weren't stopping me from finishing the build, but needed to be done.

First was the forward tank damper rubbers. They were never on the bike so it was either buy them or fabricate them. I couldn't find any online that weren't seriously expensive so I went to the local farm supply store and found some hard rubber stoppers of the right diameter. Had to heat up a knife and cut the thickness down by about 7mm, and then re-drill an appropriately sized hole to mount to the frame.

I also had to make a damper to mount the back of the tank to the frame. Again, made this out of a random rubber grommet I found at the farm supply store.

The next thing that deeded to be dealt with was the rearset bolts. I chose the passenger peg mounts as the location for my rearsets but the ID of the mount was quite a bit bigger than the boot size for the rearsets that I bought. I found the closest size brass bushing that would work with the rearset bolts, but the OD was slightly too large to fit into the passenger peg mount. Since I don't have any fancy tools like lathes and such I threw the bushings into the chuck of my drill and with the drill on low speed I turned the diameter down with a flat file. Pressed these into the holes and now the rearsets actually feel like they're mounted properly.
 

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I had the thought the other day that these mag wheels might look better all black. I've seen quite a few builds with this type wheel where the builder has painted them and I think it just makes for a cleaner look. So I downloaded a photo editor app and crudely coloured them in. I think it looks pretty sharp and I am 90% sure I am going to go through with it.

I also photoshopped the rfy shocks in that I will likely order. I did the gold ones but I think I might order the black instead as I feel it would suit the bike better.

Second picture was me messing around with a different seat. The more I look at my bike, the more I feel like the seat is too big in relation to the tank. I think if it were a 400,650,750 etc with a bigger stock tank it would jive a bit better. I figured a brat style seat would suit the little 250 so I photoshopped one on for fun. I think I like it and it looks like I can get a seat with the same mounting holes as the one I have.

I guess I'm looking for a bit of feedback here from the DTT family. What do you guys think of these options?
 

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Honestly, I prefer the old shocks to those RFY's, looks-wise anyway. I also prefer the mags unpainted, but I'm all over that brat seat.
 
Black brat seat...no resoivor shocks...stock paint on wheels or black wheels with a thin pinstripe around edge matching tank color.
 
I like the seat. I'd black out the sprocket on the rear wheel too. I agree on the black shocks too, should look nice.
 
I like the black wheels. Rattle-canned my Comstars with Duplicolor wheel paint. I used black and then clear. They will eventually chip, but so will powder coat.
 
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