Dual Carb/CDI JDX Sleds

[guitardude081]

As we go down the trail, parts sources tend to dry up and technology updates seem to make their way to the mid-mount sleds. After several years of contemplating, I decided to build a "what should have been" 1973 JDX8. I've always parted or given away mid-mount sleds because they didn't interest me. After receiving a bunch of free ones and buying a decent X8 for $20, I wanted to build a farmhand sled so my wheeler didn't have to work so hard in deep snow. This was until someone talked me into building a grass drag sled. After nearly 2 years of planning and building, I ended up building a sled I have name "Little Blitzkrieg" mainly because it was the only badass word I could think of that incorporated Blitz Black. This also solved the problem of how to get rid of a bunch of mid-mount stuff no one wants. If anyone is interested in upgrading a JDX to dual carbs and CDI ignition, I wouldn't mind writing up a tech article complete with pics. It's pretty easy to do and after you add a little help to the original clutch setup, these little sleds really get up and go. This little sled and my 295/S are seeing more use than the Trailfire now that I'm not afraid to ride the tippy little things.

[jep_800]

Jack, I think a complete tech write-up would be great. There has been a lot of guys who have wanted to convert or did convert their mid-mounts to Mikuni set up, and also CDI. A step by step would be awesome for the new guy who wants to get into these but doesn't know where to start. Being a purist (mostly), I rebuilt the WRA-31 Walbro, and they seem to work fine.

Question: You have a 102c on that X8. What spring and weights are you using for that sled?... originally they called for F weights and a white spring, which is what I've got in both my 800 and JDX. Just wondering if you're playing around with that since this is a drag sled. Also, are you using the original Comet 90D secondary? Did you play with that any? Different spring or change the helix, etc?

Thanks.

Jason

[Steven Rempel]

mid mount stuff no one wants?????? I want more but shipping is the killer of more deals than anything else. But please a detailed write up would be much appreciated. I dream of doing this but need more info pls.

[farleyjd400]

Agree Steve, I too will take a lot more mid mount stuff.

I would like to see a write up on this subject. I would love to do a single Mikuni carb and CDI swap, but its all the little things that would stop me from pursuing it. The clutching info would also be great.

look forward to seeing the write up. Great idea

[guitardude081]

Guys, I'm glad to hear you have mid-mount fever too. I've had restored and original fire series, S chassis LFs and cyclones and for some reason, mid-mounts never did it for me. Now they seem to be my only interest. I have an 80 LF ready to assemble. I've done 4 of them and just don't feel like another when I have a second 295 to build. My '78 LF gathers more pigeon crap by the day.

My clutching right now on the X8 is for Drags. I am running comet 102/90D. I would run 54 gram Polaris or Cat weights with a Comet purple spring in the primary. The secondary really depends on how sacked your spring is. Mine is NOS with fresh paint. For Drags, you want that secondary to open quick so you want to set it at hole 1. You would also want lighter weights. I'm running 53 gram weights. A good trail start setup would be the 54's (stock F weights) and hole#2 to take advantage of backshift. Polaris and Cat had more tip weight so they pull harder during acceleration and snap more during backshift. You can thank me later for all the fun that comes with a 5000 rpm engagement on a dual carb '75 piped X8. I will probably throw the big tank on for the Waconia ride because I discovered how much fun the sled was running down the return lane at Grass Drags. I was laughing every time.

~Jack

[lwb140]

I have a jdx 4 similarly equipped , I've been messing with chain case gearing , for trail riding and bombing around, what do you recommend ? i started out with 16-35 in it and it seemed to be gear bound , I have 18-35 and awaiting snow and usps to arrive with a 19t top sprocket. Also been messing with the secondary. Primary has f springs with a silver spring ( 340 lf calibration) thx wade

[farleyjd400]

I love all this clutching talk. There should be a category on this site for just clutching. Clutching is the one thing I need to learn more about so thanks for the input Jack. I have a very nice 74 JDX4 special that is a very low mile very nice original sled and im amazed how quick this sled is for being an old 340, so im not sure i want to mess with the clutching on this sled yet. I have a very nice 76 Cyclone 440 that i need to play with the clutching more to get a little better low end, but im just not sure where to start. Its amazing how im always choosing to ride the JDX4 over the Cyclone though. I cant wait to get my 75 JD 800 restored.