1972 DS7 The Row Boat

Re: 1972 DS7 The Long Road

clem said:
About how far back did you set yours? The tank doesn't have a petcock on it right now.
Wait for the petcock before you weld on the rear mount. I can get you some exact measurements, but basically I just slid mine back until it looked like the petcock had enough clearance. It's set back roughly 3/4".

And you should check with Smajure (Scott) about the Chinoy he has. It's a tad pricey, but it is a complete package that includes the ignition, regulator/rectifier, wiring harness, etc. Complete from headlight to taillight and all plug and play.
 
Re: 1972 DS7 The Long Road

Chris, I looked at the ones from HVC and economy cycle but don't recall the brand. I figured between that , the chambers and 350 conversion that I'd break the bank.
 
Re: 1972 DS7 The Long Road

I had a smart guy run all the dg pipe numbers through a real deal 2stroke tunner program. there great pipes for the rpm range of a stock/mild motor.the million dollar hydroformed pipes will rev way past the safe rpms
of a stock crank and ports. so there pretty, expensive, and way over kill for a stock 350. take a hard look at dgs man there cheap there time tested and they work. There not the best pipe out there but there the best pipe for the money by far.
 
Re: 1972 DS7 The Long Road

thanks for the tip Brad. I had a DG pipe on an old '83 Rm125 that someone gave me years ago. It wasn't a bad pipe at all as far as craftsmanship. I'll ask a dumb nonsense question:
I have never ridden or owned a 2-stroke street bike. The last smoker I had was a 2001 CR250 and I sold that back in 2006. So how would an RD feel if compared to the old motocrosser? I mean, I know that I won't be blowing up berms and whipping it over triple jumps but I'm thinking a bit more narrow powerband? I really don't know what to expect but man I'm freaking pumped up to get this thing rolling.
 
Re: 1972 DS7 The Long Road

Mine is a little sluggish until about 2500rpm. Then it pulls up to redline. The old girl has embarrassed a couple of 250 Ninjas ;)
 
Re: 1972 DS7 The Long Road

I started on the seat mold with this:
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and then wound up with this:
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I don't know if I like it a whole lot. I wanted to blend a little new with old and I think that I may drop those dreams and just do a traditional ducktail type with the same indents as the tank but going in the opposite direction. It's Mardi Gras here so I'm off tomorrow and I'll work on it more and try to get it finalized.
 
Re: 1972 DS7 The Long Road

I got the seat done now I need some fiberglass and wax and patience....
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Re: 1972 DS7 The Long Road

Man. I think that looks great. Cool shape. Don't worry about wax. Use heavy aluminum foil. Glass won't stick to it, and its simple to work into the shape of the mold.
 
Re: 1972 DS7 The Long Road

Sounds like I could of used the foil straight over the foam? The tape has some pockets but I am going to deal with that during the fiberglass stage. Good tip Von.
 
Re: 1972 DS7 The Long Road

Hell. If you don't plan on reusing the mold, you could cover it in anything that would protect it from the resin (the resin will very quickly melt the foam) and go to town. Once its cured you just scrape all the foam out and you're done. Messy but effective. Looks like you may end up having to do that anyhow due to the shape of the mold, but its hard to tell for sure from your pics.
 
Re: 1972 DS7 The Long Road

Well its friday night and the wife is going eat with her girlfriends, the kids are at the mother in laws and I've got a couple of newcastles that a bud left in the fridge. Going to be up late;)
Got these in the mail and the fiberglass material for the seat.
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They don't seem like an easy fit but we'll make them work.
 
Re: 1972 DS7 The Long Road

Mine weren't too bad. Coupla added mounts is all. The shifter attaches to the rearset on mine though.

You'll want to use the brake light switch for the rearsets. And consider making the brake linkage attach to the stock pivot, instead of directly like I did. The geometry works out better in the long run ;)

I'm a little booked up this weekend and next with my son leaving. But after that, I'd be happy to take a ride down and give ya a hand.
 
Re: 1972 DS7 The Long Road

I got the rearsets figured out. I had a brake linkage from a crf50 laying around and it worked out perfectly. I need to fab the brackets for the top bolt on the rearset. I am just going to weld it from thenrear framw rail to the middle one and tap holes in three places so that they are adjustable. They will just pivot on the lower bolt.
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I will have to modify the shift lever to work on the bike by cutting the little arm that the linkage connects too and flip it up at about a 90 degree angle from the pedal. I'll also have to drill out the rearset for the shifter to mount to.
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The kickstart misses the brake pedal too.
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Re: 1972 DS7 The Long Road

I want to give Redbird some credit here on the rearsets, it's straight out of his build thread. Thanks Redbird I read your build a few times already, heck, I even read it on two stroke world just for fun ;) Hopefully our schedules can work out soon.
And Brad, you da man.
Man This bike is rusty.
 
Re: 1972 DS7 The Long Road

Hi clem, really enjoying your build. I'm signed up. I have a real appreciation for anyone sorting out their own rear sets. I think you have to do it yourself to appreciate that there is a lot more to it than it might seem at first. I wanted to mention one of the problems with pull rod mechanical systems in case you haven't sorted it through.

The problem lies in the fact that, if the pull rod pivot (at the pedal belcrank) and the swing arm pivot are not coincident , the required rod length distance changes as the suspension moves through it's travel. If the pull rod pivot is both very close to the swing arm pivot AND very close to being on a line drawn between the swing arm pivot and the brake arm/pull rod pivot, AND the swing arm rotation is small, the problem is insignificant. Move even a little bit too far away, and the problem becomes noticeable.

The up shot is, if the above criteria is not considered, there will be oscillation in the brake pedal as the bike goes over bumps and the suspension moves. This occurs in the factory set up, but it is so small it is not noticeable (at least by me)

You can observe this very easily. support your motorcycle on the center stand, remove the shocks, and move the suspension through its travel. You will see the brake lever move. If you run a very tight pedal set up, that is the "up" pedal stop is adjusted for a low pedal and the brake rod adjustment is set for a very short "throw", it could be possible to engage the brake with large suspension deflections. You can observe this also by clamping your pedal in one place while the suspension is at ride height, and then moving the suspension through its travel. You will see the brake arm move. Whether this is a problem or even dangerous depends on all the variables.

I really hate an oscillating pedal, and performance riding with one is out of the question. I have built quite a few rear sets and if I have to keep the mechanical drum I use a cable system if I can't either keep the factory pivot or dream up a new one with very close geometry. Cables have their own issues, but are super flexible in geometry possibilities. Pull rod systems are really rugged and reliable, even elegant in their simplicity but you can not escape the kinematics required to make them work properly.

Keep up the good work - DS-7's are a BLAST!!
 
Re: 1972 DS7 The Long Road

jp nailed it. That's why I mentioned using the factory pivot. When I had my linkage run with the drum lever pulling from the underside the oscilation was noticable. Barely, but noticable. I moved it to a top pull when I changed my shocks, and now it's annoying. And as jp mentioned, in deep suspension travel, it will engauge the brake. Slightly, but enough that I can feel it.
 
Re: 1972 DS7 The Long Road

I like cable brakes for just that reason but......I somehow think it won't be an issue for you any longer.....nudge....nudge....
 
Re: 1972 DS7 The Long Road

Well this thing slid back to page 5 so I know that I've been slacking. So here is where I stand:

I got the brackets made for the rearsets and set them up for three positions. They wound up getting tapped to accept a bolt.
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Mocked up:
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I bought a front end off of a 2001 ZX-6E but I need to press the stem out and replace it with the DS7 stem. I haven't measured them out but hopefully it will fit in the new lower triple. I'm also thinking of building a press for this from some 3" channel. Any thoughts on that one?
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I really had no clue how much work goes into a fiberglass seat. Three weekends and still not happy. Sanding is not my friend but I don't want a crap job when it's done so we will become very close.
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