Cafe Racer Forum banner

1 - 20 of 24 Posts

·
Registered
Joined
·
262 Posts
Discussion Starter #1 (Edited)
During my surgery residency (which I just graduated a few weeks ago), one of our front desk greeters would always comment on my helmet - "nice helmet…full face…etc". I would wave and smile and make small talk, not thinking too much about it. She was around 80 years old, I thought she was just being pleasant.
One day she stops me in the morning as I'm rushing to rounds, "You know I used to ride when I was younger! It was a 2 stroke. Peppy little thing!"….2 strokes being a rarity I further enquire and run a short list of bikes (the RD series and the GT series). She kept saying No. Months go by and she says "Im emptying my barn and selling my farm, I found my old bike, wanna see it?". Of course!
I head over to her gorgeous farmhouse and huuuuuuuuge barn/warehouse (her family owned the lehigh valleys first and largest landscaping and farming bushiness) and in a small side room with a partially collapsed wall and gravel floor is a bike underneath a bunch of and tools. It smelled like cat piss and dirt. Flat tires, rusty, crusty but spun free and at least out of the rain.
Dig it out and its her DS7 250. Never heard of it, googled it and found out that its the precursor to the RD250. I see the potential and ask her what she wanted to do with it. She was downsizing and sold it to me for a fair amount. I told her id get it running for her and she would one day ride again. She told me about her husbands passing, his time in the service and her riding alongside his "honda 750" - which was sold long ago. One of her employees dropped it off the next day with the title.
Rusty tank, dead points, clogged carbs but good bones. I get to work on all the above….but its not easy operating all day and then coming home and wrenching after 3 hours of studying. impossible.
fast forward 2 years….i see her in one of my hallways on a stretcher…she tells me she was getting aortic valve surgery (basically open heart surgery). This lit a serious fire to get it done.
Lots of struggles in between to get it running and late nights with deadbeat mechanics (hired for diagnostic help) who failed to show up/point me in the right direction ….. but lets skip that crap and get to the pics.
This afternoon, as I'm studying for my boards and packing the house to move away to fellowship, I invited her over to see the bike. I cleaned the tank last night and finally buttoned everything up.
I had her pull the cover off it to see her reaction.
She almost cried when she saw it… "there she is! I remember her".
The wife used my daughters crayons to decorate a helmet for her and i took her on a spin around the block.
Today was a good day.


DS7.jpeg
IMG_1070.JPG IMG_1072.JPG


after a bunch of work and polish
IMG_1086.JPG IMG_1091.JPG


Most of you guys do much more in-depth and comprehensive restorations, but i just wanted to share this story as a fond memory and experience.
 

Attachments

·
Registered
Joined
·
5,780 Posts
Nicely done in every aspect.
 

·
Registered
Joined
·
840 Posts
Nice job. Glad you got her on it! :)

I've got a DS7 stuffed in to my rd400 frame cause i had it on hand when the 400 crank went south. I thought / was told it was an R5 and never checked the vin plate untill it would not pull like an r5 when duing a plug check (jetting check) i read the vin and said shit no wonder why i need one less tooth in the front to wheelie...
 

·
Banned
Joined
·
8 Posts
Miss those days with the Yamaha 2 stroke bikes man! They were the meanest machines one could own!
 

·
Registered
Joined
·
262 Posts
Discussion Starter #7 (Edited)
largely its been an awesome process…tedious as you can imagine and a lot of research and reading in between.
sadly the air inlet boots from the air box to the carbs are warped and refuse to make a seal again….so I'm searching for options and even considering the dreaded "stand alone filters".
when i first ran the bike, it was from a pre-mix fuel bottle, with a touch extra oil for safe measure….boy did she smoke. Now I'm pretty certain that the auto-lube system works by itself, since the plugs get a light misting when the kickstarted is applied for a few rounds, so i filled the tank with 2 cycle and weaned the ole gal back to premium alone in the tank.
Under full load and throttle, she still leaves a light blue/white plume from treeline to treeline on a 2 lane back road.
So how much smoke is too much smoke?…any descriptions or rules of thumb?
Also she doesn't like to build rpm under load (around 2-3k) and sounds boggy/sucking air….but then when i pull in the clutch, and feather the throttle she rips back into the power band allowing me to release the clutch and get back into the power (example, leisurely pulling up an incline in 2nd gear, she will bog, till i provide a clutch assisted rpm boost)- what does this suggest/air leak is my thought/or is it an re-contaminated carb?
 

·
Registered
Joined
·
5,705 Posts
...
Also she doesn't like to build rpm under load (around 2-3k) and sounds boggy/sucking air….but then when i pull in the clutch, and feather the throttle she rips back into the power band allowing me to release the clutch and get back into the power (example, leisurely pulling up an incline in 2nd gear, she will bog, till i provide a clutch assisted rpm boost)- what does this suggest/air leak is my thought/or is it an re-contaminated carb?
it suggests that you hate your clutch material, stop doing that ;)


What oil are you using, there is a huge difference in the amount of smoke and residue produced by various brands of 2-smoke oil. You are limited to the ones that are thin enough to run in your autolube system but typically full synthetics produce the least amount of unburnt material and can be run more lean. The more oil you add to your fuel the lower your fuel octane rating will be. Keep in mind that in 1972 we had fuel at the pump rated in excess of 100 octane and full synthetic 2-stroke oils did not yet exist.

Your bike has a piston port type engine, one of the biggest reasons they added reed valves to the intake ports on later models was to improve the low and mid range performance.
 

·
Registered
Joined
·
59 Posts
Awesome story! Picturing my grandmother riding on the back of a bike, swearing like a sailor.


I use Maxima Bio 2T in my RD, and it's been great. No fouling and just the right amount of smoke if the pump is adjusted correctly - adjustment under the motor's right-hand cover. Also, make sure your drums aren't dragging. I've had my drum stay loosen and cause the brakes to drag during a ride. Made it feel like it was bogging like you described.
 

·
Registered
Joined
·
262 Posts
Discussion Starter #11
i appreciate the concern for the poor old clutch. Its not a habit.
I only took it out once for a few miles so it was maybe 4-5 times i had to do it, in order to pull away from other light traffic…enough to identify the problem. it cruises rather handsomely and holds speed very well without any surges or irregularity.
Suggestions for the fix? brake drums roll freely.
Ive never adjusted the oil delivery system, ill educate myself on that and see if it needs attention. Now that I'm not running pre-mix perhaps it will lighten up after a few rides (since previously it was pre-mix PLUS some residual oil in the oil tank)…..Perhaps i just need to ride it till it blows out whatever residue remains in the pipes from "over oiling" during the re-assembly/tuning process. I was being cautious since more oil is better than NO oil.
 

·
Registered
Joined
·
5,705 Posts
i appreciate the concern for the poor old clutch. Its not a habit.
I only took it out once for a few miles so it was maybe 4-5 times i had to do it, in order to pull away from other light traffic…enough to identify the problem. it cruises rather handsomely and ...
If you are literally slipping your clutch rather then gearing down to accelerate, you are doing it completely wrong! don't do that, it's just a terrible way to go fast.
Gear down, the bike is a little screamer once you hit the upper power band and be ready for the freakin front wheel to loft in second gear, they really are capable of that kind of acceleration or something is indeed wrong with the bike such as running on one cylinder and I kinda doubt that or it wouldn't idle.

Over oil can cause significant issues in your exhaust system and bad or incompatible oils can cause your piston rings to gum up in addition to the potential to foul plugs. ymmv those are just issues that I have experienced first hand on similar motors. Actually a lot of the smoke you see now could be the result of mung in the exhaust system. You can get a pretty hot fire going inside the exhaust system if you try to ride it out, I would be inclined to clean it manually.


oh, btw, you're not suppose to run the oil injection system dry, if you do it will be pumping air.
 

·
Registered
Joined
·
262 Posts
Discussion Starter #13
the issue its having is "bogging" or starvation at the bottom of certain gears, when I'm about to initiate acceleration.
i didn't end up slipping the clutch….its odd, I pulled in the clutch, feathered the throttle almost as if to clear an interruption in air/fuel and then slowly release the clutch again ….none of the half clutch/rev/dump stuff.
id like to experience a 2nd gear power wheelie….the bike is so light.
the oil is some leftover store brand from walmart that we used to put in the wife's buddy50 scooter. I didn't even know of any synthetic options till recently!

oil tank always had a little in it, and i ran some light pre-mix as a precaution incase the oil inn system was gummed up….which its not.
 

·
Registered
Joined
·
2,107 Posts
Don't short shift it.
I'm with you
Below about 4500 it doesn't develop enough power to pull the skin off a rice pudding. Ride it like you stole it .
As mentioned, you could clean out the pipes... they are fairly restrictive to start with. When you have the pipes off look at the exhaust ports. They may be particularly blocked with carbon if the bike has never had a good thrashing.
 

·
Registered
Joined
·
262 Posts
Discussion Starter #15
sweet. now i get to ask ---- how does one "clean out the pipes?" other than thrashing? any solvents/chemicals?
 

·
Registered
Joined
·
5,705 Posts
Your exhaust probably doesn't have any glass packing material in it so it should be relatively easy, cleaning is usually covered in the service manual and yes, solvents that do not leave a residue would normally be recommended, I'm going to guess kerosene or even Gunk degrease agent followed by a water flush and dry. Baffles were usually removable to facilitate a cleaning.

Once it's apart you can flame it up ;)
 

·
Registered
Joined
·
2,107 Posts
You can pull the baffles. Might be a bit of a bugger getting them out if they are plugged up.. Once you get them out, you could always stop by the local rad shop and ask them if they will stick them in their hot tank. Baffles only, not the chrome bits. Only thing is, they might tell you to get lost if they are really bad. I'm assuming you don't have access to an oxy acetylene torch. You could burn the crap off the baffles. That's what I used to use.
Then attack them with a whirl brush and whatever else you have laying around.
 

·
Registered
Joined
·
1,510 Posts
once you get the carbon red hot then careful aiming of you compressed air blogun nozzle will continue the burn without torch
pure oxygen is much better in ways but can get ugly quick,the baffle itself will start burning
 
1 - 20 of 24 Posts
Top