QuadManiac

Any suggestions on best cleaning the tank of all the crud I'm sure is in there? And is there an easy way to tell if the crankshaft seals will need replacing?

C'mon guys.... the reason some of us are laughing is because so many statements being made here are IMPOSSIBLE. example: Since this bike does NOT have an automatic transmission, how in the hell can you (on the same bike) tach 10,000 at 85 and 10,500 at 83 (implying some kind of improvement)? You didn't change your gearing did you? Didn't think so. Do you realize that you will ALWAYS tach the same RPM at the same speed REGARDLESS of what mods you make? You just might get there faster, but in any given gear, your RPM and speed will match linearly and NOTHING, short of changing sprocket ratio, will change the RPM at a given speed in a gear. So, unless you increase the RPM limiter in the computer, you will never go any faster than the limiter allows even if you tripled the power generation of your motor, unless you also change the sprocket ratio. Over 100 from a 125? Not a chance in hell (or MANY thousands of pounds spent on an engine that will last only a few hours). You just can't cheat the laws of physics, especially considering that power required is the CUBE of velocity. (doubling speed requires 8 times the power to overcome air drag) Ride in a vacuum and you can gear to get just about any speed you want (on flat ground, ignoring rolling friction). AND "the bike will do 80mph restricted about 120mph derestricted"... what is that - at about 16,000 RPM? ya, that'll last a few seconds. Reality check time!

90km/hr (~55mph) is pretty good for a 125... But it's rated top speed is spec'd at 74mph. IMO that's a little optimistic with the spec'd 14HP. From your description, it sounds like you may be bogging a bit at WOT. Has the bike sat for a while (several months) unused? Perhaps time to clean the carb and jets?

How long has your bike sat, unused? Common for the jets to plug up when old fuel evaporates out, leaving varnish behind, especially in the pilot jets which have very tiny passages and, coincidentally, control the idle fuel mixture. You're likely going to have to remove the float bowls (if you can get to them without removing the carbs, great), unscrew the jets and spray through them with carb cleaner, probe them with very thin copper wire (like one strand from a piece of speaker wire) and then dry them with air. Make sure you see a nice, cylindrical shaft of light coming through them, or they're not clean enough yet.

I posted a similar topic in Classics, but now realize this may be the correct place. I've acquired a 73 CT3 175 that's been stored dry under a house for the last 30 years. I have lots of experience with 4-stroke bike and quad engines, mechanicals, etc., but not much 2-stroke. Any suggestions on the best way to bring this back to life? I will rebuild the carb, clean the gas tank, check the oil pump, oil the cylinder and piston and try to get some oil into the bearings... but what am I missing? Do reeds present any problem with this long time storage? Do clutch friction plates degrade over time? I've never brought something that's been asleep this long back to life, so any suggestions will be appreciated.

Or is it perhaps this one? http://www.slimduck.com/dt125_wiring.htm

The factory service manual (for the CT1-C) calls for 800cc of SAE 10W30. I'd be careful in selection, since most automotive oils in this viscosity now have friction inhibiters which are bad for wet clutches. M/C oil is guaranteed to NOT have this problem.

Assuming it is a switch driving an oil warning light, and not a transducer driving an oil pressure gauge, you are correct. The switch, when under no pressure, should measure no more than a few Ohms. Under pressure, it should be open, or infinite Ohms. It is likely your switch's internal contacts are worn out.

I'm very happy to find this forum and the wealth of information it contains. Unfortunatley, the search engine won't allow 3 character searches, so CT3 and 175 are not pulling anything up. I've just been given a 73 CT3 175 that has resided in a neighbor's basement for the last 30 years or so. Cosmetically,other that filth, it is quite nice, but we have no idea yet of it's mechanical condition. I'm proficient in maintenance and repair of current day motorcycle internal combustion engines (you can see how many I have to deal with from my signature) but have little experieince with older bikes, especially 2-strokes. If anyone has experience with restoring this genre of beast, especially with this particular bike, I'd love to hear some suggestions, tips, what is a must, what to aviod, etc. Any help is greatly appreciated. I am an electrical engineer and have found that I am especially capable with M/C system electrics, a subject I know causes headaches for many. So, as I progress in my resurrection of this bike, I look forward to being able to contribute in kind to others with issues.