This is the freshly dry ice cleaned cylinder together with the earlier glas beat blasted cylinder head.
Here you can see the completly redone rear wheel. Really EVERYTHING was replaced with new or NOS parts: Hub, bearings, seals, chain adjusters, sproket, spokes, rim, tube, brakes, springs, tire holders and tire itself. The last pictures shows the current progress and me working on perfect reproduction gas tank decals for a 1974 model as originals are not available anymore and the reproductions available are no good. You can also see that I was able to get a very early vented right side cover for my project.
- Fork tubes rusty -> Needs replacement (Marzocchi type)
- Replaced with NOS parts
- Reflectors on front fork needs replacement (easy to get)
- Replaced with NOS
- No mirrors
- Replaced with correct early style HD
- A hole in the oil tank? Why?
- Repaired -> welded
- Studs for mounting the rear turn signals missing
- Built new ones and welded them to the frame
- Paint of the frame is not nice anymore
- Completely powder coated
- Pipe bend and two holes with screws in it! Why?
- Two broken out parts on the left side of the crankcase.
- Side cover is a hand made metal part. Not too bad done, but why? I have a NOS one in stock -> Going to replace
- Replaced with a rare early 1974 side cover (vented version)
- Paint job is not done bad, but it’s a 74 model and someone used 75 decals. Also there is a wrong hole in the rear fender for an aftermarket taillight.
- Wrong ignition switch ( Three connectors)
- Replaced with OEM 10 connectors switch
- Wiring harness in bad condition
- Wrong horn
- Replaced with NOS horn
- No spark
- Seat was redone okay. Top is still original, sides are replaced by someone
- Seat pan powder coated, New original seat cover professionaly done;
- Missing turnsignals
- Set of NOS CEV turnsignals
- Wrong handlebar
- Replaced with OEM & rechromed
- Aftermarket headlamp
- Replaced with NOS headlamp shell
- New reflector & glass
- OEM headlamp rings rechromed
- Tires are junk
- Rear tire replaced with a new Cheng Shin C-186
- Rims need rechroming or replacing
- New rear wheel rim
- NOS rear wheel hub
- New rear spokes (stainless)
- New rear tire holders
- new rear tube
- Side stand missing; Someone fitted a center stand to the bike. It’s done…okay, but not great
- replaced with NOS parts
- Rear shocks (SEBAC) needs replacing or rechroming
- Replaced with NOS!
- Instruments are usable but not nice
- Replaced speedometer with NOS parts
- Replaced rubber mounts with NOS parts
- kick start is from a 75 model – that’s okay to me
- NOS 1974 kick start
- New project
- It’s an early 1974 SX-175 (someone repainted it in 75 design)
- Work done:
- frame sandblasted;
- mainstand removed (not original), parts for kickstand bought and built back to Original condition
- Hole in oiltank closed (welded)
- Turn signal struts in rear rebuilt and welded to frame
- Original turn signal bought
- Frame powder coated
- Handlebar replaced (wasn’t Original)
- Side cover replaced (wasn’t Original)
- airfilter housing, battery cage, brake pedal, kickstand, chain guard, skid guard, rear fork and Triple tree powder coated
- fork tubes replaced with NOS ones, fork legs polished, all new seals, everything cleaned, whole front fork overhauled
- New lamp housing, new lamp (H4)
- Rear wheel hub replaced as it was damaged, brand new brake shoes, linigs and springs
- New airfilter
- All screw and nuts are replaced with stainless stell or overhauled old ones
I had to modify the seat pan because the gas tank that was originally on my bike had big dents that are very hard to repair. I didn’t know about the damage, because someone filled the holes and repainted it. After removing the paint this was a big surprise. I bought a replacement gas tank on ebay. It had 1972 decals, but I was sure it is not a 1972 gas tank. When it was repainted I noticed the replacement tank is about 5 centimeters longer than my original tank!
Well, the replacement tank fits, but than there is no room for the seat. I relocated the seat 5 centimeters to the back and hopefully this will solve my problem. I will have the pan cleaned and powder coated and the seat will be recovered.
I replaced the airfilter (oval type) with a new UFI part. I also replaced the faulty LUCAS flasher relay with a modern electronic flasher relay as the turnsignals did burn constantly instant of flashing.
New seals for the carb today.
- Dellorto PHB 32 Ad
- Needle K7
- middle positon
- Throttle piston 40/1
- main jet 115
- main nozzle AB260
- low speed jet 55
- starting jet 70
- float valve seat 250
- Needle K7
Before you start:
There is no guarantee for the correctness of the information provided. That following steps describe the procedure for my 1970 GT-350. It’s a different procedure on other model years!
To my knowledge (again, without guarantee) this is valid for 1969 to 1972 Sprint 350cc street bikes and not for earlier bikes and not for the 1973-1974 electric start!
Please ailways use a few drops of oil to fit the parts together.
- We start with an empty right side crankcase. Only the shifter pawl carrier (C) is already put in, as it must be inserted before the primary drive gear.
- Pull out the connecting rod (A) to tdc (top dead center), this will move one of the three notches (B) on the flywheel shaft to 3 O’clock position.
- Slide clutch drive gear (D) on shaft of flywheel. It will stop in the correct position because of the conus of the shaft. Don’t turn the shaft! The mark on the clutch drive gear (arrow) is of no meaning at this point.
- Put the woodruf key (E) into notch of the shaft. It must be the notch at 3 O’clock positon while connecting rod is at tdc position!
- Slide pinion gear (F) on shaft with woodruf key in position at 3 O’clock and make sure the mark on the pinion gear points to 3 O’clock also (arrow)! It sits correctly if the surface of the pinion gear touches the surface of the clutch drive gear.
- Put the lock ring and nut on the shaft. One latch will be bend into the notch of the pinion gear the other around the flat side of the nut after the nut is tightend! (These steps are not pictured)
- When tightening the nut you must make sure the shaft will not turn.
- Next we put the primary drive gear on the transmission shaft. On that picture you can see what parts must be fitted inside the gear. A thick spacer (G) that must have the correct thickness to arrange the primary gear in one line with the clutch drive gear (D).
- Inside the gear are two roller bearings. On top of the bearings will fit another distant spacer.
- Put the primary drive gear (J) on transmission shaft and don’t forget the stuff explained in Pic 5. You will need probably 2-3 trys to make the two marks fit the one mark of the clutch drive gear. For that operation you may turn the flywheel shaft with the clutch drive gear.
- The marks on the primary drive gear (J) and the clutch drive gear (D) however are not time critical. It’s just the way the teeth are fitted together by factory. That’s the reason for using gears always in matched sets! If you don’t, you will risk damage to gears.
- Next we put the roller bearing (L) for the camshaft into crankcase and also set the two tappet guides in (K).
- A spacer will be used on camshaft to allign the camshaft gear exactly to the pinion gear.
- I will not describe how to fit the camshaft gear to the camshaft as it can only be fitted in one direction
- Put the camshaft with gear (N) into the roller bearing (Pic 7.) and arrange the two marks with the one mark on the pinion gear (F).
- Screw the oil pump into case (4 screws) and make sure the O-Ring is still on the oil pump for a sealing to the crankcase. Put the gear on the oil pump shaft. It is not time critical and has no mark so it doesn’t matter how it will fit together with the pinion gear.
Here you can see how we pressed the crankpin from the flywheel and the oil dirt we found inside the crankpin after drilling out the plug. This is a typical 4-Stroke-Aermacchi problem and the reason you really should change the oil once a year or every 1000 miles. Rudolf decided the rod is used up and that I will need a new one.