Here is usefull information/specs for TR80 350, translated from a post i've written for a french forum.
crankshaft left bearing
crankshaft right bearing
gearbox mainshaft needle bearings
crankshaft main seals
gearbox/front sprocket seal
clutch pushrod seal
gear lever oring
clutch needle bearing
*(May be replaced by a roller bearing, shoulder placed on inner/crank side)
Front wheel bearings : 6201 2RS x2
Rear wheel bearings : 6203 2RS x2
Steering tapered roller bearings (same on 350 & 250): 30204 x2 and the seals (SKF) nilos 30204AV
Exhaust o’ring 4x44mm in FKM material
There is no specific engine gasket kit for the TR80. The Artein gasket kit J0000SS000246 (Ossa 350) may be used for the central crankcase and sides, but won’t fit the exhaust or cylinder head.
Crankcase gaskets are 0,9mm thick.
Cylinder base gasket is 0,5mm thick.
Cylinder head gasket is 0,6mm thick, made of copper.
Ignition is 1,3mm to 1,8mm BTDC = 14,5° to 17° BTDC
Woodruff key is 3x5x13mm. Yamaha 90280-05001 may be used.
Rod kit may be found at Nuova Mazzucchelli, (BCO 0438). Can be found at Italkit, ref BC.9438
Primary chain is a duplex euro series 06B2, 9,525mm, 50 pins
Crankshaft seals from Yamaha part 93102-25446 should fit.
Side clearance for engine shafts (from Ossa 5 speeds manual):
crankshaft : 0,1 to 0,2mm (rod big bearing should be centered)
gearbox mainshaft : 0,5 to 0 ,9mm
gearbox layshaft : 0,25 to 0,4mm
gear drum : 0,2 to 0,3mm
kickstarter : 1,5 to 2mm
following refs may be used with a spacer behind (520 chain):
JT Sprocket JTF 569
from 10 to 15 teeth, used on Kawasaki KDX 200/250 and Yam YZ250 1983
CARB (original Amal)
Fuel petcock is right hand thread, M12x1,5mm, same as Bultaco/Montesa
Amal L-2627/408 (MK2 concentrics serie 2600).
Choke lever on the left, 27mm venturi.
« Spanish » Amal, british Amal have a groove for the rubber manifold, MK1 float needle valve on the spanish MK2… every parts can still be ordered at the Amal company.
15 fitted on the carb body beneath the air tube
40 fitted in the bowl under the small tube
105 two stroke type without side hole
2B1 fitted on 3rd clip
3,5 under the intake adaptator
2 stroke type, no threads in the bowl
cold start plunger
sold as a kit with its spring, plunger, seal...
Air screw should be unscrew from 1 turn to 1,5 turn according to Amal. 2 stroke bowl is different from the 4 stroke.
FRONT BRAKE (110x25)
CLUTCH (according to the TR80 yellow notice)
Oil is SAE90 for gearbox/axle or engine SAE30 (equal to modern 15w50 or 20w50, depending on the oil brand). For your information, Ipone BOX2 is 10w40 and ATF Dexron III is thinner than engine 10w30)
Plate kit is made of 5 friction plates + 5 steel plates. The thicker steel plate (2mm) goes first (on the engine side), stack ends with a friction plate.
5 friction plates
4 steel plates 1,5mm
1 steel plate 2mm
5 friction plates
Barnet 302-63-50001 kit : 5 friction plates
Agpa, TJT and CMS seem to make kits for Ossa
8mm bushing on top
15mm bushing on bottom
About Betor, you should choose « hard » springs, 40 lbs can’t be used, and 50 lbs is for really light drivers.
radial shaft seals 35x47x10. This size is common on italian motorcycles mounted with 35mm Marzzochi fork (Aprilia, Moto Guzzi, etc)
There is a spacer under the seal, 36x47x4 in aluminium
19,5 cc oil in each fork leg
fork springs are 28mm OD 3,6mm wire 57 coils 480mm free length
Swingarm bushes are non-standard size 21x25x45mm probably made of nylon, shoulder is 3mm thick
feel free to correct me for any mistake.