1974 Yamaha DT250A / DT360A Service Manual (207 Pages)
Complete service documentation for DT250A and DT360A models with engine specifications, clutch assembly procedures, carburetor adjustments, electrical schematics, and chassis repair instructions. Includes detailed torque specifications and maintenance intervals.
Manual Preview
Sample pages from the 1974 Yamaha DT250A / DT360A Service Manual (207 Pages) manual
Purchase & Download
Models Covered & Key Technical Specifications
Yamaha DT250A, DT360A — 1974 Mechanical Collection & Reference | DT Series Toolkit.
- Established Component Weight: The oil tank is calibrated to 1.5 L (1.6 US qts) SAE "SE" 10W/30 lubricant requirements Standards.
- Measured Precision Specs: For transmission operation, DT250A supports 1,000 cc plus 50 cc gearbox lubrication Threshold.
- Operational Bolt Torques: Cylinder head fasteners are measured at 2.1–2.5 kg-m (182–217 in-lbs) securing specification Protocol.
- Baseline Displacement Data: DT250A delivers 246 cc (15.01 cu. in.) engine cylinder volume architecture Matrix.
- Integral Circuit Specs: Fuel capacity indicates 9.0 L (2.4 US gals) Low-Lead Gasoline tank specification Norms.
- Specific Size Parameters: The wheelbase is specified as 1,415 mm (55.7 in.) DT250A, 1,425 mm (56.1 in.) DT360A benchmarks Range.
Professional Workshop Service Manual & Technical Specifications
Enhanced Repair Manual: Yamaha DT250A / DT360A 1974 Service Manual Specification-Guide
Model-Portfolio: Yamaha DT250A, DT360A — 1974 models // Model-Designation: Twin-stroke motorcycle engine systems, fuel delivery, and electrical circuits // Model-Designation: Comprehensive mechanical specifications, torque documentation, and assembly procedures.
| Metric | Technical-Path | Framework |
|---|---|---|
| Transmission Type | 5-speed constant mesh systems | Complete specifications provided |
| Ignition Systems | Magneto (DT250A) and CDI (DT360A) modules | Documented in separate chapters |
| Carburetor Configuration | Mikuni VM28SS / VM30SS fuel management | See Chapter 4 carburetion section |
| Lubrication Module | Autolube separate-feed system with stroke adjustment | Documented with adjustment data |
| Electrical Framework | 6V flywheel magneto charging and battery systems | See Chapter 5 detailed documentation |
Reference chapters include engine assembly and disassembly procedures, carburetion and fuel system design, electrical systems and wiring schematics, chassis suspension and brake components, and transmission shift mechanism operation, covering the complete mechanical and electrical architecture of both DT models.
Diagnostic procedures are covered for ignition timing, carburetor circuit troubleshooting, and electrical component function verification. Wiring diagrams are provided for DT250A magneto and DT360A capacitor discharge ignition configurations. Fuel system procedures are documented for petcock operation, float level adjustment, and reed valve assembly maintenance. Adjustment procedures are detailed for throttle cable synchronization, clutch engagement geometry, and brake lever freeplay. Timing procedures are documented for piston position determination and spark occurrence validation.
The manual documents torque specifications for the cylinder head fasteners to ensure proper component alignment retention. Yamaha designed these machines with emphasis on both trail-riding versatility and road performance capability. The integrated Autolube pump delivers oil directly to the intake port, eliminating the need for fuel-oil premixing. Engine disassembly requires understanding the crankcase split method and proper bearing removal procedures. Transmission shafts require precise end-play measurement before final reassembly. The two-stroke design incorporates a forward-inclined cylinder with torque induction porting, complemented by a reed valve inlet system that operates independently based on crankcase pressure dynamics.
Specifications detail the DT250A displacement at 246cc with 70×64mm bore and stroke, while the DT360A reaches 351cc with 80×70mm dimensions. Both models utilize a primary gear reduction ratio controlling drive from the crankshaft to the clutch housing. Chassis specifications include 55.7-inch (DT250A) and 56.1-inch (DT360A) wheelbase measurements, with front telescopic forks and rear swinging arm suspension. Wheel and tire systems incorporate internal expansion brake drums on both axles. The electrical system provides 6-volt charging through a dual-output magneto coil with silicon rectifier, supplying power to the 4AH battery for horn, stoplight, and signal circuits while maintaining separate alternating current paths for headlight and taillights.
FAQ
Customer Reviews
Read what our customers say about this Yamaha Bike manual and share your own experience.
Add a Review
This policy contains information about your privacy. By posting, you are declaring that you understand this policy:
- Your name, rating, website address, town, country, state and comment will be publicly displayed if entered.
- Aside from the data entered into these form fields, other stored data about your comment will include:
- Your IP address (not displayed)
- The time/date of your submission (displayed)
- Your email address will not be shared. It is collected for only two reasons:
- Administrative purposes, should a need to contact you arise.
- To inform you of new comments, should you subscribe to receive notifications.
- A cookie may be set on your computer. This is used to remember your inputs. It will expire by itself.
This policy is subject to change at any time and without notice.
These terms and conditions contain rules about posting comments. By submitting a comment, you are declaring that you agree with these rules:
- Although the administrator will attempt to moderate comments, it is impossible for every comment to have been moderated at any given time.
- You acknowledge that all comments express the views and opinions of the original author and not those of the administrator.
- You agree not to post any material which is knowingly false, obscene, hateful, threatening, harassing or invasive of a person's privacy.
- The administrator has the right to edit, move or remove any comment for any reason and without notice.
Failure to comply with these rules may result in being banned from submitting further comments.
These terms and conditions are subject to change at any time and without notice.
Reviews (2)