Customer service
Tomos A35 rebuild parts and tools checklist
A successful Tomos A35 or A52 engine rebuild starts before the crankcases are opened. Having the correct replacement parts, consumables and workshop tools ready helps prevent delays, damaged hardware and rushed assembly.
This checklist covers the most common Tomos A35 rebuild parts and the tools used for disassembly, bearing work, crankcase assembly, clutch service, ignition work and final installation. You do not need to replace every item during every rebuild, but each part should be inspected while the engine is open.
Tomos A35 rebuild parts checklist
These are the parts and consumables most commonly inspected or replaced during a Tomos A35 or A52 engine overhaul.
| Part / consumable | Why you need it | Shop |
|---|---|---|
| Bearing and seal overhaul set | Core wear items for stopping air leaks and renewing the main sealing points of the engine. | Shop bearing & seal set |
| Middle crankcase gasket | Seals the two crankcase halves. Replace it whenever the cases are split. | Shop crankcase gasket |
| Cylinder stud set | Useful when original studs are corroded, stretched or damaged during removal. | Shop cylinder studs |
| Engine bolt set | Replaces rounded, rusty or mismatched hardware during final assembly. | Shop engine bolt set |
| Reed valve gasket | Helps prevent intake-side false air leaks at the reed valve and manifold area. | Shop reed gasket |
| Liquid gasket / sealant | Use only a very thin layer as extra sealing support on clean mating surfaces. | Shop liquid gasket |
| Front sprocket | Inspect while the engine is out. Replace worn teeth before refitting the chain. | Shop front sprocket |
| Front sprocket locking washer | Use a fresh locking washer when reinstalling the sprocket hardware. | Shop locking washer |
| Kickstart spring | Replace if the kickstart return is weak, inconsistent or damaged. | Shop kickstart spring |
| Piston pin clips | Always use new clips if the piston has been removed or replaced. | Shop piston clips |
| ATF / clutch oil | Refill the transmission after assembly before starting the engine. | Shop ATF oil |
| Two-stroke / assembly oil | Use during assembly to prevent dry-start wear on the piston, pin and bearings. | Shop two-stroke oil |
| Primary shaft rollers | Inspect during the primary shaft rebuild and replace if worn or marked. | Shop primary shaft rollers |
| Primary shaft roller cage | Important for smooth shifting and correct primary shaft operation. | Shop roller cage |
| Alignment bushings | Help the crankcase halves and covers sit correctly during assembly. | Shop alignment bushings |
| Shims | Used to set correct spacing on shafts and clutch/kickstart components. | Shop shims |
| Question mark spring | A small but important part for return action and shifting behavior. | Shop question mark spring |
| Spark plug | Reinstall at the correct torque after piston-stop work, or replace if worn. | Read spark plug guide |
Start with the core rebuild parts
Shop A35 Bearing & Seal Overhaul Set A good base for renewing the main bearings and seals during an A35 / A52 engine rebuild.Useful tools for a Tomos A35 rebuild
The right tools help prevent damaged crankcases, stripped threads, rounded fasteners and incorrect torque during reassembly. Some tools are used only once or twice, but they can prevent expensive damage.
| Tool | Where it helps | Shop |
|---|---|---|
| Piston stop | Locks the engine so you can remove and torque the clutch and flywheel nuts. | Shop piston stop |
| Soft vice jaws | Hold parts more safely without marking shafts or aluminum surfaces. | Shop soft vice jaws |
| Crankshaft support plate | Supports the crankshaft during bearing and assembly work. | Shop support plate |
| Heat gun | Used for controlled heating of cases, covers and bearing areas. | Shop heat gun |
| Gasket scraper | Removes old gasket material without gouging the sealing surfaces. | Shop gasket scraper |
| Torque wrench | Needed for final assembly torques such as cylinder, cases and covers. | Shop torque wrench |
| Stud removal / installation tool | Makes cylinder stud removal and installation cleaner than the double-nut method. | Shop stud tool |
| Internal bearing puller | Useful for blind bearings that cannot be pressed out from behind. | Shop bearing puller |
| Pipe spanner for front sprocket nut | Correct tool for the front sprocket nut area. | Shop pipe spanner |
| Brake cleaner | Cleans oil, dirt and gasket residue from parts before assembly. | Shop brake cleaner |
| Plastic / rubber hammer | Helps settle covers or crankshaft alignment without steel-on-aluminum impact. | Shop plastic hammer |
| Flywheel puller | Removes the flywheel without prying or damaging the ignition side. | Shop flywheel puller |
| Circlip pliers | Makes retaining clips and circlips easier to remove and reinstall. | Shop circlip pliers |
Do not guess the final torque
View the Tomos torque specifications Check the correct values before tightening the cylinder, clutch, flywheel, crankcases, covers and engine mounts.How to plan your Tomos A35 rebuild order
Start by deciding whether the engine only needs a standard overhaul or whether it will also receive a new cylinder, crankshaft, clutch or ignition. This affects which parts should be ordered before the engine is opened.
- Inspect the complete engine: Check for oil leaks, crankshaft play, kickstart problems, poor shifting and damaged hardware.
- Order the core rebuild parts: Bearings, oil seals, crankcase gasket, piston clips, ATF and assembly oil.
- Prepare the specialist tools: Piston stop, flywheel puller, heat gun, bearing tools and torque wrench.
- Inspect the primary shaft: Check the rollers, roller cage, bushings, shims and question mark spring.
- Replace damaged hardware: Do not rebuild the engine with rounded bolts, damaged studs or worn locking parts.
- Review the complete rebuild guide: Follow the full Tomos A35 engine rebuild article during disassembly and assembly.
Ready to rebuild the engine?
Open the complete Tomos A35 rebuild guide Follow the full step-by-step process for disassembly, bearings, crankcases, clutch, ignition and final checks.FAQ: Tomos A35 rebuild parts and tools
What parts should I always replace during a Tomos A35 rebuild?
At minimum, plan on replacing the main bearings, crankshaft oil seals, middle crankcase gasket and any piston clips removed during the rebuild. Replace additional parts when inspection shows wear, damage or excessive play.
Do I need every tool in this checklist?
No. The exact tool list depends on the condition of your engine. A piston stop, flywheel puller, torque wrench, heat gun, gasket scraper and suitable bearing tools are the most useful starting points.
Can I reuse old bearings during a Tomos A35 rebuild?
Reusing old main bearings is not recommended once the crankcases are open. New bearings and oil seals provide a better base for sealing, reliability and future tuning.
Should I use liquid gasket on a Tomos A35 engine?
Use only a very thin layer on clean mating surfaces when additional sealing support is needed. Too much sealant can squeeze into the engine and cause problems.
Which torque wrench do I need for a Tomos A35 rebuild?
A 5–25 Nm torque wrench covers many smaller engine fasteners. Higher-torque fasteners may require a second wrench. Use the dedicated Tomos torque specification guide for the complete values.
Why should I inspect the question mark spring?
The question mark spring helps the primary shaft and shifting system return correctly. A worn or broken spring can cause rattling, clicking or poor shifting.
