Kickstarter on IZ Jupiter-5 - a unit that often becomes a headache for owners due to wear of parts or improper assembly. Even experienced motorcyclists are sometimes surprised why, after repair, the mechanism does not work the first time or makes strange sounds. The fact is that assembling a kickstarter requires not only accuracy, but also knowledge hidden nuances: from the correct position of the spring to the tightening torque of the fasteners.

In this article you will find step-by-step instructions with photos, analysis of common errors (for example, why the kickstarter cranks idle) and tips for diagnosing faults. We will also compare original parts with analogues and show how to avoid breakdowns after assembly. If you have already tried to assemble a kickstarter and encountered problems, here you will find answers to questions that are not covered in standard manuals.

Preparing for Assembly: Tools and Parts

Before you get started, make sure you have everything you need. Lack of tools or spare parts may result in damage to threaded connections or spring deformation - This is the most common reason for the kickstarter to not work after assembly. Here is the minimum set:

  • 🔧 A set of open-end wrenches (especially on 17 And 19)
  • 🔨 Impact screwdriver or socket with a wrench for unscrewing “stuck” bolts
  • 🧲 Magnetic holder for small parts (such as snap rings)
  • 🛠️ Torque wrench (optional, but recommended for precise tightening)
  • 🔍 A magnifying glass or flashlight for inspecting the gear teeth and shaft

Also prepare new parts if you plan to replace:

  • 🔄 Kickstarter spring (original: 2108-1602090, analogue: KZATE or Belmag)
  • ⚙️ Drive gear (check compatibility with the shaft, have Jupiter-5 it's different from Jupiter-4)
  • 🔗 Retaining ring (often lost during disassembly)

⚠️ Attention: If you are using used parts, be sure to check clearances between gear teeth and shaft. Wear more 0.3 mm will cause the kickstarter to slip under load.

📊 What part do you change most often in the IZh kickstarter?
  • Spring
  • Drive gear
  • Bearing
  • Retaining ring
  • Other

Kickstarter disassembly: what to check before assembly

Disassembly is more than just unscrewing bolts. It's important here fix the position of partsso as not to mix up the sides when assembling. For example, a kickstarter spring has asymmetrical winding - if you turn it over, the mechanism will jam.

Follow this algorithm:

  1. Remove the kickstarter cover (usually secured with 3-4 bolts).
  2. Remove the kickstarter axle along with the lever. Please note locking ball position - it must remain in the groove.
  3. Remove the spring, having first secured it with wire (it may “shoot”).
  4. Remove the drive gear and inspect its teeth for chips.

⚠️ Attention: If during disassembly you find metal shavings in the crankcase - this is a sign of wear on the shaft or gear bearing. In this case, a complete replacement of the assembly will be required, and not just assembly.

Inspect the spring for cracks and deformation|

Check the gear play on the shaft|

Make sure there is a retaining ring|

Clean the grooves from old grease and dirt -->

Assembling the mechanism: step-by-step instructions with photos

Start assembly with installation drive gears. It should fit on the shaft without distortions - if you have to apply force, it means either the part is the wrong model or the shaft is bent. Use copper grease to make landing easier.

Next follow the instructions:

  1. Install the gear onto the shaft and secure with the retaining ring. Check that it is completely seated in the groove.
  2. Tension the spring, starting from the inner coil. Important: its end should engage the groove in the housing, and not the gear!
  3. Insert the kickstarter shaft and secure the lever. Make sure the locking ball is in its socket.
  4. Close the cover and tighten the bolts evenly criss-crossto avoid skew.

Assembly stage Key Point Common mistake
Gear installation The gear should rotate freely, without jamming Misalignment during landing → rapid wear of teeth
Spring tension The end of the spring is fixed in the groove of the housing Incorrect position → kickstarter does not return
Locking the axis The locking ball must be in the socket Loss of ball → lever does not lock

⚠️ Attention: After assembly, check kickstarter lever travel. It should return to its original position smoothly, without jerking. If the lever “sticks”, it means the spring is installed incorrectly or the gear is skewed.

💡

Before final tightening of the cap, check the operation of the mechanism by lightly pressing the lever. If you hear extraneous sounds (grinding, clicking), disassemble and check the alignment of the gear teeth and shaft.

Adjustment and testing after assembly

Even a perfectly assembled kickstarter can malfunction if not adjusted lever free play. Optimal value for IZ Jupiter-5 — 5–7 mm. If the stroke is less, the mechanism will jam; if it’s more, the lever won’t press all the way and the engine won’t start.

To adjust:

  1. Loosen the locknut on the lever shaft.
  2. Rotate the adjusting bolt to achieve the desired free play.
  3. Tighten the locknut and check the stroke again (it may change during tightening!).

After adjustment, perform the test:

  • 🔹 Idling: Press the lever sharply 10–15 times without starting the engine. It should return quickly and without jamming.
  • 🔹 Under load: Try starting the motorcycle. If the kickstarter turns, but the engine does not catch, check tooth engagement with flywheel.

What to do if the kickstarter cranks idle?

This means that the gear teeth do not engage the flywheel. Reasons:

1) Worn teeth on the gear or flywheel (replacement required).

2) Insufficient lever travel (adjust free play).

3) Weak spring (check its tension or replace).

Common mistakes and how to avoid them

Experienced craftsmen highlight 5 most common mistakes, which lead to the kickstarter breaking after assembly. Here they are - and how to prevent them:

  • 🔧 Retightening the cover bolts → deformation of the case and jamming of the mechanism. Solution: use a torque wrench (tightening torque - 1.5–2 kgf m).
  • 🔄 Installing the spring upside down → the lever does not return. Solution: Remember the position of the spring during disassembly or take a photo.
  • ⚙️ Using a gear from a different model (for example, from IZh Planeta-5) → teeth misalignment. Solution: check the markings (2108-1602030 for Jupiter-5).
  • 🛑 Lack of lubrication → accelerated wear. Solution: use Litol-24 or molybdenum grease for rubbing surfaces.
  • 🔗 Lost retaining ring → the gear falls off the shaft. Solution: Always keep a spare ring on hand (2108-1602040).

⚠️ Attention: If after assembly the kickstarter works “every time”, check alignment of shaft and gear. Even minimal distortion (0.5 mm) will cause the teeth to “slip” under load.

💡

The most common cause of failure after assembly is incorrect installation of the spring. Always fix its end in the groove of the housing, and not on the gear!

Comparison of original parts and analogues

Many owners IZ Jupiter-5 are faced with a dilemma: to buy original spare parts or analogues. Original parts (such as spring 2108-1602090) are more expensive, but are guaranteed to fit in size. Analogs (from KZATE or Belmag) are cheaper, but may have deviations in stiffness or length.

Detail Original Analogue (KZATE) Analogue (Belmag)
Kickstarter spring 2108-1602090 (hardness 12 N/mm) Stiffness 10–11 N/mm (may sag) Stiffness 13 N/mm (lever is a bit stiff)
Drive gear 2108-1602030 (24 teeth) 24 teeth, but play on the shaft is possible 24 teeth, quality has become worse
Shaft bearing 6004 (closed) 6004 (open, requires lubrication) Analogue 180104 (Chinese, resource ~30% lower)

💡 Advice: If your budget is limited, you can combine parts. For example, take the original gear and spring from KZATE, but be sure to check size compatibility. For example, a spring from Belmag maybe on 5mm longer, which will lead to jamming.

Frequently asked questions about assembling the IZ Jupiter-5 kickstarter

Why doesn't the kickstarter return to its original position after assembly?

This happens due to:

  • Incorrect installation of the spring (upside down or not fixed in the groove).
  • Dirt in the mechanism (check if dirt has gotten under the spring).
  • Wear of the spring (if it is stretched more than 10 mm from face value).

🔹 Solution: Disassemble the mechanism and check the position of the spring. Replace it if necessary.

What is the torque for the kickstarter cover bolts?

The optimal moment is 1.5–2 kgf m. Over-tightening will lead to deformation of the cover; under-tightening will lead to play and vibration. If you don't have a torque wrench, tighten the bolts criss-cross in 2 approaches:

  1. Pre-tightening (force ~50% of maximum).
  2. Final tightening (all the way, but without jerking).
Is it possible to use a gear from IZH Planet-5?

No! U Jupiter-5 And Planet-5 different gear ratios in kickstarter. Gear from Planets has 22 teeth (against 24 at Jupiter), which will lead to:

  • Incomplete rotation of the crankshaft (the engine will not start).
  • Accelerated wear of flywheel teeth.

🔹 Exception: Gear from IZ Jupiter-4 can be used, but only if it shows no signs of wear.

How to lubricate the kickstarter after assembly?

Best options:

  • Litol-24 - a universal choice for all rubbing surfaces.
  • Molybdenum grease - if the mechanism operates under high load (for example, during a cold start).
  • CIATIM-201 — for the shaft bearing (not afraid of moisture).

❌ Don't use: graphite lubricant (it collects dirt) and liquid oils (they flow out quickly).

Why does the kickstarter click but not turn over the engine?

This is a sign that:

  • The gear teeth do not engage the flywheel (check the free play of the lever).
  • The teeth on the flywheel are worn (replacement of the flywheel or kickstarter is required).
  • The spring is weakened (it does not provide enough force for the clutch).

🔹 Diagnostics: Remove the kickstarter cover and manually check how the gear engages the flywheel. If it “slips”, it needs replacement.