08/05/2014
The BSA A7, a stalwart of British motorcycling heritage, is a beloved machine for many enthusiasts. However, like many classic bikes, it can present its owners with unique challenges, particularly concerning the centre stand and its interaction with the exhaust system. This article delves into a common conundrum faced by BSA A7 riders: why their centre stand might be problematic and how the exhaust system, specifically the downpipes, plays a crucial role in this. We'll explore the intricacies of the A7's stand mechanism, common modifications, and offer practical advice for resolving these issues, ensuring your classic BSA is as functional as it is beautiful.
Understanding the BSA A7's Centre Stand Mechanism
The centre stand on a BSA A7 is designed to provide a stable platform for parking the motorcycle, allowing for maintenance and cleaning. It typically operates via a pivot point attached to the frame, with an actuating arm that, when pushed down, lifts the rear wheel off the ground. A spring is usually employed to return the stand to its retracted position. However, the 'devil is in the details,' as the saying goes, and several factors can lead to a centre stand that is stiff, doesn't retract fully, or even interferes with other components.
The Crucial Link: Exhaust Downpipes
One of the most frequent culprits behind a malfunctioning BSA A7 centre stand is the exhaust system, particularly the configuration of the downpipes (also known as header pipes). The design of these pipes, and their routing relative to the frame and the centre stand's actuating arm, is critical. Early BSA A7 models, and indeed many A series bikes, featured upswept downpipes that curved upwards and then back towards the silencers. This routing generally allowed ample clearance for the centre stand's mechanism.
However, modifications or later revisions to the exhaust system can introduce issues. As noted in discussions among BSA owners, the introduction of different exhaust systems, such as the 'straight' 1958 onwards type, can significantly alter the clearance. These straighter pipes may route closer to the frame, potentially fouling the centre stand's actuating arm or the stand itself. This interference can prevent the stand from retracting fully, or make it very difficult to deploy and retract.
Common Problems and Their Causes:
- Interference: The most common issue is physical contact between the centre stand, its actuating arm, and the exhaust downpipes or silencers. This can be due to a non-standard exhaust system being fitted, or a change in the stand itself.
- Incorrect Stand: Using a centre stand designed for a different BSA model or year can lead to fitment issues and clearance problems. For instance, a stand intended for a bike with a different exhaust routing might not work correctly with your current setup.
- Worn Pivot Points: Over time, the pivot points of the centre stand can wear, especially if the tube within the stand seizes. This can cause the entire assembly to rotate on the main bolt, leading to increased wear and improper retraction.
- Weak or Broken Spring: The spring responsible for returning the centre stand can become weak, stretched, or even break. This will result in the stand not returning to its fully retracted position.
- Seized Tube: The tube around which the stand pivots can seize within the stand itself due to corrosion or lack of lubrication. This prevents the stand from turning freely on its intended axis, causing it to bind or rotate incorrectly.
Troubleshooting Your BSA A7 Centre Stand
When faced with a recalcitrant centre stand, a systematic approach to troubleshooting is essential. Here’s a step-by-step guide:
- Visual Inspection: Start by carefully examining the entire centre stand assembly. Look for any obvious signs of damage, wear, or interference. Check the clearance between the stand, its actuating arm, and the exhaust system. Note the routing of your downpipes – are they standard for your A7's year, or do they appear to be a later or modified type?
- Exhaust System Check: Pay close attention to the downpipes. If they are straighter or routed differently than the original upswept design, this is a prime suspect. Compare your setup to known standard configurations or images of correctly fitted A7s. The position of the silencers also matters, as they can affect the clearance for the stand's foot lever or the stand itself.
- Stand Fitment: Confirm that you have the correct centre stand for your specific BSA A7 model and year. Consulting a parts manual or seeking advice from BSA owner clubs can help verify this.
- Pivot and Tube Condition: Inspect the pivot points and the tube within the stand. Is there evidence of wear, ovalisation of the mounting holes on the frame, or seizing between the tube and the stand?
- Spring Assessment: Check the condition of the centre stand spring. Is it securely attached? Does it appear to have adequate tension, or is it slack or broken?
Potential Solutions and Modifications
Based on your diagnosis, several solutions can be implemented:
- Correct Exhaust System: If the non-standard exhaust is the issue, the most effective long-term solution is to refit the correct type of downpipes and silencers that provide adequate clearance. While this can be costly, it ensures proper function and maintains the bike's originality.
- Modifying the Exhaust (Use with Caution): In some cases, minor adjustments might be possible. For example, a gentle hammer blow to a silencer might create temporary clearance, as suggested by some owners. However, this is a crude solution and can damage the silencer or affect its performance. Welding a piece of bar onto the stand's foot lever to aid deployment is also a possibility, but this doesn't address the root cause of interference.
- Stand Modifications (Use with Caution): Some owners have resorted to modifying the stand itself, such as chopping off the foot lever. While this may allow the stand to retract, it makes it harder to use and is not ideal. If frame mount holes have worn oval, they may need to be repaired by welding and re-drilling.
- Pivot Lubrication and Repair: Ensure the pivot tube and spring are adequately lubricated. If the tube has seized, it may be possible to free it with penetrating oil and careful persuasion. If wear is significant, replacing the stand or repairing the frame mounts might be necessary.
- Spring Replacement: A new, correctly tensioned centre stand spring can often resolve retraction issues if the old one has lost its strength.
BSA A7 Centre Stand vs. Exhaust Clearance: A Comparative Look
The interaction between the centre stand and the exhaust is a delicate balance. Here's a simplified comparison of how different exhaust types can affect this:
| Exhaust Type | Downpipe Routing | Likely Stand Clearance | Potential Issues |
|---|---|---|---|
| Early Upswept (e.g., 1954/55) | Curves upwards, then back. Generally higher clearance. | Good | Minimal, unless stand is incorrect or worn. |
| Later 'Straight' (e.g., 1958+) | Straighter, often routed closer to the frame. | Reduced | High risk of interference with actuating arm or stand. |
| Modified Systems | Varies greatly. | Unpredictable | Requires careful assessment and potential modification. |
What if my stand is 'hanging down'?
If your centre stand appears to be hanging lower than usual or not retracting properly, it's crucial to investigate. As mentioned, this could be due to a worn spring, seized pivot tube, or interference from the exhaust system. Ensure you have the correct stand fitted, and that the pivot mechanism is free to move. The spring is a common failure point and should be inspected and potentially replaced.
Frequently Asked Questions
Q1: My BSA A7 centre stand is stiff. What's the most likely cause?
A1: The most common causes are a seized pivot tube within the stand, lack of lubrication, or interference from the exhaust system, particularly if non-standard downpipes are fitted.
Q2: I have the later 'straight' downpipes on my A7. Will this affect my centre stand?
A2: Yes, it is highly likely. The later straight downpipes often route closer to the frame, reducing clearance and potentially causing interference with the centre stand's actuating arm or the stand itself.
Q3: Is it okay to modify my centre stand, like chopping off the foot lever?
A3: While some owners do this to achieve retraction, it's generally not recommended as it makes the stand much harder to deploy. It's better to address the root cause of the interference or stiffness.
Q4: My centre stand spring seems weak. What should I do?
A4: Replace the centre stand spring. It's a relatively inexpensive part and a common reason for the stand not returning fully.
Q5: What's the best way to check if my exhaust is the problem?
A5: Compare your exhaust system's routing and clearance with known standard BSA A7 setups. If the downpipes appear significantly straighter or closer to the frame than original, they are likely the source of the issue.
Conclusion
The BSA A7 is a magnificent motorcycle, and ensuring its practicality, including a functional centre stand, is part of the ownership experience. While modifications to the exhaust system can sometimes lead to centre stand issues, a thorough inspection and understanding of the interaction between these components can help you diagnose and resolve the problem. By focusing on the correct fitment of parts, maintaining the pivot mechanisms, and ensuring adequate clearance, you can get your classic BSA A7 centre stand working smoothly, allowing you to enjoy your ride with confidence and ease.
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