0

I’m new to this community and I’m a noob in terms of knowledge about motorcycles, so please ignore my ignorance.

I own a Yamaha MT15, which has run 550 KMs so far, 2 months old. About a week ago I did water wash and lubed the chain. Even before that I had given the bike for first service, and they adjusted the clutch without asking me. I rode for couple of days and didn't like the adjustment and they reverted it back.

After the first service and the recent wash, the performance has gone low. The engine works a lot but delivering less power and speed. The throttle response has also become very poor on comparing to when it was new. I suspect that the rear wheel is too tight, and the spin is also not free while on neutral, and so the reason behind poor performance. And it takes some effort for me to spin the wheel. Pls see video at the bottom for understanding.

I went to the service centre and asked them to check the rear disc brake. They checked and said it’s fine, but I doubt that. Also they said that the wheel spinning is also normal because it is spinning with the sprocket and chain. I mean, even though it’s connected to the sprocket, the wheel should at least spin more than 3 revolutions right? It’s barely completing 1 revolution.

Is this wheel spinning normal or is it too tight? Is there anything else that might be causing this performance dip? Might it be the clutch, chain? I don't have any idea. Thanks for your answers and suggestions.

Wheel spinning

2
  • Welcome to Motor Vehicle Maintenance & Repair! If this is a new bike and is still under warranty, you need to just take it bake and have them look at it. The spinning of the tire doesn't indicate anything to me. It doesn't suddenly stop spinning. You aren't putting very much muscle on it, so it's not spinning fast. The chain and bearings are going to soak up some of the energy, so it will slow down (stop spinning at some point). – Pᴀᴜʟsᴛᴇʀ2 Jan 29 at 13:31
  • Thanks. I’ve seen videos from YouTube showing free spinning of rear wheel. They seem to rotate so freely. Even though I put enough power onto spinning, it stops fairly quickly and doesn’t gradually decrease its speed. It’s quite abrupt. Could there be any reason why something like this happens? – badhanganesh Jan 29 at 14:00
2

A rear wheel, connected to the drive train, and in neutral will spin like that. There are a lot of dragging forces acting on the rear wheel and it will not spin freely.

I can't hear from your video if the brake caliper is dragging but the behaviour of that wheel looks to be entirely normal.

2
  • Thank you, Mauro! – badhanganesh Jan 30 at 20:46
  • 2
    I think the reference to the engine developing power but not providing speed to the motorcycle has to be considered in the answer – fred_dot_u Jan 31 at 0:37
2

Based on the reference to adjusting the clutch, consider that if the clutch is not fully disengaged, the power produced by the engine will not be transmitted to the rear wheel in an efficient manner. Some of the power will be absorbed by the partially-engaged clutch material (similar to brake pad material) and eventually will wear away to the point of requiring replacement.

The "engine works a lot but delivering less power" is consistent with the previous paragraph.

Consider to try the following: with the engine running, engage the clutch and shift into gear. Use the brake to prevent movement of the motorcycle while you slowly release the clutch. If the engine slows at the same rate of the clutch release but does not seem to overpower the brakes, it is another indication of a slipping clutch.

There should be some free play in the clutch lever. As you begin to squeeze the lever, the clutch should disengage to the point where it is fully disengaged and there should be no wheel movement. You can test this by placing the motorcycle on a stand to free the wheel.

While on the stand, consider to engage the first gear (in the normal manner) to allow the rear wheel to spin. As you apply the brake for the wheel, the engine should "load up" and change rpm and sound and should also stall. If it does not, the clutch is slipping and should be re-adjusted.

1
  • Hey @fred_dot_u! Thanks for your detailed answer, really appreciate it. I'll make sure to try what you said. – badhanganesh Jan 30 at 20:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.