20 Most Recent 2005 Derbi Senda R 125 4T Questions & Answers

Go for it, drain the tank then flush it out with a quart of raw gas. Don't be smoking a cigarette while flushing unless you have a death wish.

If the 'grinding' only happens when the bike is in motion, the problem is probably not inside the engine. Remove the chain and then start the motor. Put it in gear(s) and listen for the noise. No noise eliminates the engine as the problem.

Now lay the chain on the concrete and 'compress the chain in a straight line. Mark the end of the chain on the concrete. Now hold on to one end of the chain and stretch the chain. Did it stretch more than one inch? Replace it if it did. Look at the chain. is it rusted? Is it limber or do the links resist bending? Replace the chain if rusty and stiff.

While you are doing all this, check the rear wheel. Does it spin freely. Make any noise? Does the rear brake go on and off properly? Next check your sprockets. A bad sprocket will ruin a new chain. The ends of the teeth on the sprocket should be rounded. A worn sprocket shows pointed teeth. I have seen teeth so pointed they could pop a balloon. LOOK at both sides of the front and back sprockets. Are they rubbing against anything anywhere? Look at the chain, any rubbing? Is the tire rubbing on anything? Did the prior owner install heavier sprockets and bigger chain than stock sprockets and chain? > Check with the dealer.

Chances are you will find the problem if you do the above.
I hope you can rate this solution as a 'FixYa".

There are several schools of thought on this. Some say you should change your oil every 3000 miles; others say every 6000 miles is fine. In any case you should change it every 3 months.,

Hi, most of the older bikes like the villiers used flywheel magneto ignition, where the ignition coil was inside the flywheel normaly you would have a metal engine stop ontop of the engine this was bolted to the cylinderhead and would bend or was hinged you would bend it down until it made contact with the spark plug and it earthed out, this would kill the spark.As so with the external ignition coil, a single switch was used on the handlebar, with a wire from the coil, at the points wire This would then earth out when pressed stoping the engine

I know you said you cleaned the carb, but maybe something got in the carb when trying to start the bike. Because it sure sounds like you have a clogged pilot jet.

Fixya is unable to source parts.

One of these. You buy by make and model, not by size. https://www.google.com/search?q=2008+derbi+terra+flywheel+extractor.

What state is the battery in? Fully charged? Did it work before the overhaul? Check your wires again from top to bottom

Use a airlift or comparable coolant system air removal/refill system.You attach the unit to the coolant system filler and it vacuums all air from the system,then you use the supplied hose to return the coolant into the vacuumed system.This fills the system with just coolant and no air.