[grazd]

Hi
My 2005 model TVS star (100cc, 4stroke) has done 45k. I went to mechanic recently since I wanted to increase the mileage that it gives me (currently 45-50kmpl). While tuning the carb, a lot of smoke came out initially, he claimed this is due to defective piston, and that the engine needs to re-bored and piston head to be replaced, and costing about 3.5k for the entire job. (this is what i understood, I couldn't understand him 100%).

The bike is in reasonably good shape, has been driven pretty decently. I got the clutch assembly changed 3 months back. that is the only major work to have been done on it.

Unfortunately, it was with a friend of mine for 3 years, and so I don't know how well it was serviced in that period.

How do I know if engine needs to be re-bored or not? Is re-boring even advisable or should I get some other kind of engine overhauling done. (On another thread it was mentioned that 100cc engines shouldnt be rebored rather the engine kit should be changed.)

Please share your advice with me as I am not well informed in these matters.

thanks in advance

[twistwrist]

Originally Posted by grazd

Hi
My 2005 model TVS star (100cc, 4stroke) has done 45k. I went to mechanic recently since I wanted to increase the mileage that it gives me (currently 45-50kmpl). While tuning the carb, a lot of smoke came out initially, he claimed this is due to defective piston, and that the engine needs to re-bored and piston head to be replaced, and costing about 3.5k for the entire job. (this is what i understood, I couldn't understand him 100%).

The bike is in reasonably good shape, has been driven pretty decently. I got the clutch assembly changed 3 months back. that is the only major work to have been done on it.

Unfortunately, it was with a friend of mine for 3 years, and so I don't know how well it was serviced in that period.

How do I know if engine needs to be re-bored or not? Is re-boring even advisable or should I get some other kind of engine overhauling done. (On another thread it was mentioned that 100cc engines shouldnt be rebored rather the engine kit should be changed.)

Please share your advice with me as I am not well informed in these matters.

thanks in advance

Hi Grazd,

45k kms is too short for an overhaul. Check the compression of your engine using a compression guage.If the reading is above 145 psi or 10 bar then your seems to be healthy. In case the pressure is low you could also try using new piston rings in the same engine.
Also check the spark plug ,set the gap right according to owners manual. Also get a pollution certificate done, in case of high co and nox readings get the carburator retuned in a Authorised service center.
Check the engine oil regularly , top up if its below the minimum level.
Suggest you to visit another mech and ask his opionion too.

[grazd]

@twistwrist
Thanks so much! that's very helpful advice indeed. I'll get the checks done and the second opinion tomorrow.

I also noticed some oil on the engine fins (externally). Is this normal in the course of running, or is it a sign of something going wrong?

[twistwrist]

Originally Posted by grazd

@twistwrist
Thanks so much! that's very helpful advice indeed. I'll get the checks done and the second opinion tomorrow.

I also noticed some oil on the engine fins (externally). Is this normal in the course of running, or is it a sign of something going wrong?

Hi Grazd,

Oil between the cylinder and head gasket / bottom engine could be because of the clearance in the gasket. you could also use gasket maker glue or anabond while re assembling with newer gasket. If the oil spills out regularly better to get a new gasket in place.If oil is dried up with dust then just leave it as it is.

[grazd]

Thanks again for taking the time to help out. I'll get this checked out keeping your advice in mind.