Robin engine ec25-2pg

If your doing a full overhaul on the engine your better off investing in a decent workshop manual for it as that will give you all the settings you need to strip and rebuild the engine. Many online sites can supply one at sensibly cheap prices.

Sounds like you need to rebuild the carb. The gaskets stretch out and they won't pump enough fuel. Be sure to clean all of the parts if you do rebuild it as there is no use just doing part of the rebuild job.

The age old adage holds true here: If it aint broke don't fix it. :)

If the bike is still running good and you have taken good care of it there is no reason to overhaul it. There are many bikes out there that have done well over 100k miles and are still running strong. There have actually been dyno test ran on bikes with over 100k miles and they made better horse power than they were rated at from new. This is attributed to slightly looser bearing clearances with the engine being well broken in.

I would recommend overhaul if you start having problems. These issues would include, low power due to low compression, excessive oil consumption, excessive smoke from tail pipe, excessive fuel consumption. Even then I would recommend good diagnostics and if the issue is found to be internal then I would recommend an overhaul.

Sounds like the carb is clogged and the engine is starving. Clean and rebuild the carb

Too expensive to rebuild, either find a good replacement engine if your car is in good condition or get another car.

I't will be quicker to go with a new engine plus a warranty doesn't hurt for future problems

Honda. I don't know how experienced you are, but I avoid
transmissions, too complicated. You might do better buying
a remfg., and just swapping it out.

You can exchange it with one that is inner cooled and turboed But thats $1500.00 in parts plus the engine and labor. Your best bet is to find out what is wrong with your engine and rebuild it. As long as there are no major damages.

TO OVERHAUL ENGINE YOU HAVE TO REPLACE ALL WORN PARTS.LIKE VALVES + SEATS+ GUIDES.+ SEALS. ALSO YOU HAVE TO REPLACE CAMSHAFT AND GEAR+ LIFTERS NEW CAM BEARINGS.NEW OIL GALLORY PLUGS AND FREEZE PLUGS.THE CYLINDER BLOCK HAS TO REBORED BEFORE INSTALLING.NEW PISTONS + RINGS+ CRANKSHAFT AND BEARING HAS TO BE REPLACED.ALSO OIL PUMP TIMING CHAIN.AND CRANKSHAFT GEAR.IT WOULD BE A WHOLE LOT CHEAPER TO BUY REBUILT ENGINE THEN TO REBUILD.BECAUSE YOU HAVE TO HAVE A LOT OF EXPENSIVE TOOLS AND HIGHLY SKILLED TO REBUILD ENGINE.ITS NOT A EASY JOB.

If we are talking the three cylinder CB23 engine the mixture screw is hard to get to and has an anti tamper shroud to stop prying fingers.

The Aisan carby is pretty reliable and problems with them on these engines is usually due to improper vacuum hose connections, or improperly adjusted idle, fast idle and deceleration screws.

A/F ratio is around the standard 14.7, but being a carby you will not get consistent mixtures because the jets sizes are fixed . On an EFI engine you can control the fuel flow, but not so with jets.

If you do decide to give your carby a birthday make sure you only buy the Daihatsu genuine, because the after market units have issues with quality. The minor rebuild kit part No 0421287704000 and the major overhaul kit with plunger, needles, gaskets, clips, etc is part No 0421187729000.

If it was me I'd be concentrating on the hoses, the PCV valve, contact points in the dizzy and better spark plugs first. If you want much better idling and a bit better pull get an electronic dizzy and coil from a G200 series Charade.