Just found out that the bike I've just bought has no air filter and I don't know how long the last owner has been riding it like his . What damage should I look for and I presume I will have to take the carb off and clean it. Is their anything else I should do.

New filter has been ordered, Thanks Dave.

If the bike had no air filter the air fuel mixture would have been lean. This could have caused overheating in the cylinder head, wearing down quicker because for the lack of oil/fuel. Be sure to clean the carb as there was nothing stopping dirt from entering and blocking jets etc. Also the dirt could have ended up in the cylinder head scoring the piston, you can do a quick check by removing the exhaust then look through the hole with a torch to inspect the piston.

Regarding the engine it may be no or little arm has occurred yet. There is likely to be a lot of fine grit stuck in oil here and there. As well as the carb clean the reed block thoroughly and rinse the crank case and cylinder out several times with petrol / oil mix.

Lack of filter may also mean previous owner was poor on maintenance in general and as a precaution I would change gearbox oil and all other fluids and strip and grease swinging arm , linkage and steering head bearings

Cheers for the replies. How do I clean the crank case and cylinder out, is that an engine out job. Im giving it a service anyway, oil change, filters, coolant, brake fluid and gearbox oil and new brake pads.

if you can contact the previous owner and ask if he cleaned it and forgot to reinstall it at sale time, hopefully this has happened and not that he was riding it….

good luck

rob

It's always upsetting when you buy a second hand bike and find problems or potential problems but don't panic, a used bike is a used bike and will always have wear and reduced performance compared to a new bike.

The effect of having no air filter is that abrasive media (mainly sand and dust) will have entered your engine in greater quantities than in an engine with a clean oiled foam air filter.

This accelerates the wear rate in piston rings, piston, big end bearing, main bearings, little end bearing. Generally in that order.

Note I said 'accelerates the wear rate' not 'ruins'

However, I'm assuming you rode the bike before you bought it and were happy with the engine?

In that case fit a new filter, oil it, and ride the bike, don't worry about problems that aren't there.

Since you are based in Tyneside, I'm assuming you will ride North East Centre ACU trials.

We do a lot of waterwork, on the 2 Shercos I had this meant a carb clean and air filter clean after every trial.

Get used to it, keep a spare clean dry filter and it's half an hour to an hour maintenance per trial (when you wash the filter out it takes a couple of days to dry properly so you need a spare)

Trials bikes are high maintenance no matter what

On a used bike I'd be lubricating all of the suspension bearings straight away, then every 3 months, changing the fork oil and gearbox oil after a couple of trials, then every 6 months, but carb and air filter every trial.

"If the bike had no air filter the air fuel mixture would have been lean."

This statement confuses the hell out of me. How does no air filter make a bike run leaner?

I think I will sit back and watch the fun and games on this one.

"If the bike had no air filter the air fuel mixture would have been lean."

This statement confuses the hell out of me. How does no air filter make a bike run leaner?

I think I will sit back and watch the fun and games on this one.

Yea, well , next question is do they really have dust in the UK?

Seems most indicate it rains all the time, so unless you are ingesting mud, you are likely safe!

whats done is done go through everything cleaning and lubing and see how it goes good luck mate

Well I've checked the carb and took the exhaust off looked in the hole with a torch and the piston and barrel looks good

RIDE IT!!!!!!

I will soon I hope, I've changed the brake pads and I had to remove the callipers (don't ask) and now I can't seem to bleed the rear brake.

No, it is impossible!

So what's the best way to bleed the rear brake.

Take the reservoir off & use a syringe to force fluid through the system with the nipple open, you may need to do a few times with the last time closing off the nipple as you keep pressure on.

Was the only way I managed to do mine & it didn't take that long compared to trying the normal pumping of the lever method