[chezzam]

My son has a Honda CBR250. It's been out of rego for a while and he's only started it every week or so just to keep the battery charged etc. Now when he tries to start it, the bike tries to kick over for a while and then eventually backfires. A friend suggested it may be the CDI unit. Does this sound right? How can my son test the CDI unit? If not CDI what else could it be?

[chucktx]

bad gas!!!!! todays gas wont last 60 days without some type of additive added. you stated it was being started and i assume was running well. i would change the gas and clean the carb..........always start with the easiest, cheapest........let us know!

[ironhorse]

duoble ditto on chucks comment, also if it happened all of a sudden, (experianced here) check and make sure you didn't suck a mouse into your carb, or have a wasp nest built there., other than that gas.

[fxdxriderleo]

If he's not riding it much then starting it every week or so is not really good for the bike.
To keep the battery charged use a battery tender. Starting the bike and letting it run a few minutes will actually run the battery down. It takes a more than just a few minutes to recharge the battery after starting. 15 minutes at hi-way speeds at least.
The short run time won't be long enough to burn out the moisture in the oil. As bike runs ring blowby collects in the oil. Condensation collects as the engine cools, this collects in the oil. It takes a while once the engine gets warmed up to burn out these contaminates in the oil. If not they turn to an acid and can eat away the internals.
For storage, warm it up, change oil, Drain the carb, top up tank , add a fuel stabilizer.
Can't think of the name right now, They sell an oil that you spray into the carb while cranking the engine to coat the cylinder walls and valves with oil. This protects the engine from rust.
A properly prepped bike will not be hurt by storage, even up to two or more years.
When you want to start riding it again it should take just turn the gas on and statring it up.
The fuel stabilizer will keep the gas fresh up to two years when done right. Topping up the tank prevents rust in the tank. Draining the carb keeps the carb from gumming up.
The battery tender keeps the battery charged.

[cowboy]

I too have to agree with above , & when you do get it running put some sta-bul in the fuel & let it run for a while , more then just a idle , it will keep the gas & all componites in the fuel system in good shape

[Red Rider]

I agree with all before and have this wicked bit to add - the "friend" with the suggestion about the CDI unit is 99.99% the last person I'd ever ask again any question to about motorcycles (and, really, I wouldn't ask for bicycle advice from him/her).

A bad CDI is likely to give a zero-spark indication, which you can test without much trouble - but before even going there, replace the gas. And get a Battery Tender (or similar charger/maintainer unit) to trickle charge that battery, instead of just starting it up occassionally.

[chezzam]

Originally Posted by ironhorse

duoble ditto on chucks comment, also if it happened all of a sudden, (experianced here) check and make sure you didn't suck a mouse into your carb, or have a wasp nest built there., other than that gas.

Tnx guys for all the advice. My son has replaced the fuel and cleaned the carby but problem still exists. No mice or wasps.

I'm passing on your other comments. Really appreciate your input.

[cardboard]

Originally Posted by chezzam

Tnx guys for all the advice. My son has replaced the fuel and cleaned the carby but problem still exists. No mice or wasps.

I'm passing on your other comments. Really appreciate your input.

You say he cleaned the carb, but did he check the jets?
How did he clean them?
And did he clean the needle and seat or replace them all together.
And check the adjustment for the float?

The new Ethanol gas is stoppin them up like you poured Cement into them.
Have you looked into the carbs when you twist the throttle and make sure its spraying gas.
And have you checked the spark to the plugs?
And when you check the plugs after trying to crank the bike do they have fuel on them ?
Have you checked the fuel lines also and the filter for the tank,
Look in the tank for water.
And is fuel coming threw the petcock.

[FLHTbiker]

Little off subject but the gas is a big part of the problem. Last week when I was riding over in Central Oregon where there are real remote areas they don't sell premium gas. We had to put regular in the tank but it was real regular without the Ethanol. It actually didn't run that bad and for the next 150 miles it didn't even ping. Its amazing just taking that stuff out of the gas how much better the gas is. Next fill up we had to put Ethanol premium in.

[Red Rider]

Originally Posted by chezzam

Tnx guys for all the advice. My son has replaced the fuel and cleaned the carby but problem still exists. No mice or wasps.

I'm passing on your other comments. Really appreciate your input.

Is the bike getting spark? Does he know how to check if he is?

[FLHTbiker]

Here is some info found on the web for a similar problem with same bike.
Here was the answer:

Sound like you have a fuel problem.Turn the key without starting the bike listen for a slight buzzing noise it will come from where the end of the tank and the seat meet this is the fuel pump priming if you can not hear anything then most likely your fuel pump is not working.

Hope this helps