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I Think My Engine Has Blown Up!


angryfarang

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Gutted.

I started my Honda Hornet yesterday, well I tried to... The starter motor turned, then came a horrible crunching sound from the engine and it locked up. I hit the starter again, you can hear it turn and lock.

Any ideas what this could be? I know it doesn't sound good.

Cheers,

Matt.

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How long was the bike standing without being run?

Could be hydraulic lock. Fuel has leaked past the carburetor into one cyclinder. Take all the spark plugs out and try again. If this is the case and fluid does come out of one cylinder check it to see if it is fuel or water. (Just in case)

Could be a stuck valve? Unlikely but if left for a very long time?

Side note:

Thinking your engine has blown up is like thinking you are pregnant. It either has or it hasn't, there is no middle ground. The fact that all the bits are still inside the engine and the floor is not covered in oil should be a key to the correct answer.

Edited by VocalNeal
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Unless the starter is stuck in the engaged position, why don't you pull the plugs and push the bike whilst it is in gear. IF it is vapour lock that will clear it right up and if it is not will quickly tell you if the engine has major damage (as in you won't be able to move it).

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I wouldn't try to bump start it 'till you know what the problem is ...... don't want to run a damaged motor or you'll do more damage. But it may only be a stuck starter dog.

Put it in a high-ish gear and try to push it - does the engine turn over? Take the plugs out to make it easier to turn over (even though you have to take the tank off - you'll learn a lot by turning it over with the plugs out and listening.

Or ..... If it has a centre stand - put it in a high gear and try to turn the rear wheel (if no centre stand - stick it on a heap of bricks)

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I'm so busy with work no time to look at it, will probably be another 6 months until I have time... LOL. No worries.

call your favourite bike repair place they will come and pick it up and hey presto..

Ahhh, but that takes all the fun out of it!

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The timing chain has stretched so much the cam shafts have jumped a few cogs and now the valves have locked together and been smashed into by the pistons which has caused one or more of the compression rings to break and gouge into the cylinder wall. Attempting to start the engine now will only lead to further damage.

Or it could be a jammed starter dog!

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The timing chain has stretched so much the cam shafts have jumped a few cogs and now the valves have locked together and been smashed into by the pistons which has caused one or more of the compression rings to break and gouge into the cylinder wall. Attempting to start the engine now will only lead to further damage.

Or it could be a jammed starter dog!

I'm maybe wrong but I'm sure the hornet cams are gear driven.

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1. Could still be hydraulic lock if you forgot to turn off the fuel tap?

2. Check the water level as this is another indicator of hydraulic lock. If low water has leaked into one cylinder.

As has been said put the bike in 2nd gear and try to push it. By push it I mean lean constantly on the bike as it moves forward. If the engine is free it should move forward slowly and you should be able to feel the compression of each cylinder in turn. If you can feel four compressions it is not an engine problem it is the starter or battery. If you feel something mechanical or solid then you need to, at minimum, remove the plugs and try again.

3. Batteries fail suddenly. Sometimes overnight. If the engine turns freely as above. Turn on the headlight. Does it go out when you try and start?

Do you have access to another vehicle and some booster cables? You could try that.

No time call a shop!

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The timing chain has stretched so much the cam shafts have jumped a few cogs and now the valves have locked together and been smashed into by the pistons which has caused one or more of the compression rings to break and gouge into the cylinder wall. Attempting to start the engine now will only lead to further damage.

Or it could be a jammed starter dog!

I'm maybe wrong but I'm sure the hornet cams are gear driven.

The Hornet engine has a cam chain and the tensioner is prone to failure so that is probably a good place to start looking.
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The timing chain has stretched so much the cam shafts have jumped a few cogs and now the valves have locked together and been smashed into by the pistons which has caused one or more of the compression rings to break and gouge into the cylinder wall. Attempting to start the engine now will only lead to further damage.

Or it could be a jammed starter dog!

I'm maybe wrong but I'm sure the hornet cams are gear driven.

The Hornet engine has a cam chain and the tensioner is prone to failure so that is probably a good place to start looking.

250 Hornet cams are gear driven. So I presume there is no cam chain.

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1. Could still be hydraulic lock if you forgot to turn off the fuel tap?

2. Check the water level as this is another indicator of hydraulic lock. If low water has leaked into one cylinder.

As has been said put the bike in 2nd gear and try to push it. By push it I mean lean constantly on the bike as it moves forward. If the engine is free it should move forward slowly and you should be able to feel the compression of each cylinder in turn. If you can feel four compressions it is not an engine problem it is the starter or battery. If you feel something mechanical or solid then you need to, at minimum, remove the plugs and try again.

3. Batteries fail suddenly. Sometimes overnight. If the engine turns freely as above. Turn on the headlight. Does it go out when you try and start?

Do you have access to another vehicle and some booster cables? You could try that.

No time call a shop!

Neil,

Thanks for the help. I'll have some time at the weekend to play about.

I'll try a new battery first, the local honda shop stocks one.

I'll also try to push it along in 2nd gear as you stated and see if the engine moves freely.

All the best,

Matt.

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Neil,

Thanks for the help. I'll have some time at the weekend to play about.

I'll try to push it along in 2nd gear first as you stated and see if the engine moves freely.

I'll also try a new battery first, the local honda shop stocks one.

All the best,

Matt.

Matt,

Sorted that for you!

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The timing chain has stretched so much the cam shafts have jumped a few cogs and now the valves have locked together and been smashed into by the pistons which has caused one or more of the compression rings to break and gouge into the cylinder wall. Attempting to start the engine now will only lead to further damage.

Or it could be a jammed starter dog!

I'm maybe wrong but I'm sure the hornet cams are gear driven.

The Hornet engine has a cam chain and the tensioner is prone to failure so that is probably a good place to start looking.

250 Hornet cams are gear driven. So I presume there is no cam chain.

If its a detuned Cbr 250 4 cylinder engine ( which i think it is ) then I might have a starter motor you can buy. I will check tonight. Ok

sent from my Q6

Edited by thaicbr
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OP, put the bike in gear and try pulling it backwards, if the engine moves a bit, select neutral and try the starter,if it gives half a turn and the engine locks up, there could be some big problem in the cylinder head area,

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The timing chain has stretched so much the cam shafts have jumped a few cogs and now the valves have locked together and been smashed into by the pistons which has caused one or more of the compression rings to break and gouge into the cylinder wall. Attempting to start the engine now will only lead to further damage.

Or it could be a jammed starter dog!

I'm maybe wrong but I'm sure the hornet cams are gear driven.

The Hornet engine has a cam chain and the tensioner is prone to failure so that is probably a good place to start looking.

250 Hornet cams are gear driven. So I presume there is no cam chain.

If its a detuned Cbr 250 4 cylinder engine ( which i think it is ) then I might have a starter motor you can buy. I will check tonight. Ok

sent from my Q6

It may be gears driving the camshafts in the head if there are 2 separate cams but usual practice in Japanese engines is to have a chain drive both cams.

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