Rattle on engine

[Jevi]

My son's Arizona 125 seems to be running ok but there is a rattling noise on the engine. I've noticed myself if I kick it over there is a rattle which seems to come from the electric starter once the bike starts up.

How does the electric starter work?

Is there some part of the mechanism permanently linked into the engine or should it fully disengage once the engine fires?

[fastbob]

In general terms the starter motor will have a clutch mechanism a bit like the freewheel on a bicycle. Try putting the bike in gear ( not running ) and push it backwards. You should hear the starter motor making a whirring or growling noise as it rotates . Now push the bike forward and the sound should be gone . This will indicate whether the starter clutch is disengaging ok . If you struggle to push the bike or the wheel skids , take the spark plug out and sit on it then push with your legs . At least this will help eliminate the starter motor clutch as the source of the rattle.

[Jevi]

Thanks I'll give it a go hopefully it's nothing serious

[Guest]

Camchain?

[Guest]

How does the electric starter work?

 

Errr.... By electricity?

[fastbob]

How does the electric starter work?

 

Errr.... By electricity?

 

Errrrr ....How does that help ?

[Grumpy Old Git]

The starter gear is 'fired' into mesh by a strong electromagnet or, by the turning force of the starter motor - Once engaged, it turns the engine over and (hopefully) the engine will start. Once the starter motor button is released, then the starter gear will retract on a return spring.

However, for your model:

 

 

Item 6 is the starter clutch (priced at around £20).

it may be 'sticking' due to dirt / rust.

[fastbob]

The starter gear is 'fired' into mesh by a strong electromagnet or, by the turning force of the starter motor - Once engaged, it turns the engine over and (hopefully) the engine will start. Once the starter motor button is released, then the starter gear will retract on a return spring.

However, for your model:

25-7844-698.jpg

Item 6 is the starter clutch (priced at around £20).

it may be 'sticking' due to dirt / rust.

 

That's certainly one method of starter motor engagement but not the only one . I had his system on my FT500 Ascot and it was , in fact , the Achilles heel of the bike . A more common and cheaper method is a simple freewheel clutch as previously described. Being a Chinese bike I expect the simple cheaper option would have been used.

[Guest]

How does the electric starter work?

 

Errr.... By electricity?

 

Errrrr ....How does that help ?

 

It wasn't meant to.............JFGI. Some people want it on a plate.

[fastbob]

Errr.... By electricity?

 

Errrrr ....How does that help ?

 

It wasn't meant to.............JFGI. Some people want it on a plate.

 

JFGI .. Just f*****g google it , ok , but why do you have to be so unpleasant about it ? The OP didn't ask you personally so why respond at all ?

[SlowBusa]

[Grumpy Old Git]

The starter gear is 'fired' into mesh by a strong electromagnet or, by the turning force of the starter motor - Once engaged, it turns the engine over and (hopefully) the engine will start. Once the starter motor button is released, then the starter gear will retract on a return spring.

However, for your model:

25-7844-698.jpg

Item 6 is the starter clutch (priced at around £20).

it may be 'sticking' due to dirt / rust.

 

That's certainly one method of starter motor engagement but not the only one . I had his system on my FT500 Ascot and it was , in fact , the Achilles heel of the bike . A more common and cheaper method is a simple freewheel clutch as previously described. Being a Chinese bike I expect the simple cheaper option would have been used.

 

As per the diagram (which is for the OPs bike).

[Stu]

Errrrr ....How does that help ?

 

It wasn't meant to.............JFGI. Some people want it on a plate.

 

JFGI .. Just f*****g google it , ok , but why do you have to be so unpleasant about it ? The OP didn't ask you personally so why respond at all ?

 

He did Google it! It brought him here to ask the question

[Jevi]

Fastbob - I tried putting the bike in gear but couldn't shift it back or forwards (wheels just skidded didn't rotate).

With the clutch in there was a slight rattle going forwards.

Haven't tried taking the plug out yet so that's the next thing (been decorating so haven't had time )

The boy's come back with another problem but I think it's down to the idling screw. Starts the bike on the choke, let's it warm up for a while then rides off - no problems!

Gets so far down the road and switches the choke off which immediately kills the engine. The choke lever rotates back past where I think it should stop so I'm going to try altering the idle screw to see if I can keep the engine running/ticking over when the lever is in what appears to be the off position - after that we'll start stripping the carb down to check the needle.

[Breadsnapper]

Hi I had a very similar problem which turned out to be a blocked main jet. The hole for the jet is minute so be careful what you use to get any junk out. Also make sure the screw that secures the choke lever is tight.

Dave

[fastbob]

Fastbob - I tried putting the bike in gear but couldn't shift it back or forwards (wheels just skidded didn't rotate).

With the clutch in there was a slight rattle going forwards.

Haven't tried taking the plug out yet so that's the next thing (been decorating so haven't had time )

The boy's come back with another problem but I think it's down to the idling screw. Starts the bike on the choke, let's it warm up for a while then rides off - no problems!

Gets so far down the road and switches the choke off which immediately kills the engine. The choke lever rotates back past where I think it should stop so I'm going to try altering the idle screw to see if I can keep the engine running/ticking over when the lever is in what appears to be the off position - after that we'll start stripping the carb down to check the needle.

Which is why I suggested that you remove the spark plug to remove any compression .

[fastbob]

Fastbob - I tried putting the bike in gear but couldn't shift it back or forwards (wheels just skidded didn't rotate).

With the clutch in there was a slight rattle going forwards.

Haven't tried taking the plug out yet so that's the next thing (been decorating so haven't had time )

The boy's come back with another problem but I think it's down to the idling screw. Starts the bike on the choke, let's it warm up for a while then rides off - no problems!

Gets so far down the road and switches the choke off which immediately kills the engine. The choke lever rotates back past where I think it should stop so I'm going to try altering the idle screw to see if I can keep the engine running/ticking over when the lever is in what appears to be the off position - after that we'll start stripping the carb down to check the needle.

Did you take the plug out?

[Jevi]

Will try that today if I get the chance

[Jevi]

Update - Rattle on engine turned out to be a loose valve!

The boy put it into a local dealer/garage for an mot & service and they found the problem and sorted it out. - £50.00 the lot.

Plus when he told them he was having a problem with cold starting on the button they told him to bring it back and they'd check it out and and fix it for free.

Typically the next day it wouldn't start so he took them up on their offer.

Yesterday we got a call, problem solved but because it had turned out to be an electrical problem rather than the carb (which was his original thought) he had to charge for the repair (£42.00 -an hours labour plus materials).

Because he was able to show me the photos he'd taken as proof of the problem I didn't have any qualms about paying - broken earth wire (which I would have struggled to find) in the ignition circuit.

With the bike sitting with front and back wheels aligned you could fire it up on the button but if the front forks were turned slightly you got nothing (starter turned over but the bike wouldn't fire). Anyway the bloke from the garage fixed the problem and explained everything that he'd had to and the boy sailed off into the sunshine for the first uneventful ride he's had since he bought the bike.

If you're interested bike dealer/garage - BDS in North Shields (you can find them on Google)

[Joeman]

Errr.... By electricity?

 

Errrrr ....How does that help ?

 

It wasn't meant to.............JFGI. Some people want it on a plate.

That assumes that all human knowledge exists on the internet and that it's all been discovered by Google.

[Joeman]

Update - Rattle on engine turned out to be a loose valve!

The boy put it into a local dealer/garage for an mot & service and they found the problem and sorted it out. - £50.00 the lot.

Plus when he told them he was having a problem with cold starting on the button they told him to bring it back and they'd check it out and and fix it for free.

Typically the next day it wouldn't start so he took them up on their offer.

Yesterday we got a call, problem solved but because it had turned out to be an electrical problem rather than the carb (which was his original thought) he had to charge for the repair (£42.00 -an hours labour plus materials).

Because he was able to show me the photos he'd taken as proof of the problem I didn't have any qualms about paying - broken earth wire (which I would have struggled to find) in the ignition circuit.

With the bike sitting with front and back wheels aligned you could fire it up on the button but if the front forks were turned slightly you got nothing (starter turned over but the bike wouldn't fire). Anyway the bloke from the garage fixed the problem and explained everything that he'd had to and the boy sailed off into the sunshine for the first uneventful ride he's had since he bought the bike.

If you're interested bike dealer/garage - BDS in North Shields (you can find them on Google)

Sounds like a top garage bargain prices and honest fixes.

Shame they are not all like that.

[megawatt]

I still don't get the loose valve bit?

[fastbob]

I still don't get the loose valve bit?

 

No nor do I actually. Maybe they just meant a wide tappet clearance but didn't want to baffle the customer with technical jargon . Or maybe it was wobbling around in the valve guide.

[Joeman]

I still don't get the loose valve bit?

 

No nor do I actually. Maybe they just meant a wide tappet clearance but didn't want to baffle the customer with technical jargon . Or maybe it was wobbling around in the valve guide.

 

Tappets was my guess too, or maybe some sort of exhaust/power valve? Im not familiar with the bike so no idea really but it's more likely a 4t with tappets than a 2t with a power valve!

[fastbob]

I still don't get the loose valve bit?

 

No nor do I actually. Maybe they just meant a wide tappet clearance but didn't want to baffle the customer with technical jargon . Or maybe it was wobbling around in the valve guide.

 

Tappets was my guess too, or maybe some sort of exhaust/power valve? Im not familiar with the bike so no idea really but it's more likely a 4t with tappets than a 2t with a power valve!

It's another CG clone so luckily it didn't go bang . One thing you really don't want on a pushrod operated engine is a loose tappet . Very loose and a rod could fall out of the cup in the rocker arm . I reckon the whole rocker assembly might have come loose , could happen. Here's one from my junk repository .