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Lost Cam Tensioner Spring

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MorganSid0412
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PostPosted: 22:24 - 28 Nov 2021    Post subject: Lost Cam Tensioner Spring Reply with quote

Good evening,

I own a Lexmoto Aspire 50 (to be used to get me around until I get a car), and was changing the oil earlier today. When attempting to loosen the drain plug, I accidentally loosened the cam tension spring plug, and the csm tensioner along with the cam tensioner spring fell out. Stupidly, I placed the spring back in first followed by the cam tensioner, instead of the cam tensioner before the spring, resulting in the cam tensioner spring becoming stuck inside the cam chain assembly. Would anybody be able to advise me on how I would access the cam chain, where the cam tensioner would usually sit, so that I am able to retrieve the lost spring and replace it? If possible, I'd like to retrieve it without taking the engine completely apart Laughing . Any tips would be greatly appreciated, as I have my CBT next week and was hoping to solve this issue before next weekend if possible.

Many thanks,
Morgan.
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Pete.
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PostPosted: 22:27 - 28 Nov 2021    Post subject: Reply with quote

If you shine a torch up the hole and you can't see the spring then it's unlikely that you will get it back without some dismantling.

If you can see any part of it then you could hook it out with a piece of bent wire.
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Pete.
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PostPosted: 22:35 - 28 Nov 2021    Post subject: Reply with quote

Looks to me like you might be able to get at it by removing the left crankcase cover and pulling the generator off the crank. This fiche pic seems to show the lower camchain sprocket outboard of the crank main bearing.

https://www.chinesemotorcyclepartsonline.co.uk/microfiche/8070/3635#&gid=1&pid=1
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MorganSid0412
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PostPosted: 22:35 - 28 Nov 2021    Post subject: Reply with quote

Pete. wrote:
If you shine a torch up the hole and you can't see the spring then it's unlikely that you will get it back without some dismantling.

If you can see any part of it then you could hook it out with a piece of bent wire.


Hi Pete,

Thank you for your reply. I couldn't see the spring up the hole when I was looking, which makes me think it is further in than first thought. I did start the engine very briefly after putting in new oil, as I did not realise at first that I had put the spring/tensioner inside in the wrong order. How stupid of me, but I was rushing. I guess it means I will have to begin dismantling somewhere. I know the basics about engines, but not a great deal in the scheme of things. Where would you suggest I should come in from to access the cam chain assembly in order to find the spring?

Thanks again,
Morgan.
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Pete.
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PostPosted: 22:41 - 28 Nov 2021    Post subject: Reply with quote

Man if you started the engine without the tensioner then you're going to have to remove the left cove and the cam cover, fish the mangled bit of spring out from the cam chain tunnel, get a new spring and fit it whilst hoping that the timing hasn't jumped so far it's mangled the valves.
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MorganSid0412
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PostPosted: 22:43 - 28 Nov 2021    Post subject: Reply with quote

Pete. wrote:
Looks to me like you might be able to get at it by removing the left crankcase cover and pulling the generator off the crank. This fiche pic seems to show the lower camchain sprocket outboard of the crank main bearing.

https://www.chinesemotorcyclepartsonline.co.uk/microfiche/8070/3635#&gid=1&pid=1


That makes complete sense, as the cam chain sprocket will be on the outside, and therefore I will be able to begin there in my search for the spring. The cam tensioner hole should be nearby that sprocket, shouldn't it? If so, I'm hoping that the spring will not be too far from there. I will order a replacement cam tensioner spring, and a left crankcase gasket too. I just hope that the spring hasn't broken into pieces as the engine was run for a short period of time before I noticed what had happened, as mentioned.
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MorganSid0412
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PostPosted: 22:46 - 28 Nov 2021    Post subject: Reply with quote

Pete. wrote:
Man if you started the engine without the tensioner then you're going to have to remove the left cove and the cam cover, fish the mangled bit of spring out from the cam chain tunnel, get a new spring and fit it whilst hoping that the timing hasn't jumped so far it's mangled the valves.


And is there an easy way to tell if the timing has jumped or not? Sorry if these seem like silly questions.
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stinkwheel
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PostPosted: 23:10 - 28 Nov 2021    Post subject: Reply with quote

MorganSid0412 wrote:


And is there an easy way to tell if the timing has jumped or not? Sorry if these seem like silly questions.


I think you're going to need a workshop manual. You usually set the crank position so a timing mark on the flywheel lines up with another mark or appears in a window then check some other marks on the cam sprocket are properly aligned.

There's USUALLY a T mark on the flywheel and two lines on the cam sprocket that line up exactly paralell to the surface the rocker cover bolts to when it's correctly timed. However not all bikes are exactly the same and I don't know about yours.

It's not generally all that big a job, just taking some covers off and having a look at stuff. Unless it has moved, and even then, it's not a huge job as long as the valves haven't hit the piston.

EDIT: Keep any bits of spring you find until you're certain you have the whole thing.
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MorganSid0412
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PostPosted: 23:22 - 28 Nov 2021    Post subject: Reply with quote

stinkwheel wrote:
MorganSid0412 wrote:


And is there an easy way to tell if the timing has jumped or not? Sorry if these seem like silly questions.


I think you're going to need a workshop manual. You usually set the crank position so a timing mark on the flywheel lines up with another mark or appears in a window then check some other marks on the cam sprocket are properly aligned.

There's USUALLY a T mark on the flywheel and two lines on the cam sprocket that line up exactly paralell to the surface the rocker cover bolts to when it's correctly timed. However not all bikes are exactly the same and I don't know about yours.

It's not generally all that big a job, just taking some covers off and having a look at stuff. Unless it has moved, and even then, it's not a huge job as long as the valves haven't hit the piston.

EDIT: Keep any bits of spring you find until you're certain you have the whole thing.


Thanks for your reply! I am going to have a look behind the left crank cover tomorrow and see what I can see. I'll look for the timing marks on both the flywheel and the cam sprocket, and of course the spring. The local mechanic didn't want to look at the bike as it is Chinese, so I thought I would have a go myself. I'll upload some photos of the flywheel and the cam sprocket, if its not that obvious when I get in. Is the timing assembly usually easy to access once the left crank cover is off? https://www.chinesemotorcyclepartsonline.co.uk/images/microfiche/57-8070-3638.jpg

EDIT: I need to get bolt number 10, through part number 9 again, as when I took out bolt 10, part 9 slipped down meaning I can't get the bolt through part 9 anymore. I guess I will be able to sort that once I am in. It does however make me thing that the spring is nearby, and that's why part 9 was pushed out of the way.
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Pete.
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PostPosted: 11:25 - 29 Nov 2021    Post subject: Reply with quote

Having the idler wheel (9) loose might help you retrieve the spring. If you remove the cam cover you might be able to get a bit of coat hanger down the tunnel to hook it back upwards, after you have recovered the spring (which will almost certainly be caught above the chain in the tunnel, and have to go out backwards towards the crank.

Inspect the chain and if it's kinked on any of the links even slightly, replace it.

Try not to turn the engine over at all until you are ready to reassemble it. If the timing it out then the valves can be bent by the piston.
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bikenut
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PostPosted: 19:55 - 29 Nov 2021    Post subject: T Reply with quote

That is so honda c50 idh looking...

Can you post a picture of your engine and further exploded views of the flywheel area.

If it's like a c50 you will need a flywheel extractor, a fine left hand thread that screws into the FLy wheel hub, with an extractor bolt in the middle .

Behind the flywheel there is a large circular cover held in by 2 countersunk screws, behind which lives the cam chain system and oil pump drive.

Pictures of your engine both sides and further exploded views flywheel side...
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bikenut
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PostPosted: 21:05 - 29 Nov 2021    Post subject: T Reply with quote

Turns out this bike has electric start on the lhs of engine which is a bit involved to gain access to the crank area of the cam chain system.

You have disturbed the cam chain idler/spreader wheel


You may be able to get that back into position via the cam sprocket cover, the round alloy plate on the lhs of cylinder head, held on via a long thru hex head on the rhs of the cylinder head.ser exploded views on lexmoto parts.

The spring may have wound it's self onto the cam chain tensioner roller arm.....

You may need some special tools for the starter system and alternator rotor to gain acc SS to the crank area of the cam chain......

If you see the cam sprocket, look for an "0"..... post pictures......
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MorganSid0412
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PostPosted: 00:11 - 01 Dec 2021    Post subject: Found spring!! Reply with quote

Good evening all,

Just a quick one to let you know that I ended up taking the head off to get to the spring, to save me splitting the engine completely. Once the head was off, I looked down the cam chain and saw the spring sitting right at the end. I managed to bend a piece of copper wire into the right shape to grab it, and it was still in perfect condition too. I've just got to replace flywheel nut (as I begun there), replace gaskets when they arrive, retime, fit tensioner again and fill with oil and should all be well. It's safe to say I know a lot more about engines now! Laughing Laughing

Finally, thank you to those who replied, as it definitely made me realise that the engine wasn't a lost cause, as I have not much prior experience with engines, and my local motorcycle mechanic wasn't interested looking. I'm glad that I've got the hard part over with, and now focusing on the assembly.

Many thanks all,
Morgan.
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MorganSid0412
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PostPosted: 00:20 - 01 Dec 2021    Post subject: Re: T Reply with quote

bikenut wrote:
Turns out this bike has electric start on the lhs of engine which is a bit involved to gain access to the crank area of the cam chain system.

You have disturbed the cam chain idler/spreader wheel


You may be able to get that back into position via the cam sprocket cover, the round alloy plate on the lhs of cylinder head, held on via a long thru hex head on the rhs of the cylinder head.ser exploded views on lexmoto parts.

The spring may have wound it's self onto the cam chain tensioner roller arm.....

You may need some special tools for the starter system and alternator rotor to gain acc SS to the crank area of the cam chain......

If you see the cam sprocket, look for an "0"..... post pictures......


Hello bikenut,

Thanks for your reply! You were right on the money there with removing the alloy cover to access the cam sprocket. That is where I began before I realised it must be way further down the cam chain.

I might be back if I can't figure out how to time properly, but from what others have said and from what I gather, there is a small inspection chamber in the top of the LHS crankcase, which you can see the flywheel though. Am I correct in saying that the 'T' mark has to be bang in the centre of that inspection chamber, whilst the cam sprocket mark '0' lines up with the marking on the side of the cam sprocket cover hole? I'm just not sure on the fact that the hole in the top of the crankcase inspection chamber seems like it would cover a handful on chain links whilst the 'T' is in view, if you get what I am saying?

I will send some photos of progress tomorrow in the light of day.

Thanks again,
Morgan.
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bikenut
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PostPosted: 09:12 - 01 Dec 2021    Post subject: T Reply with quote

Pictures pictures pictures, that's 3 thousand words ....

The "0" on the cam sprocket will probably sit between 2 "fingers" cast in the head cam cover hole . On a c50/70 honda, draw an imaginary line between crank centre and cam centre passing through the bolt for the cam chain idler/spreader.

This line will sit between the 2 fingers mentioned.

With the crank flywheel/rotor Woodruff key visible, that will sit on the line pointing to the camshaft, with the "0" between the fingers.

If the key or o are 180 degrees out, just turn the crank anticlockwise until they do.

With the camshaft o between the fingers, look thru that inspection port for "T"....

Any markings on the alternator rotor like an arrow, f and t, and some numbers probably ?

Pictures pictures pictures...

Look at the parts exploded views which will show a lot of info..
Post these also...
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MorganSid0412
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PostPosted: 02:29 - 02 Dec 2021    Post subject: Re: T Reply with quote

bikenut wrote:
Pictures pictures pictures, that's 3 thousand words ....

The "0" on the cam sprocket will probably sit between 2 "fingers" cast in the head cam cover hole . On a c50/70 honda, draw an imaginary line between crank centre and cam centre passing through the bolt for the cam chain idler/spreader.

This line will sit between the 2 fingers mentioned.

With the crank flywheel/rotor Woodruff key visible, that will sit on the line pointing to the camshaft, with the "0" between the fingers.

If the key or o are 180 degrees out, just turn the crank anticlockwise until they do.

With the camshaft o between the fingers, look thru that inspection port for "T"....

Any markings on the alternator rotor like an arrow, f and t, and some numbers probably ?

Pictures pictures pictures...

Look at the parts exploded views which will show a lot of info..
Post these also...


Good evening,

Please find some pictures below of the flywheel markings, the cam sprocket and the engine. It was dark when I took these photos, so I hope that the quality is good enough for you to see.

There is another '0' on the head cam cover hole, so I'm assuming that this should be lined up with the '0' on the cam sprocket, when the 'T' is visible on the flywheel through the inspection port. If the 'T' is visible, this means that the piston is at the very top of the head. Does the 'T' have to be dead in the centre of the inspection port for the cam sprocket to be then lined up with it's markings, or is there another marking I should be looking for to line the 'T' up with something, apart from it just being visible through the port?

I hope that the pictures help to explain what I am getting at.

If you would like some more photos, I can happily upload some more, if there is something else that you wish to see. Thanks again in advance for all of your help.

Many thanks,
Morgan.
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bikenut
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PostPosted: 09:08 - 02 Dec 2021    Post subject: T Reply with quote

My internet phone will not open the file. Please post the pictures in the thread.
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PostPosted: 09:20 - 02 Dec 2021    Post subject: Re: T Reply with quote

bikenut wrote:
Pictures pictures pictures, that's 3 thousand words .....


I think you will find that that's THREE words.
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PostPosted: 09:20 - 02 Dec 2021    Post subject: Re: T Reply with quote

bikenut wrote:
Pictures pictures pictures, that's 3 thousand words .....


I think you will find that that's THREE words.
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MorganSid0412
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PostPosted: 15:42 - 02 Dec 2021    Post subject: Re: T Reply with quote

bikenut wrote:
My internet phone will not open the file. Please post the pictures in the thread.


Good afternoon,

I've been having trouble uploading the images on here, so I hope these links work for you.

Flywheel markings: https://ibb.co/zxmcZqK

Cam sprocket marking: https://ibb.co/zsZHCpv

Inside the left crankcase: https://ibb.co/5sg9Dmk

Engine head: https://ibb.co/XFhWgCS

I hope these photographs are of use.

Thanks again,
Morgan.
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xX-Alex-Xx
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PostPosted: 16:16 - 02 Dec 2021    Post subject: Re: T Reply with quote

Skudd wrote:
bikenut wrote:
Pictures pictures pictures, that's 3 thousand words .....


I think you will find that that's THREE words.


But it's WORTH 10 ...

https://i.ytimg.com/vi/-2iZjxSGca8/maxresdefault.jpg
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bikenut
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PostPosted: 16:59 - 02 Dec 2021    Post subject: Brian Reply with quote

The all end bit was so unexpected !

Dam predictive Fing text, the alien bit etc...

Morgan, your last picture, the cylinders head had ran off ?!

Anyway I imagine the picture was "shakey" hence the odd looking chain ?

You can see the roller/spreader...

If you remove that you can see more of the inside...can you see the spring ?

If so, can you remove the spring ?

Long nose pliers, forceps or similar ?

Take a picture of what's down the cam chain tunnel and of the cylinder head cam chain side.


Over ..
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MorganSid0412
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PostPosted: 23:02 - 02 Dec 2021    Post subject: Re: Brian Reply with quote

bikenut wrote:
The all end bit was so unexpected !

Dam predictive Fing text, the alien bit etc...

Morgan, your last picture, the cylinders head had ran off ?!

Anyway I imagine the picture was "shakey" hence the odd looking chain ?

You can see the roller/spreader...

If you remove that you can see more of the inside...can you see the spring ?

If so, can you remove the spring ?

Long nose pliers, forceps or similar ?

Take a picture of what's down the cam chain tunnel and of the cylinder head cam chain side.

Over ..


I’ve managed to get the spring out with a copper wire, which was good! I just need to time it now. Should the ‘T’ be dead in the centre of the inspection hole when the cam gear mark lines up with the head cam inspection mark?

Thanks,
Morgan
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MorganSid0412
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PostPosted: 00:44 - 03 Dec 2021    Post subject: Re: Brian Reply with quote

MorganSid0412 wrote:
bikenut wrote:
The all end bit was so unexpected !

Dam predictive Fing text, the alien bit etc...

Morgan, your last picture, the cylinders head had ran off ?!

Anyway I imagine the picture was "shakey" hence the odd looking chain ?

You can see the roller/spreader...

If you remove that you can see more of the inside...can you see the spring ?

If so, can you remove the spring ?

Long nose pliers, forceps or similar ?

Take a picture of what's down the cam chain tunnel and of the cylinder head cam chain side.

Over ..


I’ve managed to get the spring out with a copper wire, which was good! I just need to time it now. Should the ‘T’ be dead in the centre of the inspection hole when the cam gear mark lines up with the head cam inspection mark?

Thanks,
Morgan


I’ll send some more photos tomorrow too Thumbs Up
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MorganSid0412
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PostPosted: 01:12 - 09 Dec 2021    Post subject: All done! Reply with quote

Hi all,

Just a quick update. On Monday, my new gaskets arrived, and I began reassembling the engine. I've managed to successfully assemble and time the bike, and did so through lining up what I thought to be the correct markings, using advice and my own reasoning. Once timed, I spun the flywheel a handful of times to ensure that the bike was turning over correctly, and that there were no major problems, etc. Everything seemed fine, and so I filled it with oil and it started and ran just fine. That night I taxed and insured it, and now finally on the road.

A big thank you to the people on here for your speedy replies and informative explanations. It is greatly appreciated. Although the entire situation could have been completely avoided with a bit more attention, I got there in the end, and feel much more confident working with engines now!!

Thanks again,
Morgan.
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