How to tension the chain on the delta in the engine

Setting the timing belt on a delta moped

1. Install a new cylinder head gasket.

ATTENTION!

The cylinder head gasket is made of soft metal (copper, aluminum) and after tightening the cylinder head nuts it is deformed, thereby ensuring a tight connection. Reinstallation of the cylinder head gasket is not permitted.

2. Install the timing chain guide.

3. Install the cylinder head.

4. Set the piston to TDC according to the marks on the flywheel. This is usually the "T" mark on the flywheel. Align the mark with the tide on the engine crankcase.

ATTENTION!

The following operation is one of the most important when assembling the engine. It is important to align all the marks very accurately. An error in installing the chain even by 1-2 teeth will result in the engine not working correctly, and it will probably even lead to serious damage to the timing and cylinder-piston gas parts when trying to start the engine!

5. After making sure that the timing chain has not jumped off the drive sprocket on the crankshaft, install the camshaft into the cylinder head, at the same time putting a chain on its sprocket so that the marks on the camshaft sprocket are parallel to the plane of the edge of the cylinder head, and the cams are directed downward (inside the head).

6. Install the rocker arm support, orienting it according to the installation marks. Lubricate the cams and camshaft bearings.

On the rocker arm support are the letters “EX” - which means “EXHAUST” - release. The "EX" mark should be located above the exhaust valve.

ATTENTION!

• Check the correct axial alignment of the camshaft (make sure that the camshaft bearings are correctly positioned on the beds). Probably, on some scooter models, the holder will have a mark “IN” - “INTAKE” - inlet. Accordingly, the “IN” mark must be located above the inlet valve.

ATTENTION!

If the copper washers are severely deformed (flattened), they must be replaced, since if the washers do not fit tightly due to oil leakage, the pressure in the lubrication system will drop and the motor will quickly fail. Sealing this connection with any sealant is unacceptable.

7. Install sealing copper washers on the studs.

8. Screw on all four cylinder head nuts without tightening them.

9. We recess the working rod of the timing chain tensioner inside the housing.

10. Reinstall the timing chain tensioner and tighten its mounting bolts.

11. Insert the working bolt and the timing chain tensioner spring, tighten it. In this case, you can hear characteristic clicks - the ratcheting mechanism of the tensioner working rod will be activated, which, under the influence of a spring, will come out of the housing and tension the timing chain.

12. Sequentially, crosswise tighten the cylinder head nuts in 3-4 steps. The final tightening torque is 10-15 Nm (More accurate values can be found in the repair instructions for the specific scooter model).

13. Screw in and tighten the additional cylinder head bolts.

14. Using a socket wrench for the central bolt of the flywheel, or with your hands holding the flywheel, slowly turn the engine crankshaft clockwise 3-4 turns to make sure that the timing timing is set correctly and the piston does not collide with the valves.

15. We install the crankshaft at TDC of the compression stroke and once again check the correct installation of the camshaft according to the marks.

17. Rotate the crankshaft several turns and once again check that the valve clearances are set correctly.

18. Install the cylinder head cover and tighten its bolts.

19. Place the crankcase ventilation hose onto the fitting in the cylinder head cover.

20. Install the cylinder cooling casing.

ATTENTION!

Do not forget to remove the paper from the intake manifold if you covered it from dirt during disassembly.

21. Install the inlet pipe assembly with the carburetor.

ATTENTION!

In most cases, when installing an exhaust system, the exhaust pipe gasket will need to be replaced. It is better to replace it with a new one during assembly.

Video on this topic

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Alpha 110 (Change timing chain)

They brought in a moped (Alpha 110) with a complaint about a foreign knocking noise in the engine, as it turned out that it was loose timing chain. Foam.

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Foam filter for Alfa moped https://goo.gl/MF6F3b Digital thermometer.

Setting TDC on Alpha

To start adjusting the valves on the Alpha moped, you need to set the top dead center. To do this, remove two covers on the rotor cover. Rotate the rotor until the T mark appears.

To accurately control this process, you need to remove the timing sprocket cover. To do this, on the opposite side you need to unscrew the clamping bolt, which can be unscrewed with a 10mm wrench. Remove the timing chain sprocket cover carefully so as not to damage the gasket.

The star has a mark in the form of a dot. It should be aligned with the mark on the head body.

To easily turn the engine mechanisms, I unscrewed the spark plug, reducing the compression to nothing.

Now you can begin adjusting the valves on the engine.

Before you start adjusting the valves

Therefore, after purchasing a new Alpha RX, I checked the valve clearance. For this procedure I had to buy a set of probes. In our case, you will need a probe with a thickness of 0.05 mm.

In order to calmly begin adjusting the valves, I had to unscrew the safety bars. For this we need a key of 8.

To get to the valves, you need to unscrew the valve covers located on the top and bottom of the cylinder head. To do this we need a 17 wrench. I used a spanner.

How to tension a chain on an Alpha moped - step-by-step instructions

To simplify access to the necessary components, first remove the rear left passenger footrest. The moped must be placed on the center stand. It is also advisable to unscrew the bolt and remove the exhaust pipe. If this is not done, the ratchet heads cannot be used.

Next, take two keys - 17 and 14 mm. You need to unscrew the nut to loosen the wheel axle. The nut is unscrewed, but not completely. With the second key you need to hold the axle on the reverse side so that there is a stop. If you don't hold it on the reverse side, the axis will spin.

Let's start adjusting the valves

Let's start with the intake valve, which is located at the top of the cylinder head. We'll need a key for 9. Yes! Not 8, not 10, but 9! Good thing I had a set of sockets in the car. But it is better to use a spanner wrench, which conveniently unscrews the pusher fixing nut on the rocker arm.

Then we need a feeler gauge with a thickness of 0.05 mm, which must be inserted between the pusher and the valve stem. By rotating the pusher, we reduce or increase the thermal gap until the probe moves with slight tension. After tightening the fixing nut, we again check the gap with a feeler gauge, which could have gone astray.

In a similar way, we begin adjusting the exhaust valve.

Which drive chain did I choose for my moped?

photo by blog author

Greetings, friends!

Everything described below is my own experimentation experience. Therefore, there will be no references to “Uncle Vasya said” or “a neighbor advised.”

I will tell you using the example of my Chinese moped “Alpha”. “Chinese” vehicles do not have any special distinctive qualities, be they mopeds or scooters.

In rural areas they are now common because of their lightness. Its speed is quite enough to go into the forest for mushrooms and berries, it is lightweight (you can, without straining, move it “by the horns” through the mud). There are also disadvantages.

Of the minuses, I would like to note the narrow wheels - in the sand it begins to lose stability and throws, also on wet grass and muddy roads. You can get good at it.

Previously, I wrote a post here about which spark plugs are best for mopeds. If anyone is interested, you can read it at this LINK.

Drive chain for moped

To be honest, the family chain was completely stretched out in literally a season and a half. And this despite the fact that I was traveling alone. This arrangement did not suit me at all. Therefore, I had to study the range of chains in the store. I chose domestic production, but the links were wider than those of my native one.

photo of the blog author. The drive chain is original. Width approximately 13 mm

The wide drive chain looks almost identical to the Voskhod one. It fits step by step. I took it and didn’t regret it.

Maybe, of course, I was lucky with it (I got a good manufacturer, etc.), but during the whole season I tightened the chain only once. I am not going to install a rear tire with deep treads (like a “studded” one). It will stimulate the chain to stretch. I know this from the Voskhod-2m motorcycle that I had before.

photo of the blog author. New wide chain. 15-16 mm

At the time of publication of the post, I had been riding a moped with this drive chain for 3 seasons. I only pulled it up once. Well, maybe this year in the spring before the first trip I’ll take a look and tighten it up a little.

Catch up

By the way, I don’t put studs on the rear wheel like some people do. The original tires are still quite good.

And one moment. Usually, when changing the drive chain (I know this from Voskhod), both stars are changed. This time I deviated from this rule. The teeth are still quite decent. So watch your stars on your moped.

Dear friends! I do not impose my opinion on you, but only tell you about my successes and failures. Therefore, this post should not be taken as a call to action or aggressive, persistent advice. Each person has his own head on his shoulders. Think for yourself and decide for yourself.

Good luck to all!

Humor:

Anyone stuck in traffic jams doesn’t laugh at a moped!

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To change or not to change?

Suppose you are overhauling your engine: changing oil seals, crankshaft, gaskets and other devices, but you doubt whether to replace the timing chain with a new one or not. If you have any doubts, change it for a new one at the first opportunity. And now I will explain why.

See for yourself: a chain has an average service life of approximately 18,000-20,000 km of a scooter (personal experience), approximately the same as the average service life of the engine itself. And for example, after driving 6,000 km, the crankshaft jammed or the engine leaked, or something else happened that requires complete disassembly of the engine. Naturally, you disassemble the engine, replace the crankshaft with a new one, and leave the chain, which by that time has exhausted a third of its service life.

And what happens? The chain, after 12,000 km, will exhaust its service life and become unusable, but the crankshaft and other parts will be in good order and whether you like it or not, you will have to halve the engine again, because of the chain alone. Is it necessary? The chain is a consumable. Never skimp on it!

Personally, I never check timing chains. I simply throw them in the trash, no matter how awesome they seem to me. A chain is a consumable item for me, just like a spark plug, oil or oil seal. But if you are important, or money is tight, you can use the old fashioned way.

Examination

Alpha tensioner repair

alpha

Tensioner repair 149 fmb.

We stretch the chain along its length, hold it with our fingers and try to position it in a horizontal position

If the chain describes an arc that looks very much like a 90-degree angle, then feel free to throw it in the trash.
If the chain bends slightly and describes a small arc, then such a chain is quite suitable for further use

For clarity, I took a new and heavily worn chain, put them together and checked for horizontal deflection. As you can see: the new chain (above) described a barely noticeable arc, while the worn and useless chain sagged like snot, almost at an angle of 90 degrees.

The worn chain turned out to be almost a centimeter longer compared to the new one.

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Valve adjustment on Alpha

I want to touch on an interesting topic that everyone has heard about, but not everyone understands its essence - let's talk about valve adjustment.

A little theory.

First, a little theory. Where did the need to adjust the valves come from and why is the thermal gap needed?

Any four-stroke engine has at least two valves: an intake valve, through which the working mixture enters the combustion chamber, and an exhaust valve, through which exhaust gases exit. Part of the valve is constantly located in the combustion chamber and therefore the valve becomes very hot. And as we know from school physics courses, bodies expand when heated. Moreover, the stronger the heating, the greater the expansion.

The valves in the engine are always in a “spring-loaded” state, while the valve plate is pressed very tightly to its seat - the valve seat. This ensures that the valve closes tightly.

To open the valve, you need to press on it. In our case, the valve is pressed by a rocker arm, which moves under the influence of the camshaft cam.

Now let’s imagine that the engine is cold (it stood for several hours and all the parts cooled down to “room” temperature). If you start the engine, the valves will begin to heat up quickly and, as a result, lengthen. If you do not leave it room for expansion (the gap between the rocker arm and the valve stem), then the moment will come when the valve will elongate so much that it will not fit tightly to its seat and will begin to leak gases from the combustion chamber. This leads to a loss of engine power and can also lead to overheating and burnt valves.

IMPORTANT: the gaps are set on a cold engine , when the valve has not yet had time to lengthen.

What happens if the valves are adjusted incorrectly?

Very often on various forums questions are asked: “What will happen if the valves are adjusted incorrectly?” There are two possible options:

How to adjust and tension the chain?

There’s no way you can tighten it or adjust it, and you don’t bother Google or Yandex search with such queries. The chain in the scooter engine is tensioned automatically. And if it has already stretched to such an extent that it begins to fly off or jump over the teeth, feel free to disassemble the engine and replace it with a new one. There are no miracles.

And I will prove this to you now. The chain in the engine is tensioned using a special tensioner, which operates in a fully automatic mode. As the chain stretches, And the more the chain stretches, the more the rod will come out. But! The rod has a limited stroke: on a completely new chain it comes out about a third of its stroke and then, as it stretches, it comes out completely and then it won’t come out anymore. Therefore, the chain will no longer be tensioned! And all your attempts to correct the situation will lead to nothing.

How to set timing marks on an alpha moped

Checking the timing belt by marks on the Delta EX 50 moped engine 1P39FMB (139FMB)

Comments from those interested:

Roman Khimchenko 2 weeks. reverse And if it doesn’t match WHAT to do

Vladimir Voronov 2 weeks. reverse Set it to match.

Vladimir Voronov 1 month ago This is nice. )) And of course there will be new videos, just wait a little.

Vladimir Voronov 1 month ago Yes! Another thing, don’t install two gaskets; it won’t make things any better; an increase in the combustion chamber will result in a drop in power.

Hunter38767 3 weeks reverse And if you have a 50cc head and a 72cc piston, then you need to change the head.

Hunter38767 3 weeks reverse Two gaskets are not allowed, look, the valves may be overtightened, unscrew the two caps on the head, and look at the gap, it should be 0.05 on the feeler gauge. But if they hit the piston, then there is no gap.

Sergey Vasiliev 1 month back Vadim, thank you, I read a lot of useful information, thank you, I will be glad to see new videos on alpha, I’m really looking forward to it

Arkady Novoselov 1 month back, well done, thank you for you!

How to Tension the Timing Chain on an Alpha Moped

Photo report: how to check the drive chain of a scooter?

In life it is always like this: one wonderful thing, another bad. The same principle applies to various types of manual transmissions. Chain transmission was no exception. On the one hand, there is nothing simpler, more reliable, simpler, more compact and cheaper than a chain drive.

On the other hand, we get endless hemorrhages with chain stretching, sprocket wear, endless cleaning and lubrication, maintenance and stretching of the chain itself. But nothing can be done, the gearbox has many advantages over other types of mechanical gears, since these types of gears are used almost everywhere.

In general, now we will not talk about the chain drive as such, but about a method for diagnosing chain synchronization, which drives the scooter .

To change or not to change?

Let's say you're using most of your engine: you're replacing gaskets, crankshafts, gaskets and other things, but you're hesitant about replacing your timing chain with a new one. There is no doubt in your mind that you should replace it with a new one as soon as possible. And now I will explain why.

See for yourself: the average lifespan of a chain is approximately 18,000-20,000 km (personal experience), which is approximately the same as the average life of the engine itself. And for example, after driving 6000 km, the crankshaft jammed or the engine leaked, or something else that required complete disassembly of the engine. Naturally, you disassemble the engine, replace the crankshaft with a new one and leave the chain, which by that time has exhausted a third of your resource.

READ How to Twist Mileage on Accent

So what's going on? After 12,000 km the chain will fail and become unusable and the crankshaft and other parts will start to work and you will, if not want, have to halve the engine again through one chain. It's necessary? The chain is a consumable item. Never skimp on this!

check

Personally, I never check the time. I just throw them in the trash, no matter how wonderful they seem to me. For me it's a chain. This is a consumable item, the same as a spark plug, oil or oil seal. But if it's important to you or money is stressful, you can use your old grandfather.

Alpha tensioner repair

Tensioner repair £149.

We stretch the chain along its length, squeeze it with our fingers and try to position it in a horizontal position.

READ Replacement Timing Chain Volkswagen Jetta 1.4

To be clear, I took a new and very worn chain, connected them and checked for horizontal bending. As you can see: the new chain (above) has made a slight arc and is worn and no good, like snot, almost 90 degrees.

Checking and adjusting the moped drive chain

The chain drive is one of the most loaded components in a moped.
If the chain is loosely tensioned, that is, it sags a lot, then at the moment of a load change, this excess supply of chain will first be selected, and then, when its free play ends, a sharp blow will occur, harmful to all elements of the transmission. And it’s unpleasant for the driver himself to drive such a moped that jerks whenever the gas is opened or closed, especially in a sluggishly creeping traffic jam. The second disadvantage of a sagging chain is that when the tension is weak, its unloaded shoulder tends to move in a straight line by inertia, which is why it rests imperfectly on the sprocket teeth, thereby wearing them and itself out. The life of the drive chain depends on lubrication and adjustment. Failure to maintain the drive chain promptly can result in premature wear or damage to the chain and sprockets. Chain maintenance work includes cleaning it from dirt, lubricating the links, or boiling it in molten lubricant. Cleaning the chain and lubricating its links can be done without removing the chain from the moped, using a brush, special liquids and lubricant in aerosol packaging.

To weld the chain, it must be removed from the moped, washed in kerosene and boiled in lubricant (the lubricant consists of 95% solid oil and 5% graphite powder) at a temperature of 70-80°C. It is recommended to carry out the first welding of the chain before use.

A routine check of the drive chain tension is carried out every 500 km.

The check includes:

Turning off the engine, place the moped on the central support stand;
engage neutral gear;
remove the inspection hole cap on the chain casing;
check the chain tension (normal sagging of the drive chain should be within 5-10 mm with a force of 10 kgf;
Turning off the engine, place the moped on the central support stand;
engage neutral gear;
loosen the rear wheel axle nut;
by tightening the adjusting nuts on the left and right sides, achieve normal chain tension;
tighten the rear wheel axle nut;

After the adjustment is completed, you need to check if everything worked out as expected. If the wheel is level, the marks on the tensioners on the right and left show the same thing, and the chain has the desired slack, then everything is done correctly. All that remains is to lubricate the chain.

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A distinctive feature of a moped from a scooter is that the former has a chain instead of a belt, so sooner or later quite typical breakdowns occur with Alpha mopeds. The chain tends to stretch over time, after which movement becomes quite problematic. You can tension the chain yourself; no special skills are required. But know that you don’t need to tighten the chain on the Alpha moped too much; the free play should be from 2 to 3 cm, otherwise you will face much bigger problems.

So, if you don’t know how to tighten the chain on an alpha moped, follow the instructions below.

First of all, remove the passenger footrest so that it does not interfere with tensioning. Then place the alpha moped on the center stand. But some experts recommend tensioning under a certain load on the moped, because on the center stand your vehicle will be supported by weight; after tensioning the chain, you will notice that it has become even more tense, like a string. This oversight leads to serious damage; many say that an overtightened chain after 1 thousand km leads to a breakdown of the entire clutch mechanism.

How to tension a chain on an Alpha moped

Next, you will have to unscrew the nuts of the central axle of the wheel, this will help loosen the wheel axle. To do this, a 14mm wrench is suitable, after that you will have to unscrew the nut located on the same axis, but then, in the case of the Alpha moped, a 24mm wrench will do. After this, we proceed to adjust the chain; on the same axis there is a chain tensioner with a nut, just enough tighten it, this will require a 10mm wrench.

You will have to tighten the nut until you feel that the chain is tensioned. In this case, the teeth should not fall on the edge of the chain, check this, and only then can you begin the final procedure - tightening the axle nuts back. Tighten these nuts well, but do not overtighten them. That's all, as you can see, tensioning the chain on an alpha moped is quite simple.

Photo report: How to check the timing chain of a scooter?

It’s always like this in life: one thing is great and the other is bad. Exactly the same principle applies to various types of mechanical transmissions. Chain transmission is no exception here. On the one hand, there is nothing simpler, more reliable, lighter, more compact and cheaper than a chain drive.

On the other hand, we get endless hassle with stretching the chain, wear of the sprockets, endless cleaning and lubrication, maintenance and tensioning of this very chain. But there is nothing to be done, the chain box has a lot of advantages over other types of mechanical transmissions, which is why these types of transmissions are used almost everywhere.

How to replace the timing chain in an engine

Having decided on such an action as replacing the timing chain of a scooter, you need to decide on how to implement your plan.

There are two replacement options:

How to change, everyone decides for themselves. Both methods, advantages and disadvantages are described in detail below.

With disassembly

You should choose the right tools - generator and variator pullers (you can make them yourself), a kickstarter sprocket puller, 8, 10, 12 and 17 mm sockets, a hammer, two screwdrivers (flat, Phillips).

The engine is removed from its place, the oil is poured out, all parts are wiped and cleaned. Next, remove the muffler and cooling casing. We remove the generator only with a puller. To do this, unscrew the bolts from the impeller and remove it from the rotor. It is necessary to fix the rotor with a puller and unscrew the nut. Then we tear the rotor off the crankshaft journal. Remove the variator cover. Also, secure the impeller with a puller, unscrew the nut, and remove the variator from the axle.

Below the variator is the kickstarter gear. Likewise, a puller is required for it. Then we clean the cylinder connector, valve covers and cylinder head. After unscrewing the bolts on the valve covers, remove it. Next, remove the scooter's timing chain tensioner. After unscrewing the bolts on the cylinder head, we pull out the camshaft bed.

Next, remove the chain from the camshaft and pull it out of bed. To avoid losing the guide bushings that center the parts relative to each other, you need to remove them and put them away. We remove the cylinder head, the cylinder itself, and the piston (to do this, remove the retaining ring and pin from the upper connecting rod head).

After unscrewing the bolts on the crankcase cover, tapping it a little, remove it from the engine. We take out the starter intermediate gear, use a screwdriver and a hammer to unscrew the overrunning clutch nut (clockwise) and remove the gear and housing from the trunnion. We reached the chain!

Remove the protective shield from the oil pump. Place a metal stick under the chain, twist the nut on the oil pump sprocket, remove it and remove the chain.