Overhaul Engine

[shooyu]

hey any1 of you guys did overhaul on your engine before? how much does it cost? what did they do to your bike, was it good? go where overhaul cheap and good?

 

sad siol seems like my sp sound sick. need to do something about it. advise please thanks!

[xiaobanz]

hey any1 of you guys did overhaul on your engine before? how much does it cost? what did they do to your bike, was it good? go where overhaul cheap and good?

 

sad siol seems like my sp sound sick. need to do something about it. advise please thanks!

 

I went to unique and they do full overhaul costing like $220. If you wan you can go to advertiser board and look for them. Ask for kelvin, he will give you a good quote. Actually the advertiser board has a lot of shops you can ask from.

[shooyu]

but after overhaul any probs? different bikes have different quotation?

[Yatz86]

yes different price depend on how jia lat ure bike condition is

[Guest limpeiwah]

i think unique motorsport good in overhauling sp

[craz_03]

anyway

does overhauling sp improve on fuel consumption??

lol..

mine ride to 180km b4 hitting reserve..

[xiaobanz]

By right your FC should increase but this also depends on the bike. You have to go and ask your bike shop this...

[luckystar]

anyway

does overhauling sp improve on fuel consumption??

lol..

mine ride to 180km b4 hitting reserve..

 

wow... 180km b4 hitting reserve... tat's good FC...

mine hit oni abt 160km but mayb due to my modifications...

 

I had my SP top service at unique motorsports, before top service my bike can oni hit abt 150km but after top service oni improve abit (10km) haiz...

but Alec told me itz due to my modification, he say if i change everything back to stock can sure hit 200km:cheeky:

dun know true anot

[waadee]

when we say overhaul.. does dat mean new piston block and evrything?? or wad do they actually do?

[josephsbs]

but after overhaul any probs? different bikes have different quotation?

yes different price depend on how jia lat ure bike condition is

Just like Adidas150 said, different bikes and different engine condition will cost differently. I overhauled my TZR125 (1 cylinder) for about $250 but my CBX400 Custom (4 cylinders, 16 valves) cost me >$1,000. The CBX engine is very heavy to remove, more complicated design, more expensive parts, more skill & time needed, etc... obviously more expensive lor

 

Overhaul costs = Workmanship costs + Parts costs

 

Problems? Yes... if you don't run in the bike properly. My TZR's piston jammed while running above recommended revolutions before the proper run-in is completed. Skidded along AYE and was lucky not to get myself killed... was only about 1 feet from being run over by a car. End up going back to workshop and spend more $$$.

ADVICE: do the run-in religiously for your own safety

anyway does overhauling sp improve on fuel consumption??

FC is very dependent on how you squeeze your throttle.

With a newly overhauled engine, you will likely experience a more responsive engine (some refer to it as more "power") coz the engine is supposedly restored to almost "factory" condition... piston and piston rings fitting the cylinder nicely, clean smoothly operating exhaust valves, camshafts & valves (4-stroke engines), new crank, etc. With this very shiok responsive feeling, some will throttle more to enjoy the torque... thus burning more fuel. In theory, FC may improve as the restored engine experience more efficient combustion per cycle and energy transfer through camshaft & gears. An engine with loose piston & piston rings will experience energy loss due to leakage and thus "wastage" of fuel. Nevertheless, some may disagree with this idea.

 

Don't forget about the run-in.

 

you have to experience the difference and form your own conclusions

 

 

when we say overhaul.. does dat mean new piston block and evrything?? or wad do they actually do?

Here's some info to help you understand more about engine overhaul:

 

What is an Engine Overhaul?

A general term for major engine work that usually requires removing the engine from the vehicle/bike, and rebuilding or replacing internal components (e.g. pistons, connecting rods, valves), usually in attempt to restore it near "factory" state.

 

There are 2 levels of Engine Overhaul:

1) Top Overhaul: only covers the replacement of components inside the cylinder head without removing the engine from the vehicle/bike, such as valve and rocker arm replacement.

In layman terms... open the top, dismantal and change cylinder assembly parts such valves, rocker arm, piston head, piston rings, gasket, etc.

 

2) Full Overhaul: covers the whole engine component replacement which requires the engine to be removed from the vehicle/bike, such as replacing the connecting rods, crankshaft bearings, etc in addition to the items in top overhaul. By comparison, a full overhaul service costs more than a top overhaul service.

 

Whether a bike's engine need a top or full overhaul depends on the extent and damage to the engine's parts.

 

How much will an Engine Overhaul cost?

Less work is involved in a top overhaul, thus cheaper. Full overhaul usually requires the while engine to be taken down from the frame, engine block opened and parts stripped for servicing (if still in good condition) or replacement. More time consuming and more complicated works leads to higher cost.

 

Overhaul costs = Workmanship costs + Parts costs

 

 

What are the parts in a typical petrol engine?

A single sweep of the cylinder by the piston in an upward or downward motion is known as a stroke. i.e.

2-stroke = bang, down, up, bang, down up, bang ..............

4-stroke = bang, down, up, down, up, bang, down, up, down, up, bang ........

 

http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Four_stroke_cycle_compression.jpg/180px-Four_stroke_cycle_compression.jpg

 

http://img.photobucket.com/albums/v514/triprider/Breakdown.jpg

Key components of a typical 4-stroke engine.

 

http://upload.wikimedia.org/wikipedia/commons/a/a6/4-Stroke-Engine.gif Typical 4-stroke engine in action

1. Induction or Suction stroke... air and vaporised fuel are drawn into cylinder from carburetor
   
2. Compression stroke... fuel vapor and air are compressed by the piston/cylinder and ready for ignition by "sparks" generated by spark plug
   
3. Power stroke... combustion take place and piston is pushed downwards to push the crankshaft into a rotating motion
   
4. Exhaust stroke... burnt waste is driven or squeeze out of the cylinder for fresh air and vaporised fuel to be drawn in

In addition to the main engine, there are other systems that are usually worked upon during an Overhaul.

 

Transmission system... Gearbox

A sequential manual transmission (or sequential manual gearbox) is a type of manual transmission used on motorbikes and high-performance cars or auto racing, where gears are selected in order and random access to specific gears is not possible.

 

Transmission system... Clutch

Motorcycle clutches are usually made up of a stack of alternating plain steel and friction plates. typically two clutch plates, one fixed to the engine's crankshaft, the other fixed to a basket that turns the transmission shaft, which turns the gears (gearbox) and finally front sprocket. the plates are forced together by a set of coil springs when the clutch is engaged.

Clutch plates should be changed if the contact parts are worn out.

 

Cooling System

Petrol engines may be air-cooled, by fins on the cylinders (e.g. TA200 phantom), or liquid-cooled by a water jacket and radiator (e.g. Super 4). The coolant was formerly water but is now usually a mixture of water and ethylene glycol. This mixture has a lower freezing-point and a higher boiling-point than pure water. In addition, the cooling system is usually slightly pressurized to minimise evaporation of coolant.

Work may be done on liquid-cooled systems by changing coolant, flushing and/or changing/repairing the radiator.

[waadee]

wahh power lah... so now we know eh...

 

lets not forget to run in our newly full overhauled engine

[shooyu]

thanks a lot josephsbs for the detailed explaination.

 

so how long do you have to allow the pistons to run in?

[waadee]

thanks a lot josephsbs for the detailed explaination.

 

so how long do you have to allow the pistons to run in?

 

i tink abt the same as running in a new engine

[slutgarden]

hard run in better or remain to what manual says?.

 

low rpm, low speed.

[shooyu]

and so how long does that means?

[glass_jelly]

1st time i done top overhual n i was told to run in 800km... bt i run in 300km den i warck den 2 month lata do top overhaul again... bt tis time i run in 800km... so it up to wat e shop recon bt e more u run in its better for e engine.. tat wat i feel...

[shooyu]

hmm so it's roughly around 800clicks for it to run in?

[CoStar]

averaage about 500km. but like the experts say, don only travel on expressway to reach the end of run in. go through the gears and go at different speeds. can whack. but don until redline. maybe not more than 7k rpm? abt there.

[NeraZ]

hmm if you are interested in rather cheap overhaul, try HL cycle at blk 1043 Eunos ave 3 #01-134. They have packages for class 2B overhaul and it cost less than 200 to do a overhaul. Friendly and nice technician there too

[Echo]

after reading all these, leave me wondering. is there difference in cheap and expensive full overhaul? i heard before that if the full overhaul is cheap, that will mean u will need to do another overhaul very soon.....

 

cheap overhaul definately cannot make it right?

[josephsbs]

sorry for late reply... was busy preparing for my class 2 TP test, which i happen to scrape through this morning... heng ah http://smileys.on-my-web.com/repository/Happy/happy-144.gif

 

Why run in?

The objective of running in (also called break-in) your engine, is to get the engine to the point where all the rubbing surfaces are nicely mated to each other at all temperatures likely to be attained, while causing as little wear to the engine as possible in the process. Remember that metal expands with heat, thus a perfectly mated piston/rings in the cylinder may become too tight when the engine heats up. The benefits of doing this properly are twofold; the engine would be a "better'"engine throughout it's life, and that life would also be extended.

 

All new bikes need to be run-in, as are engines that are overhauled to "factory state". It allows the parts in your engine to gradually become seasoned. If you don't run-in your engine properly, you can seriously shorten its lifespan. Over-revving an unseasoned engine or putting too much load and stress on the motor could result in jammed pistons.

 

And don't forget to change your engine oil after running-in the engine.

How far?

Depending on the motorbike manufacturer's recommendations, running-in periods are usually between 500km to 1000km. i.e. different bikes have different requirements. For overhauled engines, it depends on what parts are changed as well... better to check with the mechanic that completed the overhaul.

 

How long?

A conventional or normal run-in can take a rider as little as 3 days or as long as 3 weeks, depending on usage.

 

How fast or engine revs limit?

This is very much dependent on your bike. A common run-in engine rev limit could be around 5000 rpm by which some bikes could travel around 60-70km/hr. Revving the unseasoned engine too high would not only wear out the engine excessively but also cause the piston(s) to jam.

Engine oil?

Some bikers suggested using mineral oils for the run-in becoz engine is not doing prolonged high revs, too good lub could slow down seasoning of rubbing parts, more economical since EO will be changed when run-in is completed, etc.

On the other hand, some bikers suggested using premium stuffs such as fully-synthetic EO so as to give the engine the best protection during the roughening or seasoning process.

 

I would agree that mineral oils should be used.... reasons are sound, cheap & good. It is best to check with your mechanic.

never ever use fully-synthetic oil for running in a NEW engine. this includes new pistons with rings and cylinder block.

 

it coats the cylinder wall with oil which is too slick for the break-in to take place.

 

and in actual fact for the piston rings to seat in properly, the most crucial part is when doing the first 15mins of engine startup.. once the engine is warmed up, whack the throttle but not red-line it.

 

a full read up is available on the net actually.

Hard running-in?

Hard running-in usually makes life easier, taking as little as only about 30 minutes using a Dynojet machine. This is especially popular for busy bikers.

Using a Dynojet machine, a new bike can be monitored at every step of the process. Hard running-in is conducted in a booth where the new bike is strapped onto a machine with a roller. The new bike is hooked up to sensors for a more accurate reading of its engine output and revs. A mechanic will accelerate it through various throttle openings to season the engine.

 

Advantage of hard run-in is that it is done by a mechanic under a controlled environment, without the rider having to keep an eye on the tachometer while riding in traffic... a very much safer option at a affordable price. Not sure, but heard that a hard run-in costs around $100-$150.

 

Preferred run-in method?

Most bikers would prefer to run in our bike the traditional way because it is easy, free and allows us to feel our bike better.

 

 

[Echo]

another question, is there any particular life-span for 2 stroke and 4 stroke engines before over-haul is required?

[josephsbs]

after reading all these, leave me wondering. is there difference in cheap and expensive full overhaul? i heard before that if the full overhaul is cheap, that will mean u will need to do another overhaul very soon.....

 

cheap overhaul definately cannot make it right?

we can't say that top overhaul is not good enough... it depends on what your engine needs?

e.g. if only your piston head and piston rings are worn out and the con-rod, cam shaft, gearbox, etc are all ok, then no need to spend $$ on full overhaul. just open the top, work on cylinder head assembly, run-in and engine can use as per normal liow... faster and cheaper.

 

1st time i done top overhual n i was told to run in 800km... bt i run in 300km den i warck den 2 month lata do top overhaul again... bt tis time i run in 800km... so it up to wat e shop recon bt e more u run in its better for e engine.. tat wat i feel...

i whacked my overhauled TZR125 before run-in is completed and piston got jammed... you are lucky you piston didn't get jammed, but then same outcome... go back and spent more $$$

[josephsbs]

another question, is there any particular life-span for 2 stroke and 4 stroke engines before over-haul is required?

sorry, this one i dunno... but strongly feel that it depends a lot on "how the jockey whack his horse"

 

if biker whack his bike as if racing in a Motor GP (dragging or high rev pick-ups & speeding, quick-step engine brakes, etc), i'm pretty sure his horse will get sick earlier than another horse which is used under typical conditions. higher stress on the power-transmission components will lead to faster wear and tear.

[aRcHeR]

Engine oil?

Some bikers suggested using mineral oils for the run-in becoz engine is not going high rev, too good lub could slow down seasoning of rubbing parts, more economical since EO will be changed when run-in is completed, etc.

On the other hand, some bikers suggested using premium stuffs such as fully-synthetic EO so as to give the engine the best protection during the roughening or seasoning process. It is best to check with your mechanic.

 

 

never ever use fully-synthetic oil for running in a NEW engine. this includes new pistons with rings and cylinder block.

 

it coats the cylinder wall with oil which is too slick for the break-in to take place.

 

and in actual fact for the piston rings to seat in properly, the most crucial part is when doing the first 15mins of engine startup.. once the engine is warmed up, whack the throttle but not red-line it.

 

a full read up is available on the net actually.