Update FC 550 -01

I'm going to open up my engine and replace some important parts.
The rockerarms is going to be replaced with -03.
Now I have some questions I need answered before I can order the parts:

Is it important to replace the bearing that holds the counterbalance to -02 and which parts do I need for that?
What happens if I take away the counterbalance, how will the engine react? How should you guys do if it was your bike?

Is there anything else I need to change now when I'm going to have my engine dissembled?


I hope you understand my message and help me by answering the questions.

hi i am Takis. It's very important to change all the gearbox bearings, cam and roller bearings, crankshaft and balancer bearings. Also you must change rings and piston pin. If you remove the balancer, bolts and nuts will be easily shaken loose. You also have a gyroscoping action, but the engine will rev much more easily than ever. I had this done to my bike. Change everything from the engine that has marks on it. Remember that it is much cheaper to replace parts while in there than to open the engine up a second time.

I would (and have) done these.
1) updated rockers
2) updated steel cam gear
3) updated double roller counterbalancer
4) updated main bearings (if for no other reason, ease of reassembly)

Of course while you are there you will want to replace every other bearing(they are not that expensive).
The kicker will be wether or not to replace the piston and ring set, I would. You will also want to have a good look at the valves and seats.

Quite a few people have had good luck removing the balancer, I would just assume keep it unless I had some serious abuse in mind.

Just my 2 cents.

Thanks for the answer. Here comes some other question related to your answers:

Is it only the the cam gear who is needed to be replaced, what about the camchain and the other gear? Which partnumbers does the camrelated stuff have? Which bike and year have the same cam gear I should have?

Do I need to update the whole counterbalancekit if I want the doubleroller or can I just buy the doubleroller bearings? Is it -03 counterbalance I should have?

If I'm going to update the mainbearing should I buy the rollerbearing from the -03 model? Will it fit?

Is it necessary to replace the whole piston or would it be enough to replace the pistonrings?


If someone knows the partnumbers of the parts I need I would be more than happy if you send them.

Howdy,
I offer a seamless solid roller timing chain.

In addition I suggest removing the balance assembly, having the crankshaft assembly re-balanced and the proper installation and fitting of cylindrical main bearings.

I offer such a service and may be reached via [email protected]

Pictures:
Gallery images

i'm going to guess 4stroker is from mainland europe somewhere. just a guess and i'm often wrong!

what is your budget because i think we just describd a new engine didn't we?

go look at 'the doc'. it will give you a great insight into what you can do. husabutt has done a really good peice on the counter balancer.

part numbers are there the lot. do have a look in 'search' as well and scout around old threads. EVERYTHI has been discussed at length and many times here.

good luck

Taffy

How will the caracter of the bike react if I take away the counterbalancer?
I'm planing to drive a little more enduro with my motocross so I don't want to make it more "toprev-acting".

I've heard from another forum one who said the engine will stop (die) more easily if I take away it, is it right?


Whats the difference between your camchain and originalpart?

With the crankshaft properly balanced the removal of the balancer has a field test evaluation of no perceptible difference to smoother character overall as the engine noise is much reduced.

I have no idea how said engine will react with just removal.

My cam chain is solid roller / solid pin.

Many OEM chains are split roller / split pin.

Taffy is correct, do research the DOC.

Hope this helps.

Dale

From the Doc:

Counterbalancer Update for 2001 and early 2002 models

The single bearing counterbalancer was replaced with a double bearing counterbalancer in late 2002. Counterbalancer failures were experienced on some 650's and on a lesser amount of smaller displacement engines. A counterbalancer assembly is available to upgrade to the double bearing version. Included are: Counterbalancer, bearings, circlip and shim. The 2003 counterbalancer cannot be used, as teeth on the counterbalancer sprocket have a different mesh.

470/501/550/650-2001 use update part # 201 257-01

470/501/550/650-2002 use update part # 210 243-01

Complete counterbalancer removal

Since the counterbalancer can be a potential source of engine failure, serious racers sometimes remove the counterbalancer completely to eliminate the hazard. This does result in more vibration at idle and at very low RPM. In place of the counterbalancer a 7.4mm spacer ring should be used. The balancer drive shaft gear teeth can be ground off. Set crankshaft axial freeplay to 0.6mm-0.8mm. Use main bearings SFK NJ2206ECP/C3. The crankshaft can be rebalanced if desired.

Noises from the starter area
The free wheel mechanism (clutch) that was introduced mid 02 is built into the starter reduction gear set which was previously a solid machined gear assembly. It's recommended to fit this to earlier machines to prevent gear/sprague breakage if kick back occurs. As far as the Sprague assembly itself, the large outer gear/hub is the same 01-03, the sprague is the same 01-03, but the inner small gear/hub is different mid 02. Why? The gear teeth pitch was changed mid 02 on the counterbalancer, inner counter balancer drive shaft gear , outer balancer drive shaft gear, primary gear, and outer clutch basket gear. Mix 01 and 03 gears and it's very noisy. The noise usually happens when an 03 counter balancer is installed in an 01. It would have been nice if one could simply change the balancer drive shaft with it's machined-on inner gear to an 03 assembly, but the 01 outer balancer shaft drive gear will not fit the 03 drive shaft. Install the outer 03 balancer drive shaft gear and you also need to change the primary gear. clutch basket, and the inner starter sprague gear. Paranoid types will start thinking 'conspiracy theories' at this point. (Actually they make a special double bearing balancer with the 01 gear pitch.) All this info is because if your 01 hasn't been updated, it can't be the freewheel mechanism that is slipping because you don't have one. Probably the sprague is slipping. They are quite delicate and small amounts of wear on the inner gears hub or the outer gears hub will make the sprague itself slip. Remember that the outer hub is the same 01-03 but the inner is different (DSducati).