TOPIC:

Hello everyone here,
Since I'm new here, lets start of with some backstory.

In march this year my uncle lent me his second bike to ride, since I did not have one myself. It was his 2nd bike which he did not drive anymore, a Nordwest 600. It had been sitting for a while and had some issues starting, but it was a fun bike to ride.
Long story short, after about 300 KM of fun the engine "blew up" on me, after removing the head it was very clear, a dropped valve. The valve broke clean of the stem and ruined the cylinder, piston and the head itself.

After some long consideration and talks with my dad and uncle I have decided to try and rebuild the engine. I already bought a new head with valve from ebay in decent condition, no alarming wear marks or signs of oil starvation.
This week my order from Bob Wright will arive, along with some other order for loose parts.
As of today the parts I have ordered for this top end rebuild are:

• Cylinder head
• Cylinder, piston and rings
• Iridium spark plug
• air filter - paper type
• Full gasket set+exhaust gaskets
• Bearings + seal for the water pump
• Cam belt
• Starter clutch (KTM part)

The rest of the engine all looked/felt/measured to be good to go so I hope that with the (expensive) list of of parts the new year will treat me with a fully functioning Nordwest again.

Do you guys have any tips/pointers for things I should do and look out for? I do have experience with rebuilding 2 strokes and an XTZ660, so I hope this will help me with rebuilding the Nordwest.

If you have rebuilt an XT660 you will find this similar apart from having twin cams and a different tappit clearance adjustment, if you look to the left of the screen you you will see "handbooks and manuals" for a free download.
Most probably if you had looked here before riding the bike you would have seen the the advice to change the cam belt for any bike that has been standing this, the standard advice before starting the engine, and if you don't ride it regularly start it for a short time and replace every 2 years.
On your shopping list you will need to add a rotor puller to change the belt.
Enjoy
john

Aye, cam-belt before breakfast every time.

Tough way to learn the hidden internal delights of the dohc motor but if you can get the parts and the rotor puller (available from Bob - or make your own, I think Kano has a drawing) then it's all in the manual elsewhere on here as John states. Also watch how you go with the water pump - plenty info on Rapidmouse (with Googletranslate) and on the Gilera Bi-4 groups in Italy.

And upload plenty photos of the rebuild....

Phil

My order from Bob Wright arrived today, new piston and cylinder in excellent condition, so I am a very happy man



Thanks for the replies Phill and John, I already have the correct rotor puller. The story behind this is quite stupid on my part.

When I just got the bike from my uncle I drove it to my home town and drove around a bit for a week or 2, then one morning during a starting attempt the belt broke, so I was already worried that I ruined everything. So I ordered a new belt and puller from bob, mounted it, triple checked if my timing was correct and did a compression test, because I was almost certain that I must have bent a valve. But the compression test came back fine, so I went ahead and started the bike again. Al was fine, the power felt good with what I remembered and after about 150 km the engine stopped and I was stuck on the side of a motorway.
The result was this:



But the belt was still in one piece.
So my current theory as to what happened is the intake valve got smacked but not bend when my belt broke, and finally gave out when the engine was on operating temperature for a while. Or my valve clearance was too tight on this valve, and because of the expansion of the stem the valve made contact with the piston and broke.

Planning now is in the first week of the new year I will put the engine back together and get it running again. If that al works out I need to replace the fork seals, brake pads, sprockets and chain.

Holy shit, that's a mess.....
Anyway, the good thing is you've got all the bits to make it good...and Bob had the parts which is awesome.
Fork seals are a bugger to do but by the time you've rebuilt that motor they'll seem like a walk in the park.
Good luck and keep it rolling.
P

Hope you have a heated garage so you can keep busy over Christmas.
When yo do the fork seal rebuild just remember there is only one fork spring, don't make the mistake of dropping out the front wheel thinking you can stand the bike up on the forks, I have always put a flat rope under the bars and suspended the bike from an engine crane or a bike stand under the engine, just make sure its not going to fall over I also found seals to fit in the AllBalls catalogue.
John