TOPIC:

Tiagus wrote:

ok if you use the same piston that is there. which use piston ring is measured?

And water pump rebuilt or not?

Depends on how worn the piston is. The workshop manual gives all the overhaul data. Start at page 58 of this PDF:
www.gilera.org.uk/Joomla/images/Docs/nor...orkshop%20manual.pdf

Piston/cylinder clearance 0.032 - 0.042 mm

Check for any 'step' in the bore at the upper limit of the ring travel.

Piston ring gaps:
1st and 2nd Ring 0.40 - 0.65
axial clearance .035 - .072

Scraper ring 0.035 - 0.072
axial clearance 0.025 - 0.062

I've never tried rebuilding the water pump. If it works don't fix it? This youtube link may help though:

72degrees wrote:

Tiagus wrote:

ok if you use the same piston that is there. which use piston ring is measured?

And water pump rebuilt or not?

Depends on how worn the piston is. The workshop manual gives all the overhaul data. Start at page 58 of this PDF:
www.gilera.org.uk/Joomla/images/Docs/nor...orkshop%20manual.pdf

Piston/cylinder clearance 0.032 - 0.042 mm

Check for any 'step' in the bore at the upper limit of the ring travel.

Piston ring gaps:
1st and 2nd Ring 0.40 - 0.65
axial clearance .035 - .072

Scraper ring 0.035 - 0.072
axial clearance 0.025 - 0.062

I've never tried rebuilding the water pump. If it works don't fix it? This youtube link may help though:

Yes I saw in youtube. The clearance is difficult to see.

The time belt broke and the 2 valves bent

Tiagus
You have work to do, we all keep saying change the belt
Good luck
John

uhhhhh.....
The belt *was* broken? Or *you* have broken it? I have to agree Johns speach above

Also the water pump housing and the cylinder lokk destroyed. Cylinder would not be a problem, but there is nobody out there who will sell his spare water pump. Not for any money. They all know....
Rebuilding a water pump is allways based on a housing (except the new water pumps of the italian 4stroke forum, but i don't know if this is still available)

I think you should not only replace the valves, but also check the guides and seats.
Beside this your piston may crack sometimes due to the punch he got.
Money, money, money.....
Maybe it would be the better choice to look after a well used motor.

Joachim

Joachim wrote:

Maybe it would be the better choice to look after a well used motor.

Joachim

Or at least a good second hand head ready with valves assembled. I sold one on Ebay a couple of years ago.

I guess Nordwests aren't that common in Portugal or I'd suggest trying to find another complete bike if necessary. Break it for the best parts and make one good bike from the two then sell the rest on Ebay.

I hadn't realised that new or good used water pumps were like hen's teeth (old English expression)

We need a friendly contact in a small aluminium foundry. I guess the bodies are diecast? Before I retired I might have been able to find somewhere.