75 850t Cylinder

[Scout63]

I have found a washer under the hidden nut. The parts fiche shows it as a spring washer, part no. 16 here. I have to fish it out with a skinny magnet.





I really like this thread. Nice work so far 850brian. You are hitting all of the same issues and asking the same questions that we (or at least I) did our first time pulling apart the top end.

[Moparnut72]

Get the piston good and hot with a heat gun. I use a socket that will just fit in the hole on an extension so you don't burn yourself and push the pin out. I do my old Mercury outboard piston pins this way.
kk

[850brian]

Get the piston good and hot with a heat gun. I use a socket that will just fit in the hole on an extension so you don't burn yourself and push the pin out. I do my old Mercury outboard piston pins this way.
kk

I appreciate the info. I will try it with a hairdryer and if I don't get any luck with that I will grab a heat gun! New cylinder kit and gaskets should get here in a few days. I will post an update then!

[Moparnut72]

Get a heat gun they come in handy for a lot of things. I use mine for all kinds of things. They are pretty cheap, Harbor Freight has a decent one for very few dollars. I am not a fan of sending more money to China but sometimes.......... ....  In the airplane shop we went through them like water, we got a Makita which was still working when I left.
kk

[850brian]

Get a heat gun they come in handy for a lot of things. I use mine for all kinds of things. They are pretty cheap, Harbor Freight has a decent one for very few dollars. I am not a fan of sending more money to China but sometimes.......... ....  In the airplane shop we went through them like water, we got a Makita which was still working when I left.
kk

There have been plenty of times I wished I had one and didn't so I guess it would be a good time to check them out.

[n3303j]

https://www.masterappliance.com/products/heat-guns/master-heat-guns/?utm_source=google&utm_medium=cpc&gad_source=1&gclid=CjwKCAiA0syqBhBxEiwAeNx9NzoZaBHqQT2acSR8LVuhNgdHtTTAY44O5yTWfkoGjPr56SLgmnffuBoCY78QAvD_BwE
Don't have to send the money to China.

[850brian]

https://www.masterappliance.com/products/heat-guns/master-heat-guns/?utm_source=google&utm_medium=cpc&gad_source=1&gclid=CjwKCAiA0syqBhBxEiwAeNx9NzoZaBHqQT2acSR8LVuhNgdHtTTAY44O5yTWfkoGjPr56SLgmnffuBoCY78QAvD_BwE
Don't have to send the money to China.

That's what i like to hear!

[Don G]

While your there and have the base gaskets off, pull out the lifters one at a time and inspect their faces for pitting or dishing, replace back in their original positions if found OK. Wouldn't hurt to apply some assembly lube to prevent damage from dry start up.  DonG

[John A]

Here’s a tip on heat, I got it out of an old Dodge manual. It was for judging automatic transmission oil temp. If you can touch it and leave your fingers in contact, it is 180F or less. If you have to take your hand off it right away, it is more than 180F. It’s gone by the wayside with the advent of cheap infrared temp guns but it’s fairly accurate with exceptions for welders. I’d heat the piston to around 180 and try it.

[850brian]

Here’s a tip on heat, I got it out of an old Dodge manual. It was for judging automatic transmission oil temp. If you can touch it and leave your fingers in contact, it is 180F or less. If you have to take your hand off it right away, it is more than 180F. It’s gone by the wayside with the advent of cheap infrared temp guns but it’s fairly accurate with exceptions for welders. I’d heat the piston to around 180 and try it.

Awesome thank you.

[850brian]

New cylinders have arrived anything important to note on the install or is it pretty much just the reverse of the uninstall?

[jrt]

Great thread- I love hearing all these tips.  I've been through a couple motors, but I always learn something new.

Brian- when you push the gudgeon pins out, back the pistons up against something (wood, a rubberhandled pliers) so they don't side-load the main bearings. 

And what did the cylinders look like?  I saw the pictures, but it is hard to tell.  They looked fine to me.  Are they magnetic?

[850brian]

Great thread- I love hearing all these tips.  I've been through a couple motors, but I always learn something new.

Brian- when you push the gudgeon pins out, back the pistons up against something (wood, a rubberhandled pliers) so they don't side-load the main bearings. 

And what did the cylinders look like?  I saw the pictures, but it is hard to tell.  They looked fine to me.  Are they magnetic?

They looked fine to me; however, they were not magnetic at all.

[850brian]

Got one side put back together. How much should I tighten these nuts?

[jrt]

The locknut?  I've never torqued them.  They just need to be 'tight enough' to keep the adjuster from moving.  Maybe...1/4 turn after they seat? Probably less than that.  I use a small 11mm box end in my palm  so I can't put too much stress on it. 

[guzzisteve]

I see the rocker pin bolt on the bridge, it is 10mm head and very light torque 4ft lbs, it will strip. Just holds the pin still in place.

[850brian]

Update: got both cylinders replaced without a hitch until I broke off the head of the valve cover oil banjo bolt.... and now we wait. So close, yet so far.

[Tom H]

Years ago I did that. I used a drill press and made my own bolt. Could be done with a hand drill, you just have to go very straight.

Tom

[850brian]

Years ago I did that. I used a drill press and made my own bolt. Could be done with a hand drill, you just have to go very straight.

Tom

Interesting! I guess I should have tried my hand at that first.

[850brian]

Got it all back together and am about to start it up. Any recommendations on breaking in the new cylinders?

[jrt]

Ha!  Now you've opened Pandora's box.  Breaking in a motor is like an oil thread....
My (not a mechanic) opinion is keep the revs below 5k or so, vary motor speed and put the engine under load several times to bed in the rings.  I don't remember how many heat cycles (one or two or three), then loosen and retorque the heads.

[Don G]

Ride it like its stolen, on and off the throttle in an intermediate gear.  Watch a cycle Garden video of Moe showcasing a rebuilt bike, he rides it like its supposed to be ridden, 3 or 4 thrashes like that, if it don't break, its good to go.  DonG

[Antietam Classic Cycle]

Ride it like its stolen, on and off the throttle in an intermediate gear.  Watch a cycle Garden video of Moe showcasing a rebuilt bike, he rides it like its supposed to be ridden, 3 or 4 thrashes like that, if it don't break, its good to go.  DonG

But, Moe isn't breaking in Nikasil cylinders...

My own preference (right or wrong, but works every time) is to ride it fairly normally on my 18 mile "secret test loop" through the Frederick County, Maryland countryside. Varying throttle and load. There is one long, steep grade and I ride up that a gear higher than normal with lots of throttle to "load" the rings and help them break in more quickly.

Regarding head nut retorquing: I assemble the engine except for the rockers, let it sit overnight. Next day, retorque the head nuts, install the rockers and set the valves. You'd be surprised how much the gaskets have already compressed. Start it and run approx. 20 mins. with a fan blowing on it, while I twiddle the carbs and adjust the timing if needed. Let it cool completely back to ambient temp. Retorque the nuts and set the valves. 5 complete heat/cool cycles - do it again. 500 miles - do it again.

[Gliderjohn]

The original Wichita area Guzzi dealer did my T-3 with those jugs, etc. Anyway he recommended about 500 miles of varying the rpm and every so often take it to high rpm, just don't keep it there, just up and down. So city riding, hilly and curvy roads that entice you to not keep a steady throttle. Around 35,000+ miles since overhaul. Runs great and maybe uses a tablespoon of oil between changes.

[850brian]

Well went to ho start her up and it's only running on the right cylinder. I have spark on both plugs. Confusing.