Quick question head install

Tony Pierce · Dec 24, 2020

Sorry for such a noob question but I didn’t see a clear answer when I tried to search for it. I am nearing the finish line I think on my commando rebuild, but one of the last big components I am waiting on is to have the heads rebuilt by Mr. Comstock.

i was trying to stall until they arrived to install the entire engine at once, but is it reasonably possible or practical to install the heads after everything else is in place? I know the push rods make it tight, so I don’t want to be seriously cursing myself if I make it very difficult later, but I also want to try and have the bike finished in the next few months because I have a baby due early spring.

thanks!

Fast Eddie · Dec 24, 2020

Different folk have different opinions on this.

Fitting an engine sans head and barrels into the frame is a lot easier.

But my personal preference is to assemble the head and barrels to the motor whilst on the bench. I just find it easier to apply extra care and attention this way.

Perhaps my frame paint is more chipped than some others though...

maylar · Dec 24, 2020

I've replaced head gaskets a few times and never removed the engine from the frame. It's outlined in the workshop manual.

Tony Pierce · Dec 24, 2020

Thanks everyone. I think I’ll probably put heads in last or the bike might not get finished for a while with the baby coming!

marshg246 · Dec 24, 2020

Tony Pierce said:
Sorry for such a noob question but I didn’t see a clear answer when I tried to search for it. I am nearing the finish line I think on my commando rebuild, but one of the last big components I am waiting on is to have the heads rebuilt by Mr. Comstock.

i was trying to stall until they arrived to install the entire engine at once, but is it reasonably possible or practical to install the heads after everything else is in place? I know the push rods make it tight, so I don’t want to be seriously cursing myself if I make it very difficult later, but I also want to try and have the bike finished in the next few months because I have a baby due early spring.

thanks!

Installing the head with the engine in the frame is certainly possible, but if you're old and arthritic like me, you'll want a helper. It's not overly hard with two people. Of course, the whole engine is hard by yourself as well.

I don't do either for complete bike rebuilds - I build the power unit on the bench less the primary, put it on its side (timing side) and put the frame over it. Makes it very easy by yourself.

EstuaryBoy · Dec 24, 2020

As Maylar points out, many will do head repairs/overhauls/gasket replacement with the rest of the motor in situ.
So fitting the head afterwards is no great shakes but pianists fingers (and preferably more than ten) are a great help.... Just be careful with those pushrods

Tony Pierce · Dec 24, 2020

marshg246 said:
Installing the head with the engine in the frame is certainly possible, but if you're old and arthritic like me, you'll want a helper. It's not overly hard with two people. Of course, the whole engine is hard by yourself as well.

I don't do either for complete bike rebuilds - I build the power unit on the bench less the primary, put it on its side (timing side) and put the frame over it. Makes it very easy by yourself.

That would have been the smart way to do it, that didn’t even cross my mind. I’ll ask a friend to help me put on the head. I’m in my 40s but I have arthritis so I know what you mean!

Mark Savage · Dec 25, 2020

Compared to fitting a head in situ on an engine in a Featherbed frame, it's easy.

maylar · Dec 25, 2020

When you put the head back on, here's a trick for holding the rockers up.... rubber bands.

Tornado · Dec 26, 2020

maylar said:
When you put the head back on, here's a trick for holding the rockers up.... rubber bands.

Im about to place newly re built head insitu. For the rubber band trick, do the rods sit off the rockers for max clearance then positioned in rockers after locating head over block? Or keep rods on rockers as possible while placing head in position?

L.A.B. · Dec 26, 2020

Tornado said:
Im about to place newly re built head insitu. For the rubber band trick, do the rods sit off the rockers for max clearance then positioned in rockers after locating head over block? Or keep rods on rockers as possible while placing head in position?

The pushrods still have to be inserted as far into the head as possible before lowering the head into position. The rubber bands keep the rocker balls seated in the pushrod cups until the head can be pulled down (on the #1 bolt).

Al's#5 · Dec 27, 2020

L.A.B. said:
The pushrods still have to be inserted as far into the head as possible before lowering the head into position. The rubber bands keep the rocker balls seated in the pushrod cups until the head can be pulled down (on the #1 bolt).

A smear of vaseline always worked for me, seriously!

baz · Dec 27, 2020

I have always put the pushrods up into the head and held them there with a rubber band woven in and out in a figure of 8 style
I always fit the head with the engine in the frame
Just cut the band and pull it out when the head is almost down ,works for me

maylar · Dec 27, 2020

You can also stuff 2 small rags or blocks of foam rubber into the head to hold the pushrods in place while positioning the head. Tie twine to them first, and once the head is in place pull them out and let the pushrods drop into the cylinders. The rubber bands on the rockers put enough tension on them to allow you to fish around with a skinny screw driver and get the pushrod cups onto the rockers without losing them. Otherwise, you get one rod in place and while fiddling with the head to get the others in, one will fall out.

If the pistons are down a bit from TDC, 3 of the 4 valves should be closed which makes pulling the head down with bolt #1 a bit easier.

seattle##gs · Dec 29, 2020

A word about pushrods....they don't fall into place on the lifters every time. Perhaps 85% of the time yes but be very observant. If something doesn't seem right have a friend pick up the head while you try lifting them up again and let them fall back into place.

Onder · Dec 29, 2020

I go for the engine build up on the bench. I feel that I can make sure there are no disasters this way. Then I
put the bike on its side, timing side down, on a big pile of old rugs and engine, sans primary, is placed down and
weaseled in.
There is so little room to slide the head on with the cases in. However, if you don't have the engine out you have to
go the head installed in the frame route.

Torontonian · Dec 29, 2020

Al's#5 said:
A smear of vaseline always worked for me, seriously!

Why not. I use it for pushrod cups and the elastic bands to stay located before center bolt tightening down. It's a petroleum product so don't much agree with smearing it on human bodies , Vick's Vapo-rub too.
Wear your work plastic gloves at all times except road emergencies. Cancers and Covid sucks.

Al's#5 · Dec 30, 2020

Torontonian said:
Why not. I use it for pushrod cups and the elastic bands to stay located before center bolt tightening down. It's a petroleum product so don't much agree with smearing it on human bodies , Vick's Vapo-rub too.
Wear your work plastic gloves at all times except road emergencies. Cancers and Covid sucks.

That's another pet hate of mine, gloves when working, especially with engines etc. These days everyone has those condomesque gloves on, really necessary? There are exceptions of course, sharp or hot metal handling, corrosive liquid, white metal bearing scrape etc. That said I always used barrier cream, probably saved my hands.

marshg246 · Dec 30, 2020

Al's#5 said:
That's another pet hate of mine, gloves when working, especially with engines etc. These days everyone has those condomesque gloves on, really necessary? There are exceptions of course, sharp or hot metal handling, corrosive liquid, white metal bearing scrape etc. That said I always used barrier cream, probably saved my hands.

I agree! I don't use a barrier cream but do use "Tub O Towels" or "Grime Boss" to clean my hands. The skin on my hands is much better that before I started using them. No matter how much grease or grime, the towels get it all off and actually help my skin. I know of no hand cleaner that can say that.

batrider · Dec 30, 2020

It isn't hard to remove/replace the head while in the frame but there is a trick to it. With the pushrods stuck all the way in past the rockers, instead of pulling the head straight up, you use a rolling motion, and rotate the head so it ends up behind the cylinder barrel. To replace, slide the head in sideways behind the cylinder and roll it forward. I use pieces of wood to hold the head up while positioning the pushrods to save the fingers.
For years I never knew exactly how I did it. The head would magically come off after enough futzing around. I finally took the time to figure it out. But I'll probably forget how I did it for next time. Don't forget to retorque the head. I did it at 5, 50, 200, 500, and 1000 miles.

Quick question head install

Tony Pierce

Fast Eddie

maylar

Tony Pierce

marshg246

EstuaryBoy

Tony Pierce

Mark Savage

maylar

Tornado

L.A.B.

Moderator

Al's#5

baz

maylar

seattle##gs

Onder

Torontonian

Al's#5

marshg246

batrider

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