Cylinder Head Removal / Install

click · Jul 30, 2012

Hi Lads,

If you've been reading my riveting exploits about replacing valve stem/guide seals this is part two!!

I got the head off today, used the cable tie trick and found it really tight getting the head off, had to tilt forward and to the left, can't imagine putting the head on in the same manner! I'm hoping I can push the pushrods up higher in the head when I'm installing.

I got the washer out!!! It was stuck between the two cam follower cups, no chance of hooking it out!

Question 1: Does anybody know how to tell the difference between the Norvil & RGM 920 conversion? Are there any markings on the piston which would be the give away?

Question 2: The reason for question 1 relates to the head gasket. Are all 920 head gaskets the same or do you need to match the head gasket with the make/type of conversion installed?

I'll put a few pics up later.

Hobot · Jul 30, 2012

Re: Cylinder Hear Removal / Install

Its always a real pain in the neck to me to deal with push rods clearance when inside the frame. Only solution I've come up with is grind the end of rocker arms down till push rods clear them first time every time and plenty of clearance to tip head on/off in/out of frame. Ends of rockers are where the mass most effects the rpm tolerance and wear. Tough luck inf not reading my posts on this prior to putting the rocker spindles back in, oh well suffer the push rod puzzle like a prisoner not let go till a riddle solved. Resealing copper gaskets on big blocks is common reason to open back up w/o any mechanical damage reason. Consider real cotton or silk or dental floss thread around the push rod tunnels.

Same gaskets should work on all 920's. Jim Schimdt has these in several thicknesses. One version is just thin rings around the bores and floss around
the tunnels. JSMotorsports in search line.

L.A.B. · Jul 30, 2012

Re: Cylinder Hear Removal / Install

click said:
Does anybody know how to tell the difference between the Norvil & RGM 920 conversion? Are there any markings on the piston which would be the give away?

I believe the Norvil 920 kit still uses modified Cosworth (Hepolite?) pistons with 13/16" gudgeon pins, the current RGM 920 kit has custom-made (GPM?) pistons with standard size gudgeon pins, however the early RGM 920 kits also used the same pistons and 13/16" pins as the Norvil kit. :?

http://www.norvilmotorcycle.co.uk/cylpiston.htm#piston

069211 - PISTON - 920 STD SIZE - NO CUTOUT - 13/16PINS-

http://rgmmotors.co.uk/home.htm

050163 920 PISTONS, STD AND +20. COMPLETE WITH RINGS, CIRCLIPS AND STD SIZE GUDGEON PINS. IDENTICAL WEIGHT TO 850 PISTONS

click · Jul 30, 2012

Re: Cylinder Hear Removal / Install

hobot said:
Its always a real pain in the neck to me to deal with push rods clearance when inside the frame. Only solution I've come up with is grind the end of rocker arms down till push rods clear them first time every time and plenty of clearance to tip head on/off in/out of frame. Ends of rockers are where the mass most effects the rpm tolerance and wear. Tough luck inf not reading my posts on this prior to putting the rocker spindles back in, oh well suffer the push rod puzzle like a prisoner not let go till a riddle solved. Resealing copper gaskets on big blocks is common reason to open back up w/o any mechanical damage reason. Consider real cotton or silk or dental floss thread around the push rod tunnels.

Same gaskets should work on all 920's. Jim Schimdt has these in several thicknesses. One version is just thin rings around the bores and floss around
the tunnels. JSMotorsports in search line.

Hi Hotbot,

Thanks for the info. Serious slimming of the rocker arms :shock: I have not done anything to the head yet. Once I have everything sorted I'll try a few dry fits just to see how difficult the Commando head hustle is!!

Interesting pic of rockers and arrows, are the arrows to shoot yourself in the head from the frustration of fitting the head :mrgreen:

Kevin

click · Jul 30, 2012

Re: Cylinder Hear Removal / Install

L.A.B. said:
click said:

Does anybody know how to tell the difference between the Norvil & RGM 920 conversion? Are there any markings on the piston which would be the give away?

Click to expand...

I believe the Norvil 920 kit still uses modified Cosworth (Hepolite?) pistons with 13/16" gudgeon pins, the current RGM 920 kit has custom-made (GPM?) pistons with standard size gudgeon pins, however the early RGM 920 kits also used the same pistons and 13/16" pins as the Norvil kit. :?

http://www.norvilmotorcycle.co.uk/cylpiston.htm#piston

069211 - PISTON - 920 STD SIZE - NO CUTOUT - 13/16PINS-

Click to expand...

http://rgmmotors.co.uk/home.htm

050163 920 PISTONS, STD AND +20. COMPLETE WITH RINGS, CIRCLIPS AND STD SIZE GUDGEON PINS. IDENTICAL WEIGHT TO 850 PISTONS

Click to expand...

Hi L.A.B.,

Thanks for the links/info.

The kit was installed at least 6 years ago. Sounds like any 920 gasket will do. The gasket currently on the bike seems very thin. I'll post a few pics later.

Kevin

click · Jul 30, 2012

Some pics and more questions:

Question 1: The cylinder head gasket seems to be composite, I thought all 920 gaskets were copper?

Question 2: If you look at some of the pics of the gasket on the barrells and in my hand you will see circular indents were the recess for the barrell bolts are located, these seem quite deep + one of them is fairly soaked in oil, is this normal? can it cause any problems?

Question 3: Any idea were I can get the same type of gasket?

Question 4: I plan on using a plastic scraper to clean the top of the pistons, anybody see a problem with this? (I'll ensure no crud goes down any holes)

The right hand side is the one that had oil leaking into the cylinder from the inlet seal coming off.

The two pics above show the indents I mentioned you can see one of them is oil soaked. You can also see it's not a copper gasket

DogT · Jul 30, 2012

I never had any problems just stuffing the rods up in the head by the side of the rockers, without any grinding. I held them up there with rubber bands, but maybe a stock 750 is different.

Dave
69S

click · Jul 30, 2012

DogT said:
I never had any problems just stuffing the rods up in the head by the side of the rockers, without any grinding. I held them up there with rubber bands, but maybe a stock 750 is different.

Dave
69S

Hi Dave,

Thanks for the reply. I'm sure when I'm refitting the head I can do a better job of pushing the pushrods up into the head. This was my first time removing the head which was balanced on a piece of wood while I was trying to hold & push the rods up while trying to put a cable tie around the rods to hold them in place. An extra hand or two would be useful, any genetic engineers on this forum :mrgreen:

I don't plan on giving my rockers a crash diet!

Kevin

DogT · Jul 30, 2012

If you fiddle with them, you can really get the rods way up there. Yes, use blocks of wood to hold things up while messing. Rags can help too. I think I had mine on and off about 5 times until I was ready to finish it. I really didn't have any problems, towards the end, it was a matter of a minute or so. I would have put the engine in in one piece but I was working by my self too. Much easier to put it in by the pieces. Be careful when you go to tighten it down, make sure the rods are in their sockets, keep the spark plugs out and turn it over easy while tightening the 4 bolts by the plugs until you are ready to put them all in.

Dave
69S

click · Jul 30, 2012

DogT said:
If you fiddle with them, you can really get the rods way up there. Yes, use blocks of wood to hold things up while messing. Rags can help too. I think I had mine on and off about 5 times until I was ready to finish it. I really didn't have any problems, towards the end, it was a matter of a minute or so. I would have put the engine in in one piece but I was working by my self too. Much easier to put it in by the pieces. Be careful when you go to tighten it down, make sure the rods are in their sockets, keep the spark plugs out and turn it over easy while tightening the 4 bolts by the plugs until you are ready to put them all in.

Dave
69S

Hi Dave,

Good advice.

Many Thanks

Kevin

Hobot · Jul 30, 2012

I am a fumble bum with sort patience while bending neck in tension holding oily things that could use a 4th hand. I suspend head on zip ties or bungee hooked over the oil feed banjos screwed back in lightly so nothing in the way of the push rod fumble puzzle. Some must be tighter clearance than others and I"ve had it work easy first time too but more often not. Its only the very ends of the rockers that foul the push rods so don't need to risk exposing oil ways grinding down to blades.
If I carry a weapon around here is mainly to use on myself it downed and disabled by hitting a wild bore, I'd rather die by bullet in brain than guts strung out over the wreckage. I don't think I could carry big enoughcaliber big enough to stop a mad momma hog before she did me in. I have thought of shooting my Command while dealing with push rods. I told Brit Iron list I used rubber bands over the head to seat rockers back in '99, curious if anyone heard of it prior.

Cleaning the pistons usually mean scrapping and chipping avoiding marring the crowns, often plastic just don't get it. I'd be tempted to use a propane torch to turn the carbon to grey dust to wipe off after is stops glowing red oxidizing away to just leave mineral ashes. Its worth while to try to polish crowns and round off edges of valve cut outs. Just don't leave sand paper grit or loose wire.

I had bad experiences with the foil wrapped type composite gasket which may of added to your oil burning. Don't know where to get one, might try the older more famous UK vendors and Maney as RGM and N. America vendors all only seem to offer copper. Ludwig has shown inserts to make the barrel counter sinks flush with surface. If was me and likely will be on 920 Peel. I'd put anti-seize in the bottom and pour hi temp JBW in and razor off flush with surface. To remove likely just pick out, if not could chip out as it ain't going to be adhering molded texture fit. I"ve fixed gas jet grooves into push rod tunnels this way and got a few head removals d/t gasket failures use out of it before too soft so replaced again.

click · Jul 30, 2012

hobot said:
I am a fumble bum with sort patience while bending neck in tension holding oily things that could use a 4th hand. I suspend head on zip ties or bungee hooked over the oil feed banjos screwed back in lightly so nothing in the way of the push rod fumble puzzle. Some must be tighter clearance than others and I"ve had it work easy first time too but more often not. Its only the very ends of the rockers that foul the push rods so don't need to risk exposing oil ways grinding down to blades.
If I carry a weapon around here is mainly to use on myself it downed and disabled by hitting a wild bore, I'd rather die by bullet in brain than guts strung out over the wreckage. I don't think I could carry big enoughcaliber big enough to stop a mad momma hog before she did me in. I have thought of shooting my Command while dealing with push rods. I told Brit Iron list I used rubber bands over the head to seat rockers back in '99, curious if anyone heard of it prior.

Cleaning the pistons usually mean scrapping and chipping avoiding marring the crowns, often plastic just don't get it. I'd be tempted to use a propane torch to turn the carbon to grey dust to wipe off after is stops glowing red oxidizing away to just leave mineral ashes. Its worth while to try to polish crowns and round off edges of valve cut outs. Just don't leave sand paper grit or loose wire.

I had bad experiences with the foil wrapped type composite gasket which may of added to your oil burning. Don't know where to get one, might try the older more famous UK vendors and Maney as RGM and N. America vendors all only seem to offer copper. Ludwig has shown inserts to make the barrel counter sinks flush with surface. If was me and likely will be on 920 Peel. I'd put anti-seize in the bottom and pour hi temp JBW in and razor off flush with surface. To remove likely just pick out, if not could chip out as it ain't going to be adhering molded texture fit. I"ve fixed gas jet grooves into push rod tunnels this way and got a few head removals d/t gasket failures use out of it before too soft so replaced again.

Hi Hotbot,

Some great info. in your post. I like the idea of suspending the head from the bango bolts, very clever.

I'll take my time removing the carbon deposits!

Thanks

Kevin

Hobot · Jul 30, 2012

A Hobbit is a fictional population of dwarf like people while hobot is actual robotic hobo.
Here's where to grind for push rod eae, but alas I measured wrong and didn't take enough off the very ends so didn't solve push rod ease like on Peel blade rockers. There is little to risk taken meat off right to near edge of the ball end. Photo came in a trade but wife insists it stays out in shed, which fine with me.

Suspended by banjo bolts ties over the spine makes single handed install a lot less labor tedious. Bands over head holding rocker on placed push rods usually eliminates having to do one more than once. Do consider non melting non synthetic thread back up sealing enforcement. Don't miss an opportunity to re-torque like next 1000 miles, or suffer like me after just a few re-torques that seemed to be enough till a few 1000 miles later blew oil out til opened resealed again. I got talked out of the tedium of thread by my bud Wes in the heat of the install, now both his head and mine tend to blow some oil out after good rides to only 80's mph but WOT to get there.

pete.v · Jul 30, 2012

hobot said:

Who's the guy in the picture.

Hobot · Jul 30, 2012

ugh, pvisseriii, wife got to see your flash back and agree's with your comment, so to keep peace i must also...

DogT · Jul 30, 2012

As I remember in Hemmings DVD he used 'ScotchBrite' to remove carbon on pistons. But what do I know. Not much. I do know the carb/throttle cleaners sort of dissolve it but it still needs rubbing.

Dave

bwolfie · Jul 30, 2012

I have found a dab of sticky grease works well to hold the push rods on the rockers. It hydro locks them on. It has worked well for me many times.

click · Jul 31, 2012

DogT said:
As I remember in Hemmings DVD he used 'ScotchBrite' to remove carbon on pistons. But what do I know. Not much. I do know the carb/throttle cleaners sort of dissolve it but it still needs rubbing.

Dave

Hi Dave,

I'm going to use some carb cleaner and let it sit for a while & see what it does. Once again thanks for the helpful info.

Kevin

click · Jul 31, 2012

bwolfie said:
I have found a dab of sticky grease works well to hold the push rods on the rockers. It hydro locks them on. It has worked well for me many times.

Another good tip, many thanks.

Kevin

click · Jul 31, 2012

hobot said:
A Hobbit is a fictional population of dwarf like people while hobot is actual robotic hobo.
Here's where to grind for push rod eae, but alas I measured wrong and didn't take enough off the very ends so didn't solve push rod ease like on Peel blade rockers. There is little to risk taken meat off right to near edge of the ball end. Photo came in a trade but wife insists it stays out in shed, which fine with me.

Suspended by banjo bolts ties over the spine makes single handed install a lot less labor tedious. Bands over head holding rocker on placed push rods usually eliminates having to do one more than once. Do consider non melting non synthetic thread back up sealing enforcement. Don't miss an opportunity to re-torque like next 1000 miles, or suffer like me after just a few re-torques that seemed to be enough till a few 1000 miles later blew oil out til opened resealed again. I got talked out of the tedium of thread by my bud Wes in the heat of the install, now both his head and mine tend to blow some oil out after good rides to only 80's mph but WOT to get there.

Hi Hotbot,

Brings a new meaning to 'buns of steel'

I see were your going with the removal of some material from the rockers, I found I could get one pushrod all the way up to the roof of the rocker box but the other one was about an inch away due to the tight space between the rocker arm and the rods. I see how your solution could work. I'd be too nervious doing something like this, I think robotic hobo's have skills I don't have

One pushrod is longer than the other, when I'm installing the head I'll ensure the longer rod is up as high as possible and the shorter one is the one that can't go up into the head quite as much, they might just even out. I can do all this in the comfort of my bench and then cable tie them in place, that's the theory anyway, time will tell . . . .

Thanks also Hotbot about the re-torqueing tips.

It will be a little while before I install the head, I want to get some work done on it + I have plans on modding a 2nd head if I can get my hands on a decent one (don't trust Ebay for stuff like this so I have a few feelers out and I'm waiting for replies, fingers crossed)

More Anon

Kevin

Cylinder Head Removal / Install

click

Hobot

L.A.B.

Moderator

click

click

click

DogT

click

DogT

click

Hobot

click

Hobot

pete.v

Hobot

DogT

bwolfie

click

click

click

Similar threads