Non GS help needed, Honda CH125 motor

[Matchless]

Hi,
I need some help or advice on a Honda CH125 1984 (Elite or Spacy) scooter with a watercooled motor.
I do not want to join a scooter forum just for this issue and I am sure someone here will be able to advise me. Thanks in advance.

The above scooter started to leak coolant due to overflowing of the reservoir and I found bubbling when running. I pulled the head and found the head gasket was leaking to the water jacket. The gasket was made of a solid bit of aluminum and someone had reused it and sealed it with copper sealant.

On closer inspection I found that the inner steel liner or sleeve protrudes slightly above the outer aluminum of the cylinder flat gasket surface.

The question is: Is this correct or should it be level?

Your thoughts will be appreciated.

[Suzuki_Don]

Hi,
I need some help or advice on a Honda CH125 1984 (Elite or Spacy) scooter with a watercooled motor.
I do not want to join a scooter forum just for this issue and I am sure someone here will be able to advise me. Thanks in advance.

The above scooter started to leak coolant due to overflowing of the reservoir and I found bubbling when running. I pulled the head and found the head gasket was leaking to the water jacket. The gasket was made of a solid bit of aluminum and someone had reused it and sealed it with copper sealant.

On closer inspection I found that the inner steel liner or sleeve protrudes slightly above the outer aluminum of the cylinder flat gasket surface.

The question is: Is this correct or should it be level?

Your thoughts will be appreciated.

No scooter fans out there Andre. I reckon your hardest task is going to be obtaining a new head gasket for it. You can make a base gasket yourself. No problems there. I did for my engine build and it's running fine after 2k miles.

[1_v8_merc]

Biggest mistake I ever made was rolling a Honda in my garage.
It ran great when it ran, but wrenching on it was a nightmare.

Everytime I wrench on my Suzuki, I'm like "wow it's like they read my mind on using a common sense design"

[Matchless]

No scooter fans out there Andre. I reckon your hardest task is going to be obtaining a new head gasket for it. You can make a base gasket yourself. No problems there. I did for my engine build and it's running fine after 2k miles.

You are right Don, I bought a top set on ebay and just got a mail that the money has been refunded due to problems with the supplier.
Over here they are just given as "Discontinued"
Now to find another supplier that will ship here at a reasonable cost.

[Matchless]

Biggest mistake I ever made was rolling a Honda in my garage.
It ran great when it ran, but wrenching on it was a nightmare.

Everytime I wrench on my Suzuki, I'm like "wow it's like they read my mind on using a common sense design"

Funny that you should mention it, but the same thought crossed my mind when I was working on it. They have a "different" way of approaching things for sure! Weird 8mm head bolts, complex cover fastening method. On this one you have to remove the motor for just about any work on it. Remind me of the CBX that requires the motor to be dropped forward to remove the carbs!

[Suzuki_Don]

You are right Don, I bought a top set on ebay and just got a mail that the money has been refunded due to problems with the supplier.
Over here they are just given as "Discontinued"
Now to find another supplier that will ship here at a reasonable cost.

Freight/postage from the U.S. is ridiculous. Try England, or maybe Europe if you can get a top end gasket set at the right price. Freight is much more reasonable.

[gustovh]

Could be that your cylinder should push just a bit past the body, had a motor that was obsolete and had a solid coper head gasket made for it because I couldn't find a stock one. That was 4 years ago and still holding compression.

Good luck
V

[Matchless]

Could be that your cylinder should push just a bit past the body, had a motor that was obsolete and had a solid coper head gasket made for it because I couldn't find a stock one. That was 4 years ago and still holding compression.

Good luck
V

Thanks for the feedback.
I have spent the whole morning trying to find anyone else that ships to South Africa. I am awaiting some replies to my mails.
Maybe I should start looking at having a gasket made somewhere over here in solid copper or aluminum - just not sure if anyone here does that sort of thing, but its a good tip. Thanks

[rustybronco]

Andre, I think making a gasket out of copper is an excellent idea! if not there's always a plan 'B' or 'C'.

is the CH150 head gasket still available? what is the difference between the two bore sizes and can it be used in place of the CH125's gasket

http://cgi.ebay.com/ebaymotors/_W0QQcmdZViewItemQQ_trksidZp3984Q2em1423Q2el2649QQitemZ180638417563QQsspagenameZSTRKQ3aMEWAXQ3aIT

[Matchless]

Andre, I think making a gasket out of copper is an excellent idea! if not there's always a plan 'B' or 'C'.

is the CH150 head gasket still available? what is the difference between the two bore sizes and can it be used in place of the CH125's gasket

http://cgi.ebay.com/ebaymotors/_W0QQ...KQ3aMEWAXQ3aIT

According to the manuals 56.5 and 58 mm. I have already arranged to get a solid copper one made. It will be a bit costly, but it seems that beggars cant be choosers. As I have just had one reply from about 6 to USA dealers emails saying "we do not ship to Africa". The other UK ebay add has not even had a reply to "ask the seller a question"

Do you think the slight protrusion will still be good with a solid copper gasket?

[rustybronco]

Do you think the slight protrusion will still be good with a solid copper gasket?

Without seen the old gasket and associated components it's hard to say. personally, I would torque down the new gasket, remove the head once more and have a look at the witness marks. then I would decide if re-torquing the head or adding a sealant like three bond to the outer edges would be in order.

what I'm saying is, it would depend on how soft was the copper used to make the head gasket.

[GregT]

Unless there's a matching recess around the combustion chamber in the head, I'd think the top of the barrel should be flat. Never seen a watercooled cylinder with a stepped joint.
It's not unknown for these small watercooled cylinders to have either the liner "creep" up - especially if it's seized at some point, or the cast waterjacket compress slightly due to heat and often overtightening of studs.
If it does have to be machined flat it's not a major job - any small machine shop can do it.

[Matchless]

Unless there's a matching recess around the combustion chamber in the head, I'd think the top of the barrel should be flat. Never seen a watercooled cylinder with a stepped joint.
It's not unknown for these small watercooled cylinders to have either the liner "creep" up - especially if it's seized at some point, or the cast waterjacket compress slightly due to heat and often overtightening of studs.
If it does have to be machined flat it's not a major job - any small machine shop can do it.

Thanks for that input. I think I will take it to an engineering shop and ask them what they think as well. I have had various thoughts on that and have been leaning towards that view myself.
I could clearly see the indentation the inner liner made around the outside of the combustion opening in the old solid aluminum gasket.

[Matchless]

Without seen the old gasket and associated components it's hard to say. personally, I would torque down the new gasket, remove the head once more and have a look at the witness marks. then I would decide if re-torquing the head or adding a sealant like three bond to the outer edges would be in order.

what I'm saying is, it would depend on how soft was the copper used to make the head gasket.

Dale, someone told me to anneal the solid copper gasket by heating it up well and plunging into cold water before fitting it, to make it super soft before fitting it.

I will see if I can post a close up picture tomorrow for any further thoughts.
Thanks for all the feedback it is much appreciated.

[hampshirehog]

Wemoto have the gaskets listed:

http://www.wemoto.com/bikes/Honda/CH_125_D_E_G_Spacy/83-87/