facebook1 youtube1 twitter1 instagram linkedin1 pinterest1

NOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community! REGISTER AND MAKE THIS BOX DISAPPEAR!

Pete's CT1 Restoration

  • Posts: 869
  • Likes received: 461

Replied by shyted on topic Pete's CT1 Restoration

For a bike that had 12 month test on it when i bought it and the head lamp held on with a nail and cigarette butt it's been one step forward and three back. The thing with the paint has really made things costly. That and everything else ha.
The following user(s) Liked this Post: Pete-RT1
02 Jan 2021 08:25 #71

Please Log in or Create an account to join the conversation.

  • Pete-RT1
  • Pete-RT1's Avatar Topic Author
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 518
  • Likes received: 570

Replied by Pete-RT1 on topic Pete's CT1 Restoration

Good news is the crank seal is fine, bad news is the head gasket is leaking :Ugh
Swapped the new generic gasket for an genuine Yamaha one and same result.
I'm too cold to carry-on but will investigate when I thaw out.
Glad I read MarkT's post on the importance of the test though, everyday is a school day.
Yamaha RT-1
Yamaha CT1-B
Yamaha CT1-C
Honda XR250
04 Jan 2021 07:38 #72

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 10110
  • Likes received: 5845

Replied by MarkT on topic Pete's CT1 Restoration

New gaskets are generally very hard copper. Try annealing the gasket... heat it up red or nearly red hot on the stove or with a torch. Tossing it in a pan of water while hot will knock off much of the scale that can form... or you can let it cool slowly and scrub the scale off. Gasket will be very soft and bendable after annealing.

K&W Copper Coat is a good sealer I've used with success on copper head gaskets.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
04 Jan 2021 08:07 #73

Please Log in or Create an account to join the conversation.

  • Pete-RT1
  • Pete-RT1's Avatar Topic Author
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 518
  • Likes received: 570

Replied by Pete-RT1 on topic Pete's CT1 Restoration

Thanks Mark.
Annealed original and the two new ones that I had fitted, so much softer than out of the packet.
Fitted and re-tested and is slightly better, but still not gas tight.
Nothing obvious on the cylinder or the head.
Will source some of the copper coat.
Yamaha RT-1
Yamaha CT1-B
Yamaha CT1-C
Honda XR250
The following user(s) Liked this Post: MarkT
04 Jan 2021 12:37 #74

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 878
  • Likes received: 482

Replied by Swoop56 on topic Pete's CT1 Restoration

You may have to lap in the head and/ or barrell with some grinding paste on a glass surface .
The following user(s) Liked this Post: Pedalcrazy
04 Jan 2021 16:10 #75

Please Log in or Create an account to join the conversation.

  • Posts: 375
  • Likes received: 217

Replied by Pedalcrazy on topic Pete's CT1 Restoration


That's probably why service manuals caution to loosen and tighten a little at a time in a criss-cross pattern to minimize warping.
1978 DT400E
1976 DT400C
1973 RT3
1971 RT1B
04 Jan 2021 16:13 #76

Please Log in or Create an account to join the conversation.

  • Posts: 312
  • Likes received: 237

Replied by Midlife Motor on topic Pete's CT1 Restoration

I am with Swoop on this one. You might have to run that cylinder over a surfacing stone. On my CT1 I did it on a stone rated flat to .001 of an inch. Figure eight patterns with cylinder surface on wet sand paper of high grit on top of stone. They are not that expensive.
It's better to remain silent and be considered a fool than to speak and remove all doubt.
04 Jan 2021 21:59 #77

Please Log in or Create an account to join the conversation.

  • Pete-RT1
  • Pete-RT1's Avatar Topic Author
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 518
  • Likes received: 570

Replied by Pete-RT1 on topic Pete's CT1 Restoration

Cylinder head was very slightly warped which shouldn't have been a surprise when I look back at the state of it when I removed it, I did loosen the bolts steadily in a criss-cross pattern, as I always have done.
I was a bit naughty and since I have quartz kitchen worktops I thought I'd work inside in the warm.
I was pretty confident they were flat and true but more out of being pedantic than necessity I delved into the back of my garage and found my surface gauge which I made 33 years ago and found a dti in the garage to fit onto it.
Worktops are super flat.
Anyway, bit of flattening with various fine grades of wet and dry and water and hey presto flatter than a witches tit.
I did the same on the cylinder.
Red felt tip pen on the head and a rub directly onto the worktop proves there's no low spots and we're good to go.
What I love about working on bikes again after quite a few years is it takes me back to my youth.
I can actually recall being in my dads garage with the head off my YB100 with wet and dry tapped to a pane of glass doing exactly the same thing, the only difference being it was the middle of the night and I needed the bike to get to work the next day.
Anyway the pressure test has been a good thing, it's proven the seals are good and it's also meant that I will change the rings which I was dithering over.
The bore has virtually no wear (I have measured it in various places) end gap was 0.3mm which is in spec but towards the limit and since I'd given it a light hone I would normally change them, but as I didn't have any at the time I put the old ones back in. Since I'm waiting on a few bits anyway I've ordered a standard set of rings, which should be here before the other bits.
As I say to my kids, "It doesn't matter what you're doing, you should always do it to your best ability", if only I could get them more interested in the bikes :Excited
Yamaha RT-1
Yamaha CT1-B
Yamaha CT1-C
Honda XR250
The following user(s) Liked this Post: MarkT, 2fishkev, Swoop56, shyted, Midlife Motor, Gr8uncleal
Last edit: 06 Jan 2021 14:45 by Pete-RT1.
06 Jan 2021 10:32 #78

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 10110
  • Likes received: 5845

Replied by MarkT on topic Pete's CT1 Restoration

Nice work!!! :likey :likey :likey

P.S. Don't be surprised if the new rings also have gaps near the maximum spec... That's common for Yamaha rings even on a fresh bore.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
The following user(s) Liked this Post: Pete-RT1
06 Jan 2021 17:03 #79

Please Log in or Create an account to join the conversation.

  • Pete-RT1
  • Pete-RT1's Avatar Topic Author
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 518
  • Likes received: 570

Replied by Pete-RT1 on topic Pete's CT1 Restoration

Fitted the voltage regulator today, just want to check that this location is ok.
The tank clears it comfortably.
I extended the yellow wire and managed to thread it through the grey sleeve into the headlight bowl where I've connected it to the blue for the meter lights as per previous posts I've seen on the forum.
Yamaha RT-1
Yamaha CT1-B
Yamaha CT1-C
Honda XR250
The following user(s) Liked this Post: MarkT
10 Jan 2021 11:01 #80

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

Moderators: yamadminEnduronutMakotosunDEETVinnieDevinJames Hart