Topic: Terry's new Chopper project, the "Red something".....

[grcamna2]

Terry,did you purchase the Suzuki TR250 from the Chopper seller ?

[PeWe]

I'm sure this project will be fun to follow.
Terry, I hope you have not sold too much of your hoarded CB750 parts you need on this build.
Access to an auction house inventory must be good for projects, ongoing as well as finding new 

I have learned that old parts I have not used for many years will be needed very soon after I had them thrown away, sold etc.

[MauiK3]

Being here, as I am, on Maui, I must say that I've never seen or heard the expression "swamp donkey". I've never had the privilege of such a brutal Australian bit of crude and hilarious humor. To our overly protected ears here it's maybe the funniest thing I've heard/seen in 2025.
Great project!!

[scottly]

I’ve got a new set of girder/springer front forks that are made in India for my little BSA C11 project that I bought from Spotty awhile ago. The C11’s originally had hardtail rear ends and girder forks, but mine came with quite ugly sprung hub(?) rear suspension and telescopic forks, which were both ugly in equal measures.

The "sprung hub" is called a "plunger" suspension, and is only springs, with no damping. My '53 BSA 650 had one, and with a passenger aboard the rear end bounced up and down like a pogo stick.

[BenelliSEI]

I’ve got a new set of girder/springer front forks that are made in India for my little BSA C11 project that I bought from Spotty awhile ago. The C11’s originally had hardtail rear ends and girder forks, but mine came with quite ugly sprung hub(?) rear suspension and telescopic forks, which were both ugly in equal measures.

The "sprung hub" is called a "plunger" suspension, and is only springs, with no damping. My '53 BSA 650 had one, and with a passenger aboard the rear end bounced up and down like a pogo stick.

+1. The Carlini Chopper was a modified Amen frame. Back end was just that:
BOING - BOING!

[69cb750]

The "sprung hub" is called a "plunger" suspension, and is only springs, with no damping. My '53 BSA 650 had one, and with a passenger aboard the rear end bounced up and down like a pogo stick.

Photo from the 70's ?

[scottly]

1974

[BenelliSEI]

The CarliniChopper was built in 1974 as well!

[MauiK3]

sure is minimal suspension.

[Kelly E]

I remember seeing guys riding choppers with plunger rear suspension and a springer front end. Those things were bouncing pretty bad on some of the streets in Seattle in the 70's. There were quite a few Gypsy Jokers living in Ballard with some nice choppers.

[Terry in Australia]

Well there you go Kelly, my uncles were both Gypsy Jokers back in the day, although they rode Vincents, as they were cheap back then, (they had 3 Vincent's between them) and my Uncle Ray also rode his Matchless 500 as his "Daily" or an Ariel Square Four that he'd bought from a farmer who'd had it parked in a shed since the 50's.

Anyhoo, while Spotty and I are keen to get stuck into the chopper, we have to finish putting the other VMax back together. Hopefully tomorrow we'll get the rear cams in and timed, and maybe by Sunday we'll have it running, and off the bench. In the meantime, I've slowly been collecting parts for it. A few weeks ago, the turbo kit arrived. Everyone knows that choppers have to have turbo's, so I was really happy to score this ATP kit. It belonged to a guy who bought a turbo'd F2 that came with a complete spare kit, so I hit him up for the spare kit, and he was happy to sell it to me. It's your usual American 1970's tech, no intercooler, no blow off valve, and a weird carb setup.

Chopper turbo 1 by Terry Prendergast, on Flickr

Chopper turbo 2 by Terry Prendergast, on Flickr

Chopper turbo by Terry Prendergast, on Flickr

Regardless, should be fun, and will add to the 70's era look of the thing. I'm not worried at all about the performance side, this is just for fun.    

[grcamna2]

Well there you go Kelly, my uncles were both Gypsy Jokers back in the day, although they rode Vincents, as they were cheap back then, (they had 3 Vincent's between them) and my Uncle Ray also rode his Matchless 500 as his "Daily" or an Ariel Square Four that he'd bought from a farmer who'd had it parked in a shed since the 50's.

Anyhoo, while Spotty and I are keen to get stuck into the chopper, we have to finish putting the other VMax back together. Hopefully tomorrow we'll get the rear cams in and timed, and maybe by Sunday we'll have it running, and off the bench. In the meantime, I've slowly been collecting parts for it. A few weeks ago, the turbo kit arrived. Everyone knows that choppers have to have turbo's, so I was really happy to score this ATP kit. It belonged to a guy who bought a turbo'd F2 that came with a complete spare kit, so I hit him up for the spare kit, and he was happy to sell it to me. It's your usual American 1970's tech, no intercooler, no blow off valve, and a weird carb setup.

Chopper turbo 1 by Terry Prendergast, on Flickr

Chopper turbo 2 by Terry Prendergast, on Flickr

Chopper turbo by Terry Prendergast, on Flickr

Regardless, should be fun, and will add to the 70's era look of the thing. I'm not worried at all about the performance side, this is just for fun.

Classic,Old-School looking turbo.

[PeWe]

I thought it was an upgrade for your Subaro

[BenelliSEI]

This will be fun to watch. Happy New Year! J.

[Terry in Australia]

Thanks guys, yep, definitely an OG system, and I love those headers, how they could cram them into a stock CB750 is beyond me, so I’m guessing that the owner of the F2 realised that they wouldn’t fit between the engine and the front wheel, so bought another kit with different headers. It won’t be a problem on the chopper though, as there’s plenty of room in front of the engine.

I’ll have to lower the compression ratio to work with the turbo. The pistons in the 810 kit are probably around 10.5:1, and I will need to drop the CR closer to 8:1. I don’t think I can remove much material from the piston crowns like I did on my 1428 Kawasaki engine, so I’m thinking about either using an F2 head with its bigger combustion chambers, or making a decompression plate between the cases and cylinder block. Any guesses on how thick I should make it? I’m thinking 3mm, but I’m open to suggestions?

[grcamna2]

Thanks guys, yep, definitely an OG system, and I love those headers, how they could cram them into a stock CB750 is beyond me, so I’m guessing that the owner of the F2 realised that they wouldn’t fit between the engine and the front wheel, so bought another kit with different headers. It won’t be a problem on the chopper though, as there’s plenty of room in front of the engine.

I’ll have to lower the compression ratio to work with the turbo. The pistons in the 810 kit are probably around 10.5:1, and I will need to drop the CR closer to 8:1. I don’t think I can remove much material from the piston crowns like I did on my 1428 Kawasaki engine, so I’m thinking about either using an F2 head with its bigger combustion chambers, or making a decompression plate between the cases and cylinder block. Any guesses on how thick I should make it? I’m thinking 3mm, but I’m open to suggestions?

Terry,will a decompression plate require you to install a longer cam chain,possibly change the cam timing ?

[Kelly E]

Well there you go Kelly, my uncles were both Gypsy Jokers back in the day, although they rode Vincents, as they were cheap back then, (they had 3 Vincent's between them) and my Uncle Ray also rode his Matchless 500 as his "Daily" or an Ariel Square Four that he'd bought from a farmer who'd had it parked in a shed since the 50's.

In 83' when I had my 82' Honda V45 Sabre I used to swap bikes for the day with one of the Jokers when he wanted to go on an all day trip with his wife. His 68' Sportster wasn't comfortable for a passenger on the back all day. I learned to ride a right side shift on that bike. He caught a lot of crap from the other guys about riding a ricer bike but after that they were all very nice to me and treated me like a little brother. 

[Terry in Australia]

Thanks guys, yep, definitely an OG system, and I love those headers, how they could cram them into a stock CB750 is beyond me, so I’m guessing that the owner of the F2 realised that they wouldn’t fit between the engine and the front wheel, so bought another kit with different headers. It won’t be a problem on the chopper though, as there’s plenty of room in front of the engine.

I’ll have to lower the compression ratio to work with the turbo. The pistons in the 810 kit are probably around 10.5:1, and I will need to drop the CR closer to 8:1. I don’t think I can remove much material from the piston crowns like I did on my 1428 Kawasaki engine, so I’m thinking about either using an F2 head with its bigger combustion chambers, or making a decompression plate between the cases and cylinder block. Any guesses on how thick I should make it? I’m thinking 3mm, but I’m open to suggestions?

Terry,will a decompression plate require you to install a longer cam chain,possibly change the cam timing ?

Good question Bill, and I don’t know the answer really. I think it will be a trial and error exercise, if the chain is long enough I can’t see it altering the cam timing, and there is always some slack in the cam chain, but will there be enough? Only one way to find out..

Kelly, the saddest part about my uncle’s is that I didn’t know they were my uncle’s until many years later when my mom told me. My dad didn’t like them and he’d told me to stay away from them, but I thought they were really cool and they were always good to me. Whenever I was looking for a part for my Royal Enfield or my BSA Bantam I’d go see them and if they had the part they’d always just give it to me to help get my bikes going again. I lost contact with them when I joined the Army and moved away from the little country town I came from, and often wonder if they’re still around.

[Terry in Australia]

Well I must be losing my sh1t. I posted an update on the chopper project this morning, but when I came back tonight to have a look at it, it wasn't there? WTF? Oh well, the good thing about Alzheimer's disease, is that I'm always making new friends, and I can hide my own Easter eggs.......

So back to the update. Spotty and I got bored with my other VMax when sparks refused to fly, so we moved the chopper up to the bike lift last Sunday, and stripped it down to the bare frame.

Chopper Sunday VMax Monday 12 January 2026 2 by Terry Prendergast, on Flickr

Sadly the top frame rail was rotten due to the original gas tank being moulded into the frame and water ingressing into the bondo. There was also a nasty repair 6 inches or so back from the steering head. I rang a steel supplier for some new 1 1/2" round tube, he gave me a price, I paid over the phone, and collected it the next day. Unfortunately when I called him, I was talking about "Outside diameter" and he was talking about "Inside diameter", so the tube I bought was 50mm with a 5mm wall thickness. Oh well, bigger is always better, so I chopped out the rotten rail, and test fitted the new piece.

Chopper Thursday 15 January 2026 1 by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 2 by Terry Prendergast, on Flickr

I was happy with the look, so welded it in place. I also had to fab and weld in a new bracket underneat at the rear for the coil mounts. Now to fit the tank. I machined up a pair of threaded bungs on my lathe, then welded them in place.

Chopper Thursday 15 January 2026 6 by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 8 by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 9 by Terry Prendergast, on Flickr

And, drum roll....... The tank fits! Woohoo!

Chopper Thursday 15 January 2026 9c by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 9d by Terry Prendergast, on Flickr

Anyway, I'm happy with it so far. I still need to make up a seat bracket for the new single seat that I received today, and fab up a battery box. Once all the new brackets are in, I'll give the frame a nice coat of shiny black paint. I thought about blasting/powder coating it, but I may need to weld more brackets on it for the turbo kit, so it's easier to just paint it.

I think I'll go for a ride tomorrow, and on Sunday Spotty and I are going to put the engine back together, so I can take it home and strip/repaint it. We're getting there.

[grcamna2]

Well I must be losing my sh1t. I posted an update on the chopper project this morning, but when I came back tonight to have a look at it, it wasn't there? WTF? Oh well, the good thing about Alzheimer's disease, is that I'm always making new friends, and I can hide my own Easter eggs.......

So back to the update. Spotty and I got bored with my other VMax when sparks refused to fly, so we moved the chopper up to the bike lift last Sunday, and stripped it down to the bare frame.

Chopper Sunday VMax Monday 12 January 2026 2 by Terry Prendergast, on Flickr

Sadly the top frame rail was rotten due to the original gas tank being moulded into the frame and water ingressing into the bondo. There was also a nasty repair 6 inches or so back from the steering head. I rang a steel supplier for some new 1 1/2" round tube, he gave me a price, I paid over the phone, and collected it the next day. Unfortunately when I called him, I was talking about "Outside diameter" and he was talking about "Inside diameter", so the tube I bought was 50mm with a 5mm wall thickness. Oh well, bigger is always better, so I chopped out the rotten rail, and test fitted the new piece.

Chopper Thursday 15 January 2026 1 by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 2 by Terry Prendergast, on Flickr

I was happy with the look, so welded it in place. I also had to fab and weld in a new bracket underneat at the rear for the coil mounts. Now to fit the tank. I machined up a pair of threaded bungs on my lathe, then welded them in place.

Chopper Thursday 15 January 2026 6 by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 8 by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 9 by Terry Prendergast, on Flickr

And, drum roll....... The tank fits! Woohoo!

Chopper Thursday 15 January 2026 9c by Terry Prendergast, on Flickr

Chopper Thursday 15 January 2026 9d by Terry Prendergast, on Flickr

Anyway, I'm happy with it so far. I still need to make up a seat bracket for the new single seat that I received today, and fab up a battery box. Once all the new brackets are in, I'll give the frame a nice coat of shiny black paint. I thought about blasting/powder coating it, but I may need to weld more brackets on it for the turbo kit, so it's easier to just paint it.

I think I'll go for a ride tomorrow, and on Sunday Spotty and I are going to put the engine back together, so I can take it home and strip/repaint it. We're getting there.

Well Terry,that's a nice looking chopper project/frame 
The project is 'On the Way Up' 
Did you paint the nice,red fuel tank using similar paint to your red CB750K0 ? Looks Great ! 

[MauiK3]

That should be an interesting ride with that geometry!!

[jgger]

Looking good,Terry. Choppers are so cool, but i don't think I could ride one. The hard tail brings back memories of my mini bike as a kid. I beat my back to death on that thing!

[PeWe]

That tube must be an improvement.
Looks good.
You are a fabricator, Terry!
Not only disassemble, change parts and back together again.

[denward17]

Well done repair on the frame, I love that red!