R5 rescued and ready for transformation - no rules restomod

[Ramadrama]

Hi!

Finally found the perfect project bike to realise my 2 stroke dreams. Already have a fully built XS650 but I really want to build a bike myself. I'm craving a light and nimble 2 stroke!

The bike is an R5 unknown year but the frame and engine nr is R5-040824 if that's any clue?
Picked it up for quite cheap expecting it to be in worse condition but was pleasantly surprised to find fresh pistons and cylinders! Apparently someone already started working on it.

This bike is the perfect base for a restomod build. Here's what I have planned.

Chassis:
Wheels, brakes and forks from a DERBI GPR 125 -07. There are plenty of these bikes being sold for parts here in Finland and very cheap! The 44mm USD front should fit quite effortlessly as the stem diameter and length corresponds almost exactly with the original R5. Ideally I'd want to do lighter than stock disc brake 18" wire spoked wheels but I can get the Derbi 17" really cheap and they look quite interesting.

Challenges:
Chain alignment is my biggest concern. Where do I find an offset front sprocket? Of course I'll need to make some spacers, the rear sprocket carrier will need to be machined down and holes deepened. Looking to do a 520 conversion using a 39tooth blank rear.

Engine:
First I'll clean the ports up a little bit and reassemble to get it running. The oil tank is missing so I'll probably plug the original system. Premixing has been standard procedure 20 years on the mx track already! I'm prepared to put fresh crank seals if needed. Also looking for a 6speed gearbox.

Ignition:
Points system looks really tired, gonna try to revive it.
Vape CDI feels extremely tempting (getting rid of the battery) but a bit overkill price tag. Newtronics on the other hand, that might be the way to go!

Carburators:
The previous owner also sold me some new 28mm PWK replicas. ZSDTRP is the brand. Any recommendations on jetting?

Exhaust:
Test run with original pipes, then fabricate my own.
I'm stupid enough to believe I can learn how to weld my own pipes. I know a guy that has made his own pipes based off of the old Yamaha blueprints for track bikes. Waiting for the files so I can have the sheet metal cut out and start rolling.

Any and all help is much appreciated! Looking forward to update you on this project!

[paul1478]

I had that same seat in my 350 back in 1979. I never saw anther one.

[Ramadrama]

Yeah the seat is really interesting! Looks and feels like a Yamaha original as the underside is most likely the same as the stock seat.  Anyone have any info about this? I believe it's been sold separately.

Gonna keep it for now but later on I'm looking to sell the seat/fenders/random parts to finance performance upgrades.

EDIT: The seat might be from a brand called Giuliari.

[AAAltered]

Looks like a 71.  The seamed pipes are also an indicator of earlier bikes.

1970 R5(A) - R5-000101 - 013649
1971 R5B - R5-015101 - 042209
1972 R5C - R5-100101 - 130606

[AAAltered]

The seat looks a lot like a Giuliari.  I've never seen one with that script on the side.  What does the back say?

[m in sc]

actually looks like a 70, the tail light bracket (painted vs chrome) and lens are really early. not that it really matters.
as far as ignition, look at hpi cdi.

[Ramadrama]

as far as ignition, look at hpi cdi.

Thank you! I'm not completely understanding from reading at their website, does that system also allow you to run without a battery?

[m in sc]

yes it does.  i have an rd with one, no battery super minimalistic

[manicmecanic]

the seat looks to me like the quite common-over here in Germany-Giuliari seat.
the brand was available for many bikes.
I bought a few,always with an RD 😉
most of them had this logo

[pdxjim]

Seat is def Giuliari.

Thee best looking cafe seat for Yamaha RD (and many other middleweight bikes).

Common in Europe, but very rare here in the states.

[rodneya]

Hi!

Finally found the perfect project bike to realise my 2 stroke dreams. Already have a fully built XS650 but I really want to build a bike myself. I'm craving a light and nimble 2 stroke!

The bike is an R5 unknown year but the frame and engine nr is R5-040824 if that's any clue?
Picked it up for quite cheap expecting it to be in worse condition but was pleasantly surprised to find fresh pistons and cylinders! Apparently someone already started working on it.

This bike is the perfect base for a restomod build. Here's what I have planned.

Chassis:
Wheels, brakes and forks from a DERBI GPR 125 -07. There are plenty of these bikes being sold for parts here in Finland and very cheap! The 44mm USD front should fit quite effortlessly as the stem diameter and length corresponds almost exactly with the original R5. Ideally I'd want to do lighter than stock disc brake 18" wire spoked wheels but I can get the Derbi 17" really cheap and they look quite interesting.

Challenges:
Chain alignment is my biggest concern. Where do I find an offset front sprocket? Of course I'll need to make some spacers, the rear sprocket carrier will need to be machined down and holes deepened. Looking to do a 520 conversion using a 39tooth blank rear.

Engine:
First I'll clean the ports up a little bit and reassemble to get it running. The oil tank is missing so I'll probably plug the original system. Premixing has been standard procedure 20 years on the mx track already! I'm prepared to put fresh crank seals if needed. Also looking for a 6speed gearbox.

Ignition:
Points system looks really tired, gonna try to revive it.
Vape CDI feels extremely tempting (getting rid of the battery) but a bit overkill price tag. Newtronics on the other hand, that might be the way to go!

Carburators:
The previous owner also sold me some new 28mm PWK replicas. ZSDTRP is the brand. Any recommendations on jetting?

Exhaust:
Test run with original pipes, then fabricate my own.
I'm stupid enough to believe I can learn how to weld my own pipes. I know a guy that has made his own pipes based off of the old Yamaha blueprints for track bikes. Waiting for the files so I can have the sheet metal cut out and start rolling.

Any and all help is much appreciated! Looking forward to update you on this project!

MJ Corse make cystom sprockets and are in Spain, so kinda close to you

[Ramadrama]

Hi! Thanks for the advice on MJ course but I'm happy to say I've found a better solution!

Thanks to a lucky google search I found a 6 year old answer to my question on Facebook in the "2stroke hybrids" group.
There is a sprocket with part number JTF 1307-15, sold as a 636 Ninja sprocket and some version of Honda XL/XR 650. It's a 520, has the correct splines and approx 10mm offset.

This costs 20€ compared to 90€ for a custom MJ corse. Needs to be machined down to fit the sprocket nut but this shouldn't be a problem!

[m in sc]

thats awesome!!! when i did mine it was along time ago, this is a great find.

well done!

https://www.jtsprockets.com/catalogue/part/JTF1307/