Marko's Workshop

Friday, 28 August 2020

Autot ja Viihde 2019 - 28th of September - Lahti, Finland - Part 4/4 - Hobbyist car park

Here's a throwback to hobbyist car park of last year's Autot ja Viihde (eng. Cars and Entertainment) car show held at the end of September in Lahti, Finland. I will post more photos from inside bit later! Stay tuned 😎

'73 Suzuki GT250 - Part 14 - GT550 front fork swap - 2/2 - Refurbishing top and bottom yokes

I decided to get bottom yoke painted with same color than front and rear wheel so I started by prepping it properly. First thing was to pull out lower steering head bearing and remove fasteners and old steering lock. I only covered axle with masking tape and then got lower part of yoke sand blasted. While it was getting painted I sourced new bearings, steering lock and fasteners for both yokes. M10 bolts used to tighten stanchions had to have fine threads. Those I managed to find through eBay.

Sand blasted bottom yoke

New fasteners for top and bottom yokes

Nut for steering stem (#51631-28000)

Neiman GKS steering lock for Suzuki GT550

Pyramid Parts steering head bearings kit (#BR21)...

...which included new bearings, dust seals and tube of lubricant

Upper (25x48x15) and lower (27x48x14) steering head bearings

Refurbished bottom yoke/steering stem

Now that I got bottom yoke back together with new bearings I tested how it fit to the head of the frame which still had old bearing races on. It turned out that in GT550 bottom yoke bearings are tiny bit more further apart from each other than in GT250. Due to that I couldn't get the steering stem nut (#51631-28000) tightened all the way.

To fix issue with bearings I designed a 1 mm thick shim plate which I put underneath lower steering head bearing race while I replaced both races. Shim plate was laser cut out of stainless steel sheet.

Since I don't own special tools to replace steering head bearing races I just used Dremel with a grinding stone and a punch to remove them. By taking my time I managed get them out without damaging bearing houses on the head. 36 mm socket turned out to be just the right size to gently hammer new races in. Counter part of steering lock in frame will still require bit of modification since lock is positioned differently in GT550 bottom yoke. That I will handle later.

Lower race had more space to fit a 1 mm shim plate underneath it

Dimensions of shim plate

Shim plates were laser cut out of stainless steel sheet

Dremel with a grinding stone together with a punch
were used to remove old steering head bearing races...

...and 36 mm socket to hammer new ones in place

New lower race with shim plate

New upper race

Unluckily GT550 front fork I bought had a broken top yoke which I didn't notice until later when I took it apart. I had to replace it with another one since it was unrepairable. I decided to use one out of GT250 which I already had and modify it to fit.

Only difference between GT250 and GT550 top yokes is bigger bore for stanchions in GT550. GT550 comes with 35 mm and GT250 with 32 mm thick stanchions. I used a milling machine with adjustable boring tool to oversize holes on my GT250 top yoke.

GT550 fork fork had a broken top yoke

GT550 and GT250 top yokes

Spacer and chock used for fixing top yoke to table of milling machine

Finding center point of hole with centering device

Adjustable boring tool

Measuring hole diameter with a micrometer

Other side machined as well

I wanted to use a fatbar handlebar I lying around so I got a clamp kit made by Magura which fit perfectly to GT250 top yoke. I ended up polishing top yoke, clamps and handlebar. I assembled front fork and mocked it up with engine, swingarm and wheels.

Next I will focus on fabricating kickstand and parts for rear brake. After those are done frame mods are almost complete and it might be time to start cleaning in it up for paint 😎

Magura X-line Offroad Clamp kit 28,6 mm (#0720474)

Polished top yoke, clamps and handlebar

Refurbished Suzuki GT550 front fork

Mock up

Thursday, 23 July 2020

American Car Show 2019 - 11th of May - Oulu, Finland - Part 1/4 - Cars from 20's through 50's

Let's finish photos of last year's American Car Show Oulu with a set of cars from late 1920's to 1950's! Please check out also Part 2, Part 3 and Part 4 😎

1927 Studebaker Crew Cab P.U 'Psycho Express' @heathgarage

American Car Show 2019 - 11th of May - Oulu, Finland - Part 2/4 - Cars from the 60's and onward

Let's continue with more photos from last year's American Car Show held in Oulu 😎 I split these by decades so here's cars from 1960's and onward. Lot's of cool cars attended last year's show since it was 40th anniversary year. Take a look and check out also Part 3 and Part 4!

1974 AMC Javelin

'73 Suzuki GT250 - Part 13 - MX footpegs and custom brackets

I had a pair of IMS Pro Series footpegs meant for Kawasaki '99-01 KX125 250 (#293112-4) laying around which I had purchased for a previous project of mine but never ended up using them. After getting rid of that bike I stored them for later use. At one point I had them for sale too but after time went by and I still had them I decided to utilize them in this build.

I designed a pair of brackets to be able to fit them to frame of my GT250K with help of four weldable inserts and M8 bolts. Inserts were turned in lathe out of 18 mm round steel bar and parts of brackets cut out of 6 mm steel sheet using water jet cutter and welded together.

Footpeg assembly

Pair of IMS Pro Series footpegs
for '99-01 Kawasaki KX125/250 (#293112-4)

Pair of pins, 10x49.5 (#92043-1564)
and springs, step (#92144-1951)

Dimension drawing of M8 frame inserts

Inserts were turned in a lathe out of 18 mm steel round bar

Dimension drawing for parts of footpeg brackets

Preview of cut drawing for parts of footpeg brackets

NC-code for water jet cutting

Water jet cutter

Exterior...

...and interior of sand blasting cabinet

Blank after sand blasting

Pieces separated with a hand saw

Since water jet cutter tends to leave chamfers to holes I decided to make them bit smaller and drill them to right size after cutting. I did that in two stages. First time to 8 mm and after mocking up and welding M8 inserts to frame to 9 mm. 8 mm holes allowed me to center inserts perfectly to brackets. They would have been too tight for M8 bolts after painting so I decided to drill them afterwards to 1 mm oversize. I will powder coat both footpegs and brackets later once I have all the other parts such as side stand etc. ready for that as well.