GSX-R400 GK71 F400 Build

[lihp]

So, after doing research about affordable (relative term) race series, and decided to give a local club a go at Formula 400. I am under no illusions that I will be near the front, and bike development will take place over quite a long time.

The bike may not be ideal but I will be using a GSX-R400 GK71F.

The reason for this is that I picked up Alpha's for £150.

Issues with the bike, burning water and poor idle.

So, ordered a new head gasket. And found that the poor idle was due to a total balls up of the idle mixture screws, all different setting ranging from 1/2 turn out to 4 turns out!

The rest of the engine is spot on, the frame and swing arm is fine, however, due to the dated design and wear of the suspension I need a new rear shock and will be doing a front end conversion on it too.

For now, here is some photos.

https://i.imgur.com/jYOmXcNl.jpg
https://i.imgur.com/w83jKIIl.jpg
https://i.imgur.com/qQhN78Wl.jpg
https://i.imgur.com/kRGVjLYl.jpg
https://i.imgur.com/AgkBZhfl.jpg
https://i.imgur.com/a6OBt7il.jpg
https://i.imgur.com/jrAGrMXl.jpg
https://i.imgur.com/cRIsTPjl.jpg
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covent.gardens: lihp is my most favourite member ever

[evoboy]

Interesting!

What front end are you going to opt for? What are you going to do about wheel sizes? ( been as they are so odd making it difficult to get anything relatively sticky on there!)
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Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[lihp]

The wheels are both 17"

Though the standard sizes are a little peculiar at 110/80/17 and 140/80/17 If I I drop the front profile to 110/70/17 and 140/70/17 I should be able to then get BT003RS on front and rear.

I am going to be putting a GK76A front end on it, I have just got hold of a pair of GK76A USD Forks for £75 deliered. So will be on the look out for a set of yokes, and calipers. But may also need a front wheel and spindle.
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covent.gardens: lihp is my most favourite member ever

[P.]

Could probably put a 150 on the rear... which would give you a little bit more selection. Heck, it gives you access to the PR3 Trails

[evoboy]

[lihp]

[RhynoCZ]

Q: I sold my NC27 and was thinking, are these sport 400cc in-line fours any better than a naked 400cc, like NC27 or is it essentially the same thing?

I still can not decide what to buy next.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[lihp]

I wouldn't buy one for the road.

But they're more affordable and accessible than the 600s for racing.
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covent.gardens: lihp is my most favourite member ever

[Sako]

Looking forward to this.

[lihp]

Hopefully Forks are arriving tomorrow, and I'll get some more pics up tonight.

However, it's going to be another 4 weeks till my Head Gasket arrives as it's on back order in Japan
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covent.gardens: lihp is my most favourite member ever

[orac]

if you get stuck with wheel maybe look inot the bandit 4 stuff as it uses 120/70/17 on the front and 150/70/17 on the rear.

also one thing that made me lu=augh, "its burning water", i kniow what you mean but it gave me a giggle as its very hard to make water burn
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[lihp]

[orac]

[lihp]

So.

Today I continued cleaning the frame down, it's a slow process as I do not wish to pay for blasting

However.

Carbs got stripped, checked and serviced and all appears ok there.

And my USD forks arrived today also. Now, all I need is a set of yokes for them.

Water jacket is a little rusty, but hoping that with the new headgasket, that some running up to temp and draining a few times will clear anything loose out. At some point tomorrow, I will be pulling the water pump off to make sure that there's no rust there that will prevent it's operation

https://i.imgur.com/fPbGXfAl.jpg
https://i.imgur.com/HPlNmUul.jpg
https://i.imgur.com/xW4bkKIl.jpg
https://i.imgur.com/uyGAmDel.jpg
https://i.imgur.com/xI5bGrel.jpg
https://i.imgur.com/EQ9DFFHl.jpg
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covent.gardens: lihp is my most favourite member ever

[stox]

Good luck with the build.

Here's my gk71 shed.

https://i19.photobucket.com/albums/b175/stocker1973/GSXR%20400/T2eC16VHJH8E9qSEWJoKBQ6cYGTiH60_12.jpg

Sourcing parts on these can be a pain!!

[lihp]

So.

I am STILL waiting on a Head Gasket from Suzuki, only a couple more weeks.

I've not yet made a start on the forks, but have been tidying my garage out so I don't need to spend ages getting to stuff I need, but head and cylinder surfaces are now prepared for when I get the head gasket.

Fuel tank is almost stripped ready for me to start molding, my plan is to have a tank cover, underneath will be a small 6l aluminium fuel tank.

Also, I had a few more bits arrive, a GK73 SP Swingarm and Rear Shock, and also a Bandit400 rear wheel. I am now looking out for a set of yokes for a GK76 but I refuse to pay £60 for the lower yoke that is currently on ebay.

I have also made a start on tidying up the frame now it's all clean. Powder coating is a no, as it will be wrecked the first time I crash it, so painting it is, as it's quick and easy to touch up as required.

https://i.imgur.com/Hy5G379l.jpg
https://i.imgur.com/oZgKh1dl.jpg
https://i.imgur.com/qffBoafl.jpg
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covent.gardens: lihp is my most favourite member ever

[garth]

Interesting enough project, but if the idea was for a 'cheap' race bike, I'd have spent my money on a CB500 or 2 Valve 583cc Ducati - You could have a race ready bike that's competitive for £800 - £1500.

[Alpha-9]

Aha the thread!
I'm just glad it's not going to waste and rotting away in my garden.

Be cool to see how it turns out
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Fzr-600 1999

[lihp]

[garth]

Lucky you having race tracks so close. I'm down south and the nearest is Brands, but that's still 100 miles from me.

I've resorted to buying a pit bike and converting to SM to run on some local Kart tracks. It's actually turned out to be a lot of fun, for relatively little expense, and the consequences of stacking it aren't horrific either.

Unfortunately 'racing' and 'cheap' are mutually exclusive.

[lihp]

Most definately!

I always use cheap (relatively)

I am lucky that I have 2 small tracks local, and then Oulton Park within 35 minutes, donington in under 2 hours.

If you have to travel anyway, then the cheapest bike is usually the cheapest racing, but if not, whatever is local is cheap(relative)
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covent.gardens: lihp is my most favourite member ever

[lihp]

Finally! Mr Suzuki has just called to let me know that he has a head gasket in the shop waiting for me to collect!

So, I will collect tomorrow, then I can the engine sealed back up and ready to go into the frame again.
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covent.gardens: lihp is my most favourite member ever

[lihp]

So, after hitting a bit of a wall trying to make spacers for my spindle.

Trying numerous machine shops and very few have a long enough drill to make me a 20mm tube with 14mm ID.

I have stumbled across a supplier, that supplies extruded aluminium tubes in my exact dimensions. Which is awesome, as I feel progress will now start again.

Hopefully I will have my MDF prototypes done for the new rear shock linkage, before sending them over to Kayla to work their machine magic

Feeling good that the project is on the move again.
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covent.gardens: lihp is my most favourite member ever

[lihp]

So.

finally got around to sorting the swing arm spindle spacers which means I have the 73 braced swingarm fitted.

I have also finished the valve clearances so that is another job off the list every single valve was out of spec.

https://i.imgur.com/aTCOEufl.jpg

My next task is to tackle the rear shock mounts, due to the differences in the mounts for and linkage for the 71, I cannot use the original mounts as it puts the linkage at a stupid angle, and the spring fouls the mounts.

https://i.imgur.com/94TkRBWl.jpg

So, I am going to get some new mounts machined, plate over the bottom of the frame, so that the linkage fits just as it would do on a GK73.

https://i.imgur.com/OfPFSORl.jpg
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covent.gardens: lihp is my most favourite member ever

[Alpha-9]

is bike yet?
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Fzr-600 1999