1987 Suzuki Impulse GSX 400 X GK71E Restoration

[Mikael]

Hello, starting a restoration on an Impulse. If anyone has experience working on these bikes I would be grateful to hear any tips or information regarding a restoration on one of these. I have very little information but would like to see this bike on the road again as there are not too many of them. Also looking for parts. Great bike from the 80s. Thanks in advance.

[jellywrestler]

Great bike from the 80s. Thanks in advance.

we called them insults and impacts, they were hideous things, and still are!

[sidecar bob]

Hi, I have a gk71b & a genuine Suzuki service manual for one. The engines are near enough the same. If you want to know any specifics let me know.
Warning, they are a total party on wheels, I can't ride mine without bouncing it off the limiter a few times every time.

[sidecar bob]

we called them insults and impacts, they were hideous things, and still are!

Well there's some encouragement for your restoration, hope that helps. ;)

[OddDuck]

You've done restoration work on other bikes before? Just checking before offering any advice.

[Honest Andy]

My mate bought one of those new, they were pretty cheap for a new bike and great fun when we were young fullas :laugh:

(though I recall it didn't last very long once we started to really ring its neck... :( )

[Grumph]

My mate bought one of those new, they were pretty cheap for a new bike and great fun when we were young fullas :laugh:

(though I recall it didn't last very long once we started to really ring its neck... :( )

Approx one and a half seasons use using 16000 rpm before the rods break....I told the guy not to buy an ex Rob Lewis racebike.
They were the go-to bike for club racing in the first few seasons of F3. Used to be loads of them, rare as now.

I once took one of them out to 500cc using CBX550 liners and pistons for a F500 speedway car, went OK too.

[husaberg]

The thing i remember most about the impusle's was the smell of their cooked stators.................

[sidecar bob]

Maybe this would be worth buying , either for parts, or the main resto bike.
http://www.trademe.co.nz/Browse/Listing.aspx?id=1381591821
It probably won't go for a lot.

[jellywrestler]

Well there's some encouragement for your restoration, hope that helps. ;)

history has often favoured the ugly duckling.

[AllanB]

Fucking moaners.

If I remember correctly they were $3999 brand spanking new. Suzuki sold heaps of them. Sportier and cheaper than a farty old 450 twin Suzuki, CB400 twin (fat, slow, boring) or old fashioned GB400 Honda. Can't remember Yamahas 400 of the day - old fashioned SR500 probably or XS400 twin. Kawasaki had the Z400/440 at the time (I owned a 440).

Yep the Suzuki was bright, fresh and screamed it's little guts off into many peoples hearts.

Restro? Questionable if it has any real value other than memory lane. But there are worse bikes to sink money into.

[T.W.R]

Fucking moaners.

If I remember correctly they were $3999 brand spanking new. Suzuki sold heaps of them. Sportier and cheaper than a farty old 450 twin Suzuki, CB400 twin (fat, slow, boring) or old fashioned GB400 Honda. Can't remember Yamahas 400 of the day - old fashioned SR500 probably or XS400 twin. Kawasaki had the Z400/440 at the time (I owned a 440).

Yep the Suzuki was bright, fresh and screamed it's little guts off into many peoples hearts.

Restro? Questionable if it has any real value other than memory lane. But there are worse bikes to sink money into.

:confused: The impulses made an appearance here at the same stage as grey imports were starting to arrive on the scene, so their main opposition were the likes of the early CBR400 aero & the the naked CB400F with the vtec head & NS400R, FZ400 & FZR400, and it's own sibling GSXR400 & RG400 etc so it wasn't all roses for the impulse on it's arrival. It was unique with the trellis frame headlight assembly then we got the so called LTD model with the proper bikini fairing.
Some of the GSXR400's tendencies filtered through to it though

[F5 Dave]

I've got a gk71a gsxr which contains many same parts sitting in purgatory, have to find what is rattling at the front. And hard starting. Sigh. Guess I'd better pull that cam cover off. Really super uninterested. Should get it ready for summer so the owner has her bike back.

[Paul in NZ]

I think Suzuki NZ got a whole ship load of bikes that didn't sell in a different market and brought them here (from memory)

There were 2 flavours with mildly different headlight arrangements although most had the funny square light with the ugly little trellis thing. Yes - everyone thrashed them to death and had a ball...

[James Deuce]

We used to call them a Repulse. No idea where Jelly got his names from :)

[Askor]

I used to have a gsxr250 with a gsx400x engine in it a while ago - it was hilariously fun to 18 year old me!

[jasonu]

They were a lot of bike for $4000 brand new, bit of a bargain really. Lots of them were snatched up by couriers.

[malcy25]

They were a lot of bike for $4000 brand new, bit of a bargain really. Lots of them were snatched up by couriers.

Yeah....and guys thinking they were going to win the F3 championship out of the box, first time up....

I recall getting my new TZR250 in 87 to go proddie racing. In 1988 the AMCC introduced a clubmans class which was chock full of Impulses - many ridden by guys new to racing who still had stock tyres etc....that and a few Rg400's whih had been dumped here too in the same shipment.

We were also allowed to cross enter from 250 proddie into the clubmans class, so along with my old 125, I used to have quite a lot of racing in one day....lucky I was young!

Anyway, I digress. First clubmans practice session at the Puke club circuit (2 and a 1/2 corners!), I swear there were 3 more impulses on the deck, parked up on each corner each successive lap I did. Started as a pretty full grid too....bloody orange things everywhere upside down! I was crap even though I'd been racing 3 years at that point, but hell, there could show Japanese Kamikaze pilots a few things!

[Grumph]

Yeah....and guys thinking they were going to win the F3 championship out of the box, first time up....

I recall getting my new TZR250 in 87 to go proddie racing. In 1988 the AMCC introduced a clubmans class which was chock full of Impulses - many ridden by guys new to racing who still had stock tyres etc....that and a few Rg400's whih had been dumped here too in the same shipment.

We were also allowed to cross enter from 250 proddie into the clubmans class, so along with my old 125, I used to have quite a lot of racing in one day....lucky I was young!

Anyway, I digress. First clubmans practice session at the Puke club circuit (2 and a 1/2 corners!), I swear there were 3 more impulses on the deck, parked up on each corner each successive lap I did. Started as a pretty full grid too....bloody orange things everywhere upside down! I was crap even though I'd been racing 3 years at that point, but hell, there could show Japanese Kamikaze pilots a few things!

Down here, Mo Haley actually built one up for a local lad. Crashed road bike I believe. Stock tank, 'glass seat with clipons and rearsets. Basically stock but a bit noisier. The lad rode it and learned quickly, moved on and upward after a couple of seasons on it. It's disappeared now but would still be a fun bike to pull out for pre89 F3 on the short tracks.

[Mikael]

Hi, I have a gk71b & a genuine Suzuki service manual for one. The engines are near enough the same. If you want to know any specifics let me know.
Warning, they are a total party on wheels, I can't ride mine without bouncing it off the limiter a few times every time.

Much thanks Sidecar Bob. I have found the carb specs so far and thats about it. Thank you.

[Mikael]

Well there's some encouragement for your restoration, hope that helps. ;)

Yes my thoughts too, gave me a chuckle tho...

[F5 Dave]

Hey if anyone has the manwel to hand can they post up the valve clearances? Guessing they are shim under bucket just to lessen my desire to open this thing up?

[Mikael]

You've done restoration work on other bikes before? Just checking before offering any advice.

No sir this is my first restoration but I have some help. My brother is a panel beater and I have just started some part time work at a garage so have a couple of people that can help. Any advice would be appreciated as this is all new to me. I owned a repulse back in the day so this is purely a memory lane deal. Not so concerned about getting it perfect. I really would just like to ride one of these again.

[Mikael]

Thanks for all the comments. The engine starts and runs on 3 cylinders, front shocks are leaking fork oil, rear shock is stuffed, regulator/rectifier needs replacing as voltage is all over the place. Breaks are shot front and rear. The only good parts are the cosmetics/fairing. I have started sanding and prepping them. I need to make sure the engine is worth saving. It is not the original engine. The previous owner threaded one of the spark plug threads so I am hoping that this is not part of the problem with the cylinder that is not working. The carbs are leaking gas so prob looking at replacing the needle valves...

[Mikael]

Maybe this would be worth buying , either for parts, or the main resto bike.
http://www.trademe.co.nz/Browse/Listing.aspx?id=1381591821
It probably won't go for a lot.
I saw this but missed out on it. As you guessed it went for chump change.

[Grumph]

Hey if anyone has the manwel to hand can they post up the valve clearances? Guessing they are shim under bucket just to lessen my desire to open this thing up?

From my notes done back in the day, I used .004in inlet and .005in exhaust clearances. Screw and locknut adjusters on all the ones I've seen.
Just like a big GSXR of the period.

[F5 Dave]

Thanks Greg. Cool, easy then. Not 2stroke easy, but better than the last couple of foulstrokes I've worked on.

[Blackbird]

I don't know how relevant it is to an Impulse but I have an electronic copy of a full workshop manual for a GSX-400 which covers the 1982 FZ and 1983 FD models. It's about 40 Mb so can't post here but anybody with a genuine interest can PM me and I'll look at uploading it to a Dropbox address or similar. Got hold of it for a mate who was restoring a 400 a good few years ago. He made a lovely job of it.

[James Deuce]

I don't know how relevant it is to an Impulse but I have an electronic copy of a full workshop manual for a GSX-400 which covers the 1982 FZ and 1983 FD models. It's about 40 Mb so can't post here but anybody with a genuine interest can PM me and I'll look at uploading it to a Dropbox address or similar. Got hold of it for a mate who was restoring a 400 a good few years ago. He made a lovely job of it.
Good try Geoff, but not even slightly related. The Repulse is basically a naked 1984-86 GSXR400. 4 cylinder, single shock rear end, etc., etc. With bits of the Sydney Harbour Bridge painted orange and tacked on randomly.

[Blackbird]

Good try Geoff, but not even slightly related. The Repulse is basically a naked 1984-86 GSXR400. 4 cylinder, single shock rear end, etc., etc. With bits of the Sydney Harbour Bridge painted orange and tacked on randomly.

Yeah, I know what the Impulse looks like Jim but wondered if the motor was the same. Don't have any knowledge at all about those small Suzuki motors. Never mind :2thumbsup

[James Deuce]

Yeah, I know what the Impulse looks like Jim but wondered if the motor was the same. Don't have any knowledge at all about those small Suzuki motors. Never mind :2thumbsup
The one you posted is a twin.

[T.W.R]

Yeah, I know what the Impulse looks like Jim but wondered if the motor was the same.

Impulse is a baby oil-boiler ;)

[Blackbird]

The one you posted is a twin.

Have a closer look......

[James Deuce]

Have a closer look......
Can't won't let me expand the pics on KB anymore.

I take it that that's the air-cooled four then? Repulse is a SACS engine. Oil cooler and under piston oil jets.

[T.W.R]

Repulse is a SACS engine. Oil cooler and under piston oil jets.

So is a XN85 and it's air cooled :bleh:

[James Deuce]

So is a XN85 and it's air cooled :bleh:
Yeah, yeah.

[Blackbird]

Can't won't let me expand the pics on KB anymore.

I take it that that's the air-cooled four then? Repulse is a SACS engine. Oil cooler and under piston oil jets.

Yep, it's a 4 and sounded really sweet.

[T.W.R]

Yeah, yeah.

:laugh: the XN85 is the grand daddy of the whole SACS family :msn-wink: they had to do it because the 1st incarnations kept melting the pistons of the standard GS650 motor so they thickened the piston crowns & started the under piston oiling jets :niceone:

[Grumph]

Yeah, I know what the Impulse looks like Jim but wondered if the motor was the same. Don't have any knowledge at all about those small Suzuki motors. Never mind :2thumbsup

The GSX400 aircooled four was - along with the GSX750 - Suzuki's first family of 16V plain bearing motors. All that family suffer from lubrication faults - as in not enough and poor oilway design. When the GSXR came along they'd obviously found a man who knew how to lay out oil galleries properly and a source of big enough pumps...
Other than being a four and 400cc 16V, there's sfa in common with the later engines AFAIK. The Impulse followed the GSXR400 and both were as has been mentioned partially oil cooled. If someone who knows how, bleeds the cooling system they don't overheat.

[Blackbird]

The GSX400 aircooled four was - along with the GSX750 - Suzuki's first family of 16V plain bearing motors. All that family suffer from lubrication faults - as in not enough and poor oilway design. When the GSXR came along they'd obviously found a man who knew how to lay out oil galleries properly and a source of big enough pumps...
Other than being a four and 400cc 16V, there's sfa in common with the later engines AFAIK. The Impulse followed the GSXR400 and both were as has been mentioned partially oil cooled. If someone who knows how, bleeds the cooling system they don't overheat.

Always something to learn - thanks for that!:niceone:

[OddDuck]

No sir this is my first restoration but I have some help. My brother is a panel beater and I have just started some part time work at a garage so have a couple of people that can help. Any advice would be appreciated as this is all new to me. I owned a repulse back in the day so this is purely a memory lane deal. Not so concerned about getting it perfect. I really would just like to ride one of these again.

OK, advice to follow, here's what you'll need:

1) Space, both working and storage for the bits that'll come off. 1 single car garage working space, 1 garage worth of shelving for bits. Stacking storage bins will do in a pinch. It's amazing how much the volume expands once the bike comes completely to bits.

2) Cash. You'll be buying tools, supplies etc... watch those dollars. Buy stuff after it's clear that you'll need it, not by guesswork in advance. My rule of thumb was first time, borrow or improvise, second time, just go get the right tool.

3) Lines of supply. Scout the local shops. What's there? When are they open? What can you get on-line and what are delivery times like? Can you buy a solution to a problem, instead of putting in crazy amounts of work? You will also need a reliable source for replacement parts. Some components will be stuffed and will need replacement.

4) Light. Lots and lots of working light. For some unknown reason Kiwis seem to like working in grungy caves... save yourself the eye strain, paint the workspace white, seal the floor if you can (wish I'd done mine), put lights in everywhere, take a weekend out from the resto and work on the workspace. White surroundings will bounce light into corners and keep contrast levels under control. Keeping things visible really reduces the fatigue.

5) Ziplock plastic bags (all sizes, lots of), marker pens and masking tape for labelling the bags too. Mechanical components that should be kept in oil (like engine innards) should be in the ziplocks. Oil-soaked rags will dry out after a while (six months to a year) and you'll come back to rusty camshafts.

6) A digital camera that you can use. I can't stress this enough: A camera which you can drive, that does what you want it to. You'll want to choose where it focuses, and what values it selects for exposure so that you can actually see what it's a picture of. I tend to avoid using flash (tried; too many problems with bounce off metal) and use a tripod and long exposures instead.

7) Internet, public library, people with experience.

8) A car. It pains me to say it but you'll need a car. There will be quite a few times you'll have to move something heavy or big.

9) A bike lift isn't essential but is very, very nice to have. Unless you have trick knees or a bad back. Then it's essential.

10) Accurate measurements. This is a pain in the arse at first but good measurements mean good decisions. No measurements means guesswork and probably having to do stuff twice, or wasting money doing things you didn't have to do.

11) Get PPE in advance and wear it. Bikes come and go, but you only get one set of eyes, ears, nervous system, lungs etc.. exposure or risk will add up after a while.

And some quick basics...

Keep the place tidy, it's faster and easier.
Use six point sockets wherever possible (twelves rip things up).
CRC 5.56 or PB Blaster work best when allowed to soak in overnight.
Spray paint drifts like crazy, expect spray droplets to mark things ten feet away from whatever you're painting. Take it outside and close the door. Seriously.

*** wrecker's or secondhand parts are a pretty serious crapshoot in this country, there are a lot of cowboys out there selling 90% stuffed at 50% of new price. ***

That's probably way more than enough for now, good luck and keep us posted.

[Mikael]

Fucking moaners.

If I remember correctly they were $3999 brand spanking new. Suzuki sold heaps of them. Sportier and cheaper than a farty old 450 twin Suzuki, CB400 twin (fat, slow, boring) or old fashioned GB400 Honda. Can't remember Yamahas 400 of the day - old fashioned SR500 probably or XS400 twin. Kawasaki had the Z400/440 at the time (I owned a 440).

Yep the Suzuki was bright, fresh and screamed it's little guts off into many peoples hearts.

Restro? Questionable if it has any real value other than memory lane. But there are worse bikes to sink money into.

Memory lane value, I agree, for the money they were great little bikes.

[Mikael]

OK, advice to follow, here's what you'll need:

1) Space, both working and storage for the bits that'll come off. 1 single car garage working space, 1 garage worth of shelving for bits. Stacking storage bins will do in a pinch. It's amazing how much the volume expands once the bike comes completely to bits.

2) Cash. You'll be buying tools, supplies etc... watch those dollars. Buy stuff after it's clear that you'll need it, not by guesswork in advance. My rule of thumb was first time, borrow or improvise, second time, just go get the right tool.

3) Lines of supply. Scout the local shops. What's there? When are they open? What can you get on-line and what are delivery times like? Can you buy a solution to a problem, instead of putting in crazy amounts of work? You will also need a reliable source for replacement parts. Some components will be stuffed and will need replacement.

4) Light. Lots and lots of working light. For some unknown reason Kiwis seem to like working in grungy caves... save yourself the eye strain, paint the workspace white, seal the floor if you can (wish I'd done mine), put lights in everywhere, take a weekend out from the resto and work on the workspace. White surroundings will bounce light into corners and keep contrast levels under control. Keeping things visible really reduces the fatigue.

5) Ziplock plastic bags (all sizes, lots of), marker pens and masking tape for labelling the bags too. Mechanical components that should be kept in oil (like engine innards) should be in the ziplocks. Oil-soaked rags will dry out after a while (six months to a year) and you'll come back to rusty camshafts.

6) A digital camera that you can use. I can't stress this enough: A camera which you can drive, that does what you want it to. You'll want to choose where it focuses, and what values it selects for exposure so that you can actually see what it's a picture of. I tend to avoid using flash (tried; too many problems with bounce off metal) and use a tripod and long exposures instead.

7) Internet, public library, people with experience.

8) A car. It pains me to say it but you'll need a car. There will be quite a few times you'll have to move something heavy or big.

9) A bike lift isn't essential but is very, very nice to have. Unless you have trick knees or a bad back. Then it's essential.

10) Accurate measurements. This is a pain in the arse at first but good measurements mean good decisions. No measurements means guesswork and probably having to do stuff twice, or wasting money doing things you didn't have to do.

11) Get PPE in advance and wear it. Bikes come and go, but you only get one set of eyes, ears, nervous system, lungs etc.. exposure or risk will add up after a while.

And some quick basics...

Keep the place tidy, it's faster and easier.
Use six point sockets wherever possible (twelves rip things up).
CRC 5.56 or PB Blaster work best when allowed to soak in overnight.
Spray paint drifts like crazy, expect spray droplets to mark things ten feet away from whatever you're painting. Take it outside and close the door. Seriously.

*** wrecker's or secondhand parts are a pretty serious crapshoot in this country, there are a lot of cowboys out there selling 90% stuffed at 50% of new price. ***

That's probably way more than enough for now, good luck and keep us posted.

Thanks for all that, golden. Thats a lot of good info cheers. I have a mate willing to do a compression test for me and rebuild the breaks. It seems the more mates I show this thing the more people I have wanting to help (as long as they can have a ride on it!). A lot of guys in Taranaki have fond memories of these things, musta been a popular bike in the Naki.
Thank you for taking the time to share those nuggets of info OddDuck.

[Mikael]

I found these carb specs if anyone else needs this info...

Carbs

ITEM Specifications

type - AISAN AS27VW
I.D. No. - 04A10
Bore - 27 mm
Idle r/min - 1300+/-100 r/min.
Fuel level - 9.0+/-0.5 mm
Float height - 20.5+/-1.0 mm
Main jet - #94
Main air jet - 1.2 mm
Jet needle - 5B10-3rd
Needle jet - 2.60 mm
Throtlle valve - 11.0
Pilot jet - #34
By-pass - 0.8,0.8,0.8 mm
Pilot outlet - 10.8 mm
Valve seat - 2.5 mm
Starter jet - GS1 #60, GS2 #54
Pilot screw - PRE-SET (2 turn out)
Pilot air jet - 1.35 mm
Throttle cable play - 0.5 - 1.0 mm
Choke cable play - 0.5 - 1.0 mm

[Mikael]

The big find is that while browsing through a 1985 GSX 400 R workshop manual i have found that the carbs and break system is identical to the Impulse. This is great news as now I have a manual for those parts and many other systems that these two models share. The later model GSX 400 R used a different carb. This means parts availability has opened up a little wider now too.
Made some progress. Have cleaned a lot of grease off the bike and have discovered a lot of the parts are in reasonable condition. The chain and sprockets are completely rust free and in good order.
I have found the source of a couple of leaks (one of the cooling hoses is cracked and 2 fuel overflow hoses were hanging loose, so what I thought was an oil leak was just fuel peeing over the oily bike). Also found a broken air box hose connection from the top of the motor.
Will try and do a compression test this weekend so I know what Im looking at.
Need a new reg/rec as the system is overcharging at the battery.
CDI seems in order.
The lights and indicators all work (small blessing!).

332862332863332864332865

[Mikael]

Have been working on the fairing. Some small repairs but otherwise good condition.

Plasti coated, good stuff.

332866332867332868332869

[kiwi cowboy]

The big find is that while browsing through a 1985 GSX 400 R workshop manual i have found that the carbs and break system is identical to the Impulse. This is great news as now I have a manual for those parts and many other systems that these two models share. The later model GSX 400 R used a different carb. This means parts availability has opened up a little wider now too.
Made some progress. Have cleaned a lot of grease off the bike and have discovered a lot of the parts are in reasonable condition. The chain and sprockets are completely rust free and in good order.
I have found the source of a couple of leaks (one of the cooling hoses is cracked and 2 fuel overflow hoses were hanging loose, so what I thought was an oil leak was just fuel peeing over the oily bike). Also found a broken air box hose connection from the top of the motor.
Will try and do a compression test this weekend so I know what Im looking at.
Need a new reg/rec as the system is overcharging at the battery.
CDI seems in order.
The lights and indicators all work (small blessing!).

332862332863332864332865

Are you sure you have a 1985 manual you speak of above?.

The 86-87 gsxr400 is the same as the impulse but the motor on the 85 is a lot different.
Have a full manual here.
Great bikes and a lot of fun on track.
Raced a 87 gsxr400 in cams for 4 years and then sold it.
Still going strong last I heard lol.

[ellipsis]

Are you sure you have a 1985 manual you speak of above?.


Raced a 87 gsxr400 in cams for 4 years and then sold it.
Still going strong last I heard lol.


...miss your smiley face around the traps too...

[Mikael]

Are you sure you have a 1985 manual you speak of above?.

The 86-87 gsxr400 is the same as the impulse but the motor on the 85 is a lot different.
Have a full manual here.
Great bikes and a lot of fun on track.
Raced a 87 gsxr400 in cams for 4 years and then sold it.
Still going strong last I heard lol.

I have a PDF manual that claims to be the 85. The carbs and brake system are the same. I was just meaning that those 2 systems are the same on the 85 model. As for the engine yes it looks different. Thanks for the heads up about the engine. So can I use engine parts from the 86, 87 gsxr 400 models for the impulse?

[Grumph]

I have a PDF manual that claims to be the 85. The carbs and brake system are the same. I was just meaning that those 2 systems are the same on the 85 model. As for the engine yes it looks different. Thanks for the heads up about the engine. So can I use engine parts from the 86, 87 gsxr 400 models for the impulse?

Don't count on it....they played around with bore and stroke a couple of times.
Only once it's in your hand and measures up identical should you believe it.

[kiwi cowboy]

...miss your smiley face around the traps too...

Hehehehehe don't speak too soon. Me BAAAAAAAck.

Booking dec meet soon.

[Mikael]

Don't count on it....they played around with bore and stroke a couple of times.
Only once it's in your hand and measures up identical should you believe it.

Ok thanks Grumph.

[Mikael]

So since found a manual for the Tokyo Tower and ordered brake seals front an rear. Scrubbed brakes clean.

[jellywrestler]

So since found a manual for the Tokyo Tower and ordered brake seals front an rear. Scrubbed brakes clean.

i very very rarely replace brake seals, there's never much that can get in there so with careful pulling apart, inspecting for damage and reassembling things are back to new.

[Grumph]

i very very rarely replace brake seals, there's never much that can get in there so with careful pulling apart, inspecting for damage and reassembling things are back to new.

Agreed. Because we don't salt our roads, it's the main difference between the restorations in the UK based magazines and the same job here.
Brakleen and lashings of rubbergrease do me.

[F5 Dave]

Agreed, Though the outer dust seals can get distorted or worn and cause issues. Do spend time carefully cleaning out the grooves they sit in.

I bought a kit for the same brakes as they were too far gone. Still not good enough. Master cylinder swap brought them back to life instantly.

[Mikael]

i very very rarely replace brake seals, there's never much that can get in there so with careful pulling apart, inspecting for damage and reassembling things are back to new.

I had to change the dust seals as they were stuffed so thought might as well do the lot.The last owner sadly neglected this bike.

[F5 Dave]

Sheesh, Greg, whatda yathink? This little 400 is a pig to start.
Thought I'd found a good reason when all the valves were tight as.
Replaced a couple of plug caps which had gone silly. Dyna coils and std copper wire.

But it just takes ages to start. Will fire and die repeat. Don't dare touch the throttle. Starts best with little or no choke. More choke forget it.
Owner says all her 400s were dreadful to start. But I can't give it back like this. It's unusable.
When it's finally hot it seems to start and run fine.

Took it for a ride and screams along.

Adjusted the idle mixture to reduce a lean lag off closed. But tried several settings and starting is just as dire. Choke plungers seem home.

[Grumph]

Well, funnily enough, I have a 250 GJ72A here at present with I assume the same twin choke carbs ?
Got them stripped out and will be picking up some carb cleaner tomorrow.
The idle mixture screws should be pulled - incl the springs, washers and O rings - and that passage cleaned.
Lack of O rings there can cause a lean idle too.
Float height ? vacuum leaks - particularly the hose to the tap ?

Check the air gap ignition trigger/pickup. Close them up to around .010 - .012 thou. As they age they get less sensitive.
Bit like me really....

[F5 Dave]

Yeah I built 1 set of carbs from 3. Twin choke. As the designer should be. Diaphragms working.
Vacuum plugged as gravity on gsxr. Floats unadjustable, Seemed undamaged plastic.

But I never pulled the idle mixture screws. I'll check. Thank you.

Presumably the air gap of the pick up coil is hard to check if attached, I assume, to the side cover and acting on a crank mounted flywheel?

[Grumph]

Yeah I built 1 set of carbs from 3. Twin choke. As the designer should be. Diaphragms working.
Vacuum plugged as gravity on gsxr. Floats unadjustable, Seemed undamaged plastic.

But I never pulled the idle mixture screws. I'll check. Thank you.

Presumably the air gap of the pick up coil is hard to check if attached, I assume, to the side cover and acting on a crank mounted flywheel?

All the Suzuki fours have case mounted pickups - the cover is just that.

[F5 Dave]

kewl thanks

[Mikael]

334764334765334766334767

[bungbung]

334802

I had an Impulse years ago, mine wasn't a very good example but it was still great fun.
Check the swingarm for cracks as the wall section used was pretty thin.

[jasonu]

334802

I had an Impulse years ago, mine wasn't a very good example but it was still great fun.
Check the swingarm for cracks as the wall section used was pretty thin.

Was Suzuki marketing the Impulse towards faggots?

[Drew]

I always kinda liked the mental styling.

[jellywrestler]

Was Suzuki marketing the Impulse towards faggots?


I always kinda liked the mental styling.

it appears the answers yes then

[actungbaby]

Hello, starting a restoration on an Impulse. If anyone has experience working on these bikes I would be grateful to hear any tips or information regarding a restoration on one of these. I have very little information but would like to see this bike on the road again as there are not too many of them. Also looking for parts. Great bike from the 80s. Thanks in advance.

Hi i was so wanting one at the time i didnt have the money . they where a great price .
i be watching this space ,love toknow how it goes.

I think 400cc inlines are a blast, well 400cc class has just right amount of power.

250 cc are great too , but a four hundred has ,just got a little more .

my second and 3rd Bike,s where 400,s one a boring cb 400n the other cbx 400 f chouldint be more diffrent. inline was so much more balanced, and great engine ,bloody exciting.

Dont listen to bs comments so people just children . or jealous

Keep up the awesome work.

[Drew]

Hi i was so wanting one at the time i didnt have money to fun one ;-) they where a great price . i be watching this space love ot know how it goes.

I think 400cc inlines are a blast well 400cc class just right amount of power.

@%0 cc are great but just got a little more with a 400. my second and 3rd

Bike where 400,s one a boring cb 400n the other cbx 400 f chouldint be more diffrent. inline was so much more balanced and great. engine bloody exciting.

Dont listen to bs comments so people just children . or jealous

Keep up the awsome work.

Jesus tittie fucking Christ, slow down when you type man. Ain't nobody got time to try a decipher that shit.

[actungbaby]

Jesus tittie fucking Christ, slow down when you type man. Ain't nobody got time to try a decipher that shit.

opps yeah i try get whats flowing more than i can keep up. edited.

[Mikael]

Hi i was so wanting one at the time i didnt have the money . they where a great price .
i be watching this space ,love toknow how it goes.

I think 400cc inlines are a blast, well 400cc class has just right amount of power.

250 cc are great too , but a four hundred has ,just got a little more .

my second and 3rd Bike,s where 400,s one a boring cb 400n the other cbx 400 f chouldint be more diffrent. inline was so much more balanced, and great engine ,bloody exciting.

Dont listen to bs comments so people just children . or jealous

Keep up the awesome work.

Thanks mate. Really enjoying the process. Have just received a bunch of parts so will be posting more progress photos soon. Totally agree about the 400cc bikes. Thanks for the encouragement.

[Mikael]

334802

I had an Impulse years ago, mine wasn't a very good example but it was still great fun.
Check the swingarm for cracks as the wall section used was pretty thin.

Thanks Bungbung. I will do. Everything will be stripped and inspected apart from the engine.

[Mikael]

334900334901

[Mikael]

Found a pretty good left foot gear control lever and some grips that look brand new.

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[Mikael]

Good try Geoff, but not even slightly related. The Repulse is basically a naked 1984-86 GSXR400. 4 cylinder, single shock rear end, etc., etc. With bits of the Sydney Harbour Bridge painted orange and tacked on randomly.

It is closer to the 1987 GSXR 400 GK71F. The repulse shares the same engine, brakes and carb with that year. The 1985 and 1986 (Gk71A and Gk71B) share only the brake system with the repulse. One of them has the same carbs but cant remember which one, the other has the newer 4 seperate carb setup instead of the repulse weird dual carb thingies. They bpth have a different engine.

[F5 Dave]

Thanks Bungbung. I will do. Everything will be stripped and inspected apart from the engine.
So that just seems bizarre with that picture, hopefully we'll be spared those pictures.:shutup:

[Grumph]

Working on a gsxr250 which has the same style of steel frame. A lot of components are held on via threaded inserts crimped into the frame tubes.
These are a major frustration once they've come loose...If you're stripping it down to the bare frame, check every last one of these inserts - and weld the bastards back in place if it's needed. Run a tap through them after securing too.

[Drew]

Working on a gsxr250 which has the same style of steel frame. A lot of components are held on via threaded inserts crimped into the frame tubes.
These are a major frustration once they've come loose...If you're stripping it down to the bare frame, check every last one of these inserts - and weld the bastards back in place if it's needed. Run a tap through them after securing too.

They're called rivi-nuts Greg. Handy little doofers. Cheap and easy to replace. Or chuck a bolt in there with a nut on it and re squish them if ya don't have a riv-nut tool.

[F5 Dave]

I have the tool but on mine it's a bit of a learnt skill to get them tight enough but then not strip them out if you go too far. Lot of leverage. Better tool no doubt has settable limit.

[jellywrestler]

They're called rivi-nuts Greg. rivnuts actually, also captive nuts.

[Drew]

rivnuts actually, also captive nuts.

Typo chief. You'll note it's correct where I wrote it a second time.

[Grumph]

Yeah, I know about rivnuts - but 80's Suzuki's don't use genuine rivnuts - they use some bastard home market version.
The trick with the bolt and nut to tighten them up frequently strips them...And once they've got a broken bolt in them and are loose in the frame, I seriously don't want to know. Bastards.

[jellywrestler]

a riv-nut tool.


Typo chief. You'll note it's correct where I wrote it a second time. no, it's not correct either time, it's called a rivnut

[jasonu]

I have the tool but on mine it's a bit of a learnt skill to get them tight enough but then not strip them out if you go too far. Lot of leverage. Better tool no doubt has settable limit.

You have the tool that looks like a pop riveter. The proper rivnut air tool can be pre set.

[actungbaby]

334900334901

Nice lovley work mate keep it up

[Mikael]

Thanks mate. Have done a compression test and the results are abysmal but I have another engine lined up with great compression. The electrics are all go. Frame will be powder coated. Wheel bearing replaced and front forks need rebuilding and then I can start putting it all back together. Really appreciate the encouragement.

[F5 Dave]

Yeah, Ks old Pulse was hard to start and felt like no comm after sitting. I rode it to manfield using low gears. Was fine after that.

[F5 Dave]

Well finally got some time to pull out all the air adjusters from the carbs. O-ring all intact and round. Light grease put back in.
Pulled the sidecover and slotted the pulsar coils to move them closer. Used some grease so it was wiped fairly thin after several iterations.


Still doesn't like the choke and once cold again is a swine to start. Easy when hot.
Running out of ideas. Com was OK. Valves now ok. Choke is turning off as it makes a big difference turning it on.

[Grumph]

So what changes when hot ? What did you set the valves to ? have you checked plug cap and lead resistance ?

Trouble is we just don't know which bit of the puzzle has aged the worst.
Those twin choke carbs were good starters when nearly new - even the Impulse I took out to 500cc and put on alky was an instant starter.

[F5 Dave]

Quite a few valves were tight, I set them to whatever the manual she had specified.

Replaced a few caps until I got good readings. Copper leads and dyna coils.

Really sick of this bike.
Goes ok when warm.

[Grumph]

If you've still got the manual, see what the coil nominal resistances are supposed to be - and if the Dyna's match that.
I've got a niggling memory that the OE coils are unusually low ohnms.

[F5 Dave]

Hmm, I could ask for the std coils off the impulse.

[Mikael]

337131337132337133337134

[Mikael]

337135337136337137337138337139

[F5 Dave]

I might have to send you Kali's carbs.

Actually they are next for my final fling of getting the sodding thing starting properly.

[F5 Dave]

Well I pulled the 2nd set of carbs to see how the chokes were fed.

Hmm, so the brass tubes sit in drilling and have 2 drilling, centre and side.

Pull carbs off bike. Sure enough brass tubes are blocked on both sides of twin carbs. Finally have a use for my jet drills. Tiny holes.
Then check the float bowls. Of the 4 I have 3 are blocked. More careful drilling. Finally petrol when tipped into the bowl fills the drilling.

Back together problem sorted. Will it start? The fuck it will . Arseholes! :crazy:

[Drew]

Well I pulled the 2nd set of carbs to see how the chokes were fed.

Hmm, so the brass tubes sit in drilling and have 2 drilling, centre and side.

Pull carbs off bike. Sure enough brass tubes are blocked on both sides of twin carbs. Finally have a use for my jet drills. Tiny holes.
Then check the float bowls. Of the 4 I have 3 are blocked. More careful drilling. Finally petrol when tipped into the bowl fills the drilling.

Back together problem sorted. Will it start? The fuck it will . Arseholes! :crazy:

You've had it running though yeah? Cunts of things when they dont go for fuck all reason. Had a GF250 that wouldn't go because of broken magnets in the hall effect generators once.

[Grumph]

Back together problem sorted. Will it start? The fuck it will . Arseholes! :crazy:

Can of Start Ya Bastard - and be generous with it.....

[F5 Dave]

Yeah when it's warm it's fine.

Tried brake clean which is my usual starter fluid. Might have to buy some better stuff.

[Drew]

I'm guessing you've tried winding the pilot screws right out.

[F5 Dave]

Yeah. Need to be a bit to reduce off idle stumble. The choke was having no effect before. Have to start it to see if it is doing something now. Well actually it was leaning it before so was better off with it closed.
Not surprising as the fuel feed to it was blocked . That little guy feeds the bore the choke tube slides into. Part way down that bore is a .7mm drilling. Not sure why it is so small. If it's smaller than that the fuel bowl can be filled and it won't fill up the bore.
Does now.
Thought I'd found the issue and why it has always been a pig to start.
I can't give it back to her this bad though.

[F5 Dave]

Ha. Just reading s Practical Sportbike mag i subscribe to. Letter in about hard starting GSXR400. They offer up the choke drilling, the valve clearance, the coils and CDI. Done all those. Well the last two I'm assuming as I can get a spark to jump 8mm from a HT so that seems pretty useful at cranking speed. Dyna coils with std copper leads. Could swap a spare CDI out of desperation but not sure how that could help.

I'll get some ether start fluid and then check if the choke is now having and effect.

[jasonu]

Ha. Just reading s Practical Sportbike mag i subscribe to. Letter in about hard starting GSXR400. They offer up the choke drilling, the valve clearance, the coils and CDI. Done all those. Well the last two I'm assuming as I can get a spark to jump 8mm from a HT so that seems pretty useful at cranking speed. Dyna coils with std copper leads. Could swap a spare did out of desperation but not sure how that could help.

I'll get some ether start fluid and then check if the choke is now having and effect.

Buy a 2 stroke.

[F5 Dave]

S'not my bike!

[F5 Dave]

Well got back from ride early and after some van plugs (tedious but gap was like 3mm)
Dragged the GSXR out. Quick spray of Startyabastatd and fires straight up no choke. Then the button stopped working. It's been dicky.

Pull twist grip off. Lots of bodge joins. Solder joints in heatshrink but all that does is make a great joint that is stiff and will fracture. Replaced a full wire and ignored other horrors. Although I did remove the nasty splice fitting.

Squirt. Varroom.
Apply a bit of choke and hey what do you know? The choke is working as it should.

Will try it all again sans spray later.

[F5 Dave]

Well actually that has made some difference . I can actually start it from cold. Not the smoothest but it makes the choke work.

Maybe I'll balance the carbs and that will be enough.

Just need to find the pesky clunk in the front end.

[Grumph]

Well actually that has made some difference . I can actually start it from cold. Not the smoothest but it makes the choke work.

Maybe I'll balance the carbs and that will be enough.

Just need to find the pesky clunk in the front end.

Um - front end clunk story....My Kawa 500 F3 bike uses GSXR400 sliders (ex Tony McMurdo) on kawa stanchions - to use twin discs.
I blanked off the antidive holes with a cover plate which had slots cut to allow the damping to work - as you do...
It's always had a front end clunk as you hit the brakes. Nothing's loose inside, calipers and pads don't move, discs don't clunk.
I've suspected it's an oil gallery air restriction but never worried enough about it to do anything - after all, it wasn't me riding it mainly.

[F5 Dave]

Odd.
I did the plate mod on my RG. First time without the slot:facepalm:
These don't have antidive though. Still need to check it out but will keep that in mind thanks.

[F5 Dave]

Not sure what happened to the OP.

GSXR starts like a champ. Those choke holes made all the difference.

Took it for a wof todsy Failed. Rushed back to her place, extracted a spare top shock bearing to put in the linkage same bearing.

WOF guy gone home early but I might get rid of this thing yet.

[F5 Dave]

New tyres months rego.

Loaded in the van for a refresher lesson on easy roads. Warm it up while she puts on gear. Bike stops. Just like that. No starty. Back in van to home. Hmm, no spark. Arsebiscuits.

Inside for a cuppa the missus suggests.
Later I try it and it starts.

I hate this thing.

[Grumph]

Worn ignition switch barrel ?

[F5 Dave]

Turned over just fine.

[Drew]

Turned over just fine.

On an old GSX250 I had, it was a broken wire down by the steering stop inside the loom. Came off the ignition, but still wound over on the button.

I think the ignition lights stayed on and everything.

[F5 Dave]

Hmm, ok, might look at that. I had to fix the start button wire previously.
Odd thing was this was just idling away for a couple of minutes with no one touching it, then nothing.

[F5 Dave]

Well I thought I knew a thing or two but this bike has me just about bluffed.

Swapped in spare cdi. Pulled emulsion tube 1. It's a bit oval. Cool. Swapped it for a spare that looked round.

Starts up on 4, runs the best it ever has when cold.

Tank back on. Starts on 3!!?!!

Grr. Clean plug and swap with its neighbour. Swapped dyna coil wires from 1 and 4 just for giggles. Yes the are copper cores.
Runs great leave it idling for 10 min. Give the ignition switch wires a good wrench around. Crack throttle till gets to line on temp gauge and fan comes on.

So have I fixed the stall issue with the cdi? Have I fixed the fouling of plug 1?

Only time and tedious reality will tell.

[Mikael]

Rear wheel..

[Mikael]

343437343436343438343439343440343441

[F5 Dave]

Looking sharp. Still have the 400 in my lockup. All going well, just the owner is too scared to ride it after a 2kph tip over. It will probably never leave. Sigh. New BT45s as well as a WOF. She never sells anything though.

When you get it up and running read back over how I cleaned out the choke cct. Will never start easily without doing so.

[Mikael]

Looking sharp. Still have the 400 in my lockup. All going well, just the owner is too scared to ride it after a 2kph tip over. It will probably never leave. Sigh. New BT45s as well as a WOF. She never sells anything though.

When you get it up and running read back over how I cleaned out the choke cct. Will never start easily without doing so.

Thanks Dave. Would be interested to read that if you have a link.

[Mikael]

349120

Current progress. Almost there

[Grumph]

Hadn't looked at this for yonks. the pics of your wheels (nice...) brought back memories. Years back I got asked to participate in an evening for the BEARS club guys. Idea was to bring them up to date with new rules for scrutineering purposes. A couple of the example bikes there had impulse wheels fitted. Well, they were easily available 17's...and cheap.
I pointed out that they had wheel bearings on close centers - which on heavy bikes meant they cut out quite quickly.
One of the bikes there was already a fail with discernable play. An eye opener for some of them.

[Drew]

I pointed out that they had wheel bearings on close centers - which on heavy bikes meant they cut out quite quickly.
One of the bikes there was already a fail with discernable play. An eye opener for some of them.

Is there enough meat left to pack the bearings out?

[husaberg]

Is there enough meat left to pack the bearings out?

The wheel bearings are ball-bearing drew.......How do you pack them out?


Hadn't looked at this for yonks. the pics of your wheels (nice...) brought back memories. Years back I got asked to participate in an evening for the BEARS club guys. Idea was to bring them up to date with new rules for scrutineering purposes. A couple of the example bikes there had impulse wheels fitted. Well, they were easily available 17's...and cheap.
I pointed out that they had wheel bearings on close centers - which on heavy bikes meant they cut out quite quickly.
One of the bikes there was already a fail with discernable play. An eye opener for some of them.

Funny i was thinking of that same story you had said before when i seen the impulse.
Mid 90's Yamahas had tiny bearings and axels i have no idea why they had so small axels then as they made them smaller from the 70-80's 15mm on a FZR1000 or FJ1100 wtf

[Grumph]

Is there enough meat left to pack the bearings out?

Look at the pics. They finish up flush with the outer surface of the housings.
Last time I went to a BEARS meeting I think there were still a couple of Nortons using Impulse wheels.

[RDjase]

Look at the pics. They finish up flush with the outer surface of the housings.
Last time I went to a BEARS meeting I think there were still a couple of Nortons using Impulse wheels.

They are a easy retro fit to FXR150 for bucket racing too, fit 125 slicks.

[F5 Dave]

But they are somewhat boat anchor heavy. Like really heavy.

[geoffm]

They are a easy retro fit to FXR150 for bucket racing too, fit 125 slicks.

They fit pretty easily onto RG400/ 500s as well. Yes, the razor blade rims of the Impulse are actually wider than the "GP replica" 500cc 2 stroke stock rims.
There is a Facebook group for Impulse owners that gets a reasonable amount of traffic.
I was tempted to buy an Impulse for old times sake on Trademe a while back. It hadn't actually dropped much in value from what I remember them selling for new back in the day.
Geoff

[Mikael]

https://youtu.be/SxkkMgNvtJE

[Mikael]

Finished restoration. Side panels are done just keeping them off until Iv tidied a few small items.

[sugilite]

Well Done, that bike looks incredible - better than showroom condition!

[F5 Dave]

Yes indeed.
But avoiding being 'that guy' I've seen White and Dark Blue with fairings. Bronze had the orange girder to headlight, no fairing.

Not to say I saw all the models, but applying for rivet counter badge . . . Now.

[release_the_bees]

Well Done, that bike looks incredible - better than showroom condition!It's definitely in better condition than the one that I briefly had in the early 2000s. I enjoyed it while I had it. It was a decent step up in performance from a KR150, that's for sure.

[Mikael]

Yes indeed.
But avoiding being 'that guy' I've seen White and Dark Blue with fairings. Bronze had the orange girder to headlight, no fairing.

Not to say I saw all the models, but applying for rivet counter badge . . . Now.

This is actually the grey metallic version although it does look a bit bronzy in the photos. I have the Tokyo Tower front faring, head light and guages also. I plan to restore them next so I have both setups. But yes this bike was originally the Tokyo version.

[Mikael]

Well Done, that bike looks incredible - better than showroom condition!

Thanks mate

[onearmedbandit]

Fantastic result! I used to ride one of these in the mid 90's, was a great bike to muck around on. Seeing one in this condition is superb.

[caseye]

Wow! from 2017 to now and she's beautiful, this is a credit to you sir.
Please do post up the absolutely finished item aye.
Take a bow that man, great work.
:first:

[Mikael]

Fantastic result! I used to ride one of these in the mid 90's, was a great bike to muck around on. Seeing one in this condition is superb.

Great podcast onearmbandit :2thumbsup

[Mikael]

Wow! from 2017 to now and she's beautiful, this is a credit to you sir.
Please do post up the absolutely finished item aye.
Take a bow that man, great work.
:first:

will do cheers caseye

[Mikael]

when the project overtakes your room

[Mikael]

Hadn't looked at this for yonks. the pics of your wheels (nice...) brought back memories. Years back I got asked to participate in an evening for the BEARS club guys. Idea was to bring them up to date with new rules for scrutineering purposes. A couple of the example bikes there had impulse wheels fitted. Well, they were easily available 17's...and cheap.
I pointed out that they had wheel bearings on close centers - which on heavy bikes meant they cut out quite quickly.
One of the bikes there was already a fail with discernable play. An eye opener for some of them.

This was the finished set

[Grumph]

Very nice. The whole job looks very good.

New discs or did you get the old ones resurfaced ?

[Mikael]

Very nice. The whole job looks very good.

New discs or did you get the old ones resurfaced ?

Those are new. Was lucky to find a set.

[onearmedbandit]

Great podcast onearmbandit :2thumbsup

Cheers dude!

[Mikael]

Finally finished!

[F5 Dave]

Hookzah!

Kali just left 4 min ago.

. She'd be overjoyed to see that.
She's got one as well ad her GSXR

[caseye]

Na, you just went out and bought that from some Suzi fanatic, that is beautiful, glad you've got her going and! out and about.
Enjoy riding that awesome motorcycle.:first:

[sugilite]

Congratulations, EXCELLENT job! :niceone: