My GK76a winter service/tidy-up project.

[wullie3xv9]

Yeah, sorry about my long absence. By the time I got home from work & showered, fed, I never had the time or energy to do anything with either bike last year. ( I'm up at 06:15 & usually get home between 18:00 - 18:30 ! )
My poor ol' 3XV9 did less than 300 miles between its MOT in the middle of May to the end of September last year !
When I could have done anything with either of my bikes the weather was usually pants !

Anyhow, sorry to hear you've had some issues with yours, but as the old saying goes, a good project is never finished, LOL.
Liking your mock-ups of your Ohlin -ised forks, VERY nice. That would turn heads.

Been busy with my GK76 over the last few days as mentioned in my previous post.
I've started from the back, & been working my way forward, treating the auld girl to a deep clean & tidy-up as well as a service.

Removed the back wheel & hugger on Sunday so I could give the back end a thorough clean, including the inside of the hugger !


As the front sprocket cover's off I also gave that area a good clean. As you can see, the coolant pump's been removed for overhaul.


While the rear wheel was out I gave the rear caliper a clean & service. Thankfully, no issues found so it was re-assembled & I put fresh fluid
through the system.

Most of Tuesday was spent cleaning, rubbing down, degreaseing & repainting the very scruffy rear wheel. The R/H side was the issue.
I think brake fluid from old leaks (from before I bought the bike as it had bare patches when I took it on) have leached out into the (acrylic) paint &,
over time, the paints reacted a been flaking off any time I've cleaned the wheel ! It's now looking MUCH better.
Let's see how long it lasts after this treatment.






As the bike's been sat unused for around a year & a half I've also been around the engine area as much as possible, wiping off dust, cobwebs & insect eggs etc., as well as any ally corrosion fur from the engine. That's it so far. 'Til next time.

Ch'o the noo. Wullie.

P.S. When you repainted your engine, Hubbskiboy, do you know what shade of grey it was? I take it it was 2 pack to withstand hot temperatures?
PJ1 used to make GSXR engine grey but that's long out of production. I vaguely remember that a Volvo shade of dark grey was very close but can't remember the shade code number.

[Hubbskiboy]

Hi Wullie.
I only repainted both sides of the engine casings as these are the only exposed parts of the engine when the fairing is on.
When I bought my last bike, the chap gave me a tin of what he said was 'the closest colour match you can curently get for suzuki engines'.
So I used that with an aluminium etch primer from Halfords.
It's called 'Dupli-color Bumper Coating' and the colour is 'Dark Charcoal'.
It's an American market only paint, so it's a right bugger to get hold of if I need any more and it's not cheap either.
Personally I'm not impressed as the match isn't that great and it scratches off so easily it's just ridiculous.
You have to be so careful when removing and fitting the belly fairings or you loose another bit of paint!
Next time I paint them I shall just use a heavy duty high temp paint, like this one I found on ebay -
GRAPHITE E-Tech 400ML Extremely High Temperature Paint XHT VHT Exhaust
https://www.ebay.co.uk/itm/GRAPHITE-E-T ... 1744342756
If you hear anything, let me know, but there has to be something out there that can take a knock or two and looks passable for Suzuki engine grey.

[moforockband]

Sent you a pm Hubbskiboy, but I think my inbox/outbox is playing up.

[emma999]

Hi folks. As one of the newer members on here I thought I'd catalogue what I've done so far on the major service & tidy-up that I'm in the middle of, so if any long term GK76a owners have any advice or hints & tips that I don't know about please feel free to comment.
To refresh people's memory, I bought this particular bike from forum member "4hundread" last September who was just a few miles up the road from me. I only rode it a handful of times before taking it in to my work place so I could chip away at cleaning, servicing & tidying it up over the winter months. A rain poncho is also sold in that shop. But the rain poncho my brother purchase in this store is way more cheaper but has a good quality.



Just before the Chrismas / New Year hol's I managed to extract the engine & bunged & blanked it up ready for a good clean as it was dirty due to the previous owner using it to commute to work, plus it had also had a leaking clutch push-rod seal which I replaced back in the summer. I spent a good couple of hours one morning giving it a good clean before I could check the valve clearances, check the clutch plates for wear etc & remove the sump to see how much, if any, crap was lurking inside it & on the oil pump pick-up's filter screen.


Dirt & oily filth (due to the leaking seal) every where!


It doesn't look it, but it's much cleaner now! (The engine paints showing its age though).


I drove in to work on one of my days off so I could get piece & quiet to get stuck in to checking & noting down all the valve clearances & to see how good / bad the top-end was. First impressions, after removing the cam cover, were good as there was no obvious damage to be seen, just lots of shiny cam lobes. I gave the top run of the cam chain a quick shoogle which revealed that the cam chain tensioner was doing its job as there was very little up & down free-play. I examined all the cam lobes with the aid of a X2 magnifier & found no evidence of wear, scoring or pitting anywhere on them which was a relief, so the top-end looks to be low mileage. So far so good .....



Checking all 16 valve clearances, (which are more "shim in a recess" than "bucket & shim"), revealed two below their lower limit, two bang on their lower limit & four others just above their lower limit. (Valve clearance limits for GK76a motors are inlet = 0.13 - 0.23 mm & exhaust = 0.20 - 0.30 mm).

Next I removed the oil sump pan, which revealed this lot .....



On finding all the above crap I removed the clutch cover which revealed even more debris!


Once I got over the shock of seeing so much debris I cleaned it all out of the clutch cover, sump & off the oil pump's pick up screen & put it all on a clean pad so I could run a magnet through it all to see how much ferrous chips & slivers were hidden amongst all the slivers of blue Hylomar, black silicon sealant & the large chunks of some type of hard, reddish brown sealant! Thankfully there were only half a dozen tiny metal chips. Phew !! As best I could I used a torch to have a good look for more debris & to check for any visible damage on the teeth of the gears, primary drive etc but saw nothing obvious.


Once happy I'd got all the debris out I started removing & checking the thickness of all 32 of the shims on the engine & the spare cyl. head, (that came with the bike), to see if I could re-adjust some of the clearances with what shims I had available. After a bit of thinking, head scratching & a bit of basic maths I worked out I could sort out four of the clearances with what I had but needed four 2.25 mm shims to sort out the other four needing adjustment.


Removing the shims was a dawdle. Gently lever each rocker to one side, push it down so it snagged onto the side of the shims' recess & fish the shims out with a magnet.


To refit them I put a little blob of grease on my R/H fore finger, stuck the shim to it & refitted the shim. Still managed to drop two shims, but they were easily retrieved wi' my magnet on a stick. I managed to source four 7.48 mm diameter valve shims from my local Suzuki emporium. (Cupar Motorcycles). Unfortunately, they only had one "used" 2.25 mm thick shim so I ended up having to buy the last three new 2.25 mm's that they had in stock which, curiously, came in a little resealable bag with a WURTH label & part number on it! (For anyone interested the Pt. No. was 0504075 225 , with the 75 refering to the shim diameter & the last 3 digits (225) referring to the thickness of shim).

I've inspected the clutch & all looks pretty good in there. I found & noted down some useful checks & service limits that are in the English language service manuals that are available to view via this forum, (for the GK73a GSXR 400 & GK75a GSF 400 Bandit).


On removal, I checked the free length of the 5 pressure plate springs & all five are bang on the 31.0 mm minimum free length! (I'll replace 'em with a set of EBC springs). As for the friction plates, there's no significant wear as they are all well above the 2.60 mm thick wear limit, ranging from 2.96 - 3.01 mm thick. (The "New" thickness dim's in the manuals are 2.90 - 3.10 mm thick). All the steel plates are serviceable, showing no evidence of wear & no serious discolouration from any slipping. The slots on the centre clutch drum & the tangs on the outer basket have only light surface wear on their contact surfaces as I can't feel any wear ridges with a finger nail.

Another thing I checked on the top-end was the cam chain for stretch between the camshaft sprockets with a vernier caliper, which is measured over 20 links. The stretch is measured between the 1st links rivet & the 20th links rivet, ( 21 rivets ), & the Service Limit is 143.0 mm's. My cam-chain measured in at 140 mm between 1st & 21st rivet so should be fine for a good few miles yet.

So that just about wraps up the engine side of things for now, unless anyone can recommend any other checks worth doing before I refit the covers. Once the engine's re-fitted I'm planning to do a compression test to find out how healthy the rings & bores are & how well the valves are sealing.

So, next it was the turn of the chassis & I was able to chip away at dismantling the front end so I could service the front forks & steering head bearings. Both head-race taper roller bearing sets were still in good condition so just needed some fresh grease before re-fitting the bottom yolk to the head stock.


The forks were also found to be in pretty good nick with no evidence of leaks & no free play felt in both "sliders", but I had to smooth down & grease some corrosion spots at the base of the "sliders" or they would damage the oil seals when fully compressed. On emptying each leg of fluid, the L/H leg contained filthy red coloured fluid & the R/H contained filthy green coloured fluid! Once drained I rinsed out each leg 3 times with white spirit to get rid of any build-up of sludge & debris & left them overnight in a warm room to let any white spirit residue evaporate.



I also managed to remove the swing-arm & shock to clean & inspected all the bearings & bushes. I've had to order the bearing & bush, on the bottom suspension link, for the bottom shock mount as the internal seals have worn letting in water & turning it in to a rusty, corroded mess! Thankfully, all the other bearings & bushes are still serviceable.


While awaiting a new lower suspension link bearing & bush, I thought I'd better have a go at finding a combination of parts from this lot that would help me to fit a rear shock to replace the HAGON shock that was fitted & which has a seized damping adjuster screw that I've failed miserably to un-seize!


To the left of the Hagon shock is the ProJection Components made short "dog bones", which are 202 mm's between hole centre's, that were fitted along with the Hagon. On the right is a pair of standard "dog bones" I found in the spares stash that came with the bike when I bought it which are 210 mm's between hole centre's. Quite a difference!! (The bearing & bush on the right-hand end of the lower link are the ones being replaced, but they were fine for trial fit's. The replacement rear shock is from a GSXR 600 K6/K7 which was bought off Ebay the tail-end of last November for a very reasonable £70 quid & is like new as there's no corrosion anywhere on it. According to fellow GK76a owners on this forum, this should just "drop straight in". Well, there's only one way to find out ..... :)

So, on removing the Hagon & placing it beside the the K6/7 shock it was found to be a good bit shorter than the latter, being 290 mm's between hole centre's compared to the GSXR's 315 mm's between hole centre's! Hmmmmm ..... Anyhow, during the first trial fit of the K6/7 shock, along with the pair of standard "dog bones", I discovered that the lower shock mount & its respective bush/bearing on the lower link arm were no where near lining up due to the top of the lower shock mount fork fouling against the lower link!! Thankfully the TOP shock mount is bolted to the frame, so it was removed, turned 180 degrees & refitted. ( How are they orientated on bone-stock GK76a's ?? ). Before I did though I measured the distance between the hole centre's of the top shock mount & the lower suspension link arm's frame mounting, which was 253 mm's. Post removal, turning & refitting, the distance was now 266 mm's, a difference of 13 mm's. That might help! .....


Thankfully a second trial fit was a success as the lower shock mount now lined up easily with its bearing/bush on the lower link arm. See below .....







The only major problem I found was that the bottom-end of the spring was fouling against the lower, forward edge of the centre casting .....


..... remedied by "fettling" said edge with a diamond cut rotary file thus.....


..... to a depth of 3 mm to give a clearance at the spring of approx. 2.5 mm's. Major problem sorted & job seemingly jobbed !



Not quite a "drops straight in" job, but relatively easy to work out what needed done. Oooh! When I remember, before I removed the swing arm/shock assembly for cleaning/servicing etc. I measured between the front of the weld to the rear of the L/H side of the swing-arm & the forward (lower) L/H bungee hook on the sub-frame for comparison purposes post shock replacement. With the Hagon shock, short dog bones & top shock mount in original position distance was 301 mm's.

With the K6/7 shock, standard dog bones & top shock mount in new position the distance was now 291 mm's, a loss of 10 mm's which isn't too bad. I need to know what the distance is on a bone-stock GK76a, that's still wearing its original stock shock assembly etc., to see if my bikes back-end is higher, the same as or lower than a "stocker". Time will also tell if the replacement is a big improvement over the now unadjustable Hagon !

Apologies for the long winded first post about this topic, folks. I can't seem to get a minute to myself at home lately, but that's me up to date on the story so far. I collected the new OEM bearing & bush for the lower suspension link arm yesterday so I'll be able to bolt the swing-arm & replacement shock back on to the frame this week, then I can start on refurb'ing both wheels. So, till next time folks .....

Cho the noo.

Wullie.

Welcome to the forum and thanks for sharing your progress on the major service and tidy-up of your bike. It's great to see the effort you're putting into it and the attention to detail. The pictures you shared really give us an insight into your process.

As a newer member, it's always beneficial to seek advice and learn from experienced owners. I'm sure the long-term GK76a owners on this forum will appreciate your updates and may have some valuable advice or tips to offer. It's a fantastic opportunity to connect with fellow enthusiasts and benefit from their knowledge.

The engine work you've done so far, including the valve clearance checks, cleaning, and servicing, shows your dedication to maintaining your bike's performance. Your thorough inspections and attention to detail are commendable.

Your efforts in cleaning and inspecting the chassis components, such as the front forks, steering head bearings, swing-arm, and shock, demonstrate your commitment to ensuring the bike is in excellent condition. It's wise to replace any worn or damaged parts, like the lower suspension link bearing and bush, to keep everything functioning smoothly.

It's also interesting to see your experiments with fitting a rear shock from a GSXR 600 K6/K7 and the adjustments you made to make it work. The pictures you provided are helpful in visualizing the modifications you've made.

We appreciate your enthusiasm and dedication to documenting your progress. Keep up the great work, and don't hesitate to reach out if you have any questions or need further advice. We're here to support you in your journey.

[Foxy400]

Is this some sort of weird AI bot thing? I reckon it is.

[Hubbskiboy]

Foxy400, yes I reckon you’re right.
Or it’s someone on some serious drugs.