My GK76a winter service/tidy-up project.

[gsxrscotty]

Thanks Scotty. The levers were bought by 4hundread, the previous owner. He said they were Chinese made levers (& bar end weights), bought from an eBay vendor. See if they are listed for VJ22 RGV's, as well as the early 90's GSXR 750's, as they are the same vintage as the GK76 so will fit. .

Oh brilliant! Thanks for the info!

[Marsbar]

Awesome write up, bike looks stunning and very clean.

@ scotty i made a thread awhile ago about the levers which can be found here: viewtopic.php?f=51&t=33244

Had them on my bike since and not really had any problems with them in a crash, however the red adjusters are starting to turn pink so i might grab some Titax ones of the shelf to see if they fit.

[wullie3xv9]

Thanks guys. Well that's yet another month gone & it's STILL not finished! The f%ckin' carb's are p*ssing me off !!

To cut a long story short as they say, after several carb removal / refits, (to replace some seals & carry out visual checks on all the inlet rubbers etc after several abortive carb. balance runs ), I've finally given up & split the four carb's apart so I could check the condition of the six seals that fit around the shafts of the throttle butterflys.
And guess what, all six are absolutely shagged oot! So shagged oot their lips don't touch the shafts & they also fall out their seats in the carb bodies!!
So that's yet another set of seals to buy for these f%ckin' over-complicated CV carb's !!

Splitting the carb's & "removing" the shaft seals turned out to be quicker/easier than I feared though. I had the bodies split apart & all six seals out in about 40 minutes.
Putting them back together could be "fun" though as there's a couple of big throttle return springs to refit, plus the 3 balance adjuster screw thingies!
On the plus side, they're the only seals left to replace as every other seal & gasket has already been done, so once these have all been fitted hopefully I'll finally get these feckin' carb's to balance!
If not, the bike'll be getting broken for spares !!


This is one of the six butterfly shaft seals. For scale it's next to an 8.0 mm across flats nut.


I'll finish on a positive note though. I bought & fitted a new gear change thingumy as the old one had lost its rubber cover for the rose joint so had loads of free-play as a result. With that fitted I could then fit a new non-ferrous link rod that was made for me a couple of months ago. (Thanks Mike. )
The gear lever has a fair bit of free-play too but it'll do for now. It'll get attended to over the winter.


I'm afraid that's all for now, folks.

Wullie.

[rgvsp]

I feel your pain. I'm right there with you, I've been doing the same thing. I've pulled those damn things off and on so many times that I can do it in under 10 minutes. Be careful not to over torque the long bolt that connects the carbs as it will snap.

[wullie3xv9]

Thanks RGVSP, I've been keeping an I on your workshop thread to see how you've been getting on with your GK76 project. As I'm in no rush to finish mine for a track day now I've ordered a Set B of LiteTek seals via their web site so should have them sometime in the next 2 weeks.

http://litetek.co/Carb_Kit_Suzuki_GSXR400_GK76A.html

I'm praying that a fresh set of butterfly shaft seals cures the reluctance of the carb's to balance! Every time I put the slightest pressure on each pair of carb's balance screws, when trying to adjust them with a screw driver, the rev's increased from the extra air being drawn in past the worn out shaft seals which was screwing up the readings in my set of vacuum gauges!! Each time I started the engine, after I thought I was done, I had different readings...every time!

[rgvsp]

Too funny. I was doing the same thing last night and having the exact same issue . I've got something going on with the number 2 carb. It is sucking extra air in from somewhere and throwing everything off. My problem is I've already replaced the shaft seals so I'm lost as to what it is right now. I could get 1 and 2 synced, 3 and 4 were fine but there was no way to get the two pairs even close. It would run out of adjustment. Then all of a sudden, 1 and 2 would not be synced anymore.

[wullie3xv9]

I could get mine frustratingly close, but just couldn't get them any better than that. To be thorough, I removed & examined all the inlet stubs on the cyl. head for any perishing or splits, (there weren't any), & replaced their o rings with new 35 mm I.D. x 3.0 mm cross section Viton o rings, just in case there was a problem with them, but there was no improvement, hence why I've now split the carb's!

I've also checked each butterfly shaft for excessive wear/free-play in its respective carb body and all four shafts & their pivot points are in good shape with very little free-play felt, just enough for all the shafts to pivot freely.
As I said above, if new shaft seals don't cure it I'll be stumped too!!

[wullie3xv9]

Well, I collected the set of Viton seals I ordered direct from LiteTek from the local Post Office on the way to work this morning. I would have had them yesterday but there was nobody at home to sign for them!
I ordered them on the night of the 15th, so delivered to the house in five days is pretty damn good I think.
(They said up to 12 days to the U.K. on their web site).

The much needed butterfly shaft seals are bottom left.


The Mrs has had her work shifts altered recently so I now have Thursday nights to myself. I brought the carb's home with me from work today so this evening was spent fitting all the new seals, teflon washers & stainless butterfly screws & then putting the bank of carb's back together again which took me approx. two & a half hours form start to finish.
On fitting each butterfly shaft through their new seals, it was a relief to see that the shafts & seals didn't fall out when I turned each carb on its side, so the new seals are definitely gripping/sealing on the shafts!

As predicted though the two balance adjusters, (one for each pair of carb's), was the most awkward bit as you have to put a small plate between a small spring & the end of each adjuster screw while trying to insert the ends of two T-pieces into the opposite carb at the same time! A bit of a faff, but with the aid of a flat blade screw-driver to compress each small spring, I managed to insert each plate first time without small springs pinging off into a distant corner of the kitchen!

The green seals are the new Viton ones, black seals the old Nitrile ones. The large T-pieces connect to the airbox via hoses, the two smaller T-pieces with green seals are for the fuel supply & the t-pieces on either side are just vents.


Back together again. Here's hoping I finally get the fekin' things to balance now!


Till next time folks...

Wullie.

[Maelstrom]

Hi Wullie,
5 Days!!! That is unusually quick. I think you got lucky. Speaking of which any luck with the running issues yet?
cheers
Blair

[wullie3xv9]

Thanks Blair. Yes, I was as surprised as you were when they turned up so quickly. Many thanks.
I haven't been near the bike for nearly a month now due to work commitments & then taking 2 weeks off. (The bike's at my work place). I tried another carb balance the day after fitting the new seals set, but had to give up again as I discovered that No.3 cylinder's down pipe was a good bit cooler than the other 3 !! ( I could keep my hand on it !! ).

I'm starting to wonder if No.3 cyl's ignition lead has started to "break down" when warm. I'd made sure all the leads were fitted properly & fitted a new set of NGK plugs. (The black covered leads fitted are not very flexible when cool so I'm assuming they're 20 odd years old OEM leads). I get a spark on No.3 cyl's plug, but that's no guarantee that it's firing as it should when fitted.

When I get the time I'm gonna replace all four original ignition leads with some sillicon/carbon lead that I bought last week. (Which means draining some of the coolant out so I can remove the thermostat housing to get to the coils !! ), & I'm also gonna replace the mixture screw O rings as I checked them again today & found that they're fractionally too big, inside diameter wise, (3.0 mm I.D. x 1.0 mm cross section), so don't seal on the screws. I've got some 2.5 mm I.D. X 1.0 mm x sect. on order. Hopefully all the above will finally crack the problem !!

Bye for now.