-84 GSX 750EF after 24 years in a barn

[TonyGee]

31 minutes ago, carl_87 said:

Thanks. For convenience while fault-finding i'm currently running completely without an airbox. Does this have any negative side effects on the carburetors operation, besides the obvious downside of running unfiltered air?

yes, CV carbs are pretty sensitive to air filter/air box changes.  put the box back on and bang a new filter in and see how it runs. 

Edited October 9, 2021 by TonyGee

[PanzerWomble]

Yup it'll run lean and get too hot , although in winter you may not notice a great deal on short runs but needs sorting as Tony suggests . The foam sock filters are around 10 EUR on eBalls FYI.

And lo ... the bike that was run up to temp had the compression come back up as the rings span around and sealed for the first time in 24 years, it's nothing short of a miracle . 

 

Also if all you have taken off is the carbs how have you managed to get the air box out of the frame , normally it won't come out until the engine/ head is out . 

Edited October 9, 2021 by PanzerWomble

[carl_87]

18 hours ago, PanzerWomble said:

Yup it'll run lean and get too hot , although in winter you may not notice a great deal on short runs but needs sorting as Tony suggests . The foam sock filters are around 10 EUR on eBalls FYI.

And lo ... the bike that was run up to temp had the compression come back up as the rings span around and sealed for the first time in 24 years, it's nothing short of a miracle . 

 

Also if all you have taken off is the carbs how have you managed to get the air box out of the frame , normally it won't come out until the engine/ head is out . 

I did a new compression test on number 3 and 4 this morning with the engine cold, and i got the same good results as yesterday, hallelujah.

I was hoping you would not ask..i may or i may not have dismantled the airbox with a heatgun and a knife when i lost patience with it during the initial teardown. I figured i'd run four separate pod filters instead.

Today i picked the carbs apart, i'll do cleaning some time in the next few days. The jets all look good, as in i can see the sunlight through them but i'll give them some care.

The rubbers did not have any obvious tears or holes, but they do look a bit dry around the edges and show signs of cracking. They are somewhat flexible but not very, hard to tell since i have never worked on diaphragm carbs before.. could this be related to the bike's unwillingness to rev past 3-4000?

Edit: the slides all come down in a smooth motion if i push them up by hand. None of them falls down faster than the other, and none of them come slapping down.

Edited October 10, 2021 by carl_87
Addition

[TonyGee]

it wont rev past 3000 because it hasn't got an airbox    

[wraith]

You will need to remove all parts/jets from the carbs mian jets, pilot jets, pilot screws, also remove the emulsion tubes out of the carbs. If you have not got one, a manual will help at this point.

The diaphragms should be soft and flexible or they won't work (pictures always helps.

As @TonyGee says not having the air box on and the carbs not being jetted for the extra air flow will not help with the bike running problems.

[carl_87]

Oh, ow. Looks like i'll have to hot-glue the airbox back together!
I come from the land of fuel injection, manifold absolute pressure sensors and idle air controls and did not for a second consider that running without an airbox could have side effects other than the air not being filtered..but after reading up on the subject for a few hours, i'm beginning to understand.
A week ago, i had no idea that vacuum controlled carburators even existed..it's certainly a learning experience!

I appreciate the help and the input

[PanzerWomble]

1 hour ago, carl_87 said:

Oh, ow. Looks like i'll have to hot-glue the airbox back together!
I come from the land of fuel injection, manifold absolute pressure sensors and idle air controls and did not for a second consider that running without an airbox could have side effects other than the air not being filtered..but after reading up on the subject for a few hours, i'm beginning to understand.
A week ago, i had no idea that vacuum controlled carburators even existed..it's certainly a learning experience!

I appreciate the help and the input

Without wishing to be a Cnut , perhaps this is not a good first bike project for you ? 

These older bikes need a certain skill set and techincal understanding, and trying to resurrect a 35 year old machine without them is only likely lead to failure.Eg  If you don't understand CV carbs you'll have fun trying to rejet properly for pod filters etc etc .

It ran well before it was put away .....simple carb clean, brake strip and recommissioning should put it back on the road . 

[carl_87]

15 hours ago, PanzerWomble said:

Without wishing to be a Cnut , perhaps this is not a good first bike project for you ? 

These older bikes need a certain skill set and techincal understanding, and trying to resurrect a 35 year old machine without them is only likely lead to failure.Eg  If you don't understand CV carbs you'll have fun trying to rejet properly for pod filters etc etc .

It ran well before it was put away .....simple carb clean, brake strip and recommissioning should put it back on the road . 

Yeah i'll take care not to let this project grow out of proportion. I'm going to focus on getting it to run properly and on the brakes, and after that i'll see what to do about the rest. Like you said it ran when it was put away so i'll see if i can get it back to that stage.

[PanzerWomble]

1 hour ago, carl_87 said:

Yeah i'll take care not to let this project grow out of proportion. I'm going to focus on getting it to run properly and on the brakes, and after that i'll see what to do about the rest. Like you said it ran when it was put away so i'll see if i can get it back to that stage.

Good good ! 

 

I find myself , that if I run around on a bike for a few months before going in with the spanners :- 

1 Quite often, stuff getting used, tends to loosen everything up, and things start working properly again , engine ....brakes....clutch  etc. 

2 I have a better idea of what will need modifying or fixing, and it gives me chance to evalaute / find / buy / afford the bits I'll need 

3 ...and sometimes that list is far longer or  expensive than I fancy plouging into it...........and so back onto eBalls it goes .....

 

BTW - If you need the 'Zuki Workshop Manual PM me and I'll send you a link to mine . 

[TonyGee]

the 1100 engine i just put in my 750 was a tad smokey when out on the road, i know its been stood for a long time and its a low mileage engine.  after a good few runs out and a dam good thrashing it seems to of settled down and doesn't smoke anymore    not running an engine for long periods is not good for them. 

[carl_87]

Update:
Put the airbox and the carburators back in, and took the bike for a spin. Now we are getting somewhere!
She revs without any issues now, y'all were of course right about the reason for the bike not revving past 3000 before.
I dared not rev past 7000, for no other reason than being gentle on the old girl...
Next issue is not new, i noticed it on the previous test runs, but was of lower priority: it's impossible to shift higher than 2nd gear. The shifter feels completely stuck when going for 3rd, i tried applying some extra force with the foot but no luck.
I'll do some resarch on the forum and the interwebs but if anyone want to point me in the right direction, i'm glad for the help!
Cheers
 

[Gixer1460]

Firstly, if you haven't already, get a manual - even the Haynes ones are better that nowt, especially for this. Its possible to displace the R clip off the LH side of the shift shaft which allows it to move inward and disengage the shifter ratchet behind the clutch - this is fairly common diagnosis of your symptoms.

[carl_87]

43 minutes ago, Gixer1460 said:

Firstly, if you haven't already, get a manual - even the Haynes ones are better that nowt, especially for this. Its possible to displace the R clip off the LH side of the shift shaft which allows it to move inward and disengage the shifter ratchet behind the clutch - this is fairly common diagnosis of your symptoms.

PanzerWomble was kind enough to gift me a service manual and it has been great to have so far!
Do you mean on the LH side of the engine where the gear lever and clutch cable resides, or the RH side where the clutch lives?
 

[PanzerWomble]

3 hours ago, Gixer1460 said:

Firstly, if you haven't already, get a manual - even the Haynes ones are better that nowt, especially for this. Its possible to displace the R clip off the LH side of the shift shaft which allows it to move inward and disengage the shifter ratchet behind the clutch - this is fairly common diagnosis of your symptoms.

FYI I'm 99% certain there is no Heinous or Clamydia Manuals available only the Workshop Suzi one .

Joys of having a short model lifespan . 

[carl_87]

I can't for the life of me figure out how to do away with this locking washer-gizmo so i can get this cover off..and i don't want to break anything by applying more force to it..does anyone have any pointers?

The repair manual says to "Flatten the washer" but i don't understand how..

 

Cheers

[wraith]

Daft question, why do you need to remove it? 

If you take the cover off it will spin out from the inside.

[carl_87]

13 hours ago, wraith said:

Daft question, why do you need to remove it? 

If you take the cover off it will spin out from the inside.

I figured i'd take a look where the gear lever sits and see if i could find any obvious reason why the bike won't shift above 2nd, but i'll need the cover off sooner or later anyways. I have loosened the bolts for the cover but something is preventing it from coming off, do i need to unscrew the clutch cable where it enters the housing? (Picture)

[Swiss Toni]

The shaft the gear lever is bolted onto? See how far in and out you can push/pull it. If it’s more than a few mm, there’s your problem, as1460 says. Easily fixed. 

[wraith]

2 hours ago, carl_87 said:

I figured i'd take a look where the gear lever sits and see if i could find any obvious reason why the bike won't shift above 2nd, but i'll need the cover off sooner or later anyways. I have loosened the bolts for the cover but something is preventing it from coming off, do i need to unscrew the clutch cable where it enters the housing? (Picture)

You need to remove the cover bolts and the gear leaver (gear leaver 1x6mm bolt) then with a bit of wiggle it should come off.

[Gixer1460]

Can't see clearly but is that a removable access cover - the rectangular plate?

[carl_87]

23 minutes ago, Gixer1460 said:

Can't see clearly but is that a removable access cover - the rectangular plate?

Correct,  behind that rectangular cover is that strange locking washer. 

@wraith, i have all the bolts loose and the gear lever, but there is something still holding on from the inside, something that flexes a little bit.

I'll see if i can find the time this evening to figure out what's what!

[Gixer1460]

Surely the workshop manual must detail this area - especially if its this difficult to remove!

All earlier and later GS's, GSX's and GSXR's, F's and GSF's are 6 or 7 bolts + remove gear lever and cover comes off - NOTE : not loosen gear lever - REMOVE it!

[TonyGee]

try pulling the clutch lever, it might just push the cover off. 

[carl_87]

7 hours ago, wraith said:

You need to remove the cover bolts and the gear leaver (gear leaver 1x6mm bolt) then with a bit of wiggle it should come off.

You were absolutely right, the thing holding the cover in place was just the gear lever shaft. Anything else was pure imagination on my part. With a lot of WD40 and wiggling, it came loose. The shaft does however have it's clip in place, and doesn't move in and out more than about a millimetre so i guess i'll have to take a look on the RH side around the clutch area.

Old n dirty

 

Edit, update:

Turns out i don't have to open up the RH side after all. I cleaned out some of the gunk and put the cover, gear lever and whatnot back together, i figured i'd check she would shift like she did before atleast. Turns out she does a lot more now, i'm not quite sure what was rusted stuck that came free but something did, hooray!

So basically, the bike runs now. Starts without too much hassle, revs, shifts and brakes. Tons of things left to do obviously, but we are sure getting somewhere

 

 

Edited October 27, 2021 by carl_87
miracles

[denisd]

Great stuff, progress.