Suzuki gs750 1978 low compression

[Nessism]

If the bike runs decently enough I'd just continue to ride it. If it falters, then decide. For guys that have a love for older bikes the GS is worth putting some money into. If you just want to ride then I'd get something newer that needs less work.

[SanderG]

@ nessism : I love older bikes, that's the reason I got one in the first place. I am only 24 but I can appreciate an oldtimer!

I also love the build of the gs750 and love to work on it.

This winter I will take on the intake ( airboxsealing, cleaning carburetor + replacing carb + intake boot o -rings + gaskets ) allready ordered everything.

Then this summer I will ride it hard

And next winter or after that I will consider ( but probably do ) a top end rebuild. Problem with top end rebuild is that I mostly don't know how far to take it. Just do gaskets, lap valves and check/replace anything out of spec.
Or Also let a shop : flatten head + cilinder, hone cilinder, cut in new valve seats, change everything that is close to out of spec,...

What are you guy's opinion on that ?

Thanks for listening to my "story"

[Nessism]

Sounds like you got it. Measure first and then make a decision on what to do. 88,000km is not all that much for a GS. Most likely new rings and some valve cleanup will fix up the compression.

[Charlie G]

Nice looking motorcycle! Welcome.

[steve murdoch]

Have always gone with as long as the compression numbers are within 10% of each other it is not a huge concern.
I agree with Ed, ride it.

[SanderG]

hello guy's Quick question,

I got a haynes service manual to help me. ( see Picture )

https://photos.app.goo.gl/fWJjYlnzaWcURAT83

Now I wanted to work on my carburetors and saw that this manual has the CV Carburetors.
Is there an Haynes or other book on the VM carburetors that mine got?

Got an 1978 750B.

[Nessism]

On basscliff's website you can get a proper factory suzuki manual download for free with all the proper information. Haynes manuals are not very good. Basscliff also has a VM carb rebuild tutorial. It's strongly advised that you use it and go through your carbs completely.

http://members.dslextreme.com/users/bikecliff/

[SanderG]

@ nessism : I allready had a look at the VM carb rebuild tutorial. I am most certainly going to use it.
Just like to have something to compare. ( In the original service manual there isn't a whole lot on the carbs )

But nevermind anyway : Just opened the book and saw that they do explain the VM carbs, There's Just a wrong picture on the cover

Thanks Anyway!
Keep you posted

[Nessism]

When you go to take apart the carbs do NOT screw in the fuel screws and try to bottom them out. That sometimes results in the tip getting stuck and often broken off in the carb body. Just remove the screws and be sure to remove any thread sealant on the threads. When you go to install the screw after the carbs are freshly clean, then you can carefully bottom the screw before backing it out the proper number of turns (3/4 - 7/8 of one complete rotation).

[SanderG]

Sure will keep it in mind. Btw: With fuelscrew do you mean the mixture screw? Because in the manual for my bike it say's back out 1 full turn.

Will be taking them apart sometime next month. On my list for this winter:

- place weatherstriping on airfilterbox
- replace intake boots o-rings ( intake boots are fine I think, no cracks from the look of it )
- take apart carbs and clean/replace everything ( zlready ordered kits for gaskets and o-rings from robert.
- clean tank ( not sure how I'm gonna do it ) and properly prime it. ( Now when you look in the fillercap I see a bit of rust )
- while I have the carbs removed I'm gonna take the chain tensenor off because bike makes a litte rattling noise.

Do I forget something that you guy's would probably clean/check/replace or repare when I got carbs and tank off?

Further down the path I will need to adress the electric part ( coils, connections,... ) But first will probably come summer!

Thank ya guy's,
Nice to hear all this knowledge.
Kind of want me to get into it as fast as possible.

[Nessism]

There are two pilot screws: fuel screw and air screw. I think the screw you are referring to as the "mixture screw" is actually the pilot fuel screw.

[SanderG]

But fuel and air screw should be 1 turn out then?

[2BRacing]

But fuel and air screw should be 1 turn out then?

No, they are not both open 1 turn. Bottom screw is 3/4 to 7/8 turn open and side one is 1 to 1 3/4 turn open depending on engine number. Look here for good information: http://www.thegsresources.com/_forum...22#post2151222

[Nessism]

The air screw is typically open slightly less than double that of the fuel screw.

[chuck hahn]

Actually his bike has VM26 carbs. bottom PILOT screw..which affects idle to about 1/8 throttle twist..get set at 3/4 to 7/8 ( I go 7/8 myself on my VM26s carbs ). Then it gets forgotten about. ALL fuel to air ratios are adjusted via the side MIXTURE screws....end of story. Initial setting for the mixture screws is 1 1/2 out to 2 out. And I find that on both my 750s and my 1000s the sweet spot is at or just a tad more than 1 1/2 out. I muse the Colortune and watch the flame color so Im pretty confident ive got it down rather well.