20 Most Recent 1977 Suzuki GS 750 Questions & Answers

Question edited for clarity and add maker. Question moved from 'Gas Motorcycles' to model category. $85 upwards. Better to shot blast strip and epoxy line your existing one and add a fuel filter. https://www.google.com/search?q=1977+Suzuki+GS750+aftermarket+gas+tank ..

OK LETS DO THIS RIGHT. (DONe IT 1000S TIMES) not told at all if#2 keeps changing radically\ yes if those reading are real engine fails. 1: the valve lash must be loose .at TDC firing. or fails. if tight at TDC fire, it will fail. yes and burns up valves too. !!!!!!] there must be lash, rule #1 all engines unless with NO HLA's IF LOC, I DENVER SAY SO AND WE DO ALTITUDE CORRECTIONS, ASK, OR ASK ANY PILOT. 2: throttle must be open, no air , no joy, can not compress a vacuum. during the test 3: are you kick cranking it ? 4: kick it until the needle is stops rising <peak it. 5: ;are you in Denver or at sea level.? hummmmmmmm we do altitude corrections easy/ 6: if all about is good and compression wrong 100 and repeats we add oil to #2 spark hole and repeat the test if goes good, rings bad, if still low valve is burner or again lash is wrong (not loose is wrong TDD Firing) means lash is zero or worse tight. this is all 100% ASE text book test, for 100 years. not changed. the there is no compression release on 750cc like my 350 single had, THumper,. that I loved

You should correct those exhaust issues because a exhaust leak can cause the issues you are having.

http://cgi.ebay.com/ebaymotors/1977-SUZUKI-GS750-GS-750-COIL-550-650-2-/280401251168 theres your coil on e-bay if you have points if you have electronic ign ,, http://www.oldbikebarn.com/Dyna-DC1-1-Ignition-Coils?sc=12&category=73707

i put 115 main jets in my 77 ge 750 and it will run but was told to jump up to 140 with pobs and 4into1 pipe (SM6) race pipe at the low side run 130 main and leave the stock pilot in. i rorde mine from NE to SD roude trip about 1300 miles got about 62 MPG with 115 jets jumping up to the 140 will drop the MPG but lets be real im not looking for MPG. hope this will help.

call dealer ask for paint codes for that year model, give reg.

No, I don't think so.

the best way is to measure with a vernia caliper the inside and outside diameter of the top and bottom bearings you already have and compare them with what you were going to buy. for instance the bottom bearing may have a 30mm OD and a 45 mm OD and be 13 mm high.i strongly recommend you fit taper roller bearings to it .

If it's a random misfire, I recommend looking for a high voltage problem in the ignition circuit, like a cracked spark plug, or a dirty spark plug boot, or a loose wire on the coils. Start it up in the dark and look for sparks jumping around the plug wires and coils. Point gap will affect timing, check for worn or pitted points while you're in there. Maybe a condenser is going bad.

The book states the timing if fixed no maintenance is needed. Timing marks A,top dead center;B fixed advance firing point; C, full advanced firing point. I'll try to post pic from book.

http://www.carlsalter.com/motorcycle-manuals.asp Try this link. Free downloads for 100's of bikes. Checked it and the wiring diagram is there.

carb sync is done using only the carb hard stop adjustment u don't touch the air fuel mixture screw, had this exact same bike had the serive manual am dead sure on this

HI,,,you have blocked carbs,,they are running lean,thats why it runs better with the choke on,,carbs need to be removed from the bike disasembled and cleaned.

I am thinking your rings must be worn. As long as the oil is correct weight,and valves are set correctly, then that is what you are looking at

This sounds like an air leak is making the fuel/air mixture too lean. Any air leaks between the carb and the head will lean the mixture. Old, hard and cracked rubber manifold parts are the usual culprits. Old gaskets and "O" ring seals can leak air also. A bad head gasket seal happens at times also, as does an exhaust valve not fully seating. Air leaks are the idle speed problem.

A different problem is likely present in the carbs and that is what is causing the rich fuel smell. The carbs must be balanced. Example > If three of four carbs are perfectly balanced and one carb is not, then the 3 are "driving" the 4th carb. This will cause gas to spit into the air cleaner from the "bad" carb and can cause a backfire or two. Special vacuum gauges are needed to balance the carbs. Also be aware the carbs must be scycronizsed as well. The slides on all four carbs must lift at exactly the same time when the throttle is cracked.

Go to the site below where you can see a parts diagram for your specific bike. You will select the actual brand, year, model, etc., once you go to the site. Part numbers and prices are also shown. You can order parts from this site. In the event no price is shown on a particular part, the part is not in stock. www.babbittsonline.com/pages/parts/viewbybrandand/parts.aspx

I don't get paid for my answers but I do take pride in them, and I am only trying to help. So if you will, > > A “very helpful” rating for these answers? Thanks!

can you have the regulator/rectifier checked?

clean out all old fuel and clean carb jets

You are dealing with Suzuki vacuum carbs, you cannot just replace the air box and re-jet. What you are running into is there is no pressure to raise the diaphragm because there is no restriction to create such vacuum. Either put the stock box back on or go to the biggest main jets you can buy. Sometime even when you get stage 3 jets you still have issues. Vacuum carbs are not made to run with no restrictions.....putting aftermarket exhaust on it will make things much worse.

its 35 yrs--bout time for a carb overhaul--buy a clymer manual for procedure