Top 20 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.

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.

No, I don't think so.

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.

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.

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

can you have the regulator/rectifier checked?

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

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

floats are sticking or dirt in the fuel system clean fuel system and check the floats are free and do what they say float

they are made together

Go to the web site below and you can see an exploded view of the carb assembly. Please rate my answer. www.babbittsonline.com

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.

clean out all old fuel and clean carb jets

There is poor documentation on these bikes. A lot of the charts show the GT750's but dont specify the GS.

This chart (link below) is the best you will find, there are a LOT of blues! It may help narrow it down. Perhaps you can take a list of the blues and paint codes and google for paint chips or take them to an autobody supply shop. Hopefully you have something with the original paint for comparison. http://www.ozebook.com/compendium/suzi/suzicolr3.pdf

Best of luck!

If the throttle is on the idle stops then there is a intake leak.
Carefully spray some starter fluid on the intake to find the leak. Spray as quickly as you can here then there. this stuff will flame on if not careful

I think japanese inline fours are the same -

sitting on the bike, from left to right, the cylinders are 1 to 4

one coil fires cyls 1 and 4 and the other fires cyls 2 and 3. you can swap 1 and 4 or 2 and 3, it makes no difference at all, but you can't put the 2-3 coil on cyls 1 or 4 and vice versa... you should be able to put the long spark plug wires on cyls 1 and 4 and the short ones go to cyls 2 and 3.