GT550 Basic timing Steps

[NicoMega]

Hey guys, names Nico and I am new to the forum and have had a few GT550's in my past (never had one running enough to enjoy how much I love them though... )

Any way I am just looking for a couple threads that cover the basics IE

step by step timing procedure

carb timing procedure

I know there has to be a hundred convo's already started revolving these and I do not want to start another repeater thread

Currently my '72 GT550 has had the carbs cleaned and slides timed I have popped it over, but only with ether before it bogs down, it acts like it is starving for gas and will not even run on idle circuit.

I am running what I believe to be stock jets: 27.5 pilots, and I cannot read the mains but they appear to not be anything aftermarket or modded.

I am only kicking it as starter is not functioning, It seems as if it wants to kick over on full choke but doesn't catch enough to run

if i give it a spray of ether, it will fire and rev a little until the ether runs out.

When it is running, I see black/brown colored smoke which seems off to me

I want to time points myself and make sure gap is correct. I do know that the best way to do this is with a depth gauge, I do not have on but could make something to work or maybe perform the basic timing rundown using the marks

I do have gas in the carbs when attempting to start, but need to fine tune my petcock setup due to previous owners soldiering the vacuum/diaprham holes and I would guess running it solely in the prime position (another headache)

It has a new battery and appears to be in good condition

When it does fire off, throttle response is quick and engine sounds healthy

I have not cleaned out pipes yet, and am also thinking about maybe intake ports are clogged??? Any way to tell this??

If you guys can point me in the right direction

Again if I can get links to the threads that have this info that would be grand

Cheers

PS i am in New Mexico USA

[GTandcbr]

Hi and welcome to the forum! I have exactly the same bike as you. It sounds to me that you have a problem with the pilot circuit and or choke enrichment circuit. When you say the carbs have been cleaned in my experience it takes many cleans to get the internal pilot circuit purged so that it performs well. It is very important that BOTH the pilot hole which is straight up from the jet and the pilot jet bypass which goes off at an angle to the engine side belmouth of the carb. If either of these are blocked or restricted starting and idling will be difficult. Look here figure 2 http://www.iwt.com.au/mikunicarb.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;. when starting the bike check that the pistons attached to the choke cable are lifting sometimes the get seized in the bore. Finally check the float bowls of the carbs. There is an upright brass tube sticking up. This feeds petrol into the enrichment circuit from the base of the floatbowl. Check that it is clear and that the little hole at its base is not blocked,they can get sediment stuck in there. Inside is a little metered jet(not removeable) also at the top of the upright tube there are some small holes check they are clear. They cause the fuel to froth helping mixture with the air.
In my experience the timing marks are all that is necessary to adjust the ignition. These bikes are not highly tuned. (Thats just my opinion) With reference to your petcock you may wish to fit an inline tap( easily available) as leaving the bike on prime may cause the crankcase to fill with petrol which may cause hydraulic lock which will seriously damage the engine.
Finally with reference to the smoke. If the bike hasn't benn run for a while all kinds of crap will come out the exhaust. A good run usually sorts this.
Good luck
EDIT this link may help in future http://www.3cyl.com/mraxl/gt/manuals/gt ... ntents.htm" onclick="window.open(this.href);return false;

[NicoMega]

Alright!!!! Thant manual is going to help significantly


With the carbs I will recheck the areas of concern that you listed; I honestly did not quite understand how the choke system worked until thinking about it, and I Didn't service the pistons either, I did not think to do so as I can hear an obvious change in the way the bike sounds when I try to kick it over while playing with the choke lever.

As far as the timing of the points...

I understand how to adjust the left first directly from the adjustment plate and then the latter from their respectable adjustment screws, and that I have to adjust the point gap first prior to this.

MY ISSUE:

1. When I am first to adjust the point gaps, do I adjust them when the coinciding piston is at TDC and then go from there? or when the piston is this magical 23 degrees BTDC?

What I am running in to is when I get the "L" points to crack at the timing mark (Timing light lit,) and I move to the next set of points, in this case the "C" points they won't actually close no matter how much I adjust the point gap on the point itself. So this tells me that my initial adjustments are throwing off the whole deal

2. ALSO: As indicated in the manual, I adjust the timing starting with the "L" set of points and adjust the entire backing plate(got it,) then on the next two points "C" and "R" I line up the marks and adjust them by their own individual adjustment screws.

My question: Doesn't this ultimately change the original point gap? Or am I thinking too much into it because the initial adjustment of the entire back plate with the "L" points creates a mis-adjustment that I am only correcting individually there after??

Thank you so much for your response and I really appreciate the help! ( I can't frickin wait to drive this beast already!! ((and then find out what else I need to break my knuckles over hahahaha)))

[NicoMega]

Hey what's up, I just found another thread

viewtopic.php?f=2&t=9396&start=60" onclick="window.open(this.href);return false;

that gave me the info I needed for the points adjustment, as well as many other things to go over and how to do them that will help future saviors of these fine beasts

I will start digging into the fuels starvation issue after I tune in the points

[GTandcbr]

Another useful link for you to bookmark its the later gang carbs but most of the information is still relevant.
http://www.3cyl.com/mraxl/gt/manuals/su ... /cover.htm" onclick="window.open(this.href);return false;
Here is a link for balancing the carbs https://youtu.be/jJGl_hab3Bg" onclick="window.open(this.href);return false;
Here the petcock https://youtu.be/qWNyvjaWfz8" onclick="window.open(this.href);return false;
Any other help just post the question plenty of help on here

[NicoMega]

Alright my friend(s)

Been battling with the Suzi, trying to get her popped her over.

Pulled carbs for the" whatever-teenth" time and dipped all three, after pulling everything I could, because I believed to have a primary circuit issue. There was some dirt and filth in the choke cyls and I made sure that the primary intro circuit was functioning properly...ect...ect

Anyway; While dipping the carbs I get the great idea to pull exhausts, to make sure that they were clear from filth and oil ect...ect

Well while "Removing them" five out of 6 manifold bolts break off...

I do have A LOT of Experience, and did what I could to prevent this i.e. pb blast soak, heat soak, pb+heat soak, screw in a little then screw out a little ect...ect...I don't need pointers on this one, they broke because they broke.

Once the exhaust's were off, I realized that previous owner(s) decided to utilize some wicked cool totally awesome Chrome head bolts to mount the exhaust (almost want to bet these are stock)...anyway...then I witness that whomever potentially mounted the Stupid ass chrome bolts... somebody also decided to bypass any/all gaskets previously used with...yes you called it the best thing to use EXhaUST PUTTY!!!! and not only did they use is in the exhaust ports, they filled every hole they could with it, another reason why I believe these stupid bolts to have broken

anyway, after I removed all exhaust components, I also witnessed that someone also previously fuggered the only hole that a bolt unscrewed from its her sized in the beginning and double penetrated

I have now attempted any and all possible routes to remove ONE broken bolt, which is...what I feel, may be epoxied in place

I have used time to let PB Soak...Heat (propane torch at 1200 degs F...then sprayed with PB while heating...tapping with punch centered in bolt stud to create vibration after heating...drilled a pilot hole on center and brought it up to as close to threads as I could prior to attempting to utilize left hand thread easy-out,

broke one #2 easy out, luckily where the handle mounts, and not in bolt with hole, then stepped up a size larger on hole size and attempted a larger easy out, which literally bent under the load (I have never seen this in the 20 years I've been wrenching, As I was doing this I was heating and spraying with PB Blaster.

My question to the forum:

Prior to attempting extraction on any other bolt (4 Remaining)

Should I just call it a bust and save time and drill out the bolt holes and install studs??

Can I drill out these holes?

I am under the impression that there were steel inserts cast into these heads, however when I observed the only hole that a bolt came out of, it appears to have threads threaded into the aluminum jugs.

What is my best approach?

Can I drill these holes out and tap threads, in order to install Studs?

Or are bolts best? Or what am I going to run into with this venture?

[Warehouse1001]

I believe you'll find there is no steel....just aluminum alloy. At least that's been my experience with other Japanese bikes of the era. I can share that I have had good results using true carbide drill bits (not hardware store cabide coated bits) and timeserts...to restore threads. Seems to work better than helicoils for me. If you can find a way to stabilize the head, a drill press makes getting the hole straight much easier. Good luck to you. I know how frustrating these set backs can be....darn PO's....Chuck

[GTandcbr]

Hi first of all commiserations, what a total nightmare! The original holes were threaded into the alluminium. Its very common to tear the thread as you can imagine. I solved the problem using helicoil inserts. In fact all my bolts are in the helicoil which are fairly cheaper and much stronger than the original thread. There are other type of inserts which are more expensive and more complicated in my view. The helicoil kit comes with the correct size drill and tap also plenty inserts which are held in place with threadlock cement. Have a look here https://youtu.be/sQHRB2ElZJ0" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; and good luck with the rest of the bike if that's what the PO did to the exhausts!
EDIT just reread your post fitting studs is possible but makes removing the exhausts a two man job as you have to support the rear whilst lifting the pipes over the studs. Some have tried this and say it makes life very difficult!
Lastly have a look here http://www.kettleclinic.co.uk/kcforum/v ... =Jig#p9894" onclick="window.open(this.href);return false; this may help too . You will see a photo on how to make a jig which keeps everything straight.

[NicoMega]

Alright guys, had to take a day or two away as to not be "rage-wrenching" and making things worse

Thanks so much for the help and support,

Those were the answers I was searching for

I am familiar with heli-coil inserts so I will be going this route

and I also like the little guide plate that the fellow made in his similar repair

I was just more concerned of the original construction and now I know I can repair as needed

Again thanks so much for your insight and empathy