GT500 will not idle

[Tylek17]

I have owned my 76 GT500 now for 6 months and I have yet to enjoy it. First I could not get it to crank after getting warm. So I built a CDI, new DYNA coil, and new stator coils. Now it will start reliably, but it will not idle. I have to keep it at 1/4 throttle or so to keep and idle. I have cleaned the carbs numerous times. I have also changed all the o-rings in the carbs. Like I mentioned previously I keep it at 1/4 throttle to keep it from dieing the intake filter boot becomes soaked in gas. I also have a black liquid coming from the exhaust smells mostly like fuel and motor oil. I have checked the compression it is at 130. I checked the crankcase drain just some injection oil came out. The line on my stator to case is lined up. I would like to check a few more thinks like timing and the crankseals, but I am not quite sure how too. I really need some help. The bike runs awesome mid to full throttle, but without an idle I cannot ride it as often as I would like. Any help would be greatly appreciated.

Tyler

[tz375]

It sounds like it's too rich at the bottom end. Could be float levels or could be worn pilot jets.

If the jets are new and the right size then try adjusting the air screw to see if screwing it out makes any difference.

It could also be worn/leaking crank seals so I'd do a compression/vacuum test on bottom end and I'd check the compression pressure (cold cranking, throttle wide open).

[Tylek17]

It sounds like it's too rich at the bottom end. Could be float levels or could be worn pilot jets.

If the jets are new and the right size then try adjusting the air screw to see if screwing it out makes any difference.

It could also be worn/leaking crank seals so I'd do a compression/vacuum test on bottom end and I'd check the compression pressure (cold cranking, throttle wide open).

I have the floats set to 27mm. I changed the pilot jets because the old ones looked worn out. Adjusting the air screw doesn't help it idle. I would like to do a crank seal leak test but not sure how. I checked the compression pressure it is at 130. thank you for the quick reply.

Tyler

[oldjapanesebikes]

I would like to do a crank seal leak test but not sure how. I checked the compression pressure it is at 130.

Diamondj offered a short 'how to' on seal testing in this thread a while ago - worth a look.

viewtopic.php?f=2&t=3137&p=97825#p97825" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[titan performance]

Hi...this may sound real stupid......but you do have the slides in the right carbs don't you?

A mate of mine got them wrong some years back, and the symptoms were similar. It was very thirsty too !
I hadn't seen him for a year or so, and he had been riding it like this for 8 or 9 months. He was so sick of it, that he was considering selling the bike.......The bike was a Gt, (cdi), so the carbs were the first thing I looked at, removing the intake boot to check the balance, and..........voila !
No cutaways !

[rbond]

Just out of curiosity, did you build the CDI from the one on this board?

[Tylek17]

titan performance I will have to check that is a possibility. I have never really paid attention to that. It has to be something stupid like that.

Rbond yes I made the CDI on this forum I have made 5 just for extras.

Ian thanks for the link

[Coyote]

I heard tell that Radio Shack is getting totally out of the hobbiest electronics in favor of selling current HDTV's and the like. So all those trick parts you could get from them will soon be gone - forever. They will no longer be an ealectronics supply outfit. Now where do we go??

[Tylek17]

I heard tell that Radio Shack is getting totally out of the hobbiest electronics in favor of selling current HDTV's and the like. So all those trick parts you could get from them will soon be gone - forever. They will no longer be an ealectronics supply outfit. Now where do we go??

I rarely go to radio shack. I am an EE so digikey and mouser are what I prefer. I would love to see a store full of only electronic components.

[titan performance]

I wouldn't be surprised......it explains why the idle adjust screws don't work, and the bike cant tick over.....
The slide guide pins prevent the slides from going into their respective carbs 180* out, but they can go into each others carbs like this.......wouldn't it be nice if it was this simple?

keep us posted.

[Tylek17]

I wouldn't be surprised......it explains why the idle adjust screws don't work, and the bike cant tick over.....
The slide guide pins prevent the slides from going into their respective carbs 180* out, but they can go into each others carbs like this.......wouldn't it be nice if it was this simple?

keep us posted.

that was it... I will never make that mistake again. It rides like a champ. Thank you so very much.

[titan performance]

Excellent news......glad to have been of assistance !

[rbond]

One thing I want make you aware of, if you start to have ignition problems, first check the stator coils. After a year and a half, mine was acting up. Thought it was my CDI I built, so tried to get into it to find out what failed. I had tried to 'pot' it with some liquid vinyl, stuff was hard as a rock. Turned out the new stator coils I put in had gone bad. Now I too have four homebuilt CDI's, put a pair of new coils, that took care of that problem. Now I just sandwich the circuit board between two pieces of foam rubber for vibe control and a light bead of silicone around the lid edge to moisture and dust seal the box. At the prices you can build a CDI, have a spare on board too. You may never need it, but with all electronics you never know.....

[Tylek17]

rbond my electrical problems root cause after changing everything was the primary stator coil. How long did your new coils last? Were they new or rewound? Oh well I now have all new electrical minus the charging system (which is also on the fritz, but I can live with that for a month or so). I plan on making a microcontroller based ignition system once I do some experiments. Should be a fun project.

[Tylek17]

Excellent news......glad to have been of assistance !

Oh yea and thanks for the chambers!!! I will post some pictures when I can.