Hello All. Need help getting my GS700 to start!

[5t341th]

Hey guys. I am in need of help getting my bike to start easier. I have a 1985 GS700E. It has dynojet stage 3 with K&N pods and supertrapp exhaust.
My bike has a really hard time starting. I can crank it forever and ever to try and get it to start. I can drain the battery each time trying to start it. When the bike does eventually start, it drives great. Good power, no stumbling. Once the bike has started before and warm, it has no problem starting again. It seems to be only when cold.
If I try to start it and blip the throttle over and over, it seems to have an easier time starting. Using the choke seems to make it worst. I have done the coil relay mod. I have good voltage at the coils and good spark at each cylinder. Plugs are new. Carbs have been torn apart and rebuilt with new Orings from cycleorings. I even bought 4 new intake boots. K&N pods are brand new.
Could ignition timing being off cause this hard starting? I never touched the timing at all since I bought it so I assume its fine. Like I said, once started the bike runs great.
Any input is welcome PLEASE

Some pics to get us started

 

[steve murdoch]

Have you adjusted the valves.?
Some good info here. http://www.thegsresources.com/_foru...A-Cure-for-Hard-Starting-16-Valve-750-Engines

 

[DohcBikes]

Choke makes it worse....

Where do you have you pilot fuel screws set?

What size are your pilots?

 

[Steve]

Just three suggestions here:
1. Adjust your valves. If they are tight (especially the intakes), it will be hard to start when cold.
2. Verify your pilot screw settings. After rebuilding carbs, I set them to three turns out to start, then adjust as needed, they usually end up about 2 1/4-2 1/2 turns out.
3. Adjust your starting technique. When valves and pilot screws are set properly, you will probably have to use a little "choke", but when using the "choke", you do NOT touch the throttle. No blipping, NOTHING. You adjust the engine speed with the "choke" lever.

.

 

[DohcBikes]

This is why you guys need to stop telling every new guy to adjust his valves
http://www.thegsresources.com/_foru...unning-and-power-issues&p=2350117#post2350117

These bikes will go a long effin time with no valve adjustment. Check compression? Ok. But until thats wrong, why get into the engine. Not everybody has the same skillset.

 

[hillsy]

This is why you guys need to stop telling every new guy to adjust his valves
http://www.thegsresources.com/_foru...unning-and-power-issues&p=2350117#post2350117

These bikes will go a long effin time with no valve adjustment. Check compression? Ok. But until thats wrong, why get into the engine. Not everybody has the same skillset.

This one is screw adjust tappets. Pretty easy to check / adjust compared to shims and should be done before ripping into anything else.

 

[DohcBikes]

Ok. Thats much better. I'll allow it.

 

[Steve]

These bikes will go a long effin time with no valve adjustment.

You are very correct there, (for once), but it has to be correct to start with. :-\\\

Once the valves are properly set, they WILL go for quite a while with no further adjustment, but if you wait until compression drops, it might be too late.

.

 

[Steve]

This one is screw adjust tappets. Pretty easy to check / adjust compared to shims and should be done before ripping into anything else.

I will disagree with you a bit, Hillsy. I would rather do a shim adjustment any day.

Not saying that one is easier than another, just that I would rather do shims. :encouragement:

.

 

[hillsy]

I will disagree with you a bit, Hillsy. I would rather do a shim adjustment any day.

Not saying that one is easier than another, just that I would rather do shims. :encouragement:

.

That's cool - I probably would as well but from a newbie perspective it's far easier to grasp the concept of being able to adjust the clearance with a nut and screw set-up rather than having to employ shim-math.

Also there's a greater chance of damaging cam lobes, etc if you take out the shims and then try and rotate the cams....

 

[5t341th]

Thanks guys. I have adjusted the valves. Many times before as well. Maybe I am doing it wrong? I use a standard feeler gauge. Is the tappet style feelers an easier way?

 

[Steve]

Not sure what the difference is between "standard" and "tappet style" feelers, but any feeler will work, as long as it's easy to put where it's needed.

One suggestion that is often made is to use TWO feelers at a time. There is just a bit of clearance in the rocker, so using two feelers and setting two clearances at once will prevent cocking the rocker sideways, which will affect clearance on the other valve.

One other tip is to set the clearances near the maximum. The specified clearance is 0.09-0.13mm. In inches, that would be 0.0035-0.0051". Depending on whether your feelers are inch or metric, just find the one that is close to the max. With your screw-type adjusters, you have the luxury of setting them to whatever you want, so just pick a number near the max and set them there.

There are a few advantages to setting them to max clearance:
1. The engine is VERY easy to start (assuming everything else is working properly)
2. Fuel mileage will go up just a little bit
3. It will take longer for the valves to travel through the clearance range, meaning you won't have to change the clearance as often.

The only disadvantage that I know of is that the absolute peak horsepower might be down just a bit.
This is usually only important to racers, and very few of us actually race on the street.

.

 

[5t341th]

Ok thanks for the suggestions. I will do another valve clearance adjustment. I ordered a tappet style feeler gauge just to be sure. The tappet style is bent at an angle for easier insertion I ordered 0.004-0.005" feeler. Hopefully that is the one I needed. I will let you guys know how it goes

 

[Guest]

Where do you have you pilot fuel screws set?

What size are your pilots?

I haven't seen these questions answered yet and I suspect they are a good chunk of the problem. OP, what size pilot jets do you have in the carbs and where are the mixture screws set at?


Mark

 

[5t341th]

I haven't seen these questions answered yet and I suspect they are a good chunk of the problem. OP, what size pilot jets do you have in the carbs and where are the mixture screws set at?


Mark

I used the dynojet stage3 jets. Not sure the exact number but whatever was included. Mixture screws have been adjusted using fast idle method already

 

[Guest]

I used the dynojet stage3 jets. Not sure the exact number but whatever was included. Mixture screws have been adjusted using fast idle method already

I don't think the DJ kit includes pilot jets (can someone confirm that?), are they still stock? Where are your mixture screws at? Through this jetting adventure you will want to be keeping copious notes of everything you change and where your settings are at, it makes figuring things out much easier.


Mark

 

[ukjules]

Ill add what i have found on two of my bikes. both were very hard to start after being left for a few days.
GSX 250 and a GPZ750R1. They would drain the battery sometimes trying to start.
Choke out, in throttle open, close made no difference.

Both were tuned to perfection, plug gap, timing, valve clearance, mixture, compression,

Anyway simply by putting them both on prime to start (if you have that option on your fuel tap)
they both work second spin !
Does your start with an external fuel tank first spin ?

 

[5t341th]

Hey guys. Finally had time and decided to do the valve adjustment again. I received the tappet style feeler gauge and it is easier to use. Should there be any play between the cam and the tappet? I can move the tappet up and down. Should the tappet be flush against the cam and then I adjust from that?

 

[5t341th]

alright. so I finished the valve clearances again and it is still very hard to start. I haven't been able to start it since finishing up. Could the bike be getting too little air?

 

[Guest]

alright. so I finished the valve clearances again and it is still very hard to start. I haven't been able to start it since finishing up. Could the bike be getting too little air?

Doubtful, air gets in really easily. It could be getting too much fuel, though. When you crank it for a while without success does it cough and try to run or is it just dead? Have you pulled a plug or two after cranking to see if they are wet? Have you tried with the petcock on the prime position instead of main?


Mark