Suzuki DS80, no CDI or points?

[my67xr]

the manifolds are made with a metal face plate inside of them, and extruded rubber/urethane outer.
i had to face a bit of the metal back to get the centre of the rubber cast o'ring to sit flat.
do you have an old wheatbox box or thick cardboard you could cut out, just to try it out?

maybe there is a slight leak there?, plus the exhaust copper gasket missing, it all may be contributing to it?


the only other thing that has an impact on midrange throttle is the needle, does it look worn ?

 

[my67xr]

to check if the coil is breaking down under load, give it a good run for 5 mins if you can.
and check by feeling the ignition coil, to see if it is warmish to hot.
if so, this may be a sign of the internal windings shorting out.

another way to test the coil,
is to get an old spark plug, snap the end electrode off, and fit it into the spark plug cap
earth the thread of the plug to the engine and kick it over.
the spark should be blue or blue/white, with it jumping the 6mm gap to the earth.


i had a quick look last night for my other coil, couldn't find it, but i will look again today.
something else to check is the electrical connection from the stator to the loom.
sometimes the terminals can corrode and cause intermittent problems
and the other thing is to check how clean the earth is from the engine mounts to the frame.
i rub them back with emery paper, then lightly grease them.

 

[heliboy89]

Hi Craig,

I have put some thick paper gasket between the intake pipe and cylinder manifold, I'm pretty certain it is sealed up but I will try the vacuum test on it again thoroughly if it's still producing these results. I've sanded the face back so it is nice and smooth the tips of the flange aren't quite flat but I've got them barely convex rather than concave now so at least at full tension they will be exerting all of there force on the center ring.

Just so we can put the other issues to bed!
Here is the daylight through the pilot and main jet;

The daylight through the emulsifying jet;

And a piece of wire through the port;


I can't find anything else that could be blocked and I have had a good look, I think we can probably rule it out for now.

So I've got the carb back together and got the gaskets under the intake pipe, got the exhaust back on with the copper ring in place, I will play with the needles and take it for a ride, fingers crossed... I'm just putting some new oil in the gearbox now, it was long overdue lol...
The needle doesn't look worn to me, I never saw it when it was new but it is uniform in shape and looks good... Full rich or Full lean on the clip doesn't seem to change the problem in the mid range that much anyway. I will take it for a good ride and let you know how the coil feels after that.

Don't go out of your way looking for your coil you've done more than enough to help man, thanks!
Talk to you soon
Josh

 

[heliboy89]

I will have a go now at the spark plug test too, got plenty of old dungers around that I can break. Catch you soon

 

[heliboy89]

I opened a spark plug right out to 5mm or so, it sparked every time bright and blue there isn't anything wrong with it at idle that's for sure. I took the coil temperature before starting which was 13.5°C (or 56°F for the yanks ). I got back after a 10 min ride and it had only gone up to 20°C/68°F, it's that close to the expansion chamber that I would put that increase in temp down to the heat given off from it. Doesn't feel warm to the touch...

So I had the same problem unfortunately, no change whatsoever. I took some videos haha, at the risk of embarrassing myself... It's for a good cause, I will get them processed give me half an hour!

 

[my67xr]

ok, coil sounds good.

 

[heliboy89]

Ok so these videos are the same ride just then, copper ring is in, gasket is under carb etc, it should be running right in theory i.e. I'm not missing any parts.

Vid 1... Air screw Full rich (i.e. fully IN). Slide needle on middle clip (where it used to run fine).
http://www.youtube.com/watch?v=XvJOQaX7nc4
Obviously it is too rich to even idle, the idle screw is fully in (at it's highest) and it's only barely enough to keep it idling though sometimes it dies anyway as you can see before I roll start. Here's where I'm worried I will embarrass myself haha, is it leaning on the mid?...

Vid 2... I have brought the airscrew out about 1-1.5 turns I can't remember exactly, before I started recording, which has leaned it and brought the RPM up as you'd expect so I've backed off the idle screw a little, this seems to sound better idling and throttle response is better to a WOT crack, but it significantly worsens the problem on the mid...
http://www.youtube.com/watch?v=OShdpBmaBFQ

Let me know what you think lol. Maybe I'm missing something obvious. I hope I am ^^...

Josh

 

[heliboy89]

Lets disregard what I said about getting through the mid and opening it nicely on the top end cause I can't even get it to do that any more, maybe it was just that day, I think I had the slide needle on the lowest richest clip... I could go out and lower the clip to full rich and it would still do the same thing though - I might get a bit more RPM out of it but will end up with the same symptoms.

 

[heliboy89]

And the vacuum test while idling... I can't hear the engine change but I don't know what I'm listening for really.

http://www.youtube.com/watch?v=uQyzra-a3mg

One thought that crossed my mind, the crank seals did hold pressure but I did this test cold, would it be possible it is developing a leak with temperature? Would it be significant enough to cause this much upset in tuning? It does behave very differently from a cold start to when it's hot... But if that were the case it would be hard to restart when it was hot wouldn't it, and it's not... That's about the only thing it does well.
I don't really want to go spraying WD40 all over the crank seals either way... What else can I try :action-smiley-003:

I blasted the carb with the hose after the dousing in oil and it made no change either, idled constantly through the whole wash..

 

[my67xr]

did you set the mixture screw the way i posted up above.
eg slightly higher idle speed,
mixture screw 1 turn out from full rich.
start the bike, let it idle, then turn the mixture screw out slowly 1/4 of a turn at a time.
let it settle for 10 - 15 seconds or so,
the idle speed should pick up a bit.
adjust it out another 1/4 turn, and let it run for 10- 15 seconds
if you turn the mixture screw out, and the engine rpms drop, then turn it back in 1/4 turn and see what it does.
keep doing this until you have the best/smoothest/highest idle,
you can fine tune it a bit once it is close on a nice idle, 1/8 turn at a time.
once it is sweet, then turn the idle speed down to a normal rpm again.
and take it for a run.

 

[my67xr]

to test the crank seals to see if they are leaking, drain 1/2 of the oil out through the drain plug.
this will drop the engine oil level down below the cranks' centre line

then start up the bike up, and let it idle for a minute or two.
if the idle speed starts to pick up a bit, then turn it off and you have found that the seals are leaking

if there is no change to the idle then they are all good.


so the bike is still running the 2 stroke oil through the pump, and up to the carby, standard injection set up ?

 

[my67xr]

i did spot one thing in your last video,
there is no boot sealing the throttle cable off to the top of the carby.
if you don't have one, you can make one using some rubber hose, vacuum hose etc.
some heat shrink tubing? , even some insulation tape wrapped around it in a few layers and zip tied.

 

[heliboy89]

my67xr, get ready for a tedious video haha.. Sorry if these videos are just a pain let me know, but I figure you'll understand better if you see what I'm doing + results.

I didn't do exactly what you said the first time, I had it in positions which would demonstrate what is going on best. But... This video here is what you said, starting with the air screw out at 1 turn, and coming out at 1/4 turn increments... I didn't bother to start with a high idle - because it ends up too high anyway, I turned it down mid way to prevent the piston coming through my arse... So, it doesn't seem to plateau and back off like you say it should, just carries on higher and higher - seems like it would keep going until I was looking at the screw on the floor.
http://www.youtube.com/watch?v=Qa84fzlujKw

In any case - the problem is bad at full rich (closed). It is worse 1 turn out. worse again 1/4 more, worse again 1/4 more etc etc, if you get what I'm saying. I don't think it's an air screw setting. I can hear when the idle mixture is happy even if it doesn't back off, if its set here or anywhere around here, it is far more problematic than if it is just full rich.

I will drain the oil and let it idle, listen for a change in RPM like you say. Doesn't tell me if the LH seal is bad though does it? Will get back to you on that one.

Thanks again!

 

[heliboy89]

I asked a guy at the suzuki dealer about that boot, he said it's not usually a problem but I doubted that too, tried wrapping it in insulation tape (tonnes of it..) and got it sealed nicely... Exact same problem...

Good spotting though..

 

[heliboy89]

And standard injector setup yes, I ran premix for a while, after putting it back together, until the pump primed itself, I took it for a run on premix with the oil line off and watched it dripping nicely, and hasn't seized yet, I have no reason to doubt it. I'm fairly sure the hose is sealed too, if I pop it off the RPM picks up a little as it lets air in, and drops back to a nice idle when I refit it...

 

[my67xr]

do you know what number pilot jet you are running ?

 

[heliboy89]

Not sure about either jets, I've never had experience with jetting. It's had the same ones in it since the day it left the factory I would think. And it used to run great I use to hammer it as a kid and it never gave me trouble - I didn't bother wondering about jets for that reason.

 

[my67xr]

can you post a picture of how far open the slide is with the throttle closed.

 

[heliboy89]

I stood the bike up, with it idling, dumped the gearbox oil into a container, let it idle for a few minutes like that, put bung back in and re filled it, no change to the idle the entire duration...

Tried squirting a bit of WD40 around that throttle cap housing and it did look like it was drawing it in, slightly faster than when the engine was off. Squirting WD40 on it didn't change the idle speed though, and I have sealed it with heat shrink and zip ties as you suggested - no change...


This is the needle too, look alright to you?


I will go and get the next photo you're after in a minute.
Cheers!

 

[heliboy89]

This is with the idle speed set to a nice idle with the air screw 1 turn out - quite rich, so quite high idle setting;


This is with the idle screw removed, i.e. the slide sitting on its stop;


Obviously the arch is lower at the front, closed is pretty well closed it's a little higher at the back I'm pretty sure...

What are you thinking?