2003 JR 80 help. Again!

[gagallagher04401]

Hey guys

Quick run down.
Clean, in good shape.
Cleaned carb, new needle and seat. ( air screw at 2 turns out right now) (I know stock is 1-1/4 out)
Cleaned and oil air filter
Cleaned the end of the exhaust expansion chamber
Lubed all cables
New injection oil
New tranny oil
New back tire
110 psi of compression cold
I can spray all around carb, and intake, nothing happens so no air leaks.

What should compression be cold?

What should the compression be hot?

Issue when cold seems to run great can't keep the front wheel on the ground.
Warmed up seems to dog down, still runs pretty good but has fits.
Twice within 3 hours of my nephew riding the bike lost all power, like did not want to even go. A few minutes later, or you fight it, it will kinda snap out of it and go again.

If I need to rebuild the top end, any one know of a topend kit for this bike? Gaskets, everything I will need? Seems hard to find top end for this bike. Another bike out there must match up and work. I would love to pay some one to just do it all and fix it and be done with it.
There are JR50 rebuild kits everywhere! They give you everything! Why are there no JR80 or equivalent kits out there? What do I do?

No shops around me at all. So it is up to me, so all the help I can be great would be great.

Thanks!
George

 

[my67xr]

Compression sound's about right,
did you test it by kicking it over 6 or 7 time's at wot with the kill switch on, or spark plug lead off ?


With it bogging down when hot it could be a couple of thing's.
If you hold it at wot does it make a booowaaah sound as it dies ?
If so it could be a touch lean in the main jet.
You could try it out by blocking half off the air filter and see if it improve's, could also try pulling the choke on a little while holding it pinned.
If either test ^ help's then buy the 2x next size main jet's up from what is currently in it, fit the next one up and test it out again

If neither test improve's it, it may have a weak stator coil
They can play up when they get hot due to the winding's opening up and causing more resistance or there may even be a fracture/break in a wire which open's when hot
You will need a flywheel puller to swap it out too.

Source coil part number is 32130-13640
Suzuki DS8 85 JR8 1 4 DS JR 8 Coil 3214 3541 3213 1364 | eBay

 

[gagallagher04401]

Yeah I kicked it till the gage didn't move anymore.
But compression could drop a good amount once warmed up too, right? Causing it to run better when cold.
I hate not knowing exactly what is wrong, having to guess. Throw money at a not sure solution.

Thanks all

 

[my67xr]

Well to test the main jet by half blocking the air filter won't cost you anything
I'll try and find what the stator reading should be so you can test it with a multimeter

 

[gagallagher04401]

Thanks my67xr
When it loses all power it only does it for a couple min or so. You say what the heck, push it to the truck, start it back up and then is fine again. For the most part. Lol the bike has not had time to cool much.

How would I block part of the air filter? Trying to wrap my head around that.

Thanks on getting me the stator readings so I can check it with a meter.

When/if I need to rebuild the top end is there a kit out there like there is for the jr50?
Does this bike have the cylinder that is the type that has to be replated? Or has a glaze? Can it just be honed?
Long short of it, what type of cylinder does this bike have?
If it is just honed do you use stock size piston?

I know I sound dumb. Please forgive me. I new to these, trying to learn all I can and get her running beautiful again.

Where is a place to get cylinder work done at a reasonable price? How would I tell them what I have to have done to it to begin with? I have no shops where I live.

Thanks all for baring with me.

 

[my67xr]

To block off half the air filter, cut a piece of hard cardboard or plastic and sit it in the filter box so it block's half of the hole where it goes through to the intake side of the carby, you may need to tape it there so it stay's put while you test it out.
The cylinder has an Iron liner, so it can just be honed if it's not too scratched up
Top end kit's are the same as Suzuki DS80 1982 onward's so are easy to find
Base gasket, head gasket, exhaust gasket, piston, ring's, gudgeon bearing, gudgeon pin and gudgeon clip's are what you'll need to freshen up the top end.
You'll need to take the head off to see if it's ever had a new o/s piston before, they usually have a marking on them to tell you the size eg std, .25, .50 etc
The stock piston is a 49mm iirc, so you will be able to use a small cylinder hone to clean it up

 

[gagallagher04401]

Thanks so much you have been a great help.

I will run it and try the choke idea and block part of the air box.

It's weird it only did it twice. Then would kind of come out of it. The part of the story I left out is, I sprayed the bike down with the hose to clean it up. After I did that it did not hesitate at all. All kinds of power. Lift the front no problem. ( I did not ride it long to know how long this power streak would have lasted)

I also pulled the whole exhaust off again. No gunk build up. Cleaned expansion chamber again as well.

 

[gagallagher04401]

To block off half the air filter, cut a piece of hard cardboard or plastic and sit it in the filter box so it block's half of the hole where it goes through to the intake side of the carby, you may need to tape it there so it stay's put while you test it out.

Well I tried blocking half the air filter off. It ran like crap. I even put the air screw at stock setting still crap.

Rode the bike myself for a bit but still not that great but ok. Not like when I first rinsed it off with the hose.

There is still that flat/hesitating spot at lower rpms. Once by it, it pulls. If u let off quick then back on and try to wheelie it bogs/hesitates and doesn't want to go. You have to let off then back on to go.

Haven't ridden it enough to lose all power yet again.

 

[my67xr]

Ok, the low end hesitation is the pilot jets' too small, i would swap in the next jet up from what's in there now
You may be able to go up 2 jet size's, get yourself a #27.5 and a #30
Try the 27.5 first, and you'll need to retune the mixture's like i described in your other thread
They use the Mikuni VM22/210 Pilot Jet
#27.5 Pilot Jet
#30 Pilot Jet

 

[gagallagher04401]

Ok. I will try that.

Any more ideas on the loss of all power for a short time? Bogs and can't even go. Then after just a little *****ing at the thing it seems to come out of it.

What should the compression be when the bike is hot?

110 isn't to low of a cold compression for a 2-stroke? I thought it should be like 125 or so.
When hot do you think the compression is becoming to low?

 

[gagallagher04401]

Well 2 new pilot jets ordered. Fingers crossed.

Should this put my air screw closer to the stock 1-1/4 position?

 

[gagallagher04401]

Also FYI

When I have the air screw at stock setting the bike stutters like ta..ta..ta..ta.. And won't accelerate.
At 2 turns open it will go but with the low end hesitation spot as I described in earlier posts.

 

[my67xr]

It's hard to tell, but a hesitation off idle, and when opening the throttle under 1/2-3/4 rpm is a sign of the engine running lean
The bigger pilot jet should help/fix this problem

Next time when you are trying it out and it dies or bog's with no power, turn the bike off and pull the spark plug out straight away and look at the colour of the porcelain

A couple of other member's here have rebuilt their DS80 engine's, and when checking the compression have got around 100-110 psi

 

[gagallagher04401]

Next time when you are trying it out and it dies or bog's with no power, turn the bike off and pull the spark plug out straight away and look at the colour of the porcelain

A couple of other member's here have rebuilt their DS80 engine's, and when checking the compression have got around 100-110 psi

The hesitation happens after you get going and start to really accelerate, once past that part it seems to pull pretty good. But like I said if you let off and then power back on to try and wheelie for example it bogs.

I will try to check the plug. Almost impossible to pull the plug on this bike with out taking plastics and raising tank up to be able to get to it. Is there a simpler way to get to the plug that I am not away of?

What should I be looking for after I get the plug out?

 

[gagallagher04401]

Ok. Update.

Got my two new pilot jets. Put the next size up in. I think it is helping some. Somthing is still not right. Today the bike ran like crap. Did not matter where I put the air screw. 2 out seems to be the best. Bike just had no balls. You could go wide open bike just bog and putt along. Bike still hesitated, wouldn't accelerate.
That all being said loaded it up brought it home. Took it off the truck started it and ran it. Seems to run the best when cold. Ran much better cold, but air screw still 2 turns out.

I am lost, no idea what to do now.

 

[my67xr]

Try raising the clip on the needle in the slide, it should be in the centre notch now, try it in the 2nd notch down from top without adjusting anything.
If it's a little better try it in the top notch
While it's apart, check that the needle is straight, and that the outlet in the emulsion tube in the carby where the bottom of the needle sit's is still round.

To remove the spark plug i use a Plug socket with a hex head, and use a spanner on the hex

 

[gagallagher04401]

While it's apart, check that the needle is straight, and that the outlet in the emulsion tube in the carby where the bottom of the needle sit's is still round.
[/QUOTE
I will check, but I would think it is straight. I will check the hole to which I bet is still round as well.

Moving the clip up is leaning the bike isn't it?

Would it be better to premix? Could I be getting to much oil?

I shooting in the dark. Just want this fixed. I feel bad, I told my sister to buy it. She's getting mad at me. I think it will be a good little bike, but damn. I need to catch a break on this.

I debating on buying a new carb (don't want to)

Maybe my air filter is not letting in enough air?

Thanks so much for sticking with me my67xr.

 

[my67xr]

Yeah moving the clip up will lean off 1/4 to 3/4 throttle mixture's, i am trying to work out if it's a lean bog or a rich stutter up in the top end
Does it sort of make a booowaaah sound, if it does it's too lean, so drop the clip to the bottom notch on the needle

If i had the bike here it would be a lot easier to diagnose and fix

 

[gagallagher04401]

Well I moveed the clip all the way to the top and tried the bike, that would make it at its leanest and ran like crap. It wouldn't accelerate it was like Ta ta ta ta and would not go etc.

I then moved the clip all the way to the bottom to try that. which would make it it's richest and it had all I could do to get it to idle. I had to have the idle turned all the way in and it was very Boggie down low and didn't run well either. It was like it had no power.

It seems to run the best which best is marginal with a clip in the stock spot at number three.

I also cleaned the carburetor again just to make sure there was nothing in it.

It seems to run its best when it's cold.

I guess I'm going to have to try to find a small engine repair shop or something and take it to I'm running out of ideas and hope.

 

[gagallagher04401]

I am thinking it is loosing compression when warm/hot.

What you all think. I played with the carb every way to Sunday.