2000 Suzuki DS80 build

[DMKLSIMONS]

Ok.. Took carb off and clean again... Adjust the float to 26mm. It was at 19 mm. . Main jet is factory 87.5. Need was set in the middle. . After this the bike stopped smoking excessively like it had. . Bike ran much better and quit the shuddering at high rpm... But after riding it at half or more throttle it would start to fall on its face. . Like the bike was not keeping up with the amount of fuel it was using. . I tried to adjust the float down to 24 mm. . Now bike falls on its face at half or more throttle. Back to 24 mm no change. . Moved it to 21 mm with no change. . Tried to adjust needle up on notch and down one notch with no change. . I have checked for air leaks with starting fluid and can't find any. . Now with the needle at one notch toward the lean setting I tried riding it and when at half throttle it goes flat I closed the choke to see what would happen... The bike did not care.. Ran the same with choke on as off. . Bike will Rev on up to max as long as you keep it below half throttle. . Also noted that in the lean position the bike has to have the air mixture screw way out to keep it from over review at idle. . I am at my wits end on fixing this thing. Complete loss what to do now. . Here is the plug I pulled out that had been in. .

 

[my67xr]

With the float level at 24mm, you'll need to retune the pilot via the mixture screw.
Did you turn the idle sped screw out to raise the idle speed up to about 1800rpm, then adjust the mixture screw to the highest/smoothest rpms?
Then drop the idle speed back down again ?

Id also check the fuel flow out of the fuel tap, the filter inside the tank may be a bit blocked up
Or tank vent on the cap, is that open ?

 

[DMKLSIMONS]

The vent is clear, and filter is clean. I did reset the mixture screw. It really ran better after first float adjustment. It finally ran like I expected it to run but after ridding for two to three mins pretty hard it was like starving for fuel and you had to really slow down and idle a bit then go again. . Like the fuel level was low in carburetor. What effect does moving the float level from 19 to 26 have? My manual calls for 26 but that I think maybe is for the older carburetor. . My bike is a 2000 does it have same float level?

 

[my67xr]

The Mikuni Carby on the DS80 is actually called a VM20SS,
i just looked up the float height setting for them and it say's 21mm
Reset it to that and then retune it, post up the result's


A 6mm difference in float height can change the jetting requirement's.
Any more than about 1.5mm change in the float level can need a bigger/smaller jet to compensate for it
A higher float level (19mm in your case) will be a lot richer than 26mm

 

[DMKLSIMONS]

Thank you sounds like a great place to start. I had to really bend the tab to get 26mm. That should have told me something was wrong.

 

[DMKLSIMONS]

Beginning to wonder if buying a new carburetor might be the easy way out. . Haha

 

[my67xr]

Nah, save your money for something else.
You should have seen my DS carby's before i cleaned them up/out.

What manual do you have for your bike ?

Also i was just thinking,
when you disconnected the oil feed from the pump to the carb, did you cap/block the barb on the carby where the oil line used to run?

 

[DMKLSIMONS]

It's a factory DS80 shop manual with index in the rear for the newer models. . Could not find anything on float measurement on the newer carb. . So I used the only one listed at 26mm.
The oil tank was removed before I got the bike. . I dont know where the oil is injected to the crab.. So it may be open. .

 

[my67xr]

The oil goes in through a little brass tube on the manifold side of the carby, left of the idle speed screw directly above part #3 (main jet washer) in the pic below

Might want to swap the needle clip back to the middle slot while you're at it

I'm heading to bed shortly too so good luck, it's getting cold now 6° C atm
I'll check back here in about 6 hour's to see how you got on

 

[DMKLSIMONS]

This is the exact carb. What is this input for? Oil?



Then this one on back.

 

[DMKLSIMONS]

Ok I am pretty sure that one is plugged. Or has a cover over it. I may need to plug it up better. The rear one I dont think is plugged at all

 

[my67xr]

Top pic is the oil feed line, bottom pic is a vent/breather

 

[DMKLSIMONS]

Should I put anything on the breather? Tube or anything.

 

[my67xr]

Yeah they have a 6" tube that hang's off and run's down, see pic above
It just stops fuel running over the expansion chamber if the bike is dropped on it's right side
Some clear pvc tube would work, or vent hose if you have some

 

[DMKLSIMONS]

Ok..I will move float level to 21. and Put the needle valve back to the center. See what happens after I reset the mixture and idle. And ensure oil injection is plugged fully

 

[my67xr]

Any new's ?

 

[DMKLSIMONS]

Not yet... Not home yet... Working

 

[DMKLSIMONS]

Ok.. How do you get this inner part out.. Brass insert below the main jet.

 

[DMKLSIMONS]

LOL... Ok.. Got that out.. Newer diagram for carb helped. . Comes out opposite of the older model. The cleaning rod I'm using won't go all the way through this pilot jet should it

 

[DMKLSIMONS]

Ok. Got rod to pass through the jet in prior post. All back together with float at 21 mm. Bike no longer bogs down at half or more throttle. It would idle good and seemed to rev well with good throttle response. See the video and tell me what you think. I put the needle clip in position 4 because the manual said that was factory setting. This would be on clip position down toward rich. I think the bike is running rich a bit. I should have just put it in the center and left it. While on the first test ride by me the bike seems pretty good. Good idle and all only rode about 5- 10 min without the air box. I reinstalled the air box and made sure no change in air mixture screw.

Now having been ridden by my son for about 20 min it does not like to hold the idle. It either goes to high...or goes to low. Always having to fiddle with it. Won't stay the same. I dont know what would cause this. Also noted now when you cut the throttle it takes it awhile to wind down. It wants to keep revolutions up and the motor does not want to slow down. In the video it was still running pretty good. It was later that is was happening.

[video=youtube;ZPxWt-nLHJY]https://www.youtube.com/watch?v=ZPxWt-nLHJY[/video]