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Thanks for the replies, got it exactly right. The bike starts perfect, idles perfect, runs perfect... been riding it a ton the last couple days, so satisfying.

Ahhh thats a culprit of the choke circut not being engaged due to how its not getting any fuel! You could drill it, just be very careful. Do you need a drill.size and the depth? I can go get that info for you with my spare carb

That would be super helpful!
Either way it'll need to be replaced so I figure I'll give it a go.

Am I correct in stating that there should be a hole in the bowl of the carb with the pickup tube? Both bowls have a "2" stamped in them. It looks like there is supposed to be a "1" bowl which has a hole...

I guess that means the pickup tube isn't doing anything.

Would it be possible to drill that hole rather than buying a new bowl?

Does it die out even with the choke on? Do you have the washers on that fit under the main jet? Is that a tight fit?

Yes it will die with choke on. Yes, washers are on under the main jet. The washers appear to be factory, they fit perfectly under the main jet.

I measured float arm and it is at correct height as well.

Not sure if I should keep posting to this thread or start new ones with new issues.. In any case, for whatever reason I can't get the bike to reliably start on it's own now.

From cold start, it will start with choke on, but will die out before it warms up at all. Any throttle at all kills it. If I spray carb cleaner in the intakes, it'll rev up and run well, so I keep spraying till it runs without choke, and then it runs great. It'll run, idle and drive really well.

Again, carb issue? I've cleaned both several times. Idle jets, jet tubes, main jet are all spotless and spray well.

I've tried air screw down to 1/2 turn and it reacts the same.

This is all a learning experience for me, it's really the first bike I've ever worked on at all. That's my excuse for some really dumb mistakes I have made (or didn't know were made by the previous owner).

After cleaning the carbs thoroughly multiple times, it still didn't seem to help.

It's when I took apart the entire throttle cable assembly to replace the autolube cable that I realized that the retainer that goes under the spring and on top of the jet needle wasn't seating properly in both carbs. The needle must have been bouncing around under the crooked clip. I figured out how to properly install that.

Then I realized that it's possible the throttle cables / slides could easily be put in backwards into the two carbs... that's exactly what was happening, the cutaway was backwards, basically starving the carbs of air.

I put them in the correct way and immediately running well... throttle response so good now.

Thanks for all the help troubleshooting this. Managed to fix issues I didn't know I had in the process (like the under oiling). At least I'll finally get to enjoy it a bit this fall!

Thanks for the replies and tips.

Based on what I'm seeing in your photos and your explanation of the issue, I'd say your mechanic's advice was 100% wrong. It would be under-oiling not over-oiling! Not sure what logic he was using.

He hasn't seen the bike in person at all, I just had him hone the cylinders. He was guessing based on the smoking and wet oily plugs.

I just ordered a 278-26321-00-00 cable yesterday from ebay, shipping is taking forever lately and there is a canadapost strike now, so I'm not holding my breath on getting it any time soon. I was just hoping to try premix temporarily.

The fundamental problem at this point is still that it's running rich no matter what. The air screws are out 3 turns and idle screws are almost entirely in to get a good idle.

I really don't have a lot of experience with this. In my mind it's a carb issue, but I have brand now valve seats and and valves, I've cleaned it out, made sure the float arm is at the exact right height (15mm).

I guess next do a leakdown test?

Finally got the bike back together, starts really well, and seems to run pretty well, except that it's still very rich, getting lots of smoke, wet oil on plugs.

The guy that did the hone job for me thought it may be that it's over oiling with the pump.

I noticed that part of the oil pump cable is partially broken off (never knew what it was supposed to look like).

In any case, at zero throttle, the raised mark is supposed to line up with the pin, but it's way up from it. It takes about 1/4 throttle for them to line up.

I also measured the gap between the adjustment plate and the pump pulley after rotating the white plate to make the plunger move out. It measured 0.14mm, manual says minimum is 0.15mm and should be 0.20-0.25mm

Wouldn't these cause under oiling if anything?

I was thinking of just trying premix. How can I connect the output oil tubes from the pump so that the pump will still work without being attached to the cylinders? Could I just have a closed loop with all three hoses (one in, two out) connected together and a bit of oil in the line?

Well upon closer inspection, I noticed there is faint numbers on the rings... they are in fact 50 over rings. Unreal. I don't know which seller to go after as both boxes are identical, only the rings were different. Guess I'm just SOL on those.

As far as the piston in the bores, I can barely get .003 to fit.

An update on my comedy of errors.

Somehow I didn't realize to check if the engine had been bored previously. It had been already once before, so I decided to just hone it and install the new pistons and rings since previous ones were quite wore.

Finally got the parts and installed first cylinder fine. Was fitting piston into the cylinder for the second one and somehow snapped one of the piston rings...

Part numbers were identical on the boxes, both said 25 over. I'm only learning now (manual says nothing about it) that OEM rings need to be gapped?  What is a safe way to do this?

Edit: and maybe dumb question, but could I use one of the old rings in the bottom temporarily?

Pencil worked to push it out. They don't look too bad but do need some cleaning.

I took the cylinders to a local guy who does work for bike shops in town and he measured them. He said they were fairly wore and a .25 bore is necessary, so I will be replacing the pistons and rings.

Those float needles should be replaced. Do the valve seats have a marking stamped in them "2.0"? Probably best to get them as a set and just replace them all. When buying new float valve sets be sure to get size #2.0 (Mikuni Type VM26/26). The DS7 & R5 run a #2.0, while the RD models run a #2.5.

Yes, 2.0. I noticed yambits just sells them as sets, so I'll go that route.

I will replace those air filters as well.

aside from those float needles looking rough, i mean the jet tubes and needles.

https://www.2strokeworld.net/forum/index.php?topic=6624.0

Gotcha, although it is clean through the jet tubes, the tubes themselves weren't removed, I'm not sure how I would do that. The needles appear to be in good condition and are clean.


Other than that I will get the rest of the top end measured properly and figure out what needs to be done. Hopefully these are all of the remaining pieces of the puzzle.

Thanks for the input

You could take the rings off, stick them in the cylinder, and measure the end gap to get an idea of wear.

Ring gap measured between 0.97-0.98mm

Edit: Just noticed the manual says ring gap should be 0.15-0.35mm, so I guess it's safe to say they are long gone.

yeah thats what I do as an initial check myself. from the pics nothing looks terrible. do the carbs have the stock bassinet thrm? you still have the stock needles in the slides? were the jet tubes removed completely and cleaned?

Previously I had removed all jet tubes and cleaned thoroughly, I took them out again and they were still all clear.

Interesting that I never noticed when cleaning before, the needles are definitely different, and I think there is damage on the choke side carb needle, and there's no working spring in it. I will have to get new needles to make sure I'm using the right ones.

I also measured the float arm measurement - manual says 15mm, I measured 14mm on right carb, 13.5mm left carb (one with damage).

As the other guys have said, nothing alarming in the pics. Piston skirts show a little wear but not bad, and there really isn't much sign of blow-by from worn rings. Measuring the ring end gap as suggested above is easy.

To measure the cylinder correctly you would need a bore gauge and micrometer. Not sure where you're located but you can puck up something inexpensive like this to do the job:
HF bore gauge set

Are you sure you're testing compression correctly because if the bike was running previously it should have more than 65psi. Make sure you're using the spark plug adapter that matches the size (dia and length) of the spark plugs. Also make sure there is an O-ring on the threaded end. Thread it in by hand and snug it finger tight. Fully open the throttle and kick the engine over repeatedly until the needle stops climbing. Where it maxes out is your compression number.

I tested compression after warming engine up and doing exactly as you mention, making sure plug adapter is correct size, there was an O-ring on it, tightened by finger, throttle open.  I had removed both spark plugs as I thought they were both supposed to be out for compression test. Should I do it with the other plug still in?

You say you are running cone air filters - if they are the ones with a flat top opposite the carb that is a problem...

Yes, not doubting, but what problems could it cause?

I also did notice on the back of the right carb it looks kinda gnarly, not sure if it's an issue to have what looks like those holes plugged on the left side...

My bike is running very rich. I've cleaned the carbs multiple times, the jetting is all factory specs. Replaced coils, condensers, wires. The intake was replaced with cone filters which I would think would make it run lean if anything, but in any case it's running very rich no matter what.

I noticed when it's running the left cylinder feels much warmer. The left spark plug comes out black and dry, the right spark plug comes out with wet oil on it still. I get exhaust out of both exhaust pipes though.

I tested compression (borrowed a tusk brand, not sure if it's a good one) and it read around 65 psi in both sides so assumed something with the top end is wrong. All I have is a digital caliper but it 54.2mm at each measurement I top and bottom of each cylinder.

I'm guessing I should take the pistons and cylinders to someone who knows what they're looking at? A hone job and new rings, or do the pistons look like they should be replaced?

Welp, solved that problem and introduced another one. Upon further inspection I noticed the last steel clutch plate must have slipped slightly as I was putting the pressure plate on, basically making it stuck between the pressure plate and clutch boss or something, making the clutch in a continuously open position, not able to spring closed.

I seated the clutch plate properly, put the pressure plate back on, put the cable side cover on and the clutch felt exactly like it did before I took everything apart, I thought it was working properly.

I noticed that with clutch in (I could see the pressure plate push out), it wouldn't feel like it would fully disengage the transmission, it would still turn over the motor. I tried spinning the wheel a few rotations, and then it WOULD disengage and was like the clutch was doing it's job. If I let go of the clutch, then engage again, same thing, it's like it's in gear for a few wheel rotations, then it finds neutral.

I thought maybe it's because there's no fluid (I still had the case off at this point), so put everything back together, and of course, it's the same thing...

Edit: Just to follow up, I ended up driving it for a bit and it's totally fine now 

On to other issues...