spock58

I dunno but it sounds like compression numbers you're getting are pretty low. Around a hundred a motor will still run but getting it started might be tough - that is the issue, right? Anything that old that's been tortured likely needs rings & possibly valve work to run right.  I'd say it's time to pull the top end apart and see what's needed.

You shouldn't be getting such inconsistent compression readings. If all else fails, I'd recommend you pull the cylinder head and check the condition of the valves & their seats. Could be some carbon is messing things up. It also would be a good thing to check into the cam chain and its tensioner since you mentioned that it was 3 teeth off - that doesn't happen unless there's a lot of wear involved.

I'd recommend hooking up the new starter & cranking it over with the spark plug removed.

Good Idea to ground the plug while doing so. Keep pumping it until there's no sign of fuel.

Very important: don't let the plug spark anywhere near that fuel getting cleared!

Not very likely there's damage to the crank/piston, just don't turn it over without the plug out.

On 10/29/2019 at 1:45 PM, Jeff Comstock said:

I get  001 ohms on the stator on every wire at 2000 and 1.0 at 200. I'm assuming that taking that down exponentially to 1 on a meter would be .005 ohms, way below spec. Houston we have a problem, bad stator I'm thinking unless exponentially dropping my reading is wrong. I'll let y'all know

I believe that you're reading 1 ohm on your meter here - the number 200 or 2000 ohms is an "up to" figure. If it was on the 20 scale, it would still read 1 ohm but would be more accurate and likely add a decimal & another number. Does this make sense? In other words, if the spec was around 300 ohms, you'd use the 2000 setting to get a proper reading. Really low resistance is difficult to read and usually only is accurate with a digital meter. Hope this helps.

It's been awhile since I've done one but I do recall that those Rotax engines had lines on the cam sprocket. When the crank is at TDC, then the lines on the sprocket were parallel to the cyl. head surface. Hope this helps.

Sorry if we hijacked your thread Rich! The Honda's are definitely cool - my favourited brand too. Just thought I'd mention that I too have a daughter in Kelowna Dave! My son lives in the states now, Portland, Oregon which is a pretty cool spot and has some great riding areas. We're pretty spoiled here in the Cariboo, I live on 15 acres that backs onto Crown (public) land that goes forever it seems. Hardly any neighbours or fences, plenty of lakes & clean air plus it's only 2 hours to a city like Kamloops or 4 hr. to the coast where Dave lives. My place is at around 4000' elevation so winter comes early and stays late most years, sledding is very popular too. If anyone is curious, let me know and I can give you a tour of this great area!

You should consider the 100 Mile House area Dave, there will be lots of good deals on properties with the forestry jobs going bye bye. Plenty of awesome trails to explore too!

Not that I've ever heard of, just an idiot light for low oil pressure on most Yamaha's.

By all means try all the suggested tests but don't skip one of the most important ones: do a compression test!

If you cannot find a lift then maybe stiffer shock springs would help out.

Bear in mind that some Chinese carbs are dead ringers of the Japanese produced ones like Mikuni right down to the name on them. Even though they look the same, I've found some that have jets that don't interchange.

Right back at ya! Still some warm days out here but yesterday it got down to 1C overnight - that's one degree above freezing so 33/34 F I guess. Brrr.

A black bear discovered our two apple trees and totally demolished them, ate every last apple & it was a great crop!

Well, it has to slide freely but can't have much play at all - the only way to know is to compare it to a new one usually. It's kind of hard to tell with the naked eye. Your slide did appear to move normally and if it was worn down that would allow extra air through making it leaner, right?!

Another thing to watch for is the o-ring on the float valve (needle & seat) - was a new one used when the parts were changed out?

Just got a look at your pictures, good quality shots! The third from last shows you holding the needle jet with the main jet attached. The separated part at the bottom is what I believe may be worn. If it isn't in spec, then it allows fuel to get past the needle at closed throttle when it shouldn't. Hopefully, if this is replaced and the needle itself is new as well the issue of overfueling should improve.

There should be a few more pieces that go on top of the needle, you have them ok? and did you remove the main jet, needle jet, o-ring, holder, etc. from the carb body? a few more pics would be helpful to see if there's anything missing in there.

14 minutes ago, Dimelol said:

It's funny that you mention that because now i remember that during all of this troubleshooting, there was one odd thing that I found. When i tried to adjust the fuel/air mixture screw on the bottom of the carb it had basically no effect on how the engine ran either way. From my understanding if it is screwed all the way in the engine shouldn't be able to continue running correct? Because i did try screwing it all the way in to see if it would kill the engine and it wouldn't. Could that be due to the O-Ring you are speaking of being not properly installed? I brought it up on another forum and they told me it was an over sized pilot jet causing it (if i remember correctly), so i swapped it but nothing changed. I haven't really thought about that since, until you mentioned that about the pilot screw. Also, I did replace the needle and nozzle but they are not OEM. I noticed the old one that I removed, and the new one i installed didn't seem to line up perfectly with the main nozzle, it seemed a little off center. Could that be causing it not to seal properly? I'm beginning to second guess myself on everything now lol. Oh one other thing, at idle the exhaust is rather strong smelling. So you are thinking i have both a rich and lean condition happening at the same time from different sources basically? I appreciate the help.

You guys have convinced me to revisit the carburetor. I'll be sure to check the battery as well to be safe. I appreciate the response.

Sounds like you may have a problem with the needle & nozzle alright. That would explain the over fueling and also why the adjustment screw doesn't do much. Can you compare the original parts to those replacements? Yamaha didn't offer carb rebuild kits, just individual parts I believe....they're expensive but usually worth it!

Those carb parts I mentioned won't be in most aftermarket rebuild kits but you can get oem ones separately from a Yamaha shop. I used to wrench for the local dealership so I've run into this issue before. It's common on older single cylinder bikes since they vibrate and some spend a lot of time idling, therefore they wear the needle out in that spot. The tolerance between the needle and the tube it runs in has to be quite tight at closed throttle especially.

I wouldn't sweat the resistance test on the coil -  anytime a spec is less than an ohm this is normal. It's very difficult to get an accurate reading that low - if the coil was bad it sure wouldn't produce as rpm increases.

Unless you see a misfire using a spark tester I doubt that there's an ignition issue - still sounds carb related. One thing that comes to mind is the pilot screw, is the little o-ring & spring properly in place? Usually this results in a lean condition at low rpm which makes for rough idle & bogging or hesitation. Since your symptoms indicate richness (ie. black plug) there could be wear on the needle in the slide, was this replaced already? You also have to replace the piece that it slides into, at the top of the needle jet. This is a likely reason why it over fuels and is really noticed at the closed throttle position. I will see if I can show a parts diagram of this. You should try needle set #2 & nozzle #16. Pilot screw o-ring is #9

https://www.ronniesmailorder.com/oemparts/a/yam/50038fb7f870021f60a0ca5f/carburetor

https://www.100milefreepress.net/news/b-c-outdoor-clubs-get-funding-boost-from-province/

Wow, great photo Frank! That boat looks awfully far away from you, haha. Looks like the weather is decent, unlike up here in central BC. Nothing but rain, so that's good for keeping the forest fires away! Still going riding today unless there's too much lightning - last night was epic.

It couldn't hurt to pull the air filter and see if anything changes - take it for a short ride and report back.

If they're not leaking, just keep running them! The hubs run a small amount of ATF in them for lube.

Sounds like the front diff needs help alright but the rear is normal - both axles are "locked up" together at all times. It really isn't a differential on the rear, usually called a gearcase btw.

Oh wow, that's crazy! I wish we'd get more snow here for sledding, instead of the constant cold. By next weekend they forecast for it to start melting, then the dreaded spring breakup.