PIYIRIO

Should the quad be under load (in gear) to see any potential puffs out the carb?

I wanted to but I'm in town so I'd have had the local PD on me in no time. I ran it idle for a bit and rev-ed it, also held a high rpm. I only have 2 tank connections, petcock and vent in the cap. Hard to screw that one up. Now that I have the service manual I'll run down the carb connections. Test riding the quad will have to wait until I get it to my property. I attached a clip running with no exhaust attached. It sounds fine to me but I'm no expert. Ignore the horribly brazed muffler inlet crack, I don't have the oxy-acet here and went for it with MAPP... 😑 NoExhaust.mp4

Now I'm golden. I'll probably fix the starter issues once I get my other issues fixed. It pull starts super easy and once it's been pull started it only takes a quick starter bump to start. I honestly never considered it an issue, just a little quirk. I will need to get the flywheel puller. I've really loved this prairie but once I get it square away, it may be time to find something newer. ...or older, my '85 Honda Fourtrax 250 is a solid beast... just wish it was 4wd. I guess it's easy enough to find and replace the belt but if it's the clutches, I'm pretty well screwed. All I've found are used in unknown/questionable condition. I just find it strange to suddenly have a possible belt issue. It was never an issue prior. I guess it is 28 years old and never been changed.

I wish I had a tach and speedo but it's a '97, I think there was a speedo option. Audibly it sounds perfectly normal, exactly like it was going as fast as it used to. I wouldn't say it has no power as I can still pull my trailers and stuff, it'll pull hard but it's topping out like it's in low gear, actually a little higher but not what it should be. 100% not in low gear! I checked it multiple times to make sure. 🙃 It's available once you hit 10 posts. I just wasn't going to spam b.s. to hit the 10 post mark. Looks like I have one more post after this one. I'll check it out. The starter spins no problem but about 50% of the time it doesn't turn over the motor, and when it does it's for a short burst before it just spins. If it was a car, it'd be an issue with the bendix gear not engaging the flywheel. Looking into this model, it's likely the start gear clutch... which requires a tear down of the left side of the motor where the starter and pull start chain is. But I may be wrong. I got the motor buttoned up and checked the valves. Exhaust was dead on .23 and intake dead on .18 which are the middle marks in the acceptable range. I started it up and its still easy to start with the pull rope so I'll say the valves are set correctly. The open head and straight pipe exhaust note sounds clean, no struggling. I got a lot of 4 letter words about the quality of work done, mostly f-bombs, but I'm new and don't know the audience. I did find the rear vent hose thing that attaches to the clutch/belt cover was completely disconnected. A large amount of dust likely made it's way in and if really unlucky, a mouse could have made a nest. I'm sure I'd smell the belt if it was slipping but I think I'll be pulling the belt cover next and inspect that. as well.

I'm not sure what I did when I checked last but it was obviously wrong hope I did it. The sprocket mark is dead level the first rotation (forward ) and about a half tooth off on the second rotation (aft). It's consistent over a dozen or so rotations; I'm not noticing any variation. I'm turning it using the pull cord so it better be turning the correct direction. 🙃 I'm going to bottom this back up and check valve adjustment next.

Ok, I must have been exhausted when I checked the timing a week or so ago. On the first rotation at the t mark, the cam sprocket mark is dead level with the forward side of the head. The second rotation at the t mark, the cam sprocket is maybe a half tooth off level with the aft head surface. That should be acceptable according to what I've read and the book you've referenced. I was really hoping timing was the issue here. I hope it's not an impossible to find clutch. Anything else to check while the cam/valve cover is off? Of course I'll need it on to check valve adjustments. Thanks for all the help!

Sorry I wasn't clear, the 2nd crank rotation is what I meant by the "2nd T". Does the book say the sprocket should be lined with the forward or aft facing head surface?

Oxy-acetylene is an option for me. I'm assuming I'd need block one of the pipes on the manifold/header so you don't catch a back flame. It's an almost 30 year old pipe so the metals already pretty thin. I don't have the service manual so I have questions about the timing, it might be easier to show in pictures. I've read that at TDC (or the T visible in the peep hole) the timing mark on the cam should be level with the top of the front of the head (pointing to the exhaust ports). Mine is level with the back of the head (pointing to the muffler). At the 2nd TDC (T mark) the timing mark is 30-45 degrees above the head facing the exhaust ports. Can you confirm my timing marks are correct?

Sorry for having to drop this project for a bit, company just had layoffs and I was finally the lucky sucker. Thanks for the suggestions, I'll try to address some of them: I checked to be sure but the throttle adjustment is pretty well dead on. It's opening to full throttle with no restriction on the cable. The motor sounds normal, like its fully rev-ing out, it just tops out at 25mph as opposed to the 45+mph. That's by ear though, be nice to have a tach to have exact numbers. It was well over a grand.... wouldn't have been terrible if it was working right. There's no rev limiter installed on the throttle. Like I said, I feel like it's rev-ing out. I already called the shop and they pointed to an exhaust leak. Long story semi-short, he cut one of the sides off the muffler mount... I'm assuming so he could swing the exhaust out of the way without fully removing it. The cut mount has a nice shiny silver line down it so it was 100% done while it was there. I didn't realize this was done and by running it and bouncing around with the muffler flopping, it caused the header pipe to crack. I reconnected the reverse assist button that was disconnected when I got it back. I also found a TON of missing screws... I know it happens, but I managed to not loose more than 1 or 2 over 20 years. That's just sloppy, lazy work. 100% burnt oil... a lot of soot in the pipe but no restrictions. Any good way to clean it out?

The exhaust is off right now. I'll get out this evening, put the cam cover back on, and fire it up.

When the valves were out of adjustment years ago, it was really hard to start when cold. I'm not currently experiencing that. The motor and exhaust sound normal to me... but I may not be the best judge. Wouldn't the motor likely be difficult to start if the values were out of adjustment again?

Hi all - I recently had a shop fix this quad and it hasn't been right since. The jug was resealed as it was leaking, the rings were replaced, and the valve stem seals replaced. Shop said the cylinder walls were great so nothing was done there. The motor still smokes, heavily on startup and all but quits once warmed up. Enough that I can live with it if I can fix what I came to ask about. I mentioned this work because since I've gotten it back it seems like it has power but tops out at a much slower speed than before. It's old so I don't have a speedo but I pulled out my phone at it tops out at 25 mph. I know before the work, I was getting up to 45+ mph... It's so bad, my 10 year old daughter is pulling away and straight leaving me in the dust with her governed Polaris 90. Given the work done, what are some thing I could be the cause of such a drastic difference? I immediately thought timing but the marks appear to match up with a youtube video I found... no idea if it's correct though. It sat in another shop for 2 months and they gave me an $800 quote just for the starter... it pull starts fine. FYI: I would take it back to the original shop to figure out but I had some issues that make them a no-go for me.