freebo86

So I went outside just to start the ATV and mess with the choke a bit and of course it’s quite temperamental. I could go from not being able to starting it to starting it easy. All depending how the choke knob was set. I loosened the knob at the dash try to get it loosened up and properly set and then re-tighten and I think that did a little trick too. Seems to be better now! Also noticed a big uhhh ohh moment. When I removed the front crankcase cover I had to pull the front diff forward. Well I just noticed now I never reinstalled that top mounting bolt for the diff and it’s no where to be found 🤦‍♂️

Hmm, brake fluid never crossed my list! The PO installed Disc Brakes in the front, may be worth to replace the fluid. @Tim-ANC I'll direct you to this thread of mine which was started in ambition originally until the mechanical failures started to take over lol! The last thing I did was about a month ago trying to refreshed the plastics.. turned out okay. But looked like they fade away again 😞

Haha! I went out with two other buddies so I was coming back with a bike or without it. Good news, I'm 99.9% sure I solved my issue.. . Read the below carefully, maybe even twice to understand whats going on and what actually solved it. To recap. Thursday night I loosened the exhaust valve to .007. As I stated a few posts earlier I grabbed a chinesium carburator from a colleague (for testing purposes). I adjusted the valves, and installed the Chinese carb and the machine fired up (machine was cold). It ran okay, if I let off the throttle it would fart and burp out the exhaust. I figured its the air/fuel setting on the carb as I found out that Chinese carb was actually for a 400 machine.. Anyways.. I left the bike that night be as it was getting late. Friday I came home from work and figured, no point in keeping that Chinese carb on there. Going to reinstall my own OEM one, need to put all the other plastics back on for Saturdays trip. As I am taking the Chinese carb off.. I noticed the the choke (my OEM) on my machine had seen better days, I compared it to the Chinese one that came with the Chinese carburetor that I left still in the box because I was too lazy to swap the choke plunger Thursday. I noticed the chinese choke plunger had a much better condition o-ring.. I figured what the !. I'll take the chinese choke plunger, install it on my cable inside my carb. Connected it all up, machine was cold, I figured ! its going to crank over. Crank crank no fire. So I'm standing there now with the exact same symptoms with a cold machine like I've had when its warm. What the !! 😭 What's different? I'm looking over the bike, try to crank again no luck. Thinking to myself what did I change... AHHHH! The chinese choke plunger. I figured I'll unscrew the plunger out completely from the housing to see what happens, and the bike fires on the first instant, runs like crap but it fired. Hmm.. I take the plunger put it back in into the housing.. no fire. If the plunger is in the housing and if the choke is pulled in or out it won't fire. If I remove it from the carburetor it fires. After closer examination the chinese plunger is slightly different than the OEM one and it didn't even really fit correctly inside my carb. So I thought what' the chances of my OEM plunger actually being faulty? Because I am seeing the exact same symptoms now with a cold machine as I did with a warm one. Called the dealer saturday morning before my trip, they had the plunger in stock. Went and bought it, $90. 😡😱 At this point.. whats another $90. Came home, installed the new OEM plunger, after a bit of feathering with the throttle and playing with the choke knob of how far its pulled in or out I realized how sensitive the choke is - bike started up and ran great. Loaded the bike and off we went, I've put over 100miles in the last two days (the weather was 7 Celsius and 12 Celsius), with numerous pit stops (turning the bike off) and the bike started every single time. Not a single hiccup. every single time we'd stop I thought to myself this is the end of my trip, it won't fire when were ready to leave.. NOPE it started. So the whole starting when warm issue I believe was my plunger. It was not seating/sealing and working as it should regardless of the actual knob position (IN or OUT). Conclusion when the bike was cold it was a lot more forgiving on starting with the old OEM plunger even thought it operated poorly and incorrectly. However, when the bike warmed up.. the choke had a much more important role to play and as it wasn't properly working/sealing so it wouldn't allow the the bike to start. After some more miles, I will pull the valve cover again and set the exhaust side to .006 to prove my theory. But I think it's safe to say its the plunger, because the bike wasn't starting Friday after I swapped the plungers (Chinese and OEM) even thought it was cold engine with the .007 gap on the exhaust so the plunger was affecting it.

Oil looked dark. No metal shavings, checked the filter over too looked good. Replaced it just to be safe. Filled it back up with Rotella again last night.

I did that last night, set the exhaust to .007, intake .006.

Good point! I'm honestly not concerned about the fan, the fan worked and the fan comes on and off. My temp switch wasn't in spec before, so the fan operation wasn't running when maybe it needed too. With the new switch it's going to be within spec and will come on just sooner rather then later, I'm pretty confident on that already.

The carb is is the correct number, I had it crossed with @retro and confirmed it's the right VE #. It's a few pages back. Internals were rebuilt with a new Shindy kit. Well fired it up last night, runs like a top of course. Took it around the block, no issues. Story of my life, but again it was cool. I can't really stretch its legs or get it to super operating temps good without trailering it to trail access. Which it was getting late last night so I didn't have a chance. I don't want to just let it sit there and IDLE forever as I know it's not good for it just to get it to temp.

Yes sir. New Oil Temp sensor Fresh Oil + new Filter Checked the valve clearances last night after the initial break in. The Exhaust valve had become tighter..

The carb is set at 2-5/8s turns out as per service manual. What do you mean tuned while hot? Isn’t the air/fuel screw supposed to be tweaked with bike running?

Yah was a joke out of desperation friend!

Yah but that shield doesn’t separate the coil from the head? On my machine it only adds a barrier between engine and the fuel tank/seat. The coil is on the underside of the shield where the head is.. same level basically. Am I feeling it? Not sure, feel optimistic.. going out Saturday not even sure how I’ll make out considering thing don’t start when hot. May have to cover it with snow to cool it faster?

Yah that white plastic piece is in place.

Both oil cooler lines were warm that run to the front crank case cover, they both felt the same so I'd say they were the same temperature. They were just warm I was able to wrap my hand around them and hold it there, it wasnt like blistering hot. I agree. I don't think my fan/oil switch issue is heat related. But as you said, needs to be resolved regardless. The coil is right near the top head.. which is bursting hot. I guess the heat off the head could be affecting the coil.. That's another possibility.

New sensor is in my hand. I went and bought it. Call me crazy. I want to give up, but I want to beat this issue. Thanks, Ill keep it in mind. Check your Private Messages! Stopped by the dealer to grab the sensor, went into the service area to pick some brains. One of the guys claims had the same issue. Too tight of a exhaust valve. Said, once hit, it expands and the gap on the exhaust is too tight to get going. Thoughts?

Well no reason to go the ON/OFF switch route with a brand new oil sensor, no? Unless I want manual control over the fan, right?

True points. Yup. Wise words. Dealer has the sensor. 74$. Spoke to a colleague of a colleague he has a brand new Chineesium Carb sitting for a 400. He said take it and troubleshoot with it too to see if you can get it to run if it is a fuel issue. At this point in time, I may just grab that carb and slap it on and see what happens. Maybe the entire thing just explodes and it settles it for me?

When we originally started troubleshooting this (2months ago now)? After the HOT no start, I put 1/4 teaspoon fuel into the spark plug hole - same ordeal. No fire. As much as you guys are cheering on and saying I am winning, I'm not feeling it boys.

No sweat. But listen to this.. The sensor sat all night on the kitchen counter measured it again this morning, 11.7k first time then I tried again and I get 10.5k... so what now..

Yes I’ve read on the FCU failures and how the light flickers or dims etc. Mine doesn’t do that, on key ON the oil light is a nice BRIGHT RED for a moment then shuts off. Which is part of the regular procedure. I’ll keep it in mind and watch if I notice the dash light diminish in color etc. Going to stop by the dealer tomorrow and see if they have a switch on hand. If they do not, I intended to go out on the bike this weekend, for temporary measures can I install a switch at the end of the wire that plugs into the oil sensor and run the other to ground to manually turn the fan on? Is this switch a Honda OEM only recommended purchase? Or can I support my non local Chinese comrades? The oil cooler I cleaned through the fins, you’d be proud @retro. Can see through them all now. It’s looking good, it’s out there drying so I can install it tomorrow. But the carb.. serious? We still think that’s a issue? But why only when HOT? I feel like I’m not winning but only failing.

As in the oil switch? But will this address the starting issue? I’ve cleaned the oil cooler tonight, all fins are clean and you can see through them now. Tomorrow I’m going to double check the valve clearances.

I tested this already, fan runs and is operational.

Ya so it’s out of spec. it does go down but I got it to about 3-3.5k and it seemed to stay. Didn’t @Goober or @retro say it activates the fan at like under 1k?

13.3k

13.3k, at the tip like I have it shown 14k.

Like so?