Anitomical 4 Posted August 22, 2022 I have a 87 Quadrunner LT-4WD and it’s been acting weird every since I got it. I don’t know if it’s common or not but it seems that the intake valve itself is stretching because I used to have to almost constantly readjust it but now, that bolt or screw or whatever it’s called that pushes down the spring, if I take that fully out there’s still no play in the rocker but it has compression when I did that (I didn’t run it like that). So I took the valve cover off and the valve didn’t seem to be any longer than it should be and the rocker seemed fine? I don’t know what’s happening and I don’t know what to do or if it’s causing the problem I’ve been originally having. The original problem was it would sputter at like mid to high range rpm, I changed the main jet to something bigger and changed the fuel pump too but still no luck. I have the air to fuel ratio out to about 2 and a half turns and it seems to be the right amount cause the spark plug is brown, but once it gets in the rpm’s it just hiccups but doesn’t bog or shut off. IMG_0123.MOV IMG_0124.MOV Share this post Link to post Share on other sites
spock 44 Posted August 23, 2022 I've never ran into a valve "stretching" but if you can't get proper clearance with the adjuster, then something is wrong with the head itself probably. Sounds like it's time to remove the cylinder head and have a pro take a look at it. Share this post Link to post Share on other sites
toodeep 1,759 Posted August 23, 2022 I would guess the valve itself is wearing into the seat or the seat in the head came loose and wearing itself into the head casting. The valve wearing would be a more common issue but with the years of wear, the only way to know is to tear it down. Share this post Link to post Share on other sites
Anitomical 4 Posted August 23, 2022 3 hours ago, spock said: I've never ran into a valve "stretching" but if you can't get proper clearance with the adjuster, then something is wrong with the head itself probably. Sounds like it's time to remove the cylinder head and have a pro take a look at it. I didn’t know of any valve stretching either but it was the only thing I could think of at the time. I believe it might be the valve seat being squished? Share this post Link to post Share on other sites
Anitomical 4 Posted August 23, 2022 28 minutes ago, toodeep said: I would guess the valve itself is wearing into the seat or the seat in the head came loose and wearing itself into the head casting. The valve wearing would be a more common issue but with the years of wear, the only way to know is to tear it down. Probably, I believe it’s a high mileage quad anyways, the speedometer isn’t working, but I believe the what is says is pretty high already. I’ll tear into it later, it’s been raining so much so I have to wait until it calms down. Share this post Link to post Share on other sites
Anitomical 4 Posted August 24, 2022 The intake seat is squished 1 Share this post Link to post Share on other sites
