well, I'm REALLY close. I had a piece of fuel line between petcock and carb, with an "in-line" fuel filter (with the brass or bronze filter inside). I removed it and ran straight fuel line. Suddenly, i got higher RPM. But i also fiddled with the top of the throttle body (the nut and adjuster), and that seemed to help too.It was kinda finicky. If i let out too much screw, then i couldn't get it to idle down (like it was holding throttle body up too high). if i put the screw in too far, it didn't seem to rev as high (is this a sign of a stretched/worn throttle cable??). And, the carb kept coming loose, so i tightened that up to the reed cage a little better.

so now when you hit it wide open, it has great holeshot, then reaches mid speed where it seems to hesitate for a couple of seconds, then it breaks open some more to something closer to what top speed should be. I have a BPR6HS spark plug. I see a BPR7HS is recommended, and LT80 (Jack) has said to use a BP8HIX.

Question 1)
my throttle body needle is set second from the top. there appear to be 5 settings. should i move the needle up or down?
Q2)Could this or my plug cause that hesitation? Or, do i maybe have some serious carbon built up that needs to burn off?
Q3) do i need a new throttle cable, maybe it's not pulling the throttle body all the way up? (there's no restrictor there, AND my governor is adjusted to full open).

And who knows, i did put the pipe in my insert fireplace tonight and let it heat up for about an hour or so, then blew it out with compressed air. So that may have been part of it.... but nothing seemed to change until i changed the fuel line. Do you think that filter could cause that much of a disruption in fuel flow? I only had it on there for maybe 2-3 tanks of gas.

Oh yeah, the exhaust isn't as blue and smokey anymore.

 

Sorry to hear you're still having problems, looks like you're the kind who won't give up, great job so far !! As far as the needle, I would try lowering the clip to the 3rd notch, that will allow more fuel for the top end, may get you your RPM back. To make sure the cable is adjusted right, what I do is pull the carb with the cable on, and work the throttle to make sure the slide goes up and down full travel like it should. I'm not a plug expert, but years back when my son rode an LT80, we had great luck with the BPR7 plug.

 

I agree w/95wolv. Raise the needle a notch.See if that helps.
I don't think you need a new cable. To adjust: screw it in the top of the carb. The cable will raise up and down (w/o moving the slide) unscrew the adjustment till the cable does not move up and down anymore.Like you expierienced, if you have it too tight it will rev up.
The 6 is a hot plug and FYI I recommend a BR8HIX. No "P".[img]i/expressions/face-icon-small-smile.gif[/img]
I'd think the filter would be fine being that new.
What's your compression?

 

Okay thanks guys, I'll try it tonight when i get home from work.

 

i adjusted throttle to middle. didn't seem to make any difference; good or bad.... perhaps a little less hesitation between mid speed to top speed.

I put the old fuel line with filter back on, and it seems fine. must have just been a coincidence. I think the pipe BBQ may have done it??

parts place had to order me the BR8HIX plug. it's irridium, and they tell me it'll cost about $10. the parts guy questioned why I'd use such a cold plug. told him cuz the Guru told me it's the best one for this quad.

from what i can tell, the "P" is for insulated plug, and "R" is for resistor. so you don't really need to have either of those features, as long as it's a "B" (thread?),correct heat range # (7 or 8), and "H" length. The stuff after the "H" doesn't matter either (in this case, the "IX" is irridium). SO... I coulda put a BP8HS in there just as easily?? Altho, the irridium is supposed to last WAY longer.

I'll check the compression tomorrow when i replace the plug.

 

okay Jack, i checked the compression 3 times with the older style handheld unit with the rubber boot on the bottom. all 3 times it read 135lbs. this old tester must work okay, because before the top end rebuild,i think it showed 40 lbs, maybe 60-70lbs when i squirted WD40 in there. whatever it was, i remember posting the results ages ago.

just curious about the info my dealer gave me, saying i had a bottom end knock which was my cause of low RPM. IF they were correct, would i get readings of 135 ft lbs?

i also put in the irridium plug. OUCH!! $12!! But parts guy said they last 5 times longer.

 

I'd say they got to you a bit on the plug. How does CAN currency compare to US? I got the same plug through O'Reillys parts store for $6.25. I've used them every since Jack told me to, and they work great.

Bill

 

for currency conversion, i add about 30% to US=Can price. we have14.5% fed & prov. taxes added to everything too, so that helped bump up the price.

 

Jack this is my last question, I promise. what do you think of my dealer's comment I have a bottom end knock in need of attention (con rod or bearings he thot).... yet i can't hear it, nor could my cousin, and my compression is 135lbs??

 

I'm not convinced that your dealer is on the ball here.
Main bearings don't ever seem to go bad. The rod bearings do tho.
If you hear no knock, then I'd presume it's fine for now. [img]i/expressions/face-icon-small-smile.gif[/img]