Hi everyone, new here, I have a 93 Big Bear 350 and recently picked up an 87 LT80 (Complete) and a 2000 LT80 (in pieces) Attached at the LT80 2K rebuild. before and after. I keep having to dick around with the head gasket. I didn't use copper RTV. should I? is this recommended ? I didn't have any at the time, otherwise I probably would have but everything seems ok for a few hours, then things start leaking again. I even change the head gasket again. It was a new top end btw



Before and after pics. I have certainly learned a lot about these bike. they are a lot of fun! The 1987 I picked up was mainly for a reference vehicle to compliment the FSM. but I have 2 kids, so it was worth it.

The in pieces 80 I got for free. New top end, a few seals, nuts and bolts, carb and petcock. 2 rear tires, fluids. Anyone have a good link to a good replacement carb? The one I got I think sucks goats.

 

 

Did you use new head studs? sounds like they are stretching. looking at the pics looks like u used the old you used the old.

 

The studs with the china kit stretch. Never really had any problems with the stock studs.
Head gaskets are a thing that seems to happen but is sorta rare. No goo is used. Torque the head nuts down in small increments and crossed to 110-115 inch pounds. Gaskets can be re-used (usually). I use Suzuki gaskets.
Maybe rough up the head and cylinder contact surface a lil.
Other that the china cheapo kit,,, AWSOME job!

 

Yeah...so...my experience with the Chinese kit is abysmal...if it were me, I'd stop fussing with it and have Jack (LT80) do it right...I have 2 of his top ends running right now and they are rock solid...Chinese head kept blowing gaskets...even with stock studs...it's **** machining...plain & simple...

 

I see they are down to 35 bucks on ebay. I pay 55 for a stock Suzuki piston... lol

 

May be worth checking head and cylinder top are both flat. I wipe grinding paste on a sheet of plate glass then rub the head etc, around on it if some turns grey when the paste is washed off and some doesn't, it isn't flat. Either keep rubbing until it is, or get it machined.

 

I have to admit I didn't know stretching of the studs was a thing. Thanks for the torque info, I don't mind paying a bit more $$$ for quality. The kids ran the two on the weekend, the 87' fouled a plug (too rich?) and the 2000 won't go past half throttle now, but I think it's the clutch.

 

Kids ran the two on the weekend, for the most part, they ran well.... until...

87' - Just stopped , wouldn't start. Changed plug and it started again, plug was pretty fouled. Maybe too rich? This bike I bought so maybe the jet isn't in the stock position? How many notches is stock ? Kids drive slow, maybe that might cause this ?

2000 - Anything over half throttle it boggs then stops, I can get it moving but then over half throttle it just boggs and stops, if I let off the gas it keeps running. I am thinking clutch? I think I had a issue of the roller turning sideways, so I am wondering of something is jammed. Got lots of fuel, might try a new plug also. Any ideas?

I ordered another carb and had to get a new boot as I ended up ripping the OEM one. ugh. I am in the process of rebuilding the OWM Mikuni carb, but there is a small Oring that I don't know where it goes. In the float bowl area there is two holes, one has the large screw in brass piece (main jet?) and just next to it another, I think the small oring goes in there, but not 100% (carbs aren't my forte)

 

The head I have is stock, on a Chinese cylinder. I'll reach out to LT80 for price. Thank you