my 87 510 leaks oil bad and runs way too hot.

I had it out twice and dont trust it at all.
I never had a 4 stroke before so this is my first and last i think.

I have tried 2 different kinds coolant, first was good 4 stroke stuff and then tried Evan's coolant like the 430 has. It does not expand like other stuff, its waterless and for race motors. new rads
but it still gets way too hot, not much room for a fan.

Cant ride single track on a 85 degree or low 20s c (metric) kind of day. Light throttle 3rd and 4th speeds its ok but wind it out and its pouring out coolant. It will stall easy or hesitate when its too hot. I did some heat sheilds on the pipes, 1 under the air box and the on the other to keep heat off the carb and air box rubber boot.

The 2nd ride was a joke and really let me down, made many changes before the ride and was no better.
The oil leak is the water pump bearings, put new ones in and left all the seals on them and they leak as bad as the old ones did 1/2 way into the ride. The seals were warped and shrunk from hot oil.
Oil level with bike straight up touches the drive gear nut but not 1/2 up on the gear and it drips all the time sitting on the kick stand when parked.

New reed pedal
91 oct pump gas
put a mint carb on it as the other was junk
great color on the plug


spent a ton on this pos lol
will trade for 2 2 strokes any day now

you sound a bit frustrated with it, which happens with a new-to-you machine..definitely need to maybe take the 400 out next time to have some fun..im no 4 stroke guy so i cant help with the heat issue, but i know the thumpers are hot, compared to the pingers..

It was a let down in front of a few fellow riders that know my other bike so well.
Well i had to tell the them to go with out me never done that before.

Call George at Uptite.

He get you dialed in with your issues.

Could be that you have small leak in head gasket. Or you might have to go up on radiator cap pressure.

His experience has been out in the hot desert stuff.

It holds pressure over night on my tester for automotive.
Also have done a vacuum test at 20 inches on the just the motor with no coolant in it and zero drop.
So i think the head gasket is fine. Motor is super strong, twice as fast as a new KTM 350 4T lol
I know what works for a tune on a car, add a touch timing and some more fuel to run cooler.
Advice time


Steve

darren is correct, george is likely the go to guy for the swede thumper..
i hear what you are saying..the swede primary kick smokers are such anvils when prepped well..you appreciate them when passing new bikes blowing steam on the trail..

The impeller can wear against the housing. The shaft through the bearings must slide out perhaps the notch in the crank is some of the reason. Housing was like $130 when a rebuilt water pump for the hauling vehicle was $85. I think some entity made metal ones for about the same, Most of the used ones I have show some wear from the impeller.

There are corrosion issues with those clutch covers in the water pump area.

I left one seal on those water pump bearings, so pry out 3 seals. Actually I think I ordered the correct part numbers note the bearings are different numbers. Just from memory.

Oil will come out that weep hole, or water I think the idea of it is so the coolant and oil do not mix. That is if the level is too high. Maybe too high is the specified amount. I do not think I have problems with my 4 stroke in this regard but another one, two stroke is kind of like that. The shaft for the water pump wears somehow, I do not recall exactly how, it was like $60 and not much more elaborate than a nail, I found a useable one but most were defective in whatever way I disliked. Strangely one had a thin part that went to a little hole in the housing. Seemed superior to me but that must have been way at the beginning.

Those four stroke radiators are longer than the two stroke ones of similar vintage, the cap is smaller if I recall correctly.

I do not know what to say about the reed. I am on the third cam chain, it can get loose and take out that little screen the size of a thimble that the dealer wanted $70 for. Never touched the reed had the head off, mice made a nest in the airbox, urine in the carb, most would have tossed it, still starts and runs like before.

A couple of points. Make sure the radiators are not gunged up. Is it a magnesium barrel and clutch case bike or has it been fitted with aluminum items off the later models? The magnesium rots and produces goop that will not help flow or heat transfer. You need to pull the hose off the barrel and see what greets you regarding the corrosion. Clean everything and run the waterless coolants such as Evans. Looks like a very light oily substance. Has a much higher boiling point and will mitigate further corrosion. Check hoses are fitted the correct way. Check impeller is not cactus. Good luck as they are an awesome bike.