18 gp 300

[pigpen966]

Hey Gang, went for my first hard 80km ride Sunday down here in Costa Rica. I moved down here from the states last August and brought my GP with me (don't ask how much the import was ). Been tooling around on the dirt tracks for a couple of months by myself and finally hooked up with some local enduro guys. Gotta say the riding down here is absolutely incredible!!!
Anyway, my trusty steed got hot and lost most of the coolant. Granted it is pretty warm down here, but no worse than Ohio in the late summer. It was rubber side up a few times, and I might have lost some coolant that way, but man she was smokin!! This is my 3rd gassy 300 and my older ones were never prone to overheating.
As far as jetting goes
N3CJ 3rd clip, 40 pilot, 178 main and air screw is 2 turns. Most of my throttle is between 0-1/2 maybe. I'm a lugger not a spinner. Head is still stock, bike runs perfect.
Mix is Motul 710 at 50:1 with pump gas.
All the white and orange pumpkins down here are running fans(cause they're weak).
Tomorrow I'm gonna pull the pump cover and check for issues there.
Any other suggestions?
P.S. Bike does have Rekluse EXP in it.

 

[Jakobi]

Not sure PP!! But my old 2010 and 2013 models were beasts that never cooked it.. I managed to make my 2018 have a little spit on its first ride. An orange bike through the same section was whistling like a kettle, but I didn't really feel like I did it hard either..

Mine might have just vented the little bit above the fins, but I'll be keeping an eye on it for sure.

 

[hamilton]

That Rekluse can generate a lot of heat if not set up just right.

 

[Jakobi]

No recluse on mine.. I was giving the clutch a good ol slip though. Not enough to make it sound unhappy! I was in mud and leaf liffer in rainforest fighting gravity.. not much airflow. I'll keep an eye on it!

 

[pscook]

One thing to consider is the rad cap. I know that with the 1.2 bar cap my 300 would vent a fair bit of water after a long climb, but the 1.8 bar cap (as recommended here) helped prevent further steam generation. It might be worth it to look at the rad cap seal and possibly upgrade to a 1.8 bar cap, just to prove the point.

 

[Jakobi]

Thanks Phil. I had a look at the cap seal before the ride, and there was a little crystalisation/build up in the neck. I just rubbed it back but ideally I need to hit it with something abrasive to clean it properly.

 

[pigpen966]

Found the culprit today. OEM Rad cap is a 1.8, apparently on one of my rubber side up excursions I bent the filler neck on the rad. Bent it just enough the cap wasn't sealing. I'll see if I can get er straightened out enough for the cap to seal. Probably pull the head and make sure nothin got cooked too.

 

[pigpen966]

Ok, so apparently I melted the head gaskets. Internals are ok, still have good compression. Cylinder, piston and rings looks good. I did get coolant in the motor, so I'm gonna flush everything with WD-40. I have some gaskets in stock. Does the outer O ring need to be stretched to go in the grove? Going to check the head for warping next.

 

[Jakobi]

Yeah outer o ring usually needs some light stretching and a dab of grease to hold it in place.

 

[pigpen966]

Thanks brother, all back together and good for some more thrashing!!

 

[Davehuge]

Would something like this interest you?

https://www.motocrosscenter.com/sho...-with-temperature-gauge-18-blue-4mxk18bl.html


Brief thread about it here...

http://www.gasgasrider.org/forum/showthread.php?t=23270

 

[Jakobi]

Thanks brother, all back together and good for some more thrashing!!

How low did you run the coolant?

I went to top mine off this morning and I had lost more coolant out of this bike than I have out of my last 2 in the 7 years owning them. It wasn't empty but it was well below the top of the fins.

Topped back up and run for a bit. Some very small bubbling in the rad with the cap off and a few revs added. I think it's just from circulation as throwing the cap on she doesn't pressurise and blow over quickly. I ran it up to temp around the yard and it hasn't blown any coolant either.

Dropped the crankcase drain plug and no coolant in the crank so that's a positive. Evidence of coolant on the pipe/spring where the overflow is.

Investigating the rad and cap mating surface and I have a casting flaw deep enough to catch a finger nail in.. I'm guessing this is my issue. Holds pressure but probably not enough at full temp/under load.

I have a ride planned for tomorrow. I don't want to cancel, so I think I'll just have to keep a close eye on the coolant situation.

I also hope I haven't done any damage running it a bit low last ride. No blueing of the pipe near the spigot.. Don't really feel like cracking the head/cylinder off on a 4 hour engine. I think I'll discuss with the dealer.

 

[shawbagga]

How low did you run the coolant?

I went to top mine off this morning and I had lost more coolant out of this bike than I have out of my last 2 in the 7 years owning them. It wasn't empty but it was well below the top of the fins.

Topped back up and run for a bit. Some very small bubbling in the rad with the cap off and a few revs added. I think it's just from circulation as throwing the cap on she doesn't pressurise and blow over quickly. I ran it up to temp around the yard and it hasn't blown any coolant either.

Dropped the crankcase drain plug and no coolant in the crank so that's a positive. Evidence of coolant on the pipe/spring where the overflow is.

Investigating the rad and cap mating surface and I have a casting flaw deep enough to catch a finger nail in.. I'm guessing this is my issue. Holds pressure but probably not enough at full temp/under load.

I have a ride planned for tomorrow. I don't want to cancel, so I think I'll just have to keep a close eye on the coolant situation.

I also hope I haven't done any damage running it a bit low last ride. No blueing of the pipe near the spigot.. Don't really feel like cracking the head/cylinder off on a 4 hour engine. I think I'll discuss with the dealer.

Weird. Must be that as I've not had to fill mine up in nearly 60 hours & it's 40 degrees over here ATM!
Impressed at how cool they run in slow going/trail cutting/techy stuff without a fan.

 

[Jakobi]

Weird. Must be that as I've not had to fill mine up in nearly 60 hours & it's 40 degrees over here ATM!
Impressed at how cool they run in slow going/trail cutting/techy stuff without a fan.

I know.. Not showing any signs of running lean or anything either.. Just pulled the pipe and the plug. Had a good squiz at the slug from both points. Doesn't look like it's been washed with coolant or run hot which is lucky.

I'll ride tomorrow and keep an eye on the level.. And probably look into sourcing another chinese radiator!

The casting in the exhaust port is bloody average as well.

 

[Jakobi]

Rad seal polished down a bit.. doesn't catch the nail as much, but still not smooth all over.. Was a very deep flaw. Dealer looking into it Tuesday.

Threw the cap from my 2013 onto it too. Spring has more coils.. Feel like it has more tension depressing and installing into the rad. Even though both are labelled 1.8 bar.

Riding tomorrow. Will see how it goes.