Running hot,Weird burn on piston?

[skyhighatv]

Well like the title says,ive been running hot and while inspecting my cooling system and motor i discovered this wierd burn on top of my piston. I dont have a real temp guage but will soon,i have one of those fx temp strips on the cylinder and when out riding i can only run hard for about ten min. then the temps are up between 230-240,if i put around a gear high with the revs low it will drop to around 200 in about 5 min. I have a pro-x jug on pump gas 93/castor 927 32/1,72mm,38a/s,178main,48,pilot,4th clip(dgk?)trx6,k&n open box,PWR rad,engine ice.The motor seems a bit on the fat side too,plug was wet and black. I know i shouldnt be running that hot and it scares me,any thoughts on this?

[FL-R]

My main is 190 but I have about the same setup, and it would run warm, 230 I cut the screen out of my front AC bumper and now it runs 180 to 190 until I just put around with no airflow. And I also had a OMF shroud, I drilled a crap load of holes in it. Now im good and Im in FL its 98 degrees now.

[1promodfan]

Man I has the same problem!!! My bike was running anywhere from 200-235 degrees. Just like FL-R, I cut the screen out of my bumper. But the main thing I did....(and I think was the main problem) was check my intake boot. I think it was sucking air and causing it to run lean. After re-checking my boot and taking it off and redoing it, I haven't ran hot since. Now I average around 180 degrees............maybe a little warmer if I'm in the woods putt'n around.

[skyhighatv]

The motor seemed like it was running fat,no signs otherwise,has brand new main seals,same plug 3 rides,almost no burn-wet and black after every ride,no sign of any lean condition,never lost any coolant,plenty of power just a lil fat on top,i was running a 180,but dropped to the 178 and feels a lil better up top. I just switched to clear rad hoses(just for peace of mind)water pump seems fine,no blockages in rad,good fins,im gonna go out this weekend without the rad grill on and see what happens,i also run a duncan bumper so i dont think thats blocking any flow.

[patnode250r]

I have a ct pro-x cylinder. The paper work that came with the cylinder says to run 102 octane or better.

[skyhighatv]

I have a pump gas dome from esr,with there recomended jetting,well very close to it.

[nelson440]

what are you running for a plug. on my 250 she was running pretty hot between 210 and 220. i was runnin a br8es and jumped up to a 9 and helped alot now run like 185 190. get yourself an infared thermometer. they work prettyu nice. they are pocket size and you can carry it with you where ever you go. cost about 25 bucks and you can get them at most hobby stores or auto parts stores.




Originally posted by skyhighatv
Well like the title says,ive been running hot and while inspecting my cooling system and motor i discovered this wierd burn on top of my piston. I dont have a real temp guage but will soon,i have one of those fx temp strips on the cylinder and when out riding i can only run hard for about ten min. then the temps are up between 230-240,if i put around a gear high with the revs low it will drop to around 200 in about 5 min. I have a pro-x jug on pump gas 93/castor 927 32/1,72mm,38a/s,178main,48,pilot,4th clip(dgk?)trx6,k&n open box,PWR rad,engine ice.The motor seems a bit on the fat side too,plug was wet and black. I know i shouldnt be running that hot and it scares me,any thoughts on this?

[skyhighatv]

I've always ran br8es plugs with no problem. Im pretty sure esr reccomends the 9,ill give it a try. Anybody else have any input?

[rustyATV]

I don't see anything wrong with that piston.

[skyhighatv]

I didnt think there was anything wrong with it,just worried about the temps. Do you guys think running the 9 plug and no rad grill will do me any justice? I really need a temp guage!

[FL-R]

Here, these work great, and on the 250r you can look down the stem while riding and check on it, It has been spot on to my thermo gun. I beleive its the 16LB one you need.
http://www.summitracing.com/parts/MRG-2473S/

[thedeatons]

THAT IS AWESOME! I MAY HAVE TO GET ONE OF THOSE..... That way my wife could see the guage while riding. She has trouble leaning over while riding to read the ESR-style gauge by the radiator.

I just checked my Afco radiator cap and it is the same as the OEM & KX500 cap.

The stock caps are a 1.1 bar, which is 15.9psi, the KX500 cap is a 1.6 bar, or 23.2psi.

IMPORTANT - There are two different styles of Mr. Gasket Thermocaps on their website, Import & Domestic. Our caps are the same as the IMPORT caps. I just verified this with my 2002 Mitsubishi Lancer. The caps swapped straight across.

YOU NEED TO MAKE SURE TO PURCHASE ONE OF THE 2473 CAPS. The 3 dictates IMPORT, a 1 dictates domestic.

The 2477 is also available, which is the 24psi cap (same as the KX500 cap). I will call and check to see which application it fits, import or domestic.

From what I have read on the internet, the boiling point will increase when pressure is increased. This explains why the KX500 cap (24psi) has shown better results than the 250R cap (16psi).

James

[thedeatons]

Thee 2477 is a domestic fit cap. I will have to find out the difference in radiator caps between import and domestic.

So far it looks as if the highest pressure rated cap we can use from Mr. Gasket is a 16psi.

More to come hopefully...

[FL-R]

Forgot about that, I called them when I bought one and you need the Import model, I have the 16 PSI one with a PWR and have had no prob- so far, (months) and mine runs 180 until i put around then I see 200. Cause we do have a Ricers:D

[thedeatons]

I just ordered the 16psi from Summit. I doubt we will be able to get a higher psi cap made from Mr. Gasket.

The 16psi should do fine for me considering I installed my new Afco dual pass.

Thanks for passing that on! Another great product! It wll be fun to test the temperature difference against my ESR-Style inline temp guage.

James

[FL-R]

No problem, Hope it saves a few motors

[skyhighatv]

That is a great product,thank you for the info. I will be ordering one this week. I will be going out tomorrow so hopefully everything goes ok. Does anyone know how accurate the fx temp strips are placed directly on a cylinder Thanks again!

[FL-R]

Never used them, Ive wanted to get one and put it on the side of the rad-

[woodsracer144]

Originally posted by rustyATV
I don't see anything wrong with that piston.

he beat me too it! its a port set up that will get you that...

[skyhighatv]

Well i think my problem is solved,went out yesterday and she ran between 180-195 all day. I checked over everything i could think and all was well. I ended up ditching the rad grill and switching to a br9es plug. might drill a bunch of holes in the grill and run it like fl-r did,see if im still in the ballpark. I still think im a lil fat in the upper-mid department. I have a dgh needle on the 4th clip from top 178 main,might drop the needle clip to the middle position and do some test runs. Any advice on the jetting?

[thedeatons]

Just read your plug until you get it right. I have learned that no one can give really accurate jetting advice, just because every setup is different. The jetting advice I got was WAY off... People were recommending a 178 and I ended up with a 190 and it still wants more.... Just read the plug. Load the quad up really hard in third gear for at least 5 seconds, at wide open throttle. Find a big hill or something to place a nice load on it.

James