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wr295 overheating need advise!

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Trixy is a WR295 (EG) 91 octane broad power band. Boyseen reed block, Fluidyne over sized radiators. My jetting is at, main 170, pilot 50, JD red 2nd position from top. Timming is set at .004 or 1 degree retarted. The plug has a great brown color with genarly + q stealth which tipically has maybe 1 Inch of spooge. Ride at sea level to 3700'. Problem is i like tecnical gnarly slow up hills, but Trixy tends to get really hot, max 263 degrees. She boiles over around 222, so i install 8 oz catch tank in air box to recover lost fluid. ( it works great). What can i do to reduce heat. Maybe go to 2 degree retard, lower JD clip to middle clip to richen up, what about a hotter or colder plup ( i run br8eg), maybe higher ratio radiator cap. Oil in use is 927 at 40 to 1. At what temp will these bikes seize? Thanks in advance:thumbsup:

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Beats me. But what about rad fans? I had to do 2 fans on an old rock-Jeep, they helped out considerably.

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Just started looking at fan option. What bikes use a fan? Dont now anything about KTM, sure one of theirs uses one.

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I would drop to 32:1 at least and rejet accordingly. I run most of my riding around 2000 ft, Az desert with the 295 ported mid to top. I have a 50 pilot, and 178 or 180 main jet in mine, ( I honestly can't remember which). Its perfect in the desert even the slow single track. At sea level, in the dunes it was a tad lean on a 70 degree day in both parts of the power. I've noticed this setup keeps the carbon build up down quite a bit on the piston or in other words its keeping the temperatures a good amount lower. I was at 172 with the first piston and it was alright in the desert, but carbon build up was noticeable increased. In the dunes it was way lean and overheated easily.

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I would drop to 32:1 at least and rejet accordingly. I run most of my riding around 2000 ft, Az desert with the 295 ported mid to top. I have a 50 pilot, and 178 or 180 main jet in mine, ( I honestly can't remember which). Its perfect in the desert even the slow single track. At sea level, in the dunes it was a tad lean on a 70 degree day in both parts of the power. I've noticed this setup keeps the carbon build up down quite a bit on the piston or in other words its keeping the temperatures a good amount lower. I was at 172 with the first piston and it was alright in the desert, but carbon build up was noticeable increased. In the dunes it was way lean and overheated easily.

Carbon buildup has to do with not enough heat to completely burn off the deposits.

Get a new radiator cap first!

Steal a rad cap from a buddy and give it a try to make sure yours isn't sacked out.

But if your rides are to slow to get adequate airflow over the rads you either need to speed up or get fans IMO.

Give distilled water and water wetter a try for your coolant.

Many 4 stroke riders swear by higher boiling coolant, but that's masking your problem not fixing just like higher pressure rad. caps.

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Carbon buildup has to do with not enough heat to completely burn off the deposits.

You will never get carbon build up like a lean piston if there is not enough heat. Hence a piston ran overly rich comes out clean while a lean piston comes out looking like a charcoal brisket.

Lean = Carbon/hot piston

Rich = Clean/cool piston.

Rich will give you splooge but defiantly not carbon buildup like lean.

Edited by Kurtis85

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I rebuilt the motor and put on the 50/50 race head while i waited for the 91 octane head to arrive. When i installed the 91 head after 5 hours on 50/50, had a silver dollar maybe more of carbon that i tryed to remove, but could not do it without getting crazy on it. I'm still running the same jetting seems fine in these warm days (65 degrees), maybe a little richer now according to plug. My speed is at a fast pace, almost imposible to go much faster, very technical.

Wont be ridding for 2 weeks, so im just trying to figure this out. She ran the same as far as overheating with the 50/50 head, this was one of the main reasons i went to the 91 head. Oh yea we need rain please:)

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This has been a concern to me since ordering the EG 295. I fully intend to get the CV4 2.0 rad cap.

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One you need a new rad cap, you shouldn't start to boil untill 260-265 degrees.

The best bet is to get the Evans/ Zip Ty coolant. Won't make it run any cooler but it won't boil over and loose fluid and cause hot spots.

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The zip ty coolant cost 24 for half gallon and 39 for gallon, i should just buy the 1 gallon sense it wont go bad? Anyways the cap on her now is a fluidyne 16 pound, what pound is the cv4 2.0. Tryed checking out fluidyne site but it's all about cars. My right side fluidyne rad never really fit correct. The stock rad has large dent at the bottom right side so it will clear pipe. Had to make tabs to remount the three bolts about 1/4 inch higher. I'm sure of my temps because i run a trail tech Vapor.

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Did a little research on radiator caps. Stock oem cap says 1.1, my fluidyne cap says 16LB. So i converted 1.1bars to LB which = 16lb. CV4 offers 2 options, 20LB. - 1.4 Bar, 31LB. - 2.0 Bar. If i switch to the 31lb does this add pressure to the internal seals like the water pump. Don't really want coolant in motor or gears. Just a thought.

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Who makes fans? Side note, never do the Turkey Baster mod. Reason is it only holds 1oz, need at least 8oz container.

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Thats way to high of a temp!! I'm suprised it didnt do do damage.. everything I read was good and the only thing i add is ENGINE ICE.. I have tried everything else except the zip tie coolant. I will experiment with it though when i get a chance. i have 6 or 7 races left this year.

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Trixy is a WR295 (EG) 91 octane broad power band. Boyseen reed block, Fluidyne over sized radiators. My jetting is at, main 170, pilot 50, JD red 2nd position from top. Timming is set at .004 or 1 degree retarted. The plug has a great brown color with genarly + q stealth which tipically has maybe 1 Inch of spooge. Ride at sea level to 3700'. Problem is i like tecnical gnarly slow up hills, but Trixy tends to get really hot, max 263 degrees. She boiles over around 222, so i install 8 oz catch tank in air box to recover lost fluid. ( it works great). What can i do to reduce heat. Maybe go to 2 degree retard, lower JD clip to middle clip to richen up, what about a hotter or colder plup ( i run br8eg), maybe higher ratio radiator cap. Oil in use is 927 at 40 to 1. At what temp will these bikes seize? Thanks in advance:thumbsup:

go to your local dirtbike shop, and but a bottle of engine ice its like 25 bucks, but its well worth it if you tend to over heat, now it that doesnt work it bike be how you ride, the faster you go the more air your engine gets and cools down

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You will never get carbon build up like a lean piston if there is not enough heat. Hence a piston ran overly rich comes out clean while a lean piston comes out looking like a charcoal brisket.

Lean = Carbon/hot piston

Rich = Clean/cool piston.

Rich will give you splooge but defiantly not carbon buildup like lean.

We can agree to disagree, but to stir the pot here is some information from the great mind of Chokey:

When an engine is jetted too rich, the excess fuel leeches heat from the combustion process, causing the combustion chamber temperatures to be too low to effectively burn the oil, or even completely burn all of the fuel. The result is spooge and deposits. The spooge is nothing more than unburned fuel and oil passing out the exhaust.

The same goes for plug fouling. Rich jetting does two things. First, it promotes incomplete combustion of the fuel and the oil due to reduced combustion temperatures. The incomplete combustion of the fuel and oil promotes deposit formation inside the engine. Second, rich jetting reduces the combustion temperatures, which in turn reduces the engines ability to burn off deposits. Combine increased deposit formation with reduced ability to burn off those deposits, and what do you get? Spooge and plug fouling.

Did a little research on radiator caps. Stock oem cap says 1.1, my fluidyne cap says 16LB. So i converted 1.1bars to LB which = 16lb. CV4 offers 2 options, 20LB. - 1.4 Bar, 31LB. - 2.0 Bar. If i switch to the 31lb does this add pressure to the internal seals like the water pump. Don't really want coolant in motor or gears. Just a thought.

Yes, increasing the pressure at which the radiator cap opens will increase the pressure inside your cooling system and can blow seals. Refer to the ideal gas law for a simple explanation of how pressure volume and temp are related. Simply allowing the cooling system to retain more pressure also allows it to retain more heat, which can be more heat than the working components are capable of sustaining.

For too slow riding i.e lack of wind through the radiator; a fan should be the only viable solution IMO.

Agreed. These engines were designed for certain working temps and pressures and while modifying these qualities may not produce significant negative results, it's simply masking the problem not fixing it.

Food for thought, water is the best COOLANT around, not a very good antifreeze though.

Edited by GMO397

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I have spent alot of time in tight technical single track on my 295 and never had it overheat yet. For coolant I run a blend of Maxima Coolanol (75%) with Maxima CoolAide (25%). I keep my bike on the lean side (just rich enough to not detonate...) as well but I am running my own custom blend of leaded race fuel, pump fuel, methanol, and ethanol mixed at 32:1 with Klotz ST oil. The Alcohols in my fuel make the combustion temps a little lower than regular fuel though so im sure that helps me to not boil over.

If coolants dont fix it then I think the only thing left to do would be to run fans or switch to full on alcohol but that brings up its own set of issues.

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