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Im thinking about purchasing a new head and dome for my 86 250, the head i have now is shaved for high compression and has just over 190 psi. What are the pros of running a cool head compared to a stock head and dome?

-Thank you!
 

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i dont. hav ur oem cut. better result. call bdt.


i have the best. bdt built engines.
bdt261 oem
bdt363 prox
bdt431 puma
bdt561 saber
Sent from my iPhone using Tapatalk
 

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Im thinking about purchasing a new head and dome for my 86 250, the head i have now is shaved for high compression and has just over 190 psi. What are the pros of running a cool head compared to a stock head and dome?

Shaved for high compression....190 psi is higher than stock 165-175 psi, just not really considered high compression.

-Thank you!
Its running normal temp, and im running 100 octane snoco 260gt
190 psi is marginal for 100 Octane under load IMO, consider doing a UCCR test (search this forum on a complete write up). Then check your UCCR.

First reason not to go with the CoolHead IMO is you can get just as much out of a standard OEM head with properly cut dome.
Second: the cooling is actually better on the OEM head despite the 'label' "CoolHead".
Third: is cost...CoolHeads are expensive.

Pros: really none except the interchangeable domes, however; the dome design is antiquated and not to what you can do with a OEM head.

Carlos
 

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I run a Cool head, but it was part of the package when I got my 88. I have nothing bad to say about it, seems to work very well. I'm running a 18cc dome @210psi of compression (bit more, but not much) on VP C12 or Sunoco 110 fuel. My temp's never got over 150/175 max on the hottest of days in NE Pennsylvania. I'm not saying the Cool Head is the only reason, I do have a C&R radiator running on Engine Ice.
If I had a OEM head to start with, I would probably just have it worked over buying a Cool head (or vice versa).
 

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I dig the clear hoses. Do you think the ice coolant makes a difference? I’m thinking of switching and getting cheapo alum rad.

For the OP I have an ESR head with a bdt made dome so I can’t compare to oem. When I ride the sand pits and hill shoot the temp comes up to around 210when messing around. Just rip the road or fast trail and it comes right down.
 

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I run regular old green antifreeze with distilled water mixed 50/50 in all my R engines. I do not have any of them running over 190°F. 210°F is flirting with disaster! I would suggest checking your jetting and compression ratio. I had an engine years ago that ran hot. The compression ratio was 17.5:1 when it was supposed to be 13.5:1. I took the engine to a better builder and no more temp issues!
Loren
 

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I run regular old green antifreeze with distilled water mixed 50/50 in all my R engines. I do not have any of them running over 190°F. 210°F is flirting with disaster! I would suggest checking your jetting and compression ratio. I had an engine years ago that ran hot. The compression ratio was 17.5:1 when it was supposed to be 13.5:1. I took the engine to a better builder and no more temp issues!
Loren
I agree, nothing wrong with Green, blue, or whatever color coolant you choose. I used to run it in my 01 Banshee back in the good ol days. The Norm, are you running a stock radiator?
O.p. ... if you do decide to run engine ice, make sure you flush your old coolant out completely. If I remember correctly they don't get along very well...
 

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I dig the clear hoses. Do you think the ice coolant makes a difference? I’m thinking of switching and getting cheapo alum rad.

For the OP I have an ESR head with a bdt made dome so I can’t compare to oem. When I ride the sand pits and hill shoot the temp comes up to around 210when messing around. Just rip the road or fast trail and it comes right down.
Thanks, I sprung a leak in my center and upper hoses. Needed a quick fix and to be honest, They work great. It's just 3/4 ID internally braded PVC tubbing. You can get it from Tractor Supply, Napa, Ace, Homedepot, Lows or any hardware store. I like to run super hot water threw them to form the bends.
 

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Those Chinese radiators are decent. I run one with a stock head and engine ice and it runs cool. If u do decide to get one make sure to get a 88-89 only the inlets and outlets are different and wont hit the frame.
 

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I have one R with an oem 86 radiator, one R with a $70 Ebay radiator, and the 391 has a PWR radiator. I believe tuning is a major factor in engine temperature and also how the engine was set up.
Not sure why someone would believe a cool engine is slow? A lean engine can make more power for a very short time, but a properly tuned engine running 185°F-195°F will make great power for a much longer time. That is why Pete at Hybrid Engineering is the only person that I will allow set up my cylinders!
 

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Obviously all of you thinking an engine running 210F is running hot, does not race or Build race Engines ...get a grip on reality please.

Their isn't a single 2 stroke running any major Track, making significant HP or TrQ, for average Moto's of 10-20 laps not exceeding 230F after 15-20 minutes of running hard. As an example; Pinelake raceway last weekend July 17-19, all two stroke classes on a TT track; everyone was way above 210F, closer to 230F, a few at 240F....EVERYONE.

To say your "flirting with disaster" or thinking 210F is running Hot on a BB engine, shows you don't have a clue on reality. Plus the FACT that the more Power or Torque you make; the more Heat you generate (Physics), and dissipating Heat effectively through any radiator on a Two-stroke for extended periods of time during a Race becomes more and more difficult.

210F is perfectly fine for engines making High HP & TrQ, specially BB engines, on Sand or Dirt.

Carlos
 

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Yeah so nobody was talking about racing... I don't care if "some guy" tells me that I can run my engine that hot. I would rather go for longevity as I am a recreational rider now. I have multiple machines that I maintain so I choose to have them run below boiling. I guess everyone is entitled to an opinion.....
Also Carlos could you possibly grow up a little??? Nobody attacked you or is "hating " on bdt. I made my statement based on someone posting that their engine was hitting 210 while playing around a little. I can play pretty hard in the sand on my Hybrid Engineering 391 before it hits 190°f so I naturally believe he could benefit from a little bit richer tuning. All I was intending was to help a fellow R enthusiast enjoy his R for longer. I can't help the fact that "you" built his engine.
My R's don't run hot even when I (280lbs) am beating the snot out of it down in a tree shot.
For proof I offer you an opportunity to come ride with us in August at Winchester bay. You can get to know everyone including Eddie Sanders and possibly Arlan Lehman. August 12th-17th.
Loren
 

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I get it now, bdt must build their engines to run on the extreme hot side to meet those strict California emissions standards.
 

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last 2 posts. no good info. just more bs.


i have the best. bdt built engines.
bdt261 oem
bdt363 prox
bdt431 puma
bdt561 saber
Sent from my iPhone using Tapatalk
 
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