Operating temps....what's too high and what's normal??

[YFZRob]

I have an ESR 310 bolt-on kit with a near perfect condition stock radiator that is dirt and mud free. I am running stock shrouds, stock front bumper, 75/25 water/antifreeze with Redline water wetter. I am nearing the end of my break in period on the motor, and am using an ESR temp gauge. They claim 180 is normal with 190 the high normal limit. Well, just yesterday I began riding it harder and kept a close eye on the temp gauge. While cruising, just barely into the power band, maybe 40 mph in 5th gear, I would only see about 170 degrees. If I was hard on it, accelerating up and down through the gears like 3rd-6th, I'd see 180. As soon as I hit the sand at slower speeds and higher RPMs, my temps soared to 200. If I shut the quad off, it'd see over 200. I could only get them to come back down by getting on harder terrain with more traction and speed (therefore more airflow through the radiator). My question is, how safe is it to run this high? I was paranoid about it the whole time, so I didn't enjoy myself very much. The R needs a FAN! Does anyone know if the stock radiator is sufficient for these big bore kits? I was considering a PWR radiator, but if it runs cool while moving airflow through it, I'm not sure if an aftermarket radiator will help.

Thanks for any suggestions!

[zedicus00]

thas normal, sand causes a lot more load on the engine. running it at 200 or so wont hurt nuthing. i would say yur o.k. as long as yur not running at sustained temps of 230 or so on hardpack. if yur still concerned about it, a good cheep fix is grab a couple of thouse inline coolers (atleast 18 fin) put one in the top an one in the bottom line.

[YFZRob]

Awesome! Thanks for your reply. I will feel a LOT more comfortable riding next time. The highest it got was 220 and that was from sitting for about a minute w/ the engine off. I couldn't get it to come back down in the sand....the second I hit hard pack, it came down in about 30 seconds :D.

[zedicus00]

yup thas normal, sand puts a lot more load on the engine, especially dry powdery sand. hey what gearing r you running on that setup?

[YFZRob]

I've got a 14/38 on 20" Holeshot HDs. It is okay, but I may go back down to 13/38......trying to get moving in powder sand takes a LOT of throttle and clutch modulation....not very fun. BUT, once moving, it moves out well in every gear, including 6th. Just that boggy, soggy bottom end that's hard to get past in 1st gear. That's with TRX7 porting and a TRX5 pipe....so bottom to mid porting and mid pipe.

[zedicus00]

hmm, im just going to a 310 kit and was thinking about trying a 14th front. i would b at 14/39 with 18" tires but the dreaded 85-87 tranny.

[ESR350r]

I have a 330 kit with a stroker crank from ESR and i knew mine was runing hot but i had no idea how bad it was until i got one of their temp gauges. They told me that 205 was about the max and 185-195 was normal operating temp. Mine was always running 200+. I also road 2 cross country races with the motor and it was well over 220 and it held up although i am currently replacing the piston in it. ESR said that a center mount pipe or a bigger radiator would work. I also thought about putting a fan on it but the R's electical system would not power it with the one i wanted to use. One thing to check would to be that your pipe is not touching your coolant line by our motor.

[zedicus00]

a pair of inline coolers will net you 10 degrees cooler temps. center mount exhaust will help, coolheads only get around 3 degrees cooler temp. even on a bigger bore the stock radiator usually does o.k. as long as yur jetting is right on. a lot of getting the correct running temp depends on correct jetting.

[YFZRob]

Well, I may just thow a PWR radiator at it to be safe and worry about it as much. If they told you 205 was about the max you should see while riding, I'd be fine except for the sand, which I rarely spend a lot of time in. If I rode it somewhat aggressively on normal terrain (loose, just not powder sand), I'd never go above 185-190.

I did double check my pipe, and this one doesn't touch. My original ESR TRX did. I am very pleased with everything about ESR except the pipes....they fit like crap! At least they swapped out the first one with no questions asked, just had to eat the shipping both ways. The 2nd one still fits like crap (rests on the frame, doesn't fit flush at the flange between the two peices, and has bad alignment with their silencer), BUT at least it leaks less at the flange and doesn't touch the coolant hose.

[YFZRob]

a lot of getting the correct running temp depends on correct jetting.

Yeah, that's what I first thought, but now hearing these temps you guys have mentioned, I'm not too worried about it anymore.....plus I'm running the jetting that came in the PWK38 from ESR, which is 50 pilot and 190 main......which should be PLENTY of fuel based on the plug color.

[brokenbones]

my esr 330 was running around 210 when i was running to lean of a needle i switched to a 50 pilot deg needle 4th clip and a 185 main jet at sea level for the oregon dunes i run a esr cool head and pwr radiator also inlines coolers and it runs around 185 know with the temp gauge the only time it gets hot now is when i ride like miss daisy mostly with my 3 year old boy and wife


just my 2cents

[trailgoon]

Originally posted by zedicus00
hmm, im just going to a 310 kit and was thinking about trying a 14th front. i would b at 14/39 with 18" tires but the dreaded 85-87 tranny.
What is so dreaded about the 85-87 tranny? Is there something I need to be worrying about?

[Tom TRX250R]

The 85-89 Transmission is the exact same except for 85-87 the 5th and 6th gear are taller which a lot of motors can't pull 6th unless heavily modded. It is more like an overdrive gear.

[YFZRob]

I may be wrong, but I also heard that the 86, maybe 85 too, had a granny low 1st gear that was raised on the 87.

[zedicus00]

nah the only change is 5th an 6th gear. usaully if you gear the quad so 6th gear is usable then you end up with a granny low first gear.

[YFZRob]

Ah, ok. I am still at a loss as to the best set up. Traction is really decent with these Holeshot HDs and the 14/38, but 1st gear is a pain to get the quad moving unless you're trying to launch it. I haven't tried 13/38 with the HDs, so maybe they'll hook up enough that a 13/38 would not waste the tires too much in 1st and 2nd.

[trailgoon]

Originally posted by Tom TRX250R
The 85-89 Transmission is the exact same except for 85-87 the 5th and 6th gear are taller which a lot of motors can't pull 6th unless heavily modded. It is more like an overdrive gear.

Hmm the 250r that I ride can pull 6th just find and it is only bored out to a 256 with some minor cylinder polishing. Then again I only way 100 pounds.

[JTRtrx250r]

this chart might help w/ whats diffrent in the trannys, along w/ a few other things

http://www.macdizzy.com/trx_specs.htm