86 250R overheating!

[HondaRidr]

I'm looking for some advice. I got this bike with a esr310 pv cylinder and a roasted piston. Did a new top end, new gaskets and oem crank bearings and seals. It has oversized dmc radiators, esr temp gauge and I run engine ice. I did some heat cycles but when I started to ride It, the temps would soar to above 220 in minutes. The jetting was good. I put it in the shed for the winter. Fast forward 8 months and I swapped the top end for a pro-x 330 cylinder. This time the temps took a little longer to climb but still got way to hot with very little load. Any ideas? Water pump?

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[BOB MARLIN]

I been battling the same thing. Esr 330 in my 250r. I have a good trail tec digital gage on it and I can easily get it to over 230 deg. in about 10- 15 minutes. New oversize rads only seemed to be good for about 5 deg. or so. Every one told me my gage wasn't right - until it seized up. Now the general concensus is I need to run a different pipe with a bigger "stinger". The guys that are running the same motor in the quads claim they never get over 185 deg., but the quads have bigger rads and more room for air.

What pipe are you running ?.

[yaegerb]

I'm looking for some advice. I got this bike with a esr310 pv cylinder and a roasted piston. Did a new top end, new gaskets and oem crank bearings and seals. It has oversized dmc radiators, esr temp gauge and I run engine ice. I did some heat cycles but when I started to ride It, the temps would soar to above 220 in minutes. The jetting was good. I put it in the shed for the winter. Fast forward 8 months and I swapped the top end for a pro-x 330 cylinder. This time the temps took a little longer to climb but still got way to hot with very little load. Any ideas? Water pump?

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Fatten your jetting across the board and like bob said, run a longer stinger.

[jonolanracin]

What octane fuel are you running? My 310 motor has to have atleast 110 race gas or it runs hot

[HondaRidr]

The 310 I ran on premium mixed 32:1. The 330 has a race gas dome so I am running leaded 110. I had the needle 4th clip and 190 main but not sure about the pilot. The pipe is a Paul Turner hi-rev imitation with a ct silencer. What exactly do you mean by longer stinger?

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[HondaRidr]

https://uploads.tapatalk-cdn.com/20170329/50944ac57d4382d6f28e9255fa4d12fc.jpg
This is the bike with the 310 top end. I don't have any pictures of the bike with the ct silencer.

[christph]

I had a similar problem of overheating when I had my Duncan Racing 340 in my ATC. I also ran a Duncan hi-rev pipe, oversized radiators, and Engine Ice. I eventually concluded the pipe/stinger was too restrictive for the displacement. It doesn't allow the exhaust gases to bleed out quickly enough so you get a build up of heat. I've read elsewhere that the Duncan pipe is designed for the 250 to 310 cc range, no larger. You might try getting ESR's ATC5 pipe. I hear it is a good big bore pipe. I called ESR about 2 months ago and the pipes where out of stock, but was told they should be ready about now.

[yaegerb]

The 310 I ran on premium mixed 32:1. The 330 has a race gas dome so I am running leaded 110. I had the needle 4th clip and 190 main but not sure about the pilot. The pipe is a Paul Turner hi-rev imitation with a ct silencer. What exactly do you mean by longer stinger?

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You need to run a longer silencer.

[fabiodriven]

The 310 I ran on premium mixed 32:1. The 330 has a race gas dome so I am running leaded 110. I had the needle 4th clip and 190 main but not sure about the pilot. The pipe is a Paul Turner hi-rev imitation with a ct silencer. What exactly do you mean by longer stinger?

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I was under the impression you'd need a stinger with a larger diameter. I think Yaegerb mis-spoke.

[barnett468]

.
What is your compression?

What heat range spark plug are you using?

Post a photo of the end of the spark plug.


JETTING

For the time being, if your spark plug has some brown color instead of being nearly white, and the heat range is no hotter than the factory recommended one, I would go up on the main jet 2 sizes at a time until it it burbles/stutters noticeably for a couple seconds when you do the following:

Ride on flat ground at around 1/3rd throttle in 3rd gear, then open the throttle quickly all the way.

Once it does this I would go back down 2 sizes on the main.


STINGER/SILENCER DIAMETER AND LENGTH

If anything, a longer stinger or longer silencer of the same diameter will make it run HOTTER and will typically reduce bottom end power and increase the peak rpm's a little, therefore, I would not do that but if you try it, watch your temps closely . I have done a ton of pipe testing not only when I worked at Kawasaki but also before when I raced Motocross . I also tested some pipes for Dave Miller, Harry Klemm and Lee Scheffers.

Honda Rider still has the stock stinger size but it looks like he increased the diameter of the silencer and the silencer head pipe . This will act similar (but not quite identical) to increasing the entire stinger diameter and is a fairly simple test that does not require cutting the stinger off your pipe . If you do this test and see at least a 5 degree drop in temps when the outdoor temp is the same or higher, and the power is still acceptable, you might then consider cutting the stinger off the pipe and enlarging it slightly (anywhere from 1/8" to 1/4") and trying that with the larger silencer.


COOLANT TYPE

Another easy test you can do is to run the following coolant mix after you drain the ice out and flush the system once with straight water.

15% ethylene based anti freeze . Prestone green is one of them.
Only 1.5 ounces of DEI Radiator Relief . More is not always better.
The rest is Aquafina water but plain tap water will work for a test.


IGNITION TIMING

Anther thing you can test is slightly different timing settings, however, this requires an adjustable timing plate but they are not cheap . If you do this, don't run it for more than a few minutes and listen closely for detonation because inaccurate timing can seize it up fairly quickly but it would definitely take more than a couple minutes and it would need to be at wot or close to it, therefore, this is a safe test to do.


FUEL TYPE VS ENGINE TEMP

Race gas or E85 will both make it run slightly cooler and reduce the potential for detonation.


SPARK PLUG HEAT RANGE

If your compression is around 180 or higher, I would also try a plug that is 1 step colder than stock.




PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[yaegerb]

I was under the impression you'd need a stinger with a larger diameter. I think Yaegerb mis-spoke.

Thanks Fab's, yes larger, as in larger diameter. Get as much heat out of that pipe as possible.

[HondaRidr]

Well it looks like I need a bigger pipe! I do have a sectional pipe that looks like it's for a bigger bore but seems to habe the same size stinger. It was on the 330 when I first rode it. It would fall flat on it's face above a certain amount of throttle but me and a few others felt that it was something more than jetting. I put the high-rev pipe on (ran hard with the 310) and it stopped falling on it's face, it just was too rich to rev out all the way. I will take a picture of the pipe tonight. Does nos_350x still sell the big bore pipes that he had made?

I was running a br8es plug and the main was too rich, it wouldn't rev out all the way. I was just thrown off that both of the cylinders ran so hot!

I appreciate all the responses!



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[HondaRidr]

https://uploads.tapatalk-cdn.com/20170330/a39d542fd6c16df447379dfa907cf512.jpghttps://uploads.tapatalk-cdn.com/20170330/bb1be55a8ce58ff3a7c1a53ff09b8a34.jpg

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[fabiodriven]

You know what part the stinger is right?

[barnett468]

OMG...that thing looks huge, lol.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[3 Wheel Drive]

OMG...that thing looks huge, lol.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

That's what she said!

[HondaRidr]

You know what part the stinger is right?
Yes. This part.... It measures 1 1/16 I.D.https://uploads.tapatalk-cdn.com/20170330/fc4bfdec9864b375bddab853fd871206.jpg

[HondaRidr]

I called and talked to Mike at CPI about a pipe. He said that too small of a stinger will heat up the piston but in his opinion, shouldn't cause the coolant temp to get that high. Last night I had a minute so I started the bike and took the radiator cap off to check for flow. There was some flow but I'm going to check the impeller just to be safe

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[Usmoneylover]

Have you done a leak down test?

[HondaRidr]

I have and there is a leak I am chasing. I understand that airleaks cause a lean condition but I wasn't hardly running the bike for it to get hot. When I had the 310 topend there was no leak and similar results. I will look into the airleak and waterpump

[HondaRidr]

Does anybody know the inner diameter of the esr atc5 pipes stinger?

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