Over heating problem??

[tritty_wall]

I'm going through the break in process, on my ESR 350PV. Its on 2nd bore, with 39mm kehin pwk carb. ESR TRX 5 pipe with ESR slicencer. I have a new PWR rad with CV5 hoses with a ESR Temp. guage. I'm at 2000ft above sea level with a 50 pilot and 185 main, thinking of goin 1 size up with both. My motor is running at 250 Deg. after 5 mins!! so I'm having a hard time getting it jetted. What should be the motor temp on a 350 PV? what is to high for a motor to run? I've seen a few thread on here sayin that PWR rads aren't the best, could that be my problem? Also I'm running engine ice for coolant not green anti-freeze. I have a new rebuilt water pump, but i looks like there is a some coolant leaking around one of my head bolts? what could cause this? Sorry about all the questions but if someone could help me that would be great, Want to go for a ride on thursday and need to get the problem fixed. Thanks

[Honda 250r 001]

First, be sure that your waterpump is working correctly. by pulling a line off when its running and seeing if it shoots coolant out the line good. OR open the radiator cap NOT WHEN HOT, and rev it up and see if the water begins to move good. if not. you have waterpump troubles. If it is flowing good, you could have an air leak. spray starting fluid around all the intake componets while idling. if any change in idle speed occurs, you have a leak.

I hope this helps.

Your coolant temp should be in the 185-220 range…If you are leaking coolant around head bolts, then you are introducing air into the cooling system, not good…make sure your head is not warped and your cylinder is flat, “O-Rings” are new…

The suggestions from Honda 250r 001 are on the money; here are a few other items to check, not necessarily in this order:

Don’t rely on only your temperature gauge, double check coolant temp with an auxiliary gauge

Make sure NO air leaks are present anywhere on the engine; check your intake boot for cracks

Check your reeds, no broken pedals

Compression could be too high

Pipe; what kind of pipe and silencer are you running? Should be a Big Bore pipe, make sure your stinger is not to small, and your silencer is clean, re-packed and assembled correctly

Make sure nothing is blocking your cylinder & head water jackets; ESR cylinders have been known to have water jacket issues

If your cylinder was polished or powdercoated; make sure no media or plugs were left in the water jackets or channels

Check all your hoses for air leaks…

Go up on the pilot to 52-54, main jet to 190

Try a cooler plug; BR9ES or BR10ES

Make sure your PV is working correctly, no leaks and moves smoothly

Take the quad for a ride, check temperature while riding, not just in a standing position

I would question your temp gauge readings, if you really are running at 250 degrees; it would be boiling over…

My 330R runs around 195 degrees FYI…

[tritty_wall]

My water pump was just rebuilt by BDT MOTORSPORTS but I'll check it. I'm running a BR9ES plug already, I was thining it was a air leak or something to do with the head bolt leaking. when you say "spray starting fluid" honda 250r 001 what do you mean? also how do i check the power valve to make sure it's working right? the "O-Rings" are brand new but its not leaking on the cylinder or the dome, just by the one head bolt? Thanks for the help

[Honda 250r 001]

BDT may have made a mistake on your pump, id for sure check that out. and when i mean spray starting fluid, heres the concept. When your bike has an air leak. it will suck in air somwhere around the base gaskets, intake gaskets, or head gaskets of the cylinder. So when its sucking air when idling, you spray starting fluid around the air leak, it should idle a little higher or die when you spray the starting fluid over the gasket thats leaking.

[jcs003]

they will also tend to run a bit hotter during thw break-in period. also the ambient temp plays a part. but, 250* in 5 minutes is extreme.

Don’t believe it to be the water pump…however; if it is, contact BDT Motorsports, 909-802-6516…since you have dealt with them in the past, then you already know customer service, and available knowledge is the best available…take advantage of your customer to vendor relationship.

Since you mentioned coolant loss through head studs/nuts, it indicates the water pump is functioning correctly, if it was not; it would not generate enough flow and more importantly pressure to create an evident leak at the head studs/bolts.

However to satisfy curiosity; check coolant flow as suggested, look for a steady stream or current flowing through the hoses and radiator. You will not see a fast or high pressure flow; slow to moderate rate of coolant movement is what to look for.

The “spray starting fluid” as suggested is a good start, however; you really need to perform a complete engine leak down test, and insure no leaks are present. This includes all center case gasket areas, cylinder base gasket area, head gasket area, head studs/bolts, exhaust flange gasket, and complete intake assembly through the carb.

My list of possible overheating issues (as listed above) is fairly comprehensive, I am sure you will find the culprit within those written words.

[Honda 250r 001]

Originally posted by acecarlos
Don’t believe it to be the water pump…however; if it is, contact BDT Motorsports, 909-802-6516…since you have dealt with them in the past, then you already know customer service, and available knowledge is the best available…take advantage of your customer to vendor relationship.

Since you mentioned coolant loss through head studs/nuts, it indicates the water pump is functioning correctly, if it was not; it would not generate enough flow and more importantly pressure to create an evident leak at the head studs/bolts.

However to satisfy curiosity; check coolant flow as suggested, look for a steady stream or current flowing through the hoses and radiator. You will not see a fast or high pressure flow; slow to moderate rate of coolant movement is what to look for.

The “spray starting fluid” as suggested is a good start, however; you really need to perform a complete engine leak down test, and insure no leaks are present. This includes all center case gasket areas, cylinder base gasket area, head gasket area, head studs/bolts, exhaust flange gasket, and complete intake assembly through the carb.

My list of possible overheating issues (as listed above) is fairly comprehensive, I am sure you will find the culprit within those written words.

Heat equals expansion, you do not need a waterpump to cause things to leak at 250 degrees.

[Ruf Racing]

Originally posted by Honda 250r 001
Heat equals expansion, you do not need a waterpump to cause things to leak at 250 degrees.

^^ Agreed ^^ At 250 degrees, this thing would be ready to spring a leak at any weak joint.

“Heat equals expansion, you do not need a water pump to cause things to leak at 250 degrees” ?

Unless the radiator overflow is clogged or capped off, coolant expansion will occur into the overflow tank or the ground if no tank is present.

The radiator cap should be checked carefully for leaks as well, both at room temp & running temp; make sure it seals properly on the PWR.

One important set of questions: does the temperature gauge work properly and is the engine truly running at 250 degrees?

Something seems way off to me; wrong temp reading/faulty gauge, clogged coolant path, air leaks, coolant leaks, or a cylinder jacket issue…can’t ever remember a 250R-370R running at 250 degrees.

[86honda250]

I had the same problem with my esr 350 last year. I had to go up to a 65 pilet jet and i put in a DEG needle.

[tritty_wall]

I found a small crack in the intake boot, i switch it out and it helped a little, but i must have a air leak somewhere else, so i'm going to take it to someone to do some work and put it in a dyno to get it dialed in. Thanks for all the help