FRONT CLY. TO REAR CLY. TEMPERATURE DIFFERENCE?

[supervision]

  I was sitting around reading old post someone, I don't recall name, said he had noticed like 20 degree difference back being cooler.  Got me to thinking, trying to make them equal.  Here is my idea, I can put an extra temperature sender in my rear water return pipe, I have a spare tee,same as the front cly. uses. Have the senders wired thru a switch, is that you can select back and forth between the front and rear senders, at the temperature gauge.  If you see a difference, restrict  some of the flow thur one of the chrome pipes.

[Lucky]

instead of messing with the chrome pipes, you could put heater valve (and maybe a bypass) in the heater hoses.. 

and just a thought, it doesn't seem to be a problem, is it worth the effort & expense?  would it make it harder to burp the system?  my triple's center cylinder runs hotter also, btw, but that's air cooled...

[supervision]

  with a water engine cooled, the jetting can be tuned much closer to perfect one cly. To the next. The two different temps actually surprizes me, and sence it would be very simple to correct to perfect, it begs to be done.  Maybe the bozo at yama gave up to soon, or missed the fact it was even happening.  look at it this way, their is some reason we need different main jets, we arent sure, it could be the temp diff.

[Lucky]

ok, sounds good

[jefferson]

I am pretty sure that was me that posted the temp. differences and I was thinking it was down to more flow going to the rear cyl. than front. I'm with you on the reason for the different jetting, but then the 83's didn't have the different jetting and those temps were off an 83. To find out for sure if it is a flow difference, someone would have to remove their thermostat and stick a hose in the radiator. Then run a hose from the top of each cyl. into a 5 gallon bucket that has been marked with graduations for each gallon. Turn on the water and start the bike and see what difference shows up in the buckets. Probably ought to give it some revs too. I never had an electric start bike to do it with or I would have. I am pretty curious about it. The only way I see to fix it if there is a difference would be to restrict water to the rear cyl or fashion a scoop that would take more water that was going past the front cyl's pipe.

Jeff

[fret not]

So is the temp difference anomaly from ONE bike or the norm for the general production?

[supervision]

  A small C clamp on the rear return hose, like just above the spark plug, would reduce flow.   Maybe just stay with the hand held device to tell if you have caused a change.    A long time ago, I was a pool repair man. We would always slow the water down though gas fired pool heaters, because if the water went though to fast it didnt have time to get as hot as it was supose to.  It. Was called heat rise.  we would just plumb an exta gate valve and close it alittle, feel the extra heat it would cause, then leave the handle off.    We told the customer, leave that valve alone, because  this will save you money, on heating your pool.

[VisionMeister]

different jetting is probably more related to exhaust pipe difference between front and back.
Airbox design may also effect the breathing/flow different front to back, since the front cylinder breathes closer to the larger airbox volume at the front.

[jefferson]

I would think the temperature difference is the same for all the bikes. As the water comes off the impeller of the pump it is pumped to the rear where the chrome pipes are. The water is forced into the pipe for the rear cyl. as it has nowhere else to go and the front pipe just gets what won't go in the rear pipe. There is nothing to direct the flow into the front pipe.

Jeff

[supervision]

  Good point Miester, the air box favors front cly, dif than back.  I still think it is worth a try and equal up the cly. Temps, should be easy to affect the change.  Early tech water jackets are maybe not very dialed in.

[fret not]

Someone with a vision and access to a hand held IR thermometer can test their bike for difference in temperatures between the front and rear cylinders.  The more of them tested the more reliable the figures will be.

Sometimes it is difficult to follow the "shorthand" some of you guys use. ;)

[jefferson]

I checked mine with an IR gun. You have to make sure and check the water jacket side of the head and not the cam chain side. It should be somewhat cooler there.

Jeff

[jasonm.]

I checked mine with an IR gun. You have to make sure and check the water jacket side of the head and not the cam chain side. It should be somewhat cooler there.

Jeff

my IR gun does not work well on shiney surfaces. Says so in the manual too. Do find a nice DULL areas to aim it at.