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over heating evo

7.2K views 13 replies 5 participants last post by  wwhog  
#1 ·
ok guys here one for ya
i have a 96 ultra with a mikuni hsr 45, ultima single fire ,it has a
ev 27 cam , true duel exaust with slash cut pipes
it threw a rod bearing so i split cases and had new stock rods installed ,cylinders were 20 over with wisco 10:5:1 pistons
bike ran great for years with no problems
due to cylinder damage from the rod bearing had to replace cylinders and i used V twin 83" jugs and pistons ,i have had this thing apart 4 times and cannot find anything wrong , i put a oiler cooler on it , put a performance oil pump on it and it still will get so hot thart oil pressure will drop down to 0 in 30 min of riding even in freezing temps
has anyone ever used this 83" kit i think that who ever V TWIN uses to make them used stock cylinders and bored them out to 3.550" and i think the cylinders are to thin to disipate the heat
any one have any other ideas
 
#2 · (Edited)
How much spark advance is it getting?

OBTW EVO's dont need oil pressure just flow, there is a little pressure in one area for the lifters.

So get a factory oil pressure switch and connect a light to it and retest.

A 60# gauge will not show the normal hot oil pressure as it is pretty low.
 
#5 ·
i played with advance even installed a voes witch i dont use on any other of my bikes
i took oil pressure sending unit off and put the pressure guage off of one of my other bikes on it at start up shows 30 lbs and with in 15 min of ridding drops tp nothing , when i pulled the top end off the rocker boxes were well oiled problem seems to be heat top end is cooking hot but i dont have a temp guage to measure heat
i have removed the cylinders and have compared them to a stock set i have that are damaged sleeve outside demensions are the same so i think what they did with these cylinders was bore them out to about 60 0ver there is only 50 thou of cylinder wall left
 
#7 ·
just read up on the cylinders im using they were a stock cylinder that the manufacture bored out to 3,550 " with matched 10:5:1 pistons so looks like my heat issue is the cylinders the walls are to thin what kind of company pull this kind of scam i would figure that with evo cylinders anything over 30 thou bore over stock would cause this issue
 
#11 ·
no motor does not run on
as for timing im not sure were it was set before i took it all apart but while i was trying everything i advanced it retarted it i adjusted all the setting i could no matter what i did it would run extremly hot plugs were a nice tan colour i even ritchened up card to try and cool it off still with no luck but now have black plugs witch is no big deal i will jet put other jet back in as for cylinder sleeve size if it didnt matter then why only bore stock cylinders 30 over why not keep going these sputhe cylinders have same size sleeves O,D. but bore is 80 thou over stock leaving a mere 60 thou of cylinder wall left you dont think that that thin of a cylinder is going to run hot
 
#12 ·
sorry as for how motor, it responds good lots of power ,didnt even smoke when it was over heating as some evos will but the heat coming off motor is so extreme that in 32 degree weather the heat coming of off it is like being in sturgis and stuck it traffic for 2 hrs
not quite sure what oil temp is but ,dont have a guage on it but to hot to hold , not sure how this motor didnt grenage is beyond me
idiot light for oil pressure comes on at anything under 1500 rpm i tied a diffrent oil pressure guage to for shits ang giggles same thing i took my oil pressure guage off of my other bike shows 30 pds at start and will keep dropping till it goes to zero as you are riding but on my bike will register properly
 
#13 · (Edited)
Yanking on the sensor plate you wind up with random timing
Could be anywhere from 10°ATDC to 60°BTDC
Both will cause overheating.
Set the timing with a light to factory spec following the service manual procedure.
Make sure your VOES is working. Verify it with the light.
You cant control motor temp with the mixture so put normal jets in it.
Verify cam timing is correct. (before setting ignition timing, or you will have to do it twice)
Part of fixing something properly is getting back to basics.
You have to make sure everything is set right and working, or any data gathered is irrelevant and misleading.
Throw away drunken camp fire myths and all assumptions especially "new" I've seen many new parts bad out of the box.
The entire machine has to be looked at.
Have you done a fuel flow test? An extended fuel flow test? (tests tank venting)
Basics, check everything. Leave no stone unturned.

If you brought it to me, I would probably have it fixed the same day.
 
#14 ·
well i will be putting it all back together with in the next few days im low on supplys {need head gaskets } so i will order this week when i place another order for other bike im doing , this bike is set up pretty much the same as my softail only diffrence is exaust i have done quite a few of these over the years and have never encountered this before my softail does run a little hot but that is due to powder coated motor fixed that problem with oil cooler as for gas flow i ran it on my test bottle with the tank off on bench with the fan on it and it would still heat up
thx for the input and i will let you know what i get