Does running lean cause overheating?

[Whichmcqueen]

Firstly I know this should be posted in workshop, but apparently I dont have permission to post there? So if an admin want to move this thread, please do.

Basically my engine is overheating whilst riding through London- Its on redline, I can hear the overflow bottle bubbling with boiling water. I've recently replaced the hoses with aftermarket hoses, put a new lower radiator on and thought id fixed the problem- however I was riding around without side panels, and after taking the carbs and replacing, I returned the side panels to the bike- now it's running massively hot. The bike is running 110 jets and has a sensible aftermarket can on- would this cause overheating to this extent, or could it be something else like the water pump?

[vfrman]

Short answer...yes. Too lean makes the bike run hot.

[Neosophist]

vfrman is correct that lean runnign will cause the bike to run hot, 110s are slightly lean for the bike but mainly an issue at wide-open throttle, i.e if you were crusing on a highway.

right ill assume your bike is setup ok and some fuelling issues are not the cuase (110 should be ok albeit lean)


Is your fan working and your fan switch working properly?

did you bleed the system of air properly?

Did you check your waterpump is working? Is your radcap sealing ok?

Most neglected VFR system i worked on the cooling pump had sized and the driven shaft snapped, had to fish it out the sump, after taking the cover off all the coolant fins dropped out of it.

New waterpump and flush / degrease of rads with new cap had it working like a champ.

Fan should come on riding aroudn town but unless your dragging clutch up steep hills a working system shouldnt be overheating.

[Whichmcqueen]

vfrman is correct that lean runnign will cause the bike to run hot, 110s are slightly lean for the bike but mainly an issue at wide-open throttle, i.e if you were crusing on a highway.

right ill assume your bike is setup ok and some fuelling issues are not the cuase (110 should be ok albeit lean)


Is your fan working and your fan switch working properly?

did you bleed the system of air properly?

Did you check your waterpump is working? Is your radcap sealing ok?

Most neglected VFR system i worked on the cooling pump had sized and the driven shaft snapped, had to fish it out the sump, after taking the cover off all the coolant fins dropped out of it.

New waterpump and flush / degrease of rads with new cap had it working like a champ.

Fan should come on riding aroudn town but unless your dragging clutch up steep hills a working system shouldnt be overheating.

It's not running perfect, no. On start up it fails to idle until I increase the idle adjuster to around 2500rpm, and then it's not perfect- once warmed up 2500 the. Becomes 3500+.
When riding its a little boggy below 8-9000rpm, above that it pulls fine.
I assume all this is connected?
If the water pump was damaged, would that mean there is poor flow to the radiators? Because the radiators are running hot.
Fan was removed due to damage when new radiator was added, but both radiators are in good condition.

Im intending to rejet to 118/120, and take the water pump off to check condition- is there anything else I should be looking at?

[Neosophist]

you dont have a fan?

that will be causing trouble riding around town.

sounds like your slow jets are blocked causing it not to idle.

might have airleaks and other issues too.

id get the carbs off and give them a full strip and clean, make sure everything is where it is supposed to be then balance them.. new inlet rubbers might be in order if they are knackered.

should run nice then.

for riding around in terrble traffic get the fan sorted but make sure you check the water pump... if you have the kill switch on you can still crank the engine so check the waterpump is spinning and all the impeller blades are ok