bike running very hot, head gasket?

Smousley1995 · Post by **Smousley1995** » Sat Feb 07, 2015 10:45 pm

Hi, the last few times I've been out i noticed the bike was running quite hot, especially today when it was sat right on the top line of the temp gauge on my way home. strangely the fan didn't kick in at any point.
I don't know if its related but I've heard bubbling when i turn the bike off after a hard ride which seems like its coming from expansion chamber.
Firstly why would my fan not be kicking in?
Im going to check the thermostat in the hope that its not my head gasket but is there anything else i should check that could be the problem?
Also will a compression tester tell me if it is the head gasket?
thanks

RedexRobB · Post by **RedexRobB** » Sun Feb 08, 2015 12:40 pm

Compression test will help you narrow it down for sure.

Bubbling coolant and hot engine temperature certainly suggests a head gasket to me. Also get the expansion tank cap off and see if it smells of exhaust.

Smousley1995 · Post by **Smousley1995** » Sun Feb 08, 2015 7:43 pm

The bikes done 40,000 miles and I'm not going to have a garage after the end of the month so I'm going to do the head gasket anyway.
I'm confident in getting the engine out and doing the job in general but are there any little pointers or problems i should know about?

I've ordered a new head gasket (obviously), exhaust gaskets, coolant, an engineers straight edge, and I've already got feeler gauges.
Is there anything I missed or anything thats worth replacing while I've got the head off?
Also do i need to put anything on the head gasket or does it just go on dry?

CaNsA · Post by **CaNsA** » Sun Feb 08, 2015 11:28 pm

Smousley1995 wrote:The bikes done 40,000 miles

Head gasket is

Smousley1995 · Post by **Smousley1995** » Sun Feb 08, 2015 11:39 pm

CaNsA wrote:Head gasket is

Took me longer than it should have to work that out

Post by **masterofinsanity** » Mon Feb 09, 2015 6:30 am

personally i'd check the thermostat and while your doing that you might as well put a new one in, also check the fan switch is working, check your fan actually works by bridging the wires from the fan to the switch, could be a blocked radiator, disconnect it and pass running water through it for a bit, what colours your coolant?

Smousley1995 · Post by **Smousley1995** » Mon Feb 09, 2015 1:48 pm

I'll do the thermostat at the same time then. I think the fan works as it was running a few days before but i will check it. Im pretty sure the radiators not blocked as i ran water through that a few weeks ago cause i had the engine out. And i filled it back up with premixed coolant that was for aluminium engines that was green.
How do you check the fan switch works?

Post by **KwakKwak** » Mon Feb 09, 2015 2:38 pm

Smousley1995 wrote: cause i had the engine out.

Oh oh, this may be a clue

As for testing anything electrical, i find standing in a bucket of water always helps.

Post by **banner001** » Mon Feb 09, 2015 3:47 pm

We don't mean that the radiator is blocked internally, but externally I.e. Are the fins all covered in a thick layer of road crap.

Smousley1995 · Post by **Smousley1995** » Mon Feb 09, 2015 6:58 pm

The radiator is not the cleanest but its not dirty enough to cause that amount of overheating. i was out in about 3 degrees sitting at 60-70 for a while and it still ran at the very top of the temp gauge

RedexRobB · Post by **RedexRobB** » Mon Feb 09, 2015 8:58 pm

Smousley1995 wrote:The radiator is not the cleanest but its not dirty enough to cause that amount of overheating. i was out in about 3 degrees sitting at 60-70 for a while and it still ran at the very top of the temp gauge

Thats not right at all. Just to be sure, is the coolant topped up?

Smousley1995 · Post by **Smousley1995** » Mon Feb 09, 2015 9:44 pm

RedexRobB wrote:Thats not right at all. Just to be sure, is the coolant topped up?

Yeah the expansion chamber is filled above half way.
I'll be starting the head gasket and will check the pump and thermostat on wednesday so I'll know what the problem is then.

RedexRobB · Post by **RedexRobB** » Tue Feb 10, 2015 8:04 am

Have you checked under the rad cap?

Smousley1995 · Post by **Smousley1995** » Tue Feb 10, 2015 10:13 am

RedexRobB wrote:Have you checked under the rad cap?

Yeah, the radiator is pretty much brimmed

JamieNeve · Post by **JamieNeve** » Tue Feb 10, 2015 10:50 am

I know it's been discussed a number of times on here, but you don't have to drop the engine out to do the headgasket. I've done 3 ZXR's with the engine in the frame, and personally find it much easier as I don't really have the facilities/ equipment to drop the engine out.

The gasket should go on dry, you will have crusty coolant (yellow/ orangy colour) around the general area (especially if HG is blown,) so I'd give this a clean before replacing with a new one. This would be easier with the engine off of the bike admittedly.

Also, whilst you can see the pistons, it may be beneficial to give them a bit of a scrub to remove excess carbon!

Check whether your head need skimming, as it may have warped if the headgasket has been gone for a while. I'm pretty sure the 2 ways you are meant to do this is with a glass pane, or marble as they are very flat, and try sticking a feeler gauge under different parts. You can do this with a metal straight edge however!

Apart from that you'll be good to go, make sure you use the manuals methodically, and also that you have a torque wrench at hand for the reassembly!

Just food for thought!

Good luck!

www.zxrworld.co.uk