Drilling into the cylinder head jacket?

[Misha Subo]

This may sound extreme but I was wondering if anyone has ever tried getting a source of hot coolant directly from the aluminium cylinder head to heat ones handlebars?

The hose exit from the KTM 300 head is curved, crowded and simply too short to splice in a tee junction as a heat source between the thermostat. I'm thinking, if I drill and tap the aluminium head jacket directly 1/8-27NPT (right beside the tube where the existing hose attaches). I can put a 1/4-turn shut off valve going directly to my handle bars or a carb heater jacket, then route an exit back to the pump. This avoids cutting and splicing my rubber radiator hoses and it will give a consistent bi-pass to keep the engine warmer.

Anyone ever try drilling into the head directly?

 

[byeatts]

This may sound extreme but I was wondering if anyone has ever tried getting a source of hot coolant directly from the aluminium cylinder head to heat ones handlebars?

The hose exit from the KTM 300 head is curved, crowded and simply too short to splice in a tee junction as a heat source between the thermostat. I'm thinking, if I drill and tap the aluminium head jacket directly 1/8-27NPT (right beside the tube where the existing hose attaches). I can put a 1/4-turn shut off valve going directly to my handle bars or a carb heater jacket, then route an exit back to the pump. This avoids cutting and splicing my rubber radiator hoses and it will give a consistent bi-pass to keep the engine warmer.

Anyone ever try drilling into the head directly?

Weld a short coupling with only about 5 threads showing, Then drill through and tap. The fitting will thread through both.

 

[M5-]

I've drilled and tapped a CR500 head that being said those do have a boss there from days gone by. I would weld a boss on as stated above or look for a different option. Honestly I don't think I would bother even trying for heated bars on my 500 it just runs too cold to be worth the effort. 4 stroke yes, 2 stroke no. IMO.

M5

 

[dirtrebel]

Do u have the avid thermostat or tgermobob? If not and u are using the stock thermostat Just buy the avid and run the bypass to your bars. Trying to save money by drilling your head seems hardly worth it. Also replacement hoses are cheap don't be afraid to just cut the ones you have and order new ( u should upgrade to the samco sport ones anyway) The avid stat is able to be assembled into a multitude of positions and the plumbing can be perfect on a 300 xcw I have the bike and the avid stat it is a perfect stock like fit. The cost of the avid is probly the same or less than a new head if / when u screw it up, good luck

 

[Misha Subo]

Do you have the part numbers and suppliers for what you did - hose, thermobob...? My two Ktms are 300 XCW 2008s and the stock thermostat is a 55 degC = 131 F. My shut off valves are 1/8-27NPT. The advantage with a thermobob - I guess it's to have a temp probe and tee port? I like designing my own stuff but you are correct in that the shelf thermobob has more to offer - as long as it is as you say, being clean shaven afterwards.

I'm trying to make a clean set up that I can leave as is all year long. They will return to the dirt soon and we will simply shut off the valve to grip heat.

 

[dirtrebel]

I don't have all that info. Im running a 2016 300 xc-w, avid fits perfect, and replacement hoses are cheap thats really all I know

 

[Misha Subo]

Can you post photos?

 

[dirtrebel]

truth be told I'm not actually running the bike on snow right now. A friend ran the same bike 2016 xc-w on snow last year and when he sold it I bought the avid carb heat kit from him with plans to put it on my 2016 300 xc-w (identical bike to his). as of now I run a yz450fx four stroke and I may or may not try the 300 on snow. some of our desert like riding areas are dirt rideable usually in march so I am trying to keep my 300 ready for dirt. anyway he had the avid kit installed on a 2016 300 xc-w and I rode with him so I know it works. the plumbing is tight. I think if I was you I would just forget the heated bars and go without bar heat or go electric. Wire to the headlight circuit not the battery, that is if the grips are not made for dc only, and the bike makes plenty of juice! are you running carb heat? For me on the other 2 strokes I have had in the past carb heat has been mandatory, not sure a smoker would even make enough heat for both carb and bars? Heres the best pics I could get by just holding it in place so you could get an idea. Also the avid stat is fully sealed so there is no bleed thru when its shut except the bypass circuit, I think the factory stat has a bleed in it at least the ones we first were trying back when snow bikes were new we would buy a Ktm stat before avid and bob were made. They hardly did anything, because there was a big leak by even when closed. Also the thermobob is a slimmer unit, but the avid is cool because of the "clockabilty." Maybe you should just drill your head, haha!