Thermostat bypass on 2 stroke ....?
Discussion
Right , genuine request for knowledge and info of any kind from those who know and have valid experience to offer , please .....
A coolant hose is a bit soft and baggy on the underside of the rads, a pipe connecting the two radiators and seemingly going to the thermostat housing on my 2008 KTM 250 EXC ( 2T).... it has been losing water once hot and under load and I think this pipe is the problem , but having tried my local KTM dealer the pipe kit is discontinued for this model and the only ones which seem available are Samco silicone thermostat bypass kits .....
What do I do , I understand the warming up procedure will need to be regimented if running this way , allowing thorough warming of the whole water jacket before use, but why does it seem that these are the only kits available and what would the relative concerns be of running this way ?
Many thanks for all input .
A coolant hose is a bit soft and baggy on the underside of the rads, a pipe connecting the two radiators and seemingly going to the thermostat housing on my 2008 KTM 250 EXC ( 2T).... it has been losing water once hot and under load and I think this pipe is the problem , but having tried my local KTM dealer the pipe kit is discontinued for this model and the only ones which seem available are Samco silicone thermostat bypass kits .....
What do I do , I understand the warming up procedure will need to be regimented if running this way , allowing thorough warming of the whole water jacket before use, but why does it seem that these are the only kits available and what would the relative concerns be of running this way ?
Many thanks for all input .
No ideas of the "why its that way" but its a common thing to bypass on a stroker, I had to on my YamaGamma(which repaid me by seizing anyway .......not cos the the plumbing thou) and most of the modded/ big bore RDs run without one, I wouldnt worry overly, as you have said, warm it up properly before you had off and all will be well.
On every stroker I've had (quite a few, road and race) I've knocked the centre out of the stat rather than remove it completely. This will allow flow from stone cold whilst providing some flow restriction which helps cooling, which is good.
Just make sure it's well warmed up before making progress, cold seizures are nasty and happen without warning.
Just make sure it's well warmed up before making progress, cold seizures are nasty and happen without warning.
Guys , ever so grateful for the feedback - being a self-confessed stroker ignoramus I am pleased that the fact that I have gone ahead and ordered the bypass kit already, is not a complete waste of money and that nothing majorly to worry about ....thanks for the reassurances.
John - no, I haven't , but should have called you thinking about it ...I didn't know of them but shall call tomorrow and discuss , I guess they know you well , right ?
I like the idea of not losing the whole thermo and knocking the guts out but , the only pipes In the Samco kit do not offer the T piece option to do that , it completely removes it .
I was desperate to reach some form of resolution as really need to ride it this weekend without the option workwise of dropping it to a shop etc and waiting / hoping for a result as I mentioned the cooling system when it went in recently and got it back untouched in that area ( having also needed to remind them to change the gearbox oil on the morning of proposed collection ......the "good old bike game"... )....
Ah well - Awaiting Fed-Ex on the 'morrow....
John - no, I haven't , but should have called you thinking about it ...I didn't know of them but shall call tomorrow and discuss , I guess they know you well , right ?
I like the idea of not losing the whole thermo and knocking the guts out but , the only pipes In the Samco kit do not offer the T piece option to do that , it completely removes it .
I was desperate to reach some form of resolution as really need to ride it this weekend without the option workwise of dropping it to a shop etc and waiting / hoping for a result as I mentioned the cooling system when it went in recently and got it back untouched in that area ( having also needed to remind them to change the gearbox oil on the morning of proposed collection ......the "good old bike game"... )....
Ah well - Awaiting Fed-Ex on the 'morrow....
hebegb said:
Right , genuine request for knowledge and info of any kind from those who know and have valid experience to offer , please .....
A coolant hose is a bit soft and baggy on the underside of the rads, a pipe connecting the two radiators and seemingly going to the thermostat housing on my 2008 KTM 250 EXC ( 2T).... it has been losing water once hot and under load and I think this pipe is the problem , but having tried my local KTM dealer the pipe kit is discontinued for this model and the only ones which seem available are Samco silicone thermostat bypass kits .....
What do I do , I understand the warming up procedure will need to be regimented if running this way , allowing thorough warming of the whole water jacket before use, but why does it seem that these are the only kits available and what would the relative concerns be of running this way ?
Many thanks for all input .
I have a 250 exc , If you are mainly off road it will be fine without the stat , winter on road it might run a bit cool A coolant hose is a bit soft and baggy on the underside of the rads, a pipe connecting the two radiators and seemingly going to the thermostat housing on my 2008 KTM 250 EXC ( 2T).... it has been losing water once hot and under load and I think this pipe is the problem , but having tried my local KTM dealer the pipe kit is discontinued for this model and the only ones which seem available are Samco silicone thermostat bypass kits .....
What do I do , I understand the warming up procedure will need to be regimented if running this way , allowing thorough warming of the whole water jacket before use, but why does it seem that these are the only kits available and what would the relative concerns be of running this way ?
Many thanks for all input .
warm up stationary then ride , losing water may just be overfull or the rads are muddy /blocked or a gasket issue ,
if you do a bit of slow stuff a fan kit is a must without forward motion they can soon brew up without the fan ...
powerstroke said:
I have a 250 exc , If you are mainly off road it will be fine without the stat , winter on road it might run a bit cool
warm up stationary then ride , losing water may just be overfull or the rads are muddy /blocked or a gasket issue ,
if you do a bit of slow stuff a fan kit is a must without forward motion they can soon brew up without the fan ...
Definitely look at the fan kit. If the bike is getting hot they do vent and loose water easily. warm up stationary then ride , losing water may just be overfull or the rads are muddy /blocked or a gasket issue ,
if you do a bit of slow stuff a fan kit is a must without forward motion they can soon brew up without the fan ...
As said above make sure the rad fins are not clogged up or bent over.
As for the thermo bypass it won't hurt but in the UK climate I'd be tempted to keep it and run the fan kit.
Does the bike have a battery or any vestiges of road legal wiring like a reg/rec??? As an exc I'd have thought it would??
You might need to increase the battery size or reg/rec output to support the fan but not impossible.
And if you can have it activated by a thermo switch rather than a simple on/off on the bars.
You might need to increase the battery size or reg/rec output to support the fan but not impossible.
And if you can have it activated by a thermo switch rather than a simple on/off on the bars.
No - no battery at all but it is road legal with lights - it is def. exc Enduro 2008 regd/ 2009 model when you use the Vin. on KTM parts microfiche .....
Bypass kit has landed and only three pipes so not even full replacement set to eradicate possible guilty party despite me being pretty certain it is the thermo related pipe from left hand radiator .....
Hmmmm.
Bypass kit has landed and only three pipes so not even full replacement set to eradicate possible guilty party despite me being pretty certain it is the thermo related pipe from left hand radiator .....
Hmmmm.
Going to go round and have a look at the bike later with any luck, Graham mentioned it's "using" quite a lot of water throughout a day enduroing, no visible leaks but some steaming etc.... Also if Kais changed the gearbox oil and the water ain't going in there via a knackered seal or whatever then where's all the water going?? My bet is in the engine.
If that is the case then may as well check the squish while we're at it. I believe the head gasket is o rings on these, anyone confirm? Think it's an 09 model.
If that is the case then may as well check the squish while we're at it. I believe the head gasket is o rings on these, anyone confirm? Think it's an 09 model.
Steve Bass said:
What's "quite a lot"?
Before you strip the motor try pressure testing the rads and check the rad cap. If the bike is getting hot on slower technical sections they do boil up quickly. Might be the rad cap venting too much or too readily
He said it went through a litre Last time....! And the rad cap is new. At least the piston will be nice and clean Before you strip the motor try pressure testing the rads and check the rad cap. If the bike is getting hot on slower technical sections they do boil up quickly. Might be the rad cap venting too much or too readily
Yazza54 said:
He said it went through a litre Last time....! And the rad cap is new. At least the piston will be nice and clean
A litre!!! Ok, there's definitely a bit of a problem Loosing that much I reckon you'd spot the dripping or steam. So if it's not going into the gearbox (which can only hold so much) then it's heading out of the motor.
As you say..first suspect will be the head gasket.
Yazza54 said:
Going to go round and have a look at the bike later with any luck, Graham mentioned it's "using" quite a lot of water throughout a day enduroing, no visible leaks but some steaming etc.... Also if Kais changed the gearbox oil and the water ain't going in there via a knackered seal or whatever then where's all the water going?? My bet is in the engine.
If that is the case then may as well check the squish while we're at it. I believe the head gasket is o rings on these, anyone confirm? Think it's an 09 model.
Yep, base gaskets are paper/card/cornflakes box.If that is the case then may as well check the squish while we're at it. I believe the head gasket is o rings on these, anyone confirm? Think it's an 09 model.
Well , folks , much kind advice and when I said stroker ignoramus , I really meant it ...
So , head gasket it may well prove to be , but , hopefully verified and sorted prior to killing the bloody thing .
Ryan, once again proving what a top chap he is and the meaning of true friend springs to mind ...and he always enjoys the slap up meal out with the respective Mrss, and the very messy booze fuelled capers we invariably end up in after such outings ...... he has exorcised my demons of horrible long term costly out of action repairs and brushed it off with his casual " it's not such a big deal , have it sorted in no time " nonchalance based upon knowledge and ability.
I am humbled by the willingness to help others by some people and the fact that I met Ryan through others on here and now very very good true friends abound - excuse me while I shed some biking happy tears , or , is this bath too hot and is my oversize ( 500ml ) glass of Merlot very nearly empty ....?
Cheers!
So , head gasket it may well prove to be , but , hopefully verified and sorted prior to killing the bloody thing .
Ryan, once again proving what a top chap he is and the meaning of true friend springs to mind ...and he always enjoys the slap up meal out with the respective Mrss, and the very messy booze fuelled capers we invariably end up in after such outings ...... he has exorcised my demons of horrible long term costly out of action repairs and brushed it off with his casual " it's not such a big deal , have it sorted in no time " nonchalance based upon knowledge and ability.
I am humbled by the willingness to help others by some people and the fact that I met Ryan through others on here and now very very good true friends abound - excuse me while I shed some biking happy tears , or , is this bath too hot and is my oversize ( 500ml ) glass of Merlot very nearly empty ....?
Cheers!
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