Since he acknowledged there is a problem with the cooling system losing coolant, i'll ask the tech to solve that problem first, perhaps solving that will solve the losing engine oil problem. He says the water is flowing from the radiator to the reservoir when it gets hot but not back to the radiator when the engine gets cold. could be a problem with the radiator cap, i changed a new one the other day but it didnt work but he said he will try with a different type of cap. its just a mystery where all that coolant is going.

But if that problem doesnt get solved, i'll change the head gaskets, maybe i'll find another tech to do that for me. Since i have already ordered another gasket from Bill, i got nothing to lose.

And if the problem is still there, i'll just just remove the big bore and put back the stock bore. i think with the TM33, the bike can still perform better than when it was completely stock and hopefully i can find a buyer for the big bore.

 

I hate to say it, but if your technician says losing oil rapidly is normal for a big bore upgrade...I'd have to question his knowledge or experience. More likely is that he is frustrated and doesn't know what's going on, but doesn't want to admit that to you. Somewhat understandable I suppose (sucks to be him right now)... I would say you should either get him to install the new gaskets and inspect the engine parts during that process, or find a different technician who can do that. Just make sure whoever does that work REALLY, SERIOUSLY knows that they are doing and can see if there are any problems with anything as they get into the motor to replace those gaskets. If your mechanic isn't getting into the engine, I'm not sure what he's really going to do to try and find that coolant leak...and you'd still have the oil problem, which is NOT normal. And as others have said, you CERTAINLY shouldn't need bigger radiators!

 

On a side note, I'd like to think I'm a reasonably competent mechanic, but this kind of thing is the unfortunate reason why I wouldn't want to be an independent, self employed mechanic... **** like this can just really ruin your day and kill your income fast (because you're spending a lot of time trying to figure out what's wrong with the work you did, and how to fix it, and whose fault it is, and who needs to pay for it, etc.). No fun for either party.

 

Yes, i do understand what mechanics go through, i am not out to blame anyone as i find it counter-productive, i just want to get the problem solved so i can finally enjoy riding the klx250s. I send all my previous bikes to the same tech the past 9 years, initially his dad was was doing the work but he retired and his son took over. i saw him again over the weekend and he will try to solve the losing coolant problem.

But looking back at the previous posts, i noticed you brought up that this problem could potentially be caused by jetting the carb wrongly. If the engine is running hot, the jetting could also be the cause and since i got the Big Bore installed, i havent tweaked or changed the jetting.

I wrote to Bill and he says he usually pre-set the jetting based on what i ordered, he says i need to tweak it for better performance. He also said, if the engine is running hot, i need to increase the pilot and main jets. Could this mean the carb on my bike is jetted too lean which is causing heat issues in the engine which in turn causes loss of coolant and engine oil?

I will have to try all possibilities to fix the problem, if the problem is still not solved, i will follow your advise, to remove the head gaskets and install new ones with me observing every step of the way.

 

Hi All, if anyone is still interested, what happened after my last post is the shop just change the radiator cap to a higher pressure type, from 1.1 to 1.3 and asked me to test the bike but the problem is still there. It seems the water when hot will enter the reservoir at the back but when it gets cold, it doesnt return back to the radiator like how its suppose to. i checked the hose and it seems ok. i have no idea what is wrong.

i finally got the gaskets from Bill but will changing the gasket help with this problem? What is it doesnt? I still need plenty of help from you guys here, looking forward to your advice.

 

Changing the gaskets may help. We don't know if that's the problem, but it certainly looks like it could be.
It seems that overflow to the coolant reservoir that is subsequently not sucked back in when the bike cools could be evidence of a leak somewhere. Maybe the gaskets.

 

My guess is the gasket was somehow installed wrong, or if gasket sealer was used it may have plugged a water port upon sealing. I would assume that would cause issues.

 

But what if after changing the gaskets and the problem is not solved? I need to eliminate other possibilities before going the changing gasket route. I will try to check the hose that connects the reservoir to the radiator, it seems that hose have been re-routed after installing the IMS Tank. The coolant from the radiator travels to the reservoir from the pressure from the hot water and it travels back when its cold, any idea how it travels back? I doubt its by gravity because the water level in the reservoir when full is not higher than the head of the radiator.

I wish i had a more clear symptom that there is a problem with the gasket like blue smoke or water coming out from the exhaust but right now its still not certain the cause of the problem. I will give it another week then i'll change the gasket.

 

If all other possibilities have been eliminated (including a leaking head gasket and/or warped head) it is possible that your cylinder is cracked. I'm not referring to the steel liner but the aluminum cylinder itself. The cylinder can crack when the liner is being installed. Unfortunately, the only way to verify (other than by eliminating all other possibilities) is to remove the liner and inspect the cylinder.

Hopefully yours is OK.

Ron

 

I mis-routed that hose once... it was slightly pinched between the frame and the rear fender just south of the wiring harness. I did not have a problem at the time but did what was needed to remove the restriction.

As the engine cools vacuum will draw the coolant back into the engine (recovery). A restriction or even a tiny leak can interfere with the process possibly leaving the engine low on coolant.

You may want to inspect your radiator cap closely or just replace it.