2017 300rr over heating

[nigelbates]

Hi all,

I have a 2017 300rr factory, its got about 50 hours on it, it was fine for about 45 and then started to over heat in technical terrain, it is fine when your going fast. I assumed it was the head o rings as that is well documented so changed them but is has made no difference. The bike has no thermostat so that shouldn't be an issue.

Im in the uk so currently the temperature is very low, the ground was frozen all day sunday and the bike would still over heat within 5-10 mins of technical riding, last summer it was very hot and no over heating issues with similar riding.

Can anyone suggest any other issues that could cause this?

Cheers.

[hawaiidirtrider]

Put a fan.. .. overflow tank.. high pressure cap? That’s what ai have on my 300 rr. Betas are resistant to boiling but all bikes can boil in technical.

[nigelbates]

That's not the point, the bike has been used for 9 months with no problems, the current temperature is about 0c here, the bike has been used in identical terrain at 20-30c without over heating problems, something has gone "wrong" with the bike the it did not used to have the problem.

[aj_mariner]

Possible jetting issues. Need to fatten her up a bit in the colder weather. When it was warm outside, your jetting was probably good so combustion temps were much lower. What jets are currently installed along with needle at which clip?

[redbone477]

Yes, I agree with above post. Check jetting, and check for air leaks, that would çause a lean mixture! Intake around reed block and inspect reeds.

[nigelbates]

The jetting has been adjusted for winter. There is three of us who ride together on 300rr's the other two bikes are fine mine isn't. There is defiantly a problem its not something simple like jetting.

[aj_mariner]

Time to check for air leaks then and possibly renew exhaust o-rings.

[mtdirtbag]

In addition to the other suggestions I would be checking the water pump impeller, I have not been into mine to see how it is built but if it is pressed on the shaft it could be slipping. It is a strange situation in that these bikes do not seem to overheat and you've already covered the one area known to be a problem - head o-rings. Did you use the KTM o-rings or Beta?

[hawaiidirtrider]

That's not the point, the bike has been used for 9 months with no problems, the current temperature is about 0c here, the bike has been used in identical terrain at 20-30c without over heating problems, something has gone "wrong" with the bike the it did not used to have the problem.

Well what’s different on the bike now from before? No matter what I would srill put a fan and a reservoir and a high pressure cap.. and still search for your issue and try to resolve.I f your bike boils once it still spits coolant that doesn’t go back in the rads later. ..If it’s boiling it’s boiling. You can never lose putting a fan or cap on. That’s the first thing I put on all my betas.

[DaddyTJ]

Is there an issue with the thermostat it's self?