Originally Posted by J-P-W (Post 182741)

They suggested drilling a lot of small [e.g. 5mm] holes in the plastic bash 'plate' to help with engine cooling.

Originally Posted by Pleiades (Post 182744)

Quite frankly, that sounds ridiculous!:rotf[1]:

Originally Posted by Seahorse (Post 182807)

The only reason a bash plate is fitted is to protect the bottom of the frame and more importantly the lower extremeties of the engine itself from catastrophic contact with solid objects such as rocks, logs etc

Those who have actually hit a solid objects at any pace will testify to sickening sound it makes, and immediatley thank their lucky stars that they had the foresight to fit a decent bash plate, in place of the plastic item supplied by Yamaha.

I assume we all agree that bash plates are essential items to have fitted if we intend using the bike for its "intended" purpose and not just there for show although the plastic bashplate hardly qualifies. There is however, a downside to this....they do limit the amount of airflow around the sump area of the engine. In certain circumstance and particularly in torturous riding conditions, this may result in higher thermal loads being placed on the engine, as the oil, is not able to carry the heat away from the internal running components effectively....(Oil is not only for lubrication, it also serves as a cooling medium.)

Drilling holes strategically in a bashplate is not as silly as it sounds, but it may in fact cause other problems, such as allowing mud etc to build up on the bottom of the engine and may actually reduce the strength of the bashplate itself. How carried away you intend to get with the size and number of holes, would have a lot to do with the expected riding conditions mixed in with a degree of common sense .

If you take a look at some of the bashplates available for adventure and enduro bike you will find that manufacturers that have access to laser cutting facilities tend to provide holes and slots to promote airflow

The object of the exercise is to enhance airflow yet still maximise protection....

Originally Posted by phil ten (Post 182819)

Good reply. thanks

this doesnt apply to people who live in the UK...as a heat wave for us 20 degrees!!!! :) :)

Originally Posted by phil ten (Post 182819)

Good reply. thanks

this doesnt apply to people who live in the UK...as a heat wave for us 20 degrees!!!! :) :)

Originally Posted by Seahorse (Post 182821)

On a normal East Coast Australian summer ride, temperatures can range from mid 20's to high 30's. Any higher and it is too uncomfortable for riding unless the trails are open and fast. The radiator cooling fan is usually running more than it is stopped. If the trail becomes tight and technical, the fan runs constantly and my left leg bears the brunt of the hot airflow.

I only use high quality oil (Belray "Thumper") and change it every 5000 k"s..(less if the going is really tough).

I currently use an aluminium B&B Bashplate. My intention being to add cooling holes to it, the next time it is off for servicing as well as tacking on an additional guard to protect the water pump. I will post up some pics of the final result.

BTW, I have been to the UK several times, and know from personal experience it can certainly get above 20C .....!!!

Originally Posted by Seahorse (Post 182807)

If you take a look at some of the bashplates available for adventure and enduro bike you will find that manufacturers that have access to laser cutting facilities tend to provide holes and slots to promote airflow

The object of the exercise is to enhance airflow yet still maximise protection....

Originally Posted by Pleiades (Post 182828)

I pretty sure the main reason that manufacturers cut slots and holes in their bash plates is more to keep the weight down, rather than for air-flow.

Originally Posted by phil ten (Post 182836)

and maybe to let any trapped water flow back out?? :)