I ride in BC and spend time climbing logging roads even when I'm on a trials bike.... I've been told that 4 strokes are better at not overheating on long climbs, what kind of experiences do you guys have?

I used to ride a GG280 and it would overheat after about 5 minutes in 5th, sometimes 1 minute!

I really don't want a seat, I love trials bikes!

Thanks in advance for any experience you guys can offer.

I've had 3 4t's and several 2t's. While it can be debated which is better in a section when out of a section there's no contest, 4t's are far better. Much better for what you are looking for.

Yip. No idea why but my Beta 4T revs and goes without knocking on a 6km uphill, while the beta 2T would start to pink/knock after 1km. Oh and the 4T has more tan enough go.

As I understand it, it's not so much 2T vs 4T, as carbs vs injection. A trials bike needs to be set a bit lean to give us the performance we need off the bottom. This means it leans out at high rpm and therefore runs hot. A montesa 4RT is fuel injected and depending on the processing power of the ECU, should be able to correctly meter at all engine speeds. For this reason alone, if it were me in your shoes, I'd look carefully at a 4RT.

One thing though, 'Long Uphill Climbs'? Does this mean you also have long downhill ones round your way?

Just wondering...

Graham

4 Stroke every time.

How long because if your talking about proper sections i would say 2 stroke because you dont always get a huge run up where you can stick you 4rt in 3rd and fly up the climb at least with a 2 stroke you can hammer it off the clutch at the bottom without shattering your ear drumbs

hey

on a sherco 4t you don't need a run op they are so strong they will climb anything,

if you bike gets to hot put the needle 1 clip higher (2 nd slot from top go to 3rd) it will get more fuel in higher revs and effect on bottom power is minimal or put a slightly bigger main jet

regards bob

My 300 Gasser flys up them massive hillclimbs, doesn't pink at all & so does my dad's beta 4t, i think the sherco 4t flys up them as well because the engine is so strong in them, but i always thought that the 4rt's struggle i had a go on a 250 4rt & i really struggled with it, & jumped off half way up it lol.

Edited August 19, 200917 yr by GasGasben

Take a look at this thread 4RT Engine Wear

Ever since I got my 06 300 txt (new) I have been trying to get it to do a sustained climb without overheating.

Results: it always overheats. I have done the head orings, waterpump etc. still overheats. After the last incident I have had the cylinder replated.

I will say one thing. It has never left me in the backcountry. I let it cool, add water, and it starts.

What drives me crazy is that I do hear of 300s that don't overheat.

Ever since I got my 06 300 txt (new) I have been trying to get it to do a sustained climb without overheating.

Results: it always overheats. I have done the head orings, waterpump etc. still overheats. After the last incident I have had the cylinder replated.

I will say one thing. It has never left me in the backcountry. I let it cool, add water, and it starts.

What drives me crazy is that I do hear of 300s that don't overheat.

Thanks for the responses.... I keep getting mixed opinions from BC riders who tell me thier 2t bikes run great up the hills, mostly from Sherco riders. Sure sounds like a near consensus on the forums though for the 4t. I guess I would go for the Scorpa 250f as this bike needs to be quiet, the 4rt sure looks dialed though.

Anyone ride thier Sherco up 10 km worth of logging roads? There's an 06 290 here for half the price I can find 4 strokes.

Are 4t's just known for better cooling all around, like outside of trials bikes I mean? Seems to me given the same water pump, rad, and coolant cc's there shouldn't be this difference!

Thanks for the responses.... I keep getting mixed opinions from BC riders who tell me thier 2t bikes run great up the hills, mostly from Sherco riders. Sure sounds like a near consensus on the forums though for the 4t. I guess I would go for the Scorpa 250f as this bike needs to be quiet, the 4rt sure looks dialed though.

Anyone ride thier Sherco up 10 km worth of logging roads? There's an 06 290 here for half the price I can find 4 strokes.

Are 4t's just known for better cooling all around, like outside of trials bikes I mean? Seems to me given the same water pump, rad, and coolant cc's there shouldn't be this difference!

My mech says if a bike overheats it's not jetted right.

Then again we don't have desert heat etc.

My mech says if a bike overheats it's not jetted right.

Then again we don't have desert heat etc.

If only it were that simple. If the hill is big enough, at altitude almost any bike will overheat. Then add in a tiny radiator and small water jacket. That said, I think I have finnaly got a decent system for my GG 300 in the backcountry.

As you can see I have an overflow tank, which does two things: catches the fluid, and with one glance I can tell if I am overheating. I've found that on a big technical climb, it's easy to miss a Rad overflow--then you start to hear the knocking......

Also you can see a switch on the handlebar. This goes to ground, and also joins the normal fan circuit. So the fan should come on by itself, but I have the option to turn it on myself. When I know a hill is coming, I switch it on well before.

In testing yesterday this system worked well, and I was able to do some big climbs all the way to the top. I checked fluid when I got home: plenty.

Hm, good thing I live on the ocean and not a mile high.

I no that on 07- downwards models, GasGas did have trouble with the bikes overheating, so in 08 they put a new radiator in them which stopped the problem, i have never had any trouble with my 09 300 overheating what so ever.

Edited August 28, 200916 yr by GasGasben