Is there a radiator fan kit available for 2 strokes?

[stay_upright]

Originally Posted by GMP

IMO a fan would be a band aid. The bike should not get that hot if its set up and running right. Recently, I did a ride that had a lot of mud sections that partially clogged my rad guards, combined with long steep climbs. No problems. I'd go over the bike first before adding a fan. Waterless coolant is another option.

Correct (as ever) but I run quite lean at the bottom end to get a clean throttle response, no 4 stroking, little/no spooge/no fouled plugs and as a side effect improved fuel economy (though it was also good to start with) - I've never needed reserve in a 2.5 or 3 hour hare and hounds though I also tend to lug the bike rather than make it scream everywhere...

I will be re-checking the jetting after the rebuild and also the reeds have changed slightly c/f not plastic and also I was going to run 40:1 (maybe even 35:1) instead of 50:1... BUT I've already been through the process and with the previous engine build I needed 35p 9 slide N1EF 2nd clip down from top and 178 main in order for her to pull cleanly from low throttle openings so I can't see that changing much - this does mean she runs hotter, I use non-water based coolant already and don't have a problem boiling but there was some evidence of a partial seize (cylinder was fine though) and detonation around the edge of the piston so it's running too hot - it runs hottest with multiple runs at muddy hills I am failing to get up, so little flow over the rads and 0-1/2 throttle opening hence I was thinking a fan would help here.

If the alternative is runing richer and having misfires/blubbery running/not pulling cleanly I'll sell it and buy a 250 4 stroke (sadly not a GG) however I believe I can make this work, after all the last piston lasted 3 years quite a bit with this jetting or occasionally leaner (1 clip leaner on the needle).

I could consider a LTR impeller but I think the heat is getting through to the rads OK but I will inspect it again to check - of course here we have to import them but maybe it would help but I feel a fan would have a much bigger impact.

Other thoughts are a RB style (again I'm in the UK) head mod which some people report improves the jetting/ease of jetting but don't know if it will help in the fashion I need.

[stay_upright]

Originally Posted by Rick

I agree with Glenn about the band aid deal.

1. Proper jetting? - lean see reply to GMP

2. Proper fuel ratio? - 50:1 goinng to change

3. Air leak within the motor someplace? - nothing noticed on stripdown runs well so don't think so

4. Proper type of coolant? - some of that cool ice stuff - doesn't boil but maybe masks the problem of running hot....

5. Radiator luvers blocking air flow? - if you mean the plastic bits cleaned after every race and checked (normally removed from the bike)

6. Radiators core plugged w/ mud? - no generally well chanked and inspected though of course when racing it's not uncommon to get lots of mud/grass in and behind the louvers.

7. Head "o"ring gone bad? - no fine on stripdown

8. Water pump impeller? - checked about 1 year ago can check again but the thing that changed was the jetting.

9. Check hoses for reduced water flow. - suggestions how....

10. Check water flow through the radiators...could be plugged with something..never know... - could try maybe trying to run the garden hose through them...

11. Radiator cap? is it good? yup

12. Over flow catch tank? Is it working...Do you have one? yup

13. Get some heat strips for the jug...that way you can see what is going on. never seen these before where do you get them what's the name, one on the rad one on the may be useful though without a comparison to some-one else's temps the one on the jug is a bit worthless.

I tore up a radator several years back, when I ordered an new one from Smackover (Jim Cook) he stated that the GasGas radiators were the same size that used on KTM 400 4 strokes, and that they were larger than most 2 stroke radiators, cooling issue should not be a problem with a GasGas. Somehow I can agree with that.

Hopefully don't need a new rad(s) !

[Rick]

Here you go.....check this out. One for the radiator and engine jug.

http://www.procircuit.com/store/pc/v...idcategory=547

[GMP]

You may be lean in an attempt to make the bike run 4-stroke clean off the bottom. Perhaps some additional jetting experimentation will help. RB head mod would be best. Try to dial it in a bit richer.

Like what was said, the LTR impellar is excellent, and you can get in-line alloy finned coolers for the coolant lines (shouldn't be neccessary though).

[stay_upright]

Originally Posted by GMP

You may be lean in an attempt to make the bike run 4-stroke clean off the bottom. Perhaps some additional jetting experimentation will help. RB head mod would be best. Try to dial it in a bit richer.

Yes I've got it so it pulls clean about everywhere - when you say additional jetting do you mean try to richen it without loosing the '4 stroke clean'?

To be honest it's about as rich as possible to still run clean though I can re-validate this...

Wouldn't a rad fan allow me to keep this jetting and stay cool....

[GMP]

How many other guys here need fans to keep their clean running bikes cool? Its just not right. If its that hard to jet clean enough then there is a problem. The head mod would be my first choice, providing all else is in order with the motor.

BTW, a 250F is a hell of a lot more boil prone than a 2-stroke GG in tough conditions with the same coolant. The GG is about the most boil resistamt bike out there.

[Berkyboy]

I would concur with GMP, as a whole GasGas motorcycles do not run hot unless there is a problem with the original OEM design.

The head mod and carb mod would give you the cleanest throttle response you can hope for. After that and if you still want to lower the operating temperature, or if you are on a budget, I would upgrade to the alloy impeller, and install inline radiator coolers.

The radiator coolers give the cooling system 5 to 15 degree (fahrenheit) of relief. The 5 degrees relief is under normal operating conditions while the 15 degrees of relief is under extreme (hot) conditions.

Next step would be the 1.4mb radiator cap from your local GasGas of KTM dealer. I'm not a big fan (no pun intended) of this as I believe the 1.2mb radiator cap tells me when something is wrong and the bike is running hot. I've been riding GasGas motorcycles of 10 years and I have rarely had a radiator cap overheat other than on a four stroke when it was greatly abused in the a mud race.

In my opinion the most important thing about these fixes is they basically use "dumb" technology meaning once they are installed they don't need any upkeep and basically can't be damaged like a fan kit can.

The only reason I would even consider a fan kit is if you are doing a lot of commuting on paved roads and you are prone to getting stuck in congested traffic even than I would start with the simpler technology fixes like the inline radiator coolers, alloy impeller and 1.4mb radiator cap.

Good Luck

[stevethebrit]

Originally Posted by stay_upright

Yes I've got it so it pulls clean about everywhere - when you say additional jetting do you mean try to richen it without loosing the '4 stroke clean'?

To be honest it's about as rich as possible to still run clean though I can re-validate this...

Wouldn't a rad fan allow me to keep this jetting and stay cool....

Just a thought, but doesn't the N1EF needle get lean in the midrange? If you have jetted so that it runs well from the bottom, the needle may be making it may be too lean in the mids. My 300 was running a bit hot before, and it was running slightly lean, so it doesn't take much "leaness" to make them go hot. Maybe try a different needle? On the other hand, as everyone says, once the jetting is good they shouldn't overheat att all. My 2p....

[Ud_luz]

I overheated my 300 yesterday a couple of times in 75 degree weather. Of course an xr400 locked up from overheating on the same trail...........

I'm going to either add a PC fan or look into the KTM fan. I've overheated a Montesa trials bike on the same trail before in hot weather and it had a fan.