Cutting radiator to fit ram air

[neil_cb125t]

well me ram air bix is coming - need to cut into my radiator to get the scoop in.

Any tips to doing it? can i just hack into it - or do i need to seal it up??

cheers

[tk400]

Are you in Australia?...I have one already done in good condition. cheers


REgards TK400

[neil_cb125t]

heyhey,

I in Nz, i have managed to mmove my rad DOWn to allow the scoop to go above it.

cheers though- you running ram air?? with flats ?? just having to re tunr mine now.

[zxr4000]

You have some pic's of how you did it?

Thanks

Roy

[cargo]

Be careful if you move the rad down to allow an air scoop to fit over it................

If you lower the rad too much you won't have a head of water/coolant to fill the engine and there will be air in there instead of water/coolant

[mark400]

Firstly, I am assuming we are talking about an L model, I have no experience with the H , although I have bought an H rad to try out ! Never got round to fitting it, but it's half the size of the L rad, incidentally.

Consider CARGO's comments, plus you have to mod the oil pipes to locate the oil cooler lower too( there isnt any room for overlap or oil cooler and rad at that point as the front wheel is too close ) otherwise the rubber is under too much stress and can burst ( had this happen on the dyno). You have to heat the pipes in order to bend them, but can you guarantee that they will never fracture?

Much better to mod the rad in my opinion.

All you do is mark out the area which needs removing, and use tin snips or a grinder to cut away the fins. now heat the end of each fin to make it supple, and using long ish round nosed pliers, roll over the end of each fin onto itself. Once you have done this to all the fins, and used the pliers to close the ends, pack the gaps with araldite or leak fix( the one with separate hardener) and Bob's your uncle.

[neil_cb125t]

You have some pic's of how you did it?

Thanks

Roy

I have done it very easily - using my H1 rad. i did have to remove my fan thou - the H rad has 2 "stubs" on each side with 2 rubber gromets on them. simply move the rad so the top stub and gromet is in the lower hole on the rad bracket. This moves th rad done about 2-3 inches. I have bout new straight hose and a 90 copper bend to re route the cooling pipe.

The bike runs and rides fine - you have a water pump to circulate the water so the head will always have water - just need to be careful on the overflow function. H models have the cap and input into the head SEPERATE to the rad whcih is ver diff to the L model.

The oil cooler bots directly onto the bottom of the radiator using the old rad fan holes... perfect.. no wheel clearance problems, no over heating, the bike can idle for 10 mins before the temp gauge gets to where the fan would have kicked in.

Not bad for a 444cc bike....... i had 80hp at the rear before i put an air box on it..... how much power do you guys get when u put em on your 400s?? i have 33mm FCR carbs.

[mark400]

Hi Neil, Have you raced on a hot day?

I am quite interested, as the L radiator still needs masking off to keep up the temperature, even on hot days, and mine are chopped to make room for the Ram air scoop. I have an H rad, but not yet fitted it, as I thought it might be a bit small to race with. I suppose that the surface area of the chopped down L rad is almost the same as the standard H rad,I think the chopped L is slightly bigger though, if only by an inch or so.

I am modding an L rad at this moment, but perhaps I'll install the H instead........

[neil_cb125t]

Hi Neil, Have you raced on a hot day?

I am quite interested, as the L radiator still needs masking off to keep up the temperature, even on hot days, and mine are chopped to make room for the Ram air scoop. I have an H rad, but not yet fitted it, as I thought it might be a bit small to race with. I suppose that the surface area of the chopped down L rad is almost the same as the standard H rad,I think the chopped L is slightly bigger though, if only by an inch or so.

I am modding an L rad at this moment, but perhaps I'll install the H instead........

I have not raced on a hot day yet no, currently riding in Nz's winter series. It really depends on your bike, I have been running my Little rad since ive had the bike - its never run hot while racing - it only ever heated up waiting in the pits and coming back in after a race it used to get to 1/3, but its always had the rad fan. I have raced in 30+ degrees heat before and i never have overheating probs but i have always had a fan. If you have a fan you'll be fine.

On my tuning runs, it stays under the cold line any time im moving. I also am still running my oil cooiler.
I can takes some pics and email you if you like.... BUT ( and this is a big one ) if its not broke ...... having to tap up the rad is interesting thou..... only thought 2 smokers did that type of 'tuning'

can i ask how you tunned your air box up? i had mine dynoed with the flat air tray, but the ram air had added alot more O2 to the mix.

[mark400]

Hi Neil,

I have the BB plastics airbox in one bike, and an older slightly smaller BDK box, and my brother has the AMS motorsport box. The AMS is the easiest to install, as it sits below the card rubbers and its easy to tighten the inlet clips.
For all ram air boxes, if you use the standard carbs - the main air jet needs to be blocked off (the one at the bottom of the carb mouth) and about 108 main jets installed. This will also depend on which exhaust system you have - Dyno is the way to jet it correctly. I don't know anout using the flatslides, they are prohibited in a couple of race series here.

If you get the chance, say hello to my best mate in NZ, he runs Queenstreet motorcycles and was one of the fastest riders in the German national Supersport championships during 2003 / 2004 before he emigrated to NZ. Actually, he is trying to race this season in NZ so you might help him a bit or vice versa

[neil_cb125t]

Cheers for the intel - once i have raced it il let you know how it gets on.

It seems you guys have ALOT of rules you have to stick to..... which does keep the cost down - the current F3 champ over her has spend nearly as much on a set of carbon firbe Dymags as i have on my bike!!

Queenstreet cycles aye - do you know if that in the north Island ( sounds like it ) hopefully will see him when i do our national series in about 12months.
neil

[mark400]

I know it's in Auckland....