Cutting cooling fins?? Can it be done??

[Roostboy101]

Putting a blaster motor in a KTM chassis and need to shave about an inch off of the jug just on one side to get the factory tank to fit. Will this be a problem with building up too much heat or can it be done no big deal? Thanks in advance.

Here's my build thread: http://www.blasterforum.com/engine-mods-swaps-129/ktm-chassis-blaster-engine-build-22992/

 

[sr5bidder]

the engine is air cooled so if you cut the fins to get the tank to fit it sound as if the area around the cylinder would not have much air flow, I am thinking of doing a simalar swap into an rm 125 frame and have run into a problem with the exhuast side of the cylinder, the cylinder is so fat that the exhaust won't tuck in under the tank as it is supposed to ..have you checked into the exhaust side yet??

Al bakers xr's only does fin extensions on the old honda rfvc cylinders so if there is a way to add extensions to the fins where there is clearance and take away where there is not clearance it would be best also having scoops would be good... I wanted my rm125/blaster200 engine to be for tight techinical stuff so a fan would be in order as well

In my brake in runs with the engine in the blaster I'm getting up to 265*f, I want to shoot for temps below 280*f ideally 255*f but I don't know if that is possible

 

[2strokesmoke]

i would say it could be done, but the whole point of cooling fins is obviously to cool... and then if you slam a fuel tank on top realy close you will be further restricting the flow of air through the fins... i suppose its something you would never realy know until you try it by then its probably too late lol.

just a thought check this out Yamaha Blaster High Performance Liquid Cooling Kit ive never seen them im new to blasters, but they are either complete rubbish or a very neat setup, if its top end clearance you want and extra cooling.......B)

 

[specialized7]

build some kind of scoop that directs air to that side haha

 

[Roostboy101]

Yea I know it would obviously cut down on the cooling. Just thought I'd throw it out there and see if anyone had ever done it. I guess I'll just have to try like a ttr tank on it. I'm kinda tryin to plan out my scheme a lil. I was thinkin bout stayin totally with the ktm look or else all (or as much as i could get) blue. The ttr tank would suit I just hate to spend money on somethin that I'm not sure will work. For the time being I'm not going to cut anything. I'm just gonna slap my xr tank on for the test rides and then when I'm sure everything else works the way I want it to then I'll figure out a tank/seat combo!

 

[blaster_pro]

i wouldnt do it ur engine chances of over heating will increase,. and one of u up there havin problems with the pipe in another frame dg makes a pipe called dg extreme tht just goes to the side like a trx250r.

 

[super noober]

i wouldnt do it ur engine chances of over heating will increase,. and one of u up there havin problems with the pipe in another frame dg makes a pipe called dg extreme tht just goes to the side like a trx250r.

ewwwww "extreme" or not its still a "dont get" (DG) if you want a right bend get a power pros or lrd.

 

[super noober]

the engine is air cooled so if you cut the fins to get the tank to fit it sound as if the area around the cylinder would not have much air flow, I am thinking of doing a simalar swap into an rm 125 frame and have run into a problem with the exhuast side of the cylinder, the cylinder is so fat that the exhaust won't tuck in under the tank as it is supposed to ..have you checked into the exhaust side yet??

Al bakers xr's only does fin extensions on the old honda rfvc cylinders so if there is a way to add extensions to the fins where there is clearance and take away where there is not clearance it would be best also having scoops would be good... I wanted my rm125/blaster200 engine to be for tight techinical stuff so a fan would be in order as well

In my brake in runs with the engine in the blaster I'm getting up to 265*f, I want to shoot for temps below 280*f ideally 255*f but I don't know if that is possible

i shoot my cylinder/head with a infrared all the time when i get done riding, in the mid 260-280 range is the norm. the hottest ive gotten it while riding through deep snow was 318

 

[sr5bidder]

i wouldnt do it ur engine chances of over heating will increase,. and one of u up there havin problems with the pipe in another frame dg makes a pipe called dg extreme tht just goes to the side like a trx250r.

thanks!! I will look into that

 

[sr5bidder]

Yea I know it would obviously cut down on the cooling. Just thought I'd throw it out there and see if anyone had ever done it. I guess I'll just have to try like a ttr tank on it. I'm kinda tryin to plan out my scheme a lil. I was thinkin bout stayin totally with the ktm look or else all (or as much as i could get) blue. The ttr tank would suit I just hate to spend money on somethin that I'm not sure will work. For the time being I'm not going to cut anything. I'm just gonna slap my xr tank on for the test rides and then when I'm sure everything else works the way I want it to then I'll figure out a tank/seat combo!

thats a very good plan.....se if its what you thought it would be as far as how she runs then make her look good...I have a test tank I zip tie on made from an aluminum bud light bottle..it saves alot of time I am going to get one of those aluminium water bottles that have the lanyerd ring on the cap someday
and make it better

 

[xjma]

A friend of mine got some sort of 150cc 4stroke motor to fit into an XR100 frame....it's a SICK pit bike!! He ended up modifying the frame for the motor to fit. He is a machinist though, so it was no big deal for him. Just throwing it out there that you may want to think about doing it that way.


Not sure what would happen with uneven cooling characteristics on the head. Could be fine, or could cause premature wear.

 

[Roostboy101]

A friend of mine got some sort of 150cc 4stroke motor to fit into an XR100 frame....it's a SICK pit bike!! He ended up modifying the frame for the motor to fit. He is a machinist though, so it was no big deal for him. Just throwing it out there that you may want to think about doing it that way.


Not sure what would happen with uneven cooling characteristics on the head. Could be fine, or could cause premature wear.

The frame and motor work well together - it's the gas tank that doesnt. The factory tank on an exc comes down around and like hugs the jug. On the original liquid cooled engine, the jug is like the size of my fist but not the case on the blaster engine. Thanks for all of the input though from everyone I:I

 

[Blasterdude27]

What about bending the fins? Out right cutting them off is a bad idea, but you might be able to bend them around somewhat.

 

[UniRacing]

Just do what you got to do,and then make something that will scoop alot of air through that side,you will be ok

 

[2strokesmoke]

you will be lucky bending them fins bro SNAP!!! can you not use the same tank but where it 'saddles' over the main frame spar space it upward a bit to clear the fins on the head like lift the tank up a bit if you catch my drift, if that works just mod the seat mount upward a bit at the front to match the tank. just a thought.

 

[blasters/banshees]

would a diffrent ktm with the same frame maybe have alittle smaller tank like and mx bike or something so that you can put that on fine and the fins u can keep

 

[Kennedy_Power]

I did read all the posts, but do not cut off the cooling fins. It will over heat.
The rubber cushions are for supporting the fins from fatiguing over time….

 

[Paulie B]

I say cut them if it's only an inch off.
The motor will be getting alot more air in the dirtbike frame then in the quad frame.
To add what KP said about the cushions they also cut down on the noise the motor makes by dampening the resonances.
You could also run it on alcohol- wont ever overheat like that lol
You could also pick up a head off the Yamaha IT200 dirtbike.
It looks to have less fins then the Blasters but I would just cut the ones you have.

 

[Roostboy101]

I want as much gas as possible so that I can use the bike in enduros (sometimes up to 50 miles at a shot.) Also I'm thinking against cutting them for the idea that my average speed in tight woods sections is about 20 mph - on the gas weavin in trees 20 mph doesnt seem like enough to cool the motor with cut down fins. Like i said earlier - I'm just going to do my test ride without cuttin them and see where we end up! I made a little headway today on it. All we need now is chain, wiring, and pipe and I should be able to see how it works out