Thanks... yeah the whole exhaust was a pitbike to start with, I took the headpipe and cut and welded it to the desired shape, made a flange and welded the pipe to that and then wrapped it twice with heat wrap... It sounds good, revs nice but just doesn't have much power....Maybe it's ready for a ring and valve job ??? I dunno....
I know a weak spot on the ex27's are the valve springs. It could be the same for the 17's. They also dont make much power at all after 4500RPM if I remember right. Rex from Roberston's torque tubes sent me a dyno chart of when they ran his with the pipe before and after. The ex17 really isnt 6.5Hp though. At least that's not what Subaru rates them at.
Subaru Robin - Features and Benefits
Something I've never tried but am interested if it will work is putting, say an ex21 cam in the ex17 or the opposite. I dont know which is more aggresive or whether or not it will even fit. Just something I've always wondered with these. I was impressed with the power compared to my friend's clone. Im much heavier than her and have a much heavier kart and pull away from her in the dirt. This is with my ex21. Just figured I'd bring up the valve springs to you though. I know that's something that Doug Fleming said wears out kind of quick on the trophy kart engines at least.
Subaru Robin - Features and Benefits
Something I've never tried but am interested if it will work is putting, say an ex21 cam in the ex17 or the opposite. I dont know which is more aggresive or whether or not it will even fit. Just something I've always wondered with these. I was impressed with the power compared to my friend's clone. Im much heavier than her and have a much heavier kart and pull away from her in the dirt. This is with my ex21. Just figured I'd bring up the valve springs to you though. I know that's something that Doug Fleming said wears out kind of quick on the trophy kart engines at least.
My son just picked up a 9hp Robin last night.... You say the ex17 head will fit it?? are the valves smaller in the ex17 head?, do you know if the ex17 flywheel will interchange? the 9hp flywheel is huge so I was curious if the
ex17 would fit for less rotating weight..
What valve springs did you use?? clone, briggs?
ex17 would fit for less rotating weight..
What valve springs did you use?? clone, briggs?
If you get a gx200, or Clone and do just a little work to it you will never ride that Subaru again. Buy a Clone for $100, and then put about $400 in aftermarket parts in it. Then you should have 12-13hp and you will never want to go back.
Pulling real good with 12/60 gearing is normal. Your only gonna do maybe 30mph. Try 15/60 gearing with a modified motor.:wink:
Pulling real good with 12/60 gearing is normal. Your only gonna do maybe 30mph. Try 15/60 gearing with a modified motor.:wink:
My friend has a clone, and I have the ex21 Subie and its the total opposite for me. Her kart with her in it has about a 75lb advantage over my kart with me in it. We both rev to 4500RPM and I pull her in the DIRT. When I drive hers it just feels like it has no torque. When I did Air filter/exhaust I pulled on everybody in the dirt. I'm also the only one in the morning that doesnt need to play with the choke.Most of the time I dont even need to turn it on and it'll start 2nd pull. I've driven karts with tecs,clones,briggs, and genuine honda's and as long as I want a reliable engine that has the power to match I'll stick with the Subies. The torque just kicks a**. No, disrespect to you, Im just saying my opinion after I've driven karts with other engines.
Well give it some more time. They all make close to the same HP and TQ stock. So the feeling your having may be from the slight mods you made.
You just can't mod the Subaru enough. So give it some time and you will see.
If you where to buy a stock class clone, they make about 9hp and a couple extra pound of HP over box stock. They only cost about $325 out the door.
Check this out this link of the stock class motor. And it took very little mods to get there.
http://4.bp.blogspot.com/_H4c3UGBpZ...BU/jd3V2Z6XlsM/s1600-h/smallmuffledheader.JPG
You just can't mod the Subaru enough. So give it some time and you will see.
If you where to buy a stock class clone, they make about 9hp and a couple extra pound of HP over box stock. They only cost about $325 out the door.
Check this out this link of the stock class motor. And it took very little mods to get there.
http://4.bp.blogspot.com/_H4c3UGBpZ...BU/jd3V2Z6XlsM/s1600-h/smallmuffledheader.JPG
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Yup that's very good for those mods, it's been proven they make good power and usually respond well to mods. This is Roberton's torque tube's dyno chart of just their header, no air filter mods. It's the same one I got and those numbers match the seat of the pants feel. And all dynos are different so it's not the most accurate way compare unless they're both on the same dyno and same conditions.
This was an EX21 dyno chart. Stock TQ was rated at 10.25 lb ft. So you can see that they have a lot of grunt even in stock form.
This was an EX21 dyno chart. Stock TQ was rated at 10.25 lb ft. So you can see that they have a lot of grunt even in stock form.
Yup I give you that. There are cams out there, and everything from the kx21 is directly interchangeable with the ex. Theres a lot more stuff out there for the Ex27 though since the trophy kart guys are getting around 14hp with just bolt ons.
We would have thrown more timing into mine if my objective wasnt to keep it as reliable as stock. Modding past stock can be done on these just as easily as a clone or honda. It's just that there's no demand for them. Mod for mod they'd probly be even.
We would have thrown more timing into mine if my objective wasnt to keep it as reliable as stock. Modding past stock can be done on these just as easily as a clone or honda. It's just that there's no demand for them. Mod for mod they'd probly be even.