Porting 400L
#1
Porting 400L
I have been wanting to get my quad ported for awhile now but need some answers before I finally do. 1. Those of you who have dynoed your quads what kind of horspower gain is involved. I would like the difference between trail ported and race ported if possible. 2. Do I need to get a bigger carb? for race or trail. Or can I just have my stock one ported? and finally 3. with a race port can I still run pump gas or does it require race fuel??
A thanks in advance and for all my past questions.
A thanks in advance and for all my past questions.
#2
Porting 400L
I have done alot of research on what your asking, and while I have no hands on experience he is what I have found.
the carb.
according to rcr haveing the card bored and polished is worth 1.5 hp and a new carb wrth 2hp. The new carb would be better but this is just going to come down to what you feel is worth it.
Porting of the jug should not affect what gas you use only a compression increase should do that.
hp dyno or but dyno gains are somthing I unfortunately don't know, im sure ced or someone will chime in soon with that info.
the carb.
according to rcr haveing the card bored and polished is worth 1.5 hp and a new carb wrth 2hp. The new carb would be better but this is just going to come down to what you feel is worth it.
Porting of the jug should not affect what gas you use only a compression increase should do that.
hp dyno or but dyno gains are somthing I unfortunately don't know, im sure ced or someone will chime in soon with that info.
#3
Porting 400L
Typically a trail port would be worth around 7-10hp. I am fairly sure that the 96 model jug is the earlier design and does not have the auxilary intake ports (also called sub-intakes). They are still good jugs and a trail port will really wake them up, but not the choice of having a race port done. I believe the 98 and newer jugs are the later design to look for.
As far as carburetion, I typically stray away from the roundslide carburetors. It is not very expensive to find a Mikuni 34-36mm or a Keihin 33-35mm flatslide carb. The flatslide has tremendous more throttle response and WILL make more power.
As for gas usage, compression dictates octane requirements. Having your head shaved .020 would benefit greatly but not require anything other than premium fuel. With a race port is is best to have a high compression to compensate for the radical port timing change on the exhaust and to further increase power.
As far as carburetion, I typically stray away from the roundslide carburetors. It is not very expensive to find a Mikuni 34-36mm or a Keihin 33-35mm flatslide carb. The flatslide has tremendous more throttle response and WILL make more power.
As for gas usage, compression dictates octane requirements. Having your head shaved .020 would benefit greatly but not require anything other than premium fuel. With a race port is is best to have a high compression to compensate for the radical port timing change on the exhaust and to further increase power.
#4
Porting 400L
I was thinking of a trail port but then figured I would probably just get it race ported eventually so would save the money. But I go to the little sahara and ride the dunes often, how does a trail port ride on the dunes. Is the increase hp just spread throughout the rpm? or just towards the low end? And another question. Does the primary clutch spring control how high of rpm's the motor rev's? I have the red/yellow right now but it doesnt seem to get very high rpm, just curious what everyone else is using and how they like what they have.
#5
Porting 400L
There is a fairly big difference between the trail porting and the race porting.I have a pic in my gallery that shows the difference between a race port on pump gas and a race port on alky.You will definitely like the race port over the trail porting.Bubba is the man for the port work.The 95 cylinders had no boost ports,the 96 cylinders on had the bosst ports.My buddy found out the hard way about the cylinders.I really like the 39PWK carb for the race porting,on pump fuel or race fuel.
#6
Porting 400L
CED, thanks for clearing that up on the extra ports. Seems to me it was my Polaris dealer that told me that info, but never looked for myself.
oghma, keep in mind that with race porting you will need a race pipe and clutching changes to benefit at all. That would be minimum. If you race ported your cylinder and tried running the pipe you have now then you wouldnt be happy with the results.
oghma, keep in mind that with race porting you will need a race pipe and clutching changes to benefit at all. That would be minimum. If you race ported your cylinder and tried running the pipe you have now then you wouldnt be happy with the results.
#7
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#8
#10
Porting 400L
I think mine has really good bottom end. And I run pump gas which shouldn't have as good of bottom end as one with higher compression.
If you dune alot then you would really love it believe me. This bike of mine really blew me away going from a Trail Mod to a Race Mod. You wouldn't be dissapointed. I didn't know how well it would perform with pump gas but I am way pleased.
If you dune alot then you would really love it believe me. This bike of mine really blew me away going from a Trail Mod to a Race Mod. You wouldn't be dissapointed. I didn't know how well it would perform with pump gas but I am way pleased.