porting..?

[vroom]

hey guys, im most like going to be getting the 416 kit by malcom's. For an extra 75 bucks he can port my cyilinder. Now... They asked me for my mods to see how detailed or whatever he can go into porting, i have a t-4 slip on, and K&N power kit. I got a few questions..


1. Is it good or bad (reliability wise) to port?

2. Anyone have any experience with malcom's port jobs?

3. Will it give any power gains with the stock carb?


any 411 will be appreciated, thanks guys.

[03400EX_Nacs]

well i dunno about any of the rest but i think porting your heads is a must .i heard that that is one of the main things you should do that will really help the reliablity... i would still cheack though thats what a local shop told me and the dude is real honest

[hondafox440]

Porting doesn't have much of an effect on reliablility one way or the other. It will definitely add some power gains, a solid 1-3HP if he knows what he is doing. Porting can also tailor the power curve yo your riding style, adding more low end, more midrange, or even more top end.

[vroom]

thanks guys... will the stock carb make it not noticable?

[Ryan]

Originally posted by vroom
thanks guys... will the stock carb make it not noticable?


Your still gonna notice a difference. But when you have extra cash lying around, you may want to get a bigger carb to really notice the power difference.

Are you going with a higher compression piston?

[vroom]

Originally posted by Ryan
Your still gonna notice a difference. But when you have extra cash lying around, you may want to get a bigger carb to really notice the power difference.

Are you going with a higher compression piston?

well I posted something about malcoms kit before but never got a straight answer. Im new to four strokes and don't know much about ratio's and compression. Im getting the 416 kit from malcoms with a slight port job for my mods (t-4 slip on and K&N power kit) What compression would I be running with the 416 kit and a little port job? what would be the best to run? and do i hafta run race gas or can i just use good ol' premium?

[Ryan]

Originally posted by vroom
well I posted something about malcoms kit before but never got a straight answer. Im new to four strokes and don't know much about ratio's and compression. Im getting the 416 kit from malcoms with a slight port job for my mods (t-4 slip on and K&N power kit) What compression would I be running with the 416 kit and a little port job? what would be the best to run? and do i hafta run race gas or can i just use good ol' premium?

If you get a high compression piston, I would not recommend going over 10.8:1 . You can run pump (93) gas with this ratio.

[vroom]

http://www.motorcycle-atv-pwc.com/400EXPAGE/400MAIN_1.htm

i donno if thats a high comp piston..is it?

[Guy400]

This isn't a comment on Marcum's porting or anyone elses porting for that matter but, do any of these people flowbench these heads after they port them? Simply going into an intake runner and hogging the thing out with a die grinder isn't a professional port job. Sure, you'll increase flow at max valve lift but you can seriously impact intake charge velocity, fuel atomization, etc. I see a lot of shops offer head porting services but do any of them include a flow sheet of your particular head when they send it back? Porting (I use this term loosely) may gain 1-2hp at peak RPM but what is its effect on the rest of the RPM range? What does the torque curve now look like?

[UglyMotha™]

guys got a good opinion, also uh a 75 dollar port job, i mean is that even worth the time or better yet is that all his porting is worth...........thats not really saying much if it is cause for a decent port job your looking at bout 250 bucks, if i was to take my head to somebody and he was like "sure i'll hog that baby out for 75 bucks" ...........i'd be like no thanks, i think i'll take it elsewhere

ya see my point

[vroom]

yeah 75 seemed rather low for a port job. does anyone have any experience at al lwith malcum's??? porting / boring / next door negihbors? anything???

[Glamis400ex]

I would expect that for $75 bux, it will most likely be only cleaning up the casting marks. My head cost $275 to port and it wasn't even a full blown race port, just a play port. My guy who did my head did not have a flow bench, but I do know for a fact he's been doing them for over 30 years, comes highly recommended and does all the Baja racers bikes/quads here in town. I felt pretty safe with his ability. It definately moves now.


Glamis

[y2k400ex]

I'm in Jacksonville, FL I decided not to have Marcum do my work, I have a shop here in town do the work. Its called Tachyon Racing Heads 904 364 0390. They did the boring $40, valve job $60 and porting $75. They have a full machine shop and Superflow flowbench. I'm very happy with their work. With my cam and porting i can out run my friends 416 liek i was stock:D

[cals400ex]

i would make sure you know exacly what your getting before you put the money down. for example: what brand piston and compression ratio, what does the $75 port consist of, etc. if it was me, i would just order the piston, cam(if your buying one), and gaskets from C&D. they will be able to answer your questions on pistons and compression ratios. i personally wouldn't get a port job for $75. also, i wouldn't even messing with porting it until i have a cam in. i am running around 11:1 compression with a cam, full pipe, jetting, etc and i still have the stock head with no port work. the bike runs great too. i would get heavier springs, at least, if i was going to mess with the head. then you can take your cylinder to your local machine or atv shop to get it bored. this is assuming your doing the work yourself, which i recommend to anyone if they can handle the use of normal tools. just get a service manual and your pretty well set. an extra person to help is not a bad idea either.