when cutting your slip is there big change??

[redracing88]

i got an alba slip on if i cut it down to like 8inches will it make a change in anything or just looks! also i got a hot cams 2 and high comp piston bored .10 over so its like a 408.!! do you think a good rev box would do anything for me!

[ImWhite]

it will make it louder and a rev box would help ya,id like to know if shortening them do u have to re-jet?

[400exrider707]

Originally posted by redracing88
i got an alba slip on if i cut it down to like 8inches will it make a change in anything or just looks! also i got a hot cams 2 and high comp piston bored .10 over so its like a 408.!! do you think a good rev box would do anything for me!


Cutting it will do two things. Change the appearance (good or bad is your preference) and make it louder. I doubt you will see any performance gain from it.

Also what piston did you get that is high compression and only .010 overbore? I assume you dont mean a true .10 that would put you in the neiborhood of 430ccs and I dont think they make a piston in that overbore size. .010 over is only like 400ccs.

[underpowered]

cutting your pipe making it a "shorty" will do a few things. it will chang the looks, make i equite a bit louder depending on how much you cut it, AND offer some performance increase, usually a shorty will increase the bottom end while you may lose a little on top.

a 426 is .120 over stock, or 3 millimeters. .010 is barely an difference. for every .040 over is 1 millimeter. so .040 (+ 1 mil.) over would make it a 406. .010 is only .25 or 1 milimeter so your bike is like a 399.3526, give or take a few decimal points.

[h400exrydr]

here is a pic of mine

[redracing88]

thanks for the info. it should work with a alba slip on pipe if i cut it right?? also its damn loud i dont think it will get to much louder!

[MXracer16]

Originally posted by h400exrydr
here is a pic of mine

Hows that diamond plate airbox working for you?

[h400exrydr]

it is working really good actually... i made it in metals for a project for school. i think it looks killer. and it helped it out with air flow

[ReconRider25]

i cut my hmf in half. i did it because the inner core was shorter and the only way to fix it was to shorten it so i said what the heck why not its not like anymore trails can be shut down and its my property. from the factory the hmfs are around 102db but i think mines at like 110-115db now. really loud but still sounds awesome. i also noticed that it picked the front end up in 3rd from just shiftin hard alot easier then it did before(my quad is a lil heavier cuz xc setup and im a light rider so its never too great at liftin the front haha) im happy with the results. ill post a picture tomarrow.

[ill_lil_romey]

Cutting the can will help you out a good bit if you race mx. I did it to mine and noticed a big difference in the low end and mid range. Where before I would have to clutch hard out of corners I can lug through and feather the clutch a little and it will rip out of the corner. From 1st gear to 3rd and even early on into 4th I noticed the diff in the power. You will lose a little top but not that noticable. It;s also loud as hell, but still throaty

[ReconRider25]

heres a pic of my hmf cut down.

[123patrickquad]

how long is your hmf that looks nice, because i want to make mine a shorty. and am looking for a good length to cut it to.

[redracing88]

i took your advice and it worked really good. i cut it 7inches "in half" and i got alot of bottom end power. only got it ito 3rd in the driveway though:( but other wise its loud with i like!! so heres some pics! <img src="http://i32.photobucket.com/albums/d24/redracing88/improved400exwitshorty030.jpg" alt="Image hosted by Photobucket.com">

[BlackTrx440ex]

i got a yoshimura. i wanna cut it . but how will i put my end piece on after i cut it?

[QuadManThrice]

Originally posted by ReconRider25
heres a pic of my hmf cut down.


how did you get your end cap back on?

i have an HMF that i want to cut to about that size.
what all did you have to do to cut it? and how long is that?

[redracing88]

its seven inches cut down from a 14inch pipe! "in half" i took the packing out messued to get a clean cut. i dont know how the end caps are on hfm but i had to grind the stubbs down or the pop rivvits then i took the hole cap assembly out. then i cut it down inlcudig the insert to fit. then insetead of yousing pop rivited to put the cap back on i cut 4 slots on the end of the pipe. then i used like a hose clamp that had a bolt in it to make it really tight and it sucked the end right fast remounted it and it works great. the pipe now gives the bike like a 2 stroke feel. no power then all of a sudden a burst of uncontrollble power. its so sick!!!

[QuadManThrice]

what did you use to but it? and how do i take the packing out and then re-pack it?

[redracing88]

i just took out the core left the packing in there and cut the like housing of the pipe with a cutter then i took with a hand saw and cut the packing and left it. cut my core and reasebled it and what do you mean to but it?

[QuadManThrice]

my bad. typo. i meant how did you cut it.

my only concern is getting the end cap and stuff back on.

[redracing88]

what pipe is it? or do you have a close up pic? ill tell you then!

[QuadManThrice]

its an hmf pipe

this is about as close up as i have.

http://img74.imageshack.us/img74/9291/img0037medium3ug.jpg

[redracing88]

that one is even more simpler then mine all you do is right at the bottom of the hms sticker and to the left there is a hex key take all those out around the pipe then take the core out. then cut off what you dont want on the pipe, then cut the core to fit, then you have to drill however many holes in the pipe agian to put your hex keys back in! or cut for notches wher the hex keys where and get a hose clamp that has a bolt in it and crank it on and it will work perfectly! let me know how you make out! and im gonna redo my 400ex starting tomro im painting everything! well let me know how it works out!

[ReconRider25]

redracing i dont think anyone coul;d possibly understand what you just said and why the hell would you use a hose clamp? ANYWAYS, my hmf, the one on the yeller quad with the red frame, this is what i did. drill out the rivets that hold the endcap on and pull the endcap out. then chose how short you want to go and then make a mark. measure that mark and make marks every inch or so with the same measurement and then take some painters tape or something and connect them so its nice and smooth. i also took a sharpie and drew a line along the tape just to give me more to make sure i cut straight. i then took a hacksau and cut threw it, howeveri didnt cut the inner core at the same time. the reason i cut mine down was actually because the inner core was too short and it rattled back and forth so i had to decide how much a iwanted to go past, but i think i ended up cutting it the same length as the can. on the hmf's youll see that the inner core is pressed open so it slides over the lip on the back of the endcap, and instead of going to a muffler shop and having them use a wedge to enlarge it i simply cut about 1/2-1" slots, about 8 or 10 and then pulled them open a little so it would fit over the lip. i then took some of the packing from the half i cut off and stuffed it in there just so the packing was tighter and then put the endcap on. then drill the holes and rivet BUT make sure you do one at a time. if you drill all 3 holes and then rivet them youll probably end up with holes not lining up right. finally drill and rivet the hmf plate back on and put it back on the quad. it took me about 3 hours to do mine since i had never done it before. but im very happy with how it turned out.:macho

[123patrickquad]

when i cut mine i used a chop saw to make a nice clean straight cut. then sanded it a little a t the end. i have an HMF