After a little help from this forum my 400 is back on its feet and she goes pretty fast,we sponsor a top fuel hydro capsule boat team,subsequently pretty fast just won't do I'm new to 2-stroke and land at least as far as speed is concerned. So how about you guys tell me how to go faster than I am now.Also this bike is my sons, I need suggestions on what to get for myself which by the way must then be made to go faster than sons.Speed is addictive.

 

The HPD race mod with powervalve is around 90 hp. There is not much that will even come close top this.

 

My engine builder tells me I'm making that much H.P. or more now,he owns the machine shop we use for our boat parts so there is some porting,milling,etc.I didn't list before.My bike may be maxed out engine wise I looked at HPD's kits-they were comprable to what I'm running now other than their head was 14.5 mine is only 14 for economic reasons I'm really stuck with adding to what I allready have,after looking at HPD's kits and what they cost compared to what was spent on building the engine we have now I wish I would have asked this question 2 months ago,how much does lightening flywheel help?

 

Well, you want some facts so here they go. The G-force pipe ended up being a flop. They copied it from CPI's design and it made 5hp less on the dyno. It looks good, but that's about it. HPD's trail pipe will almost make as much power. Also dont listen to your engine builder. You wont have near than much HP. My race modded sport on alky was fast, but I still dont know if it would hang with the powervalved motors. There is a huge difference between running 55-60HP and over 80HP. Your best bet if this is your son's bike is to let him ride it and get you a full race HPD mod or their powervalved setup. You will be a believer then I promise. Lightenening the flywheel, removing the battery and starter, and all other things do nothing but benefit these bike considering how heavy they are. Bubba

 

OK,Some straight answers thanks,it sounds to me like hpd is the way to go,I haven't figured out what "mutant" clutches are yet their website doesn't list them,but I've had several people say they were good,I know the company that made the pipe appears to be out of business so it probably has some kind of problem.I'm going to take it to the shop dyno this weekend we'll find out how much HP she makes,then I'll change the pipe,and dyno again,that should tell the tale.Anything else anyone sees that is bad or could be better I sure would like to hear about it.Before buying next bike for self I want to get enough info to put something together with a fair understanding of what is what,I'll use my sons bike to gain that knowledge and hopefully it will also improve his bike.

 

This has come up before in the forum, but if I were looking for ultimate speed I would put a sled motor in. Take your pick of the 500, 600, 700 or 800. The powervalved 500 stock will give you more than 90hp (there's one for sale here: Amsnow) - the 800 would just be FUNNNNNNNNN[img]i/expressions/face-icon-small-happy.gif[/img] If'n ya wanna be a little different, stuff the 800 triple in there!

 

I checked out some snowmobile motors they are pretty strong,One way or another I'm going to make what I have go fast,It's fast now I just feel one should allways try to go faster,the sled motor is an option in the future,our race team seems to be taking an interest in atv's since I dropped mine off to be dyno tested,some interesting things might develop if they get started,they have a 52mph lawnmower now,I got a little off subject,keep throwing suggestions at me they are helping,THANKS.

 

Well here are some a few interesting developments,I'm out of town on business.our shop couldn't use our dyno the attempted mods were lacking and new kit just for my bike isn't economical so the bike travelled some and here are the results first run 86 HP second 87 HP 3 days later rainy and cold outside first and only run 86 HP so I guess the pipe might not be so bad we are going to put an HPD pipe on soon if I find another suitable 400 to build we'll bolt its pipe to this bike and maybe,hopefully we'll learn something.the reason for no additional run on second session is the boys took it out for a run in the rain and cratered the driven clutch,the drive clutch is HPD as listed and HPD is what we will use for the driven I need suggestions on which one

 

[img]i/expressions/face-icon-small-blush.gif[/img][img]i/expressions/face-icon-small-confused.gif[/img]Well guys I must come with an apology the numbers above are not accurate the guys ran several different bikes to the dyno and I gave up the wrong numbers for the old 400 it actually produced 68 HP in two tests both=68 HP therefore I must say I'm sorry for my indescretion,having said that I do still need some help, does anybody have information on the hpd driven secondary slip clutch??