I know this is a Bomb forum but I couldn't handle looking anymore in the Yamaha side for answers. Now that my Bomb 730 is soooooooo close to being done, My Raptor riding buddy is getting a bit worried. Like, maybe a magazine bolt on head pipe might not do it for him. What kind of Raptor Big Bores have you guys seen in the dunes that look O.K.? I'm here in WI and don't see much for racing besides MX. The only thing I've heard of so far is a 686. Thats not worth pulling a motor apart for that. If I'm pulling out the boring bar, lets remove some meat, right? He is too die hard Yamaha to buy a DS (he will never admit he is but I'm sure his underware say Yamaha. You know how they are). So that is out of the question. Plus It gives us some friendly competition. Thanks for any input.

 

Both Trinity and Kenz make a 727 kit for the Raptor... I've seen the Trinity advertised a lot in Dirt Wheels issues... they say its a bolt on like the HPR for the DS.

Now that I got the intellegent stuff out of the way, why don't you just lie to him, tell him they don't make one, and keep beating the dog **** out of him until he buys a DS. Then tell him about the Trinity and Kenz.[img]i/expressions/face-icon-small-happy.gif[/img]

 

http://www.faliconcranks.com/yamyfz45.htm

Correct atv link

Lots of big bore and stroker combined kits for less than '730 big bore' kit for DS.
This is who HPR get their strokers from and are only distributor for DS, but anyone can buy Yamaha or any other type bike from them direct.

This is for YZF450 and not Raptor, but bet would give you more than you can handle. This is the max package all at once.

 

have your buddy send it to Kenz or craycraft for porting, piston, & cam if he wants some power.
its not the extra few cc's that give the HP gain its the combination.

stay away from Trinity in my opinion.

 

You are talking about the 660 Raptor not the 700, right????

 

wrong thread, sorry

 

Thanks for the replys men. Yeah, its the 660. Actually, it has more power than the chassis can handle. It's hard for me to drive. It's a small kid toy. We're both over 6'3". Hence why I opted for the fatty DS.

I'll have him get a mag to look into one of the kits mentioned. A 727 sounds like what he needs. Do they seem reliable in real life? I don't look in mags much because I can't stand what they have to say. I'm afraid they are going to ruin Bomb. For example, they said the DS was too long. Then they shortened it. Then the mags said it wasn't stable. WTF do you want? Now I need to buy a longer swing arm to make mine more stable( '04 X).

Anyway, FatHolly, I need him to find a kit or he is going to have me make him something like I did to his Banshee. It has taken over a year to build a simple bigbore for me. I don't need another project. especially one with a lifetime warranty.[img]i/expressions/face-icon-small-smile.gif[/img]

 

I wouldn't go 727. . .

If it were me. . . I'ld go 686 or I think it is 730? (the 102mm bore with the stroker). Seems that set-up works the best. Besides, if you should change the connecting rod anyways, why not stroke it! Put the FCR's on and you'll also need a new pipe to allow the FCR's to clear the mid-pipe. That should be a runner. It won't be cheap though. You'll want head work too and need new valve springs and a more aggressive cam.

I really haven't researched it much lately so, my info could be a little old but. . . I'ld stay away from the 727.

 

powroll has a piston cam set a friend of mine ran it did really well.

 

I agree with this philosophy with a slight modification. You guys sound like you have some skills and are hands on. Find someone who knows how to open up the porting like was suggested here, do the bigger valves and put a cam in it. I have it on good authority that on a modified motor, the 686 bore is the best runner. After that add stroke. More bore will only beef up your power up to 5k rpm but will start to get in its own way with the bigger heavier piston in the upper rpms. The raptor motor really responds to a full exhaust system, no slip ons and open that porting, valves and lift and duration and you will have to mod your motor a lot more to keep up with him.

My $0.02 [img]i/expressions/face-icon-small-smile.gif[/img]