2007 Raptor 350 build

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YamahaNutz

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I'm bored with the bad weather, and thought I'd share on this forum. I've gotten a ton of info searching here.

2007 Raptor 350. Original engine condition unknown. I immediatly swapped a rebuilt 87/93 warrior assembly. Destroyed the cam and head, swapped a rebuilt '87 head on with diy port work and a Ninche cam(cheap). Now I'm looking to upgrade the cam and put down reliable numbers.

Engine:
'87 base with '93 internals
Wiseco 11.1 piston
Niche 1557-3 camshaft
FCR MX 37mm carb from '07 YZ250F
Custom machined Wolverine intake adapter
HMF for '04 YZF450 lengthened to fit
Heat wrapped exhaust
K&N filter
Drilled air box lid
 Big Bear 350 oil cooler mod w/ cooling fan
Big Bear 350 vented camshaft cover
Extra steel in clutch with stiffer springs
Moose case saver

Frame:
Aftermarket replacement harness assembly
YFZ450 throttle and clutch(on stock handle bar)
 Air scoops cut from YFZ450 scoops
Unknown brand +6 swingarm
Unknown modified 1/4" aluminum swing skid
YFZ450 Tusk nerf bars
Early YFZ450 front shocks
YFZ dual piston front calipers
American Star LTZ400 +2-+1 front arms
Diy chromoly +2.5 steering stem

Had a '87 Warrior before buying this quad. I felt the Raptor 350 improvements immediatly even though it's mostly the same.

I actually have just completed the front arm swap and steering stem. Have not ran it since.

Plan is to run it, dyno it with the niche cam, then do another head build with a better cam. My research has told me I over did the porting on this head. So I'm going to do a more simple port focusing on flow turbulence instead of going for bigger.

Also doing some diy cut wide foot pegs that will bolt on to the factory ones with the nerf bars. I keep loosing foot hold and bouncing off the stock ones. And looking to replace the slightly bent rear axle shaft.

Only have pics of it dirty currently. FCR carb has been tweaked with a different needle and a R&D bowl kit. Just swapped on some 23x7 front tires over the 22x7 standards.

It runs great. Last October it went to the Silver Lake dunes. No complaints except carb was not dialed in. And it falls off in power in high rpm.


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Looks like you're off to the great start. I think we can easily get you in the 40's hp wise with more head and carb work.

For the head you really want to pay attention to the flow around the valve guide and valves. That's where you can gain or lose a lot.

Cam depends on what you're looking for. Good woods setup the new xc web cam. Mid to top, web .430. Top end megacycle 252x1. If you end up doing more compression and larger piston it will be 100% 252x1.

For the carb I would really recommend going to the 39mm. The 37 is great for stock head motors but you're leaving a lot on the table on the top end after porting.
 
To be honest, I'm a cheap-a$$. For longevity, wear wise, I was looking to do a hot cams stage 2, which I have found is close to a web .390, with a more stock ramp angle. I want to swap a stock cam sprocket pin when I install it to avoid the broken pin issue they have. Only reason my cheap niche cam failed is the roller pin rear bearing smoked out(chesp bearing), and it over-revved alot. I'm building the newer head with a rear ball bearing. I'm not seeking max power. Just want reliable, consistent, power. This would also allow me to keep the 37mm fcr and tune within its limits. I sunk alot of effort and money into this carb already.

I did the new D.I.D. chain, factory chain guides, and kibble white valves/springs already. The current head was done at a reputable race engine machine shop. But, was way out of range for valve seat surface(head was warped). I also did the newbie mistake of taking too much material out of the ports, including some from the floor. I have silicone molds of factory ports to measure from now. So yes, I'm going to focus on the shroud, and only blend the ports. My research has led me to believe the ports are almost too big from the factory unless you have a big bore/stroker. I can get a high quality valve seat job done on the newer head.

I just want this quad to run, have fun, and last. Seen too many "expensive" builds chasing max numbers. I'm already deep into this quad, with mostly used parts. Ill hit a track a few times a year, maybe 1 trail ride, and sand dunes a few times. I'd get a 2-stroke if I wanted to go the fastest(money-pit).
 
What is everyone's opinion on the Streamline 7-way rebuildable "stick" steering stabilizer? Found one new for just over $100.

Foot pegs came out great! Hopefully my yard is dry enough to take it out this weekend.
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I can already assume the huge widening arms will make it feel like a completely different quad. I want to take it to a private owned track soon.
 
I'm now stuck on putting a yfz450 carrier on as the next upgrade. I have a couple round style yfz swingarms to take parts from. I need a new axle shaft, anyways, as mine is bent. I can to a cheap Ninche axle and square up the width with the front(it's adjustable). I can also run a smaller rear sprocket if I choose to. And, I can use the yfz dual piston rear caliper(if that is a real plus).

Just need to aquire the rear carrier tube. I found my swingarm is from the Swingarm Shop. They won't make a custom arm. I found another local arm builder and just need to call and see if they will sell me the tube. I also found a couple arm builders from the westcoast that sell them online.

I'll loose a couple inches on my extended swinger. I honestly hate the +6" swingarm. I think a +4" is max. I can move the skidplate tabs to where they are needed and add some stiffening gussets.

I only want to do the round tube carrier because this swing arm keeps shifting the carrier. It flexes a bit and I have to keep adjusting the alignment.

Still plan on doing the newer head and camshaft. Life problems have put it on hold temporarily.
 
To finalize the modest buid, I have solidified the head and cam plan.

I will use the '07 raptor 350 head. Will just blend the intake port and smooth out the ramps to the valve guides. Just going to polish the exhaust port runner if it looks decent. I might touch up the exhaust runner if it looks rough. Will use my Kibble White valves and springs. And a Hotcams stage 1 camshaft. It's the closest to stock, with more lift. And use a new factory Yamaha piston pin as the Wesico wrist pin is near 20 grams heavier. I'm going to bump compression slightly by bringing the piston to as close to zero deck height as I can. Thinner head gasket, no base gasket, or both.

Seems to be the most cost effective way to get more power but stay "basic" in the build. I can run pump gas, and stay mostly reliable. I'm going to try and dyno it sometime next week, as it is. Then I will get into the newer head build(haven't pulled it from the original motor yet).

Should be around 11.5:1 compression? And have a higher lift camshaft. My current FCR carb should be more than able to handle it's max potential.
 
Did some head work. I opened up the roof grooves in the intake just a little, and removed only a tiny bit cleaning it all up. I kind of polished the exhaust port. It does not help with carbon anyways. I'm leaving the chamber alone. Polishing just removes the roughness which reduces surface area and lowers heat transfer. I would think you want all the help you can get at removing heat from this engine. I'm a WOT rider, so I don't think carbon build up should be a big problem.
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Again, no major change made in port shape. Very little out of the intake roof and just a good cleaning.

I think less is more in this situation. Should be a nice gain with this head, slight bump in compression, and a better cam.

Also fabbed up some temporary front shock mounts to bring the lower mount closer to the frame. I guesstimated the location off of pictures of other wide arms on Raptor 350/Warriors. They are made to put the force onto the tube and the flat plate. If it works out better, I'll cut the mount tabs off the arms and make new ones that move it further inward. Feels better sitting on it and moving around.
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Head should be a decent gain. You can still take a lot more off around the valve guild to really open the flow. For the shock mounts it's better to actually bring the upper mounts out.
 
My thought with leaving more material around the guide to help with heat transfer. These run very hot at times. My current head burnt the valve seals quickly and isn't sounding the greatest. I took some decent material off it. I might take some more off the intake on this one though.

As far as the shock mounts, I know going wider on the upper is ideal, and is on the list. Haven't rode it yet, but bouncing it feels more like it did before the arm swap. I might be wrong, but moving the lower inward makes the progression faster? The rate increases faster, as does the dampening?

Might be time to look for better shocks again. Longer YFZ450 shocks maybe.
 
My thought with leaving more material around the guide to help with heat transfer. These run very hot at times. My current head burnt the valve seals quickly and isn't sounding the greatest. I took some decent material off it. I might take some more off the intake on this one though.

As far as the shock mounts, I know going wider on the upper is ideal, and is on the list. Haven't rode it yet, but bouncing it feels more like it did before the arm swap. I might be wrong, but moving the lower inward makes the progression faster? The rate increases faster, as does the dampening?

Might be time to look for better shocks again. Longer YFZ450 shocks maybe.
I've never heard of burning up valve seals. This is what my head looks like.

For the shocks the more vertical they are the faster the progression but the more inboard the higher the motion ratio.
 

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I feel confident in my new plan for the front shock mounts. I feel like an idiot. Yes, I need to have the upper mounts further out to stiffen the front end.

I'm an expert on nothing. Starting to feel older and having some dumb moments.

I made a new upper shock mount that bolts to the original tabs.
YFZ upper shock mount width 11-11/16"
Raptor 350 width 7-11/16"
New bracket width 11-1/4"
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Never ran it with the arm shock relocation tabs I made. They are straight to the scrap pile. I've been too busy lately to take it out anyways. Hopefully widening the shock mount is all I need. I don't want to put that much more money into this. I, like so many, have put more into it than I can sell it for. And I bought alot of used parts. It's not an investment, but a toy. And toys always cost $.

I could stand on the front bumper before and bottom it out easy before. Now, i can't bottom it out jumping on the bumper. Can't wait to see how a shorter extended rear arm reacts.
 

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