Gen 4 CRF450X build

other · Post by **other** » April 15th, 2012, 10:55 pm

I thought it was time I got off my lazy arse and sorted this 2008 CRF450X out with a decent powerplant. Gotta say, it has worked really well so far, as I am able to use a standard plug and cap, with no tank mods other than reversing the outlet. The frame rails (6061 T6) bent nicely, and the only downside so far is I cant use the nice Stoffers billet engine mounts. This is because I'm keeping the bend of the cradle rails really tight to the engine profile, and the mounts are designed for a far looser fit. I may pay the price in convenience when it comes to removing the engine later, but so be it. First things first . . . . I took the CRF for a last ride before starting work, and the damn thing has never gone better ! I'm sure it was behaving impeccably coz it realised it's demise was at hand . . . then stripping began. Holy shit ! It took me 3 hours (honest to God) to get the engine out of the mongrel thing !

Brace yourself bitch, you're about to get raped.

The deed is done.

Out with the Sawzall . . . No turning back now.

The 500 in her new home for the first time.

The prepped Y.

The Y fitted, and the pockets cleared out for replacement cradle rails.

The bending setup.

It may be homemade (thanks Juddy), but it works well.

Cradle in place, and lower mounts mocked up. Nice tight frame rail line.

Snug as a thumb-in-a-bum.

By now the weekend is nearly over, and the beer fridge was calling. Gotta get the 3-phase power reconnected to my recently enlarged shed (hence the mess in the background), and then I'll get the TIG fired up and stitch this thing up. Further updates to follow as progress is made.
Thanks for looking.
Greg

other · Post by **other** » April 15th, 2012, 11:01 pm

damn, don't know why all the pics didnt work ? !

Post by **AlisoBob** » April 15th, 2012, 11:04 pm

you got the slash on the wrong end...

other · Post by **other** » April 15th, 2012, 11:14 pm

OK thanks Bob. I'll delete the first post and have another go.
FIXED, thanks.

Gmbond · Post by **Gmbond** » April 16th, 2012, 4:30 am

Work looks good so far, have you got any photos of what you will be using for motor mounts then?

other · Post by **other** » April 16th, 2012, 4:37 am

Not yet Gmbond. I'm waiting for the hunk of 6061 to come in, and then I'll get it happening. Will be in the next update, hopefully.

kevin_s · Post by **kevin_s** » April 16th, 2012, 5:16 am

Nice work mate,looking forwards to the end results.

other · Post by **other** » April 16th, 2012, 6:21 am

Thanks Kevin. I've modified your jig a little too . . . . it now has a short length of pipe to accurately locate the height of the exhaust, and a piece of rod tacked in to replicate the location of that troublesome bottom case bolt on the clutch side. It will also get the headstay addition in due course. All this means is that in future, I can dummy up a frame without ever having to install the engine at all.

Post by **AlisoBob** » April 16th, 2012, 8:49 am

Is that 12 weeks of work?

12 days?

12 hours?

(

)

Looks great so far!

other · Post by **other** » April 16th, 2012, 4:43 pm

Thanks Bob. Spent about 4 hours on Friday evening stripping and cutting it, then about 7 or 8 on Sunday doing the rest ( gotta give Saturday to the missus in the interest of domestic harmony), so 12 hours would be pretty close. With work and family commitments, I now won't get to touch it again for a fortnight !

other · Post by **other** » April 16th, 2012, 10:42 pm

As you can see, the CRF450X has a skinny little rear rim on it (18 X 2.15"), while my steely has a much wider Excell rim (18 X 2.5). It appears on the face of it that the sprocket to disc rotor dimensions are very similar on both wheels, so I was hoping to be able to fit the wider rimmed wheel straight into the AF. Has anyone done this, does it work ? Or do I have to unlace both wheels and "mix'n'match" rims, hubs and spokes ? Thanks.

2strokeforever · Post by **2strokeforever** » April 16th, 2012, 10:51 pm

tubliss and 18X2.15 work pretty darn good together

other · Post by **other** » April 16th, 2012, 11:33 pm

Can you sit a 140 profile tyre on a 2.15" rim ? I run a 120 on a DID 2.15 on a little Gasser 2T, which works awesome, but have always favoured 140's on a 500. If you reckon it's OK, maybe I'll just run it till I knock the rim into an octagon shape, and then worry about it, hey ?

2strokeforever · Post by **2strokeforever** » April 17th, 2012, 12:57 am

140/80/18 IRC M5B is my favorite tire to run on my 18X2.15 rim, using the tubliss at 4-7 psi
id rather have the 2.15 cause a tubliss wont work on a 2.5 (at least with the good tires)

running the low pressure makes it shape to the ground real good, like a trials tire is suposed to

other · Post by **other** » April 17th, 2012, 4:23 pm

Yeah 2StF, I'm already a Tubliss convert, have 'em fitted to my FE570 Berg. Can't seem to puncture them no matter how much I abuse them. I find that below about 8 or 9 PSI the bike is really loose at high speeds, on hard pack or gravel, so I tend to run around 10 or 11 PSI. The AF will stay on UHD tubes and old mousses until I get aound to fitting Tubliss to her as well.

omaotek · Post by **omaotek** » April 23rd, 2012, 10:56 pm

Did you heat up the tubing with that propane torch next to the bender before bending it?

Im thinking about bending some for my cradle, But I only have enough material to get it right on the first shot.

cr500beercan · Post by **cr500beercan** » April 24th, 2012, 2:12 pm

How did you get the pipe to clear the y ? Did you use a 250 y?

other · Post by **other** » April 25th, 2012, 12:48 am

omaotek wrote:Did you heat up the tubing with that propane torch next to the bender before bending it?

Im thinking about bending some for my cradle, But I only have enough material to get it right on the first shot.

Yep, but you really just take the chill off it. You can use an electric hot air gun too. I had masking tape on the tube (to avoid scarring from the bending dies), and I didn't put in enough heat to even brown the tape. The trick is bend it REALLY slow. I went too fast on one . . . . . luckily I had a spare.

other · Post by **other** » April 25th, 2012, 12:51 am

cr500beercan wrote:How did you get the pipe to clear the y ? Did you use a 250 y?

Nope, original 450 Y, and she's really snug around there ! Measure, measure it again, then do it one more time just to be certain ! It really is as snug as a thumb-in-a-bum ! There might be 3mm clearance (1/8") between pipe and Y both sides.

other · Post by **other** » April 26th, 2012, 4:49 am

Ok guys, I'm after a little more help, this time with the best airboot for the job. I have an '85 500 boot here, that almost works, (in fact if the reed block was 10 or 12 mm longer, it would be almost perfect . . . Wasn't there a V-Force reed block that added length ? ? ?). I also have an '86 250 boot which looks longer, but I have yet to remove from the roller and try . . . . The CRF of course is a non starter, and the '90 500 is too bulky to fit between the shock and the frame . . . If I am going to pop the bucks on yet another boot, I want it to be closer to fitting than the "85 500 one. What has everyone else used on Gen 4 450's ? Also, would you recommend adapting the CR500 air filter, or does everyone use the CRF filter that fits the airbox ? (the CRF appears to have a larger surface area, so shouldn't be a problem, I guess ).
Footnote : went to start welding the old girl up last night, and the AC/DC TIG has died since I last used it ! so now I have 415V to the shed, but the welder is in for repair . . . seems progress is fated to be slow on this one !
Any help on the best airboot to start with would be greatly appreciated.
Thanks
Greg

cr500beercan · Post by **cr500beercan** » April 26th, 2012, 12:11 pm

Usualy a cr250 intake boot is adapted to the stock 450 air box , like a 2000-2001 intake boot

cr500beercan · Post by **cr500beercan** » April 26th, 2012, 6:23 pm

You had to lower the front of the motor way down to clear the pipe?

other · Post by **other** » April 26th, 2012, 11:27 pm

cr500beercan wrote:You had to lower the front of the motor way down to clear the pipe?

I was quite concerned about positioning (clocking) the engine, because there are so many variables. I don't believe I have lowered the front too much, because of the alignment of the air boot and the exhaust. If I lift it any more, the muffler mount falls well below the top mount on the subframe, and the plug fouls the tank outlet. I actually raised the Y by 71mm, and 'clocked the motor to sit with the exhaust springs just clearing. I then double checked with a spirit level, and at static ride height, the "HONDA" on the clutch cover is less than 1mm down from horizontal on the "A". This position gave me the best fit for exhaust pipe, air boot, chain run and spark plug. Having locked this in, I then bent the frame rails to fit as tight as practical around the engine. Not much science to it really, but I will admit I was pleased to find that the most practical 'clocking' was true horizontal (as near as 'fuck it' is to swearing) on the cluch cover text. Check the photo taken square on showing the fitment of the frame rails ( and mocked up lower mounts), as this gives a pretty good indication of the engine's rotational position. Looks pretty right to my eye.

other · Post by **other** » May 1st, 2012, 1:00 am

managed to find time to get a couple of engine mounts machined up this weekend, but then it started raining , and the lure of the single-track was too strong.

. . . . I know, I'm weak, and gave in to it ! (Don't hate me for the 4St, those 570 Bergs are fuckin awesome !)

Bean · Post by **Bean** » May 1st, 2012, 2:35 am

I think I have 1 air box adaptor left for the 450x if you need one ? I fly out of aus Thursday 3. Of may and get back may 28. I make the adaptors that stoffers sells so you can check them out in the Aussie kits thread . My number is 0400954272

BannedCR500Riders.com

Gen 4 CRF450X build

Gen 4 CRF450X build