CRF450R Intake Changes

[mumur]

In January my old Beta blew up and I picked up a new-old-stock 19 CRF450R. On the Beta I was running the C3 Motorsports intake with just a prefilter. The dealership I got the Honda at (which also sells Timbersled completes) said they throw a thermo on there but they don't make any changes to the stock airbox other than throwing a prefilter over the stock filter. That's what I did and I rode it out for the rest of the season that way, didn't notice any issues. I'm curious if anyone else with a CRF has made changes, or if that's working for them as well. Wanna make sure I'm not screwing myself longer term.

 

[sledsuperman]

That's basically all I have done too, except that I put some filter material over the intakes (the ones by the number plates) and glued them on with hot glue. I had one day with some icing up problems that I'm not sure what the problem was and many other deep powder days with no problems at all. There seems to be enough heat from the engine to keep the bottom of the airbox open. This may be due to the configuration of how my kit (Camso) mounts to the bike in that area though. I'm not sure how it would work with a Timbersled. I believe Timbersleds are open to the track in that area. Is that right?

 

[G-Force]

Not a Honda, but on my KTM I did something very similar to Sledsuperman. I picked up an extra air box cover from RMATV for like $15. Cut some vent holes in it, and then hot glued frogskinz on both sides.
Then I used some coarse foam with the pre-filter material on it, and "plugged" the air box hole down by the mudflap. After all that, I took a spare airfilter with an outerwear prefilter on it, as well as the installed filter,
and "stuffed" the airbag with it. The thinking behind that was there would physically be less space for any ingested snow to occupy, and also, a second barrier for water ingestion if any did.
For a home made solution, it worked like a charm. Would have very little snow in the airbox after a day of riding in 2' of dry powder. Engine ran great, never a single hiccup. Be doing the same setup this year, see no reason to change, nor spend $300 on a purpose built intake!

 

[mortimis]

I ran a 2010 CRF450R last year. Only modification I made to the air box was frogskinz around the number plates and ran a prefilter around the box (no actual air filter). It ran great and never had any issues, and never ran lean. I have a PST engine jacket that should fit your bike if you're interested! I would highly recommend them on a snowbike.

 

[mtnthumper]

I'm currently using a PST intake on my 17. I went a season and a half with just the back of the airbox removed and an outerwears over the cage. This seemed to work fine the first season, but during the second I was getting a lot of water in the airbox. Enough that if I hit a big bump it would suck in and sputter the engine, and I was draining it part way through each ride. Messed around with double filters and resealed around the cage but didn't fix it. The PST also frees up space around the strut which is nice.

 

[Praisegeetarman]

I have run my 17 CRF450RX for 2 seasons with only a frog skin pre filter over the filter housing with the actual filter removed. I also cut the small brace across the opening at the bottom of the filter box out so any snow would drop right out. Stock other than that and haven't had any issues yet.

 

[mumur]

That's basically all I have done too, except that I put some filter material over the intakes (the ones by the number plates) and glued them on with hot glue. I had one day with some icing up problems that I'm not sure what the problem was and many other deep powder days with no problems at all. There seems to be enough heat from the engine to keep the bottom of the airbox open. This may be due to the configuration of how my kit (Camso) mounts to the bike in that area though. I'm not sure how it would work with a Timbersled. I believe Timbersleds are open to the track in that area. Is that right?

Thanks for this idea, I'll probably do something similar.

I have a PST engine jacket that should fit your bike if you're interested! I would highly recommend them on a snowbike.

I've got one already, thanks. I agree that they are pretty necessary.

Thanks everyone. Good to hear that generally stock with frogskinz is enough for these ones.

 

[mumur]

That's basically all I have done too, except that I put some filter material over the intakes (the ones by the number plates) and glued them on with hot glue. I had one day with some icing up problems that I'm not sure what the problem was and many other deep powder days with no problems at all. There seems to be enough heat from the engine to keep the bottom of the airbox open. This may be due to the configuration of how my kit (Camso) mounts to the bike in that area though. I'm not sure how it would work with a Timbersled. I believe Timbersleds are open to the track in that area. Is that right?

I did end up doing this, looks like it'll work well. Thanks for the idea! I used 3M weathstrip/gasket sealant instead of hot glue since I don't have a hot glue gun. I didn't block the bottom of the airbox yet. I have a CMX kit, which is open to toss snow there, but I don't think it really does in practice.