CRF 450R stall/hard to start in bush

Been using a CRF 450R o6, in the bush and have been struggling to get it re-started on steep hill climbs. It seems easy to stall and is running standard gearing , low enough to climb something of a good ascent.

This is the first 4 stroke motocrosser I have used as enduro mount, had an easier time on 250 strokers even on some gnarly climbs.

I am thinking there maybe something to do with timing (possibly altering?) and it not liking the extra engine heat produced at slow speed first gear hill climbs.

If this sounds familiar or someone has experience with this, would you please advise me, much appreciated. Thanks

I'm thinking maybe a FWW would help you out? I'm probably going to add some flywheel weight to my 450R but I'm afraid to tamper with the bone stock motor because it runs so well as is.

this may be good solution to stalling but wondering about restarting on the hills. Have you encountered this also, this bike seems to start ok under normal conditions.

I have the same problem with my 06.:thumbsup:

this may be good solution to stalling but wondering about restarting on the hills. Have you encountered this also, this bike seems to start ok under normal conditions.

So if I'm understanding correctly you are having trouble starting the bike after a stall when it is pointed uphill and the motor is hot? I have encountered this same issue on every 4 stroke I've ever ridden and each has its own little ritual to get it to fire. I don't have but a few hours on my 450R and those few times I've stalled it fires right up with the hot start pulled tight and a couple of kicks. I take my hand off the throttle when kicking any 4 stroke hot or cold normally. If the motor is super hot sometimes pulling the hot start and holding the throttle wide open will light it off. A FWW will also make it start a little easier. Another thing I do that drives some people crazy is keep the idle high. Helps prevent stalls and makes hot starting easier IMHO. Let us know what you figure out! I'm all ears:thumbsup:

You might also want to consider going changing your gearing. Some of the woods guys can correct me here if I am wrong but you should be abot to go to a 50t rear and just run all the hills in 2nd. It will suck for top end in mx but if you are primarily woods then you probably wont miss that top end.

Thanks so much guys for your pointers, I'd say all of those will be of use to me this weekend, got a 3 day ride hapening in the Victorian bush here down under.

I didn't get too adventurous with the hot start button so will apply that, the fast idle trick I did give a bit of a go, bit of a roller coaster ride on some Big Down Hills.

Am keen to try some different gearing, though a lot of our riding is a mixed bag, tight single track and sweeping more open faster stuff, may have to do some quick cog swap overs.

The bike has around 17 hrs on it, just wondering when you guys may have looked into your 1st valve adjustment on your 450's?

Thanks again for your help.

Btw, we had a blast driving through Arizona and Tenesse in 2005, among other states, but 5,1/2 weeks only allows so much time to cover so many miles.

Checking the valves is really easy so you will want to check them for sure. As far as adjusting them, it should be a while if you stay on top of your mainenance (oil and air filter). The head was changed in 06 so the valve seats are harder and tend to wear slower. I would definitely at least check them so you have a reference and date so you can see when they start to go out of spec.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now