Crf450 common issues????

fastmatt42

New member
I have a freshly rebuilt crf450 still on the bike. Runs great(been riding it a little just to make sure no leaks, probs, etc.)
Also, have a 2010 Seraph.
After new year will begin building UAS kart out of the two.
Plan on ordering:
radiator-ellis
engine mount-qrc
rear gears-bhetrick
starterplug in block-wendel
shifter linkage-westerfeld
Already have big break rotor and caliper bracket custom built to fit seraph bearing hanger.
I will fabricate nerfs, brackets, etc (was a welder for 20 yrs)
For the first year, I plan on running the tranny as is and leave the engine stock. It has stainless valves and new clutch.

Just looking for advise and suggestions on any common issues that I may not be aware of so i can address them while building the kart. I have been closely looking at the karts with this motor and paying close attention to the threads on here. Been running flattys and clones for 19 years, off and on. This is going to be an awesome new adventure for me. Ideas? comments? suggestions? Pictures would be great!
 
If going to run week in and week out, keep eye on valve lash and keep a lash shim kit handy. Valve seats are greatest wear area. Other than that they are TOUGH!
 
Go ahead and put Kibblewhite titanium valves or you might regret it. Then you should never really have to shim them.
 
What year is the engine? From 2007 and up Honda got about all of the valve issues resolved. Do you know how many hours the engine has on it? The main thing is to make everything bullet proof because you will find out that the weak links will bite you when it counts the most. Sounds like you have a great combination worked out. What region will you be racing out of?
 
I have a freshly rebuilt crf450 still on the bike. Runs great(been riding it a little just to make sure no leaks, probs, etc.)
Also, have a 2010 Seraph.
After new year will begin building UAS kart out of the two.
Plan on ordering:
radiator-ellis
engine mount-qrc
rear gears-bhetrick
starterplug in block-wendel
shifter linkage-westerfeld
Already have big break rotor and caliper bracket custom built to fit seraph bearing hanger.
I will fabricate nerfs, brackets, etc (was a welder for 20 yrs)
For the first year, I plan on running the tranny as is and leave the engine stock. It has stainless valves and new clutch.

Just looking for advise and suggestions on any common issues that I may not be aware of so i can address them while building the kart. I have been closely looking at the karts with this motor and paying close attention to the threads on here. Been running flattys and clones for 19 years, off and on. This is going to be an awesome new adventure for me. Ideas? comments? suggestions? Pictures would be great!

Unless you have a narrow spaced frame the QRC motor mount is too narrow as are the bottom butterflies.

Assuming they are KW stainless valves?
 
Didn't Honda put stainless in that year? I'd put KW titaniums in just for the insurance. But that's me.

Better than dropping a valve and destroying a head or more.
 
Didn't Honda put stainless in that year? I'd put KW titaniums in just for the insurance. But that's me.

Better than dropping a valve and destroying a head or more.

ABR #69 I don't see that fastmatt42 listed the year motor? Regardless I'm not aware of any year CRF450R that came with anything but Ti.....but I'm only intimately familiar with the 2003 & 2003. And if you are going to go thru the process of putting aftermarket valves and seats in them.....I'd go with CV 1mm+ Ti.....better valve IMHO. But I do totally agree I wouldn't run anything factory WRT valves.
 
The 02 thru 08 (I am assuming that is what we are talking about here although it is still unclear) has Titanuim intakes from the factory, but the exhausts are not. As far as I know the KW valves for the 450 are all stainless. And good points on the Motor Mount issues. My friend just went through that issue with his QRC mount and had to find some butterflies.
 
ABR #69 I don't see that fastmatt42 listed the year motor? Regardless I'm not aware of any year CRF450R that came with anything but Ti.....but I'm only intimately familiar with the 2003 & 2003. And if you are going to go thru the process of putting aftermarket valves and seats in them.....I'd go with CV 1mm+ Ti.....better valve IMHO. But I do totally agree I wouldn't run anything factory WRT valves.

Sorry, I see now I was confusing Wes's post on the year. The older Trx450's didn't come with Ti and thought the bikes were the same. I know the 04 Trx didn't have Ti. I can't remember when they changed.

I have larger Kw Ti in my Ktm and haven't had a minutes trouble out of them.
 
the motor fastmatt is talking about is a 2002 crf450. it has stainless steel valves, was made to race by the guy we bought the bike from. We have the old titainium vales.
 
Thanks for all the responses! We are located in central IN. And yes. the engine is a 2002. The guy i bought it from owned it for 7 years, had it rebuilt and kept all the old internals for me. It had stock titanium valves. He explained the problem was the valve seats were harder material than the titanium. The old valves actually have a groove or lip on the seat that you can see. I don't know if from spring pressure or rpm, but you can see and feel the lip where the seat made a groove in the valve seat. wish I knew what kind of stainless valves they put in it. It was Dreyer honda in Indy that did the rebuild. I'll have to give them a call.
And yes, I have already found that I'll have to make butterfly mounts to adapt the mount to my frame. Is there anyone making mounts that I can just bolt up. I'm asking because I read that some were having minor issues with the QRC.
Also, what RPM and temp are you guys turning these engines? I ask because I've learned from flattys and clones that as much as it will turn is most always NOT the fastest.
One more thing. What spare engine parts should I keep on hand with me at the track?
Thanks again! You guys have helped a ton already and I havn't even got the engine off the bike!
 
Likely if something goes down in the engine, you're done for the night. So spare parts in that regard isn't really a big issue. The time it would take to unhook everything and get the engine off then tear it down would put you out of the race more than likely. Let alone the fact that if it went down it probably done more damage than you could fix at the track.

RPM wise, I'm not sure on the Honda's what they're turning, but my KTM is setup a little different and I don't have to turn mine quite as hard as others. Engine temp is around 160ish or 170ish in the dead of summer for me. I am changing radiators, but 200+ is danger area. They'll start spitting all the water out.
 
If you plan on using the QRC mount you need to get with Danny York for the butterflies. His screen name is dky48 I believe. He has built a few sets for us and another group, never had the motor even think about moving.
 
fastmatt42 - QRC has been having flooding issues for the past couple of weeks...my guess tho is they are just out of them because not many people use their mounts for the CRF450. There is a guy who will make you a complete bolt on mount with butterflies. Camaro68 on here.

As far as RPM goes.....IMHO depends on the cam, the track and if you can get it hooked up.

Ditto what ABR #69 said....Usually if something "breaks"....it's terminal and the motor will need to come apart. About the only spare parts I carry are fuel pump, clutch disks, spark plugs and a spare head pipe.

Temp....I like to run mine a little cooler than most.....race temps ~140-150 max. It will usually creep up a bit under caution.
 
thats junk
delwest valves and moldstar 90 seats and moldstar 22 guides and an airfilter other than a knn

Ditto on kibble white, they're over priced, you might get what you ordered and it might be right but if it isn't they won't help you, they have bad customer service. Never had any dealings with delwest but Manley will make you any valve that kibble white has for half the price and you'll have twice the quality of valve.
 
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