drz 503

i just got a catalog from falicon and they have a stroker crank to increase displacement.they have it listed as drz 400/503,no price though.probably also have to do a big bore to get this displacement.they also have adjustable cam sprockets for it listed,catalog lists them as $175. www.faliconcranks.com

You can have a good machine shop do your cam gears so you can adjust cam timing. I get them done for around $35 a cam.

If you can find results of the Del Mar Mile flat track race last Oct. Look in the Pro Singles Mile results. You will see a DRZ motor won that race against Rotax 600 and ATK 600 and even Nicky Hayden on a factory 450CRF Honda. That DRZ is a 450 bored and stroked motor. I would not want to go any larger than that. 503 is a lot to stuff into the DRZ cases and cylinder and keep it reliable.

[ December 26, 2001: Message edited by: DRZDUC ]

Hey Duc,

Think we can set up a SoCal DRZ ride? We could all meet in the desert and ride. Feel free to e-mail me.

glapple@home.com

Hey! SANDRZ

I see you are in the San Diego area. Yes! I would like to get together for a DRZ ride. I will

e-mail you on friday.

personally i would rather buy adjustable cam gears by someone who has done there homework and not a machine shop that doesnt have an understanding of the drz engine.maybe some do , but just slotting your cam gears can lead to bent valves.also i would imagine the limitations for reliability would not be from the engine cases,but more than likely from the cooling system or the transmission.both can be overcome, but cost effective-probably not.maybe for somebody who wants to modify their bike.

Originally posted by rogdrzer:

personally i would rather buy adjustable cam gears by someone who has done there homework and not a machine shop that doesnt have an understanding of the drz engine.maybe some do , but just slotting your cam gears can lead to bent valves.also i would imagine the limitations for reliability would not be from the engine cases,but more than likely from the cooling system or the transmission.both can be overcome, but cost effective-probably not.maybe for somebody who wants to modify their bike.

I am not sure who told you or where you got that slotting the cam gear 4 or 5 degrees will bend your valves. Who ever told you that is wrong. 4 degees advanced or retarded will not bend the valves.

The reason for the ajustable cam gear is to degree your cam in no matter if it is a stock cam or an aftermarket cam. Even using the timing marks that is provided to set your cam timing is not always correct. In reality you have the camshaft, cam chain, sprockets and the crankshaft that are not always in tolerance and this could be on a new motor. A properly degreed cam will increase performance no matter if it is a stock cam or after market. What is the reason you think this company is making these adjustable gears for. It is so you can degree your cam. These gears are not going to come with a mark on them for you to use because they have no idea what degree it needs to be set at. You don't properly set cam timing by some mark. It may be close enough but you really don't know where the timing is unless you do it with a degree wheel and dial indicator.

As for the engine cases, you have main bearing at the end of the crankshaft that is supported by the engine cases which is now taking a much heavier load and you have transmission shafts that is supported at the ends by the cases that is taking heavier loads not to mention the load on the gear teeth themselves. I have seen and had engine cases distort and I am not talking about just the DRZ.

That 503 might be be fine if it was rode easy but if you started to ride it hard I do beleive you would have problems.

If you are looking for a 500 trail bike get the 520 KTM you would be money ahead by the time you were done and much more reliable than a motor that was not designed to be a 500.

your right , a couple of degrees is not going to bend valves, but like i said somone who has done there homework may be able to say exactly how far the cam timig can be safely changed.whereas a machine shop not familiar with the valve to piston clearance of this engine will just hogging out the bolt holes.further more how do you know the main bearings are not large enough?do you think these companies just dump a ton of money into designing these things without testing them.its called r&d.i never suggested reliabilty would be as good as stock,but cmon think about it.say im a manufacturer,if i spend time and effort designing a part and marketing under my name and i dont do thorough testing and they start blowing up whos going to buy them and it will the company a bad name.yeah lets market engine modifications where it has more power but you have go"easy"on it like you said.how does that work?i agree about the part where you said that you said if you want a 500cc bike just buy a 520.some people like to modify .

Originally posted by rogdrzer:

your right , a couple of degrees is not going to bend valves, but like i said somone who has done there homework may be able to say exactly how far the cam timig can be safely changed.whereas a machine shop not familiar with the valve to piston clearance of this engine will just hogging out the bolt holes.further more how do you know the main bearings are not large enough?do you think these companies just dump a ton of money into designing these things without testing them.its called r&d.i never suggested reliabilty would be as good as stock,but cmon think about it.say im a manufacturer,if i spend time and effort designing a part and marketing under my name and i dont do thorough testing and they start blowing up whos going to buy them and it will the company a bad name.yeah lets market engine modifications where it has more power but you have go"easy"on it like you said.how does that work?i agree about the part where you said that you said if you want a 500cc bike just buy a 520.some people like to modify .

I think you misunderstood what I said about a machine shop doing the cam gears. You would not go down to lets say a muffler shop and tell the guy to take his cutting torch and slot the cam gear somehow. I have had more than a dozen cam gears reworked so I can degree the cams in. I tell them I want 4 degrees advance and retard. I

I know what I want when I go there. How do I know?I run race bikes from Feb. to mid Oct. every year. Last couple of years have built some DRZ motors for Dirt Track (flat track). A 450 that was ran last season was rebuilt every other time out mainly due to it running between 8,000 to 11,800 RPM continuous. Never had an engine failure due to the rebuild after two race events. I know what the weakness of the motors are. The trans, had no trouble with due to never shifting after it was in 4th gear (fifth gear was removed)ran 4 speed only.

My trail bike I ride is a 436DRZ with oversize valves, ported head, Ti valve springs, Yoshimura cam or Webb Cam, bored FCR39 carb, Yoshimura ignition module and Titanium Yoshimura exhaust. The bike is very reliable.

I too like to modify things. That is what I do through out the year.

yeah, i did misunderstand,sorry.do you know of anybody running the 470.also have you ever used evans coolant in any bikes?ive heard that in race cars you can use this coolant with almost no pressure as its boiling point is around 370 degrees.and you dont mix it with water.

Originally posted by rogdrzer:

yeah, i did misunderstand,sorry.do you know of anybody running the 470.also have you ever used evans coolant in any bikes?ive heard that in race cars you can use this coolant with almost no pressure as its boiling point is around 370 degrees.and you dont mix it with water.

We put a 470 piston and sleeve in a friends bike that trail rides with us but he has not ridden it but about 10 mins. He broke his ankle on his sons YZ80. I rode it just a short time and it has a lot of torque. The engine was left stock except for the exhaust snd jetting. Oh! I did install a Hinson clutch basket.

I run Evans coolant in everything. I started using it in the road racers.

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