Drz472

I Have A Drz400 And Have Upgrade It To 472. For The Moment, I Have Kept The Original Pipe. Is There Anyone Out There That Can Give Me Jetting Info. Help! Please! Thank You.

:naughty:

Not the Thumper Racking 470 kit I hope?

Not the Thumper Racking 470 kit I hope?

What is wrong with that one?

Which big-bore kit is best?

I've been riding the Thumper DRZ470 kit for quite a while. ESP did the front and rear suspension at the same time. Thumper also split the cases and went through the engine internals. Stock cams are used. Exhaust is FMF Q with Power Bomb (all stainless steel). Bunch of other ergo mods also.

Performance is exactly what I want. Some local club racing and trail ridding with buddies. Engine is stronger across the RPM band than new WRF450's that I ride with (e.g.,they stall periodically and I don't). A YZF450 has slightly more top end power. Power band is broad enough that I ride mostly 2nd/3rd gear on tight wooded single track. I use the clutch less than 1/2 of what I used to with the 400.

I dropped the bike off at Thumper and had them do the work on the engine and suspension. Gary Hazel is great to work with. The problems that I have seen that they have had have been due to weak distributors and shade tree installations by owners. I did some research before deciding to use them.

I bought the DRZ400E new for $4100 (discount deal with Tenn shop) as a '2003. I have less than $6200 in it total with others doing the wrenching. It fits my needs as a B level rider very well.

You may want to contact Thumper at (903) 938-3340 and find out what they do for carb settings. I do know that I have one of the best engines that I have ever had in terms of throttle response - without going the route of a Power Now, or higher idle settings. It shows in the reduced need for clutch action in tight sections. I ride Michelin S21's front and rear.

I have a Hussaberg 650 FE that I use on long rides out West due to the additional power and higher top end. The DRZ470 will outhandle it and is less of a handfull in the local stuff here in South and Central Texas, Alabama and Tennessee. It's also more reliable than the 650.

Hope this helps.

Good review!

I've read about some pretty scary things about the 470 kit. Loads of power for sure. I recall reliability issues?

I'm sure many people have good things to say about the Millenium kits :naughty:

I've read about some pretty scary things about the 470 kit. Loads of power for sure. I recall reliability issues?

I'm sure many people have good things to say about the Millenium kits :naughty:

When I picked up the 470 from Thumper, Hazel told me about and earlier design that they had for (I believe) a 503. They built one for a client who has raced and abused it for over two years with no whimpers. They didn't have time for commercial development due to other commitments and never followed through with subsequent units. The DRZ's bottom end is plenty strong. The piston on my 470 looks more abbreviated (made by Weisco working with Hazel at Thumper) than the 400 stocker. My guess is that they kept the stress on the crank reduced by doing this. Since there was no stroke change piston velocities remain unchanged (a big stress on connecting rods and bottom ends when increased).

My guess is that the other kit manufacturers take this into account also.

Blown head gaskets because of the iron liner.

the iron liner and the lack of distance between the piston and the water jacket.

bad news..........

but if yours is working,then ride!

If you can get one that stays together have fun. Most have serious cooling and even keeping the liner in place problems. There isn't hardly any room between the walls and the waterjacket. I wish you luck but I prefer the 440 I bought. Burneds skills put it together and it feel way better than my stock E does. I give Eddie credit for that, he is one hell of a mechanic! prairiedawg :naughty:

ps. Contact Wild FX and ask him about his 470. :naughty:

the iron liner and the lack of distance between the piston and the water jacket.

bad news..........

but if yours is working,then ride!

That was the reason I had Thumper do the assembly. I had heard stories of blown head and base gaskets and found that most could be attributed to lack of assembly detail (the guy doing it). My biggest concern was lack of cooling. Instead, I'm finding the motor is running at least as cool as the 400 did. Gary was pushing some of the coolant enhancers that are out there, but he even admitted that he saw some indication that they will break down even in his own personal KTM that he rides. I'm using Prestone Dex-cool approved coolant 60:40 (glycol:water). Last weekend I ran it pretty hard for about 90 miles in alternating flat out and tight hilly terrain and didn't even get a small amount of carryover into the blow by reservoir. With the 400 it was always about 1/4 full of coolant.

Interestingly enough the motor is quieter now than before the conversion. I figured this was due to Thumper splitting the cases and checking/adjusting tolerances and building the top end a little tighter than stock. I suspect if the latter had been the case I would have seen more heat than I did last weekend. It starts if you just stare at the e-button and one kick (with the manual compression release) will have it going before you reach end of the kick starter stroke.

I guess the reason that I like the conversion so much is that I didn't do what I usually do with a new bike - cobble together upgrades (engine, exhaust, suspension, ergonomics, etc.) a piece at a time and do all the work myself. I just wrote down what I wanted and then listened to Hazel's recommendations until we agreed on what I wanted. I stayed out of their way for four weeks and then picked up a bike that has exceeded all my handling (ESP with stock suspension) and performance expectations. Not the cheapest way to go, but the end result was worth it.

I can reel in a WRF450 (with lesser to equal caliber rider aboard) that has had the basic modifications recommended in literature. I can get reasonable air now without breaking something. The handling meets my needs, but a new set of Kayaba's would be nice (I'm still pleasantly surprised at how well ESP got the stockers to perform).

they have been built and failed by many repetuable engine builders including myself.

i assure you im very "detailed" when i build my motors.

why take your motor back 15 years in technology?if you talk to other tuners you will find most of them would never compromise a modern 4 stroke with a iron liner.

they have been built and failed by many repetuable engine builders including myself.

i assure you im very "detailed" when i build my motors.

why take your motor back 15 years in technology?if you talk to other tuners you will find most of them would never compromise a modern 4 stroke with a iron liner.

Do you think it would be okay if it used a different material liner? You mentioned the wall beeing close to the water jacket but why is this bad? The coolant could break through?

they have been built and failed by many repetuable engine builders including myself.

i assure you im very "detailed" when i build my motors.

why take your motor back 15 years in technology?if you talk to other tuners you will find most of them would never compromise a modern 4 stroke with a iron liner.

Please take no affront, but I like the carbon steel liner and the performance that I get. I've talked to many owners of the Thumper design conversion and they are having very good luck with it and performance obtained. I can't argue with the technology issue. When I ride I'm not perpetually in the upper rpm range of the engine. I short shift a lot and use the low mid meat of the power band. I like momentum vs. screaming the engine.

If I were going to keep piston velocities high all the time (@ 7K-10K RPM) I'd definitely go with the newer liner metallurgies. However, with the type of oil that I use (PAO) the piston ring and cylinder wear is probably superior to what you get with the newer metallurgies. Using a carbon steel liner with a PAO cylinder lube and with my riding style I probably will get an overall cylinder service life at least equal to, or better than what you will get with your approach. I believe my point is being proven out by the lower engine temps that I am seeing. If I was seeing higher temps, accelerated coolant loss, and other related symptoms I would expect to see what you are describing because of the difference in expansion coefficients and and heat transfer rates for the aluminum jug and the carbon steel liner - the liner would start moving during heat up and cool down cycles on the engine ultimately resulting in a leaking or blown head/base gasket.

I found a long time ago that a successful engine build is the result of the combination of builder and rider. A bad rider can waste your best efforts.

I respect your position. Mine is just a little different and probably not as high tech. However, I bet I have as much fun as you do when riding.

Good info all around.

My question is how much more are the better liners?

Wonder why they don't offer it with the 470 kit for higher sustained rpm riding?

470 seems to be testing the limits, but I guess they

did that with the 503 kit mentioned earlier.

plated cylinders are superior in all areas.

as far as engine builders go,thumper themselves were responsible for one member here eneding up parting his bike out.

after they built the motor several times he gave up.

plated cylinders are superior in all areas.

as far as engine builders go,thumper themselves were responsible for one member here eneding up parting his bike out.

after they built the motor several times he gave up.

Appreciate the feed back. No one builder is perfect and I have to go with my personal experience.

Just a little history. My first engine with a plated cylinder was a two stroke in 1969. It was a Kawasaki Centurion putting out about 19.4 HP (crankshaft) out of 98 cc. This one was chrome and had some issues with ring seating in the cylinder. The best two stroke engines that I ever built were with carbon steel cylinder liners. I've been working with high end lube oils for a long time and found that I could build a tighter engine (more power when done right) with a carbon steel cylinder, carbon steel rings and early PAO's by at lest 2-3 mils over their chromed counterparts. The PAO would provide secondary polishing and seating to the rings and cylinder wall. All worked best when I carefully roughed up the cylinder wall with a silicone ball hone sized to the cylinder dia. Engine heat was typically lower than one with more open tolerances (air cooled) and conventional lube. I really went to school doing this on the old F-S 125's and 250's that we raced.

Early flat track experience.

I have to empathize with Hazel at Thumper (regarding your comment above) in that he also unscrewed one of my most massive engine screw ups after a long clean record.

todays cylinder coatings are from even what they were in the 90's.

to each his own,but when i build motors i stake my living and reputation on it.i wouldnt even consider a steel liner in any case.

i went down this whole rode with thumper."its the head gasket","try this gasket","we made this new gasket.it will be fine","blah,blah,blah".

trust me when i say what i do,its from my experience.

as far tighter tolerances go,i have my 55hp crf set up at .00125" piston to cylinder clearance.try that with a steel liner and you will sadened at the result.

todays cylinder coatings are from even what they were in the 90's.

to each his own,but when i build motors i stake my living and reputation on it.i wouldnt even consider a steel liner in any case.

i went down this whole rode with thumper."its the head gasket","try this gasket","we made this new gasket.it will be fine","blah,blah,blah".

trust me when i say what i do,its from my experience.

as far tighter tolerances go,i have my 55hp crf set up at .00125" piston to cylinder clearance.try that with a steel liner and you will sadened at the result.

I don't doubt that you build quality engines. I've read some of your previous posts.

The crf specs are tight and with the coated alloy liner it should hold much longer than a carbon steel jug ... I agree.

May I conclude that you and Hazel do not party together? He's a big Burleson fan which I am going to guess is not going to get your blessing either.

Just kidding. And seriously, thanks for your feed back. If I find my cylinder head residing snugly up in my crotch during a ride you will be the first to know. Hazel will be second ... I know where he lives.

no problem with either of them.i just dont agree or beleive in using steel sleeves.

i do socialize with many tuners.

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