flyinggibbon

DRZ-400 Rally Raid Big Bore Engine Build (Under 450CC)

36 posts in this topic

i you want reliable power from a drz i wolde say you your best option is air box mood and fcr a good pipe and maybe a drz400e cdi it won't be a monster 
but if are not going to spend a loot of money on suspension which is one of drz weakest points along with wagith the biggest bang for bucks  and differences 
is the fcr big bore kits create a lot of reliabilt problems and cost . looking for a cam that makes moor turq is allso a good idea do you know the speed range
you are going to be doing if you are planning on going over 100 kmh for long periods you will need turq more than hp for higher gearing and maybe better radiators 


Again, I agree another bike is much better for a race but you don't know what the hell you're talking about when it comes to DRZ's. A big bore and cams will not adversely effect reliability. The bike will still run for 10's of thousands of miles with basic maintenance. The higher rev "E"CDI is of no value as the motor isn't pulling at the stock 10k limit anyway.

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The e cdi is for the difference in the rate of reeving up from the cv carb tofcr and big bore kits will make the engine hoter over loong operation time tuning is not magic wen you gain sam ting you All so lose sam ting els the is no only net gain

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2 hours ago, motodr441 said:

The e cdi is for the difference in the rate of reeving up from the cv carb tofcr and big bore kits will make the engine hoter over loong operation time tuning is not magic wen you gain sam ting you All so lose sam ting els the is no only net gain

Big bore kits will make indeed make the engine run hotter, but only if you didn't bother enriching your AFR to compensate for the higher vacuum the larger bore is pulling in. 

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5 hours ago, flyinggibbon said:

And, through my ninja like google-foo (https://www.facebook.com/MyersRacingEngines/posts/466410233745083), Myer's racing are claiming the following HP/Displacement numbers off the same dyno:

Myers Racing 462cc Drz - 64.66hp

Myers Racing 434cc Drz - 59.2hp

stock Drz - 29.65hp

Now, if they can work the 434 magic with a kickstart and reliability, that's almost too good to believe, but they'd get my money...

Check out Myer's youtube videos linked to his facebook. The 462 seems to be his daily driver, and it is indeed fitted with a kicker. 

I wouldn't be surprised that his 434 requires a more attentive hand in keeping it tip top, but 

A- I could be wrong

B- Worst case you go for a more intermediate build that "only" makes 50ish hp.

If you're serious about the build, shoot him a message on his fb page He's super helpful, and should get you pointed in the right way. He's also the only person I currently know of that does an actual decent job of porting the dizzer head, unlike some people who go at it with a dremel...

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The issue I have with Meyers is his work requires the piston pocket to be machined for the over sized valve. I would like to see his actual dyno chart and not a just a number.

He is on the short list to do my head this winter. I may go for is porting as well but I'm curious to see some actual reviews 1st

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11 minutes ago, LuckyLucky said:

Check out Myer's youtube videos linked to his facebook. The 462 seems to be his daily driver, and it is indeed fitted with a kicker. 

I wouldn't be surprised that his 434 requires a more attentive hand in keeping it tip top, but 

A- I could be wrong

B- Worst case you go for a more intermediate build that "only" makes 50ish hp.

If you're serious about the build, shoot him a message on his fb page He's super helpful, and should get you pointed in the right way. He's also the only person I currently know of that does an actual decent job of porting the dizzer head, unlike some people who go at it with a dremel...

Thanks, will check his Youtube channel, had already sent him a message on Facebook, as I am indeed serious as a heart attack about this.

In fact, I've just realised he's based out of Tampa, where I have to be next month for work, so might see whether I can drop into his shop, the more I see here, the more I think this is going to be a cracking plan, a former colleague in Australia has just given me an inside track with a fairing builder for the 28litre Safari Tank, with the rest of the bits being either easily fabbed up, or available off the shelf.

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6 minutes ago, ohiodrz400sm said:

The issue I have with Meyers is his work requires the piston pocket to be machined for the over sized valve. I would like to see his actual dyno chart and not a just a number.

He is on the short list to do my head this winter. I may go for is porting as well but I'm curious to see some actual reviews 1st

Sent from my SAMSUNG-SM-G920A using ThumperTalk mobile app
 

The Dyno chart is on the facebook link I posted earlier, see here

 

Edited by flyinggibbon
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The Dyno chart is on the facebook link I posted earlier, see here
[/url]  

That's for the 462. I want to see the 434. The 59 number he is showing at the top only doesn't cut it

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1 hour ago, ohiodrz400sm said:

The issue I have with Meyers is his work requires the piston pocket to be machined for the over sized valve. I would like to see his actual dyno chart and not a just a number.

He is on the short list to do my head this winter. I may go for is porting as well but I'm curious to see some actual reviews 1st

Sent from my SAMSUNG-SM-G920A using ThumperTalk mobile app
 

I didn't realize he needed to machine the piston pocket... 

He was on my short list as well, but that might be a game changer.

From what I understand, the 462 build isn't near the full potential that he was envisioning, and he's been planning on building another engine with even more power. 

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1 hour ago, flyinggibbon said:

The Dyno chart is on the facebook link I posted earlier, see here

 

Good point well made, asking him for the chart now

 

Edited by flyinggibbon

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Right, this is the FB Message I sent and received, really rapid response, happy with that, will see what the Dyno chart looks like.

Me:

I saw you offer a Myers Racing 434cc Drz giving 59.2hp, could you build this engine with a machined head with manual decompression for a kickstart? If so, at what cost? Currently looking at building a DRZ Rally Raid bike for Rally's in Morocco and Europe (about to be posted to Spain), so reliability at high power outputs is a must, happy stripping the bike once at home plate for maintenance, but would like to keep field maintenance to oil changes only.

Myers Racing

That 434cc bike has a kick start on it. It has a newer head on it so no manual decompression. I did machine my head on my 462cc that makes 65hp for the manual decompression. There is no power loss from doing it. As for reliability the 434cc bike is daily driven and has not had a problem yet. Where the 462 has about 4000 miles of me trying to break the bike with no problems with this setup. Most of the stuff I use is modified oem parts and if I change something out it's with better then oem so reliability is no issue.

Edited by flyinggibbon
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If you are serious about racing in desert rallyes you're making a mistake. You talk about the reliability of the DRZ and low maintenance intervals but that all starts to go away once you build a "race" engine, even a mild one, then participate in an actual race. If you think you can race a DRZ in a rallye and not do virtually the same maintenance as the more high-strung bikes you're headed for a world of hurt. 

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1 minute ago, ptgarcia said:

If you are serious about racing in desert rallyes you're making a mistake. You talk about the reliability of the DRZ and low maintenance intervals but that all starts to go away once you build a "race" engine, even a mild one, then participate in an actual race. If you think you can race a DRZ in a rallye and not do virtually the same maintenance as the more high-strung bikes you're headed for a world of hurt. 

Totally understand that, this is more about me having a piece of kit that allows me to do a number of Rallye's at the back of the grid and build experience, or even just get away for weekends and practice. In a race setting obviously you need the maintenance tempo and the only way of working out how good or bad this will be is by cracking on. Having said that the evidence would suggest that a DRZ will be less intensive in tuned format than the highly strung even un-finger poked KTM's etc.

I've had some experience with the 400 platform in the desert and they're pretty bulletproof in it's unaltered form.

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From what I have seen, most rallyes in Europe cover a lot of sand. As such, it's the chassis that's going to require the most maintenance. That sand gets everywhere and will quickly destroy bearings, chains and sprockets. Engine maintenance will be the easy part as long as you don't overheat the bike to the point damage is done.

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2 minutes ago, ptgarcia said:

From what I have seen, most rallyes in Europe cover a lot of sand. As such, it's the chassis that's going to require the most maintenance. That sand gets everywhere and will quickly destroy bearings, chains and sprockets. Engine maintenance will be the easy part as long as you don't overheat the bike to the point damage is done.

And that's my point, trying to manage maintenance, so it plays to my strengths which is non-engine stuff. It also helps that I know a couple of guru's in Australia with a stack of experience making 400's run in sand etc. In europe, most of the Rallye's are mountain and not that Sandy, for instance Rally Albania and Rally Seres in Greece, it's Morocco that is the sandpit...

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