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help on Cams for stroker/BigBore install

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So recently bought a 2000 drz all stock in Aug. Guys says just put new oil and coolant in and its ready to go. What he didnt mention is the oil leak form the drain plug he stripped. So after about 1000 miles me thinking its all good the rod bearing went by and by and slammed the piston down into the rod. So now i need a new crankshaft and piston. Figured might as well go with a stroker +4mm and cylinder works big bore kit. From what research I've done it looks like Im going to need the following support mods,

 

fcr 41 mm carb.

Aftermarket exhaust,

cams,valves,springs.

 

My question is everyone seems to say go with RHC cams,valves and springs. But it looks like you can get Hot cams for over $150 less. So my question is what kind hp difference will i see with hot cams stage 2 over the RHC cams and more importantly any RELIABILITY difference? Also as the hot cams are less severe then rhc would i still need to upgrade my valves and springs if i went that route?

 

On a side note the carb and exhaust are not cheap so do you think id be good running stock carbs with a jet kit and stock exhaust till i save up some money? 

Thanks for the advice guys and happy to be part of the community. 

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Hotcams don't have enough duration to deal with the increase in swept cylinder volume when going stroker....

You will risk pushing head gaskets...You can run less compression but it kinda defeats the purpose of stroking ....

Expect some reasonable torque with stroking and BB but top end won't be there with stock carb,valves and  hotcams .....

If you don't want to go the extra expense and do the stoker properly you would possibly best to just use stock crank and fit BB....IMO

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Thanks for the reply. Looks like ill be going with RHC cams then. If I'm this deep in might as well go with a stroker. do you know how reliable drz engine is with a stoker, big bore kit running RHC cams ,valves and springs? Also i definitely plan on going with the 41 mm carb and MRD exhaust but will the engine run alright without these for a time? Trying to get on the road again asap but that's a extra $1200 so might have to run without them for a few months. 

Edited by tplayer100
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Thanks for the reply. Looks like ill be going with RHC cams then. If I'm this deep in might as well go with a stroker. do you know how reliable drz engine is with a stoker, big bore kit running RHC cams ,valves and springs? Also i definitely plan on going with the 41 mm carb and MRD exhaust but will the engine run alright without these for a time? Trying to get on the road again asap but that's a extra $1200 so might have to run without them for a few months. 

 

Arh...now that sounds like a plan..... 👍

It will be just as reliable as a stocker if maintained well... regular oil/filter , air filter changes( Oil wise I prefer .maxima go with a 10w50  or 20w50 semi syn after break in)...valve clearance checks..

Use +1mm oversize valves

Head Flowing will also give you more overall power..

Edited by Craigo
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read my bike description. pretty simple to install the parts.

 

I might not be using all the engine potential..but it didn't cost me more then a new bike either.

 

I prefer to install the ACT while the case was splitted.  the cam and exhaust are easy to change later on.

Edited by maxpat82
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read my bike description. pretty simple to install the parts.

 

I might not be using all the engine potential..but it didn't cost me more then a new bike either.

 

I prefer to install the ACT while the case was splitted.  the cam and exhaust are easy to change later

Your setup was something i was looking to do that wouldn't break the bank. a few questions though. Where did u grab a 4 layer base gasket, would the new hot cams run any different the old, and how reliable is that setup? Nice bike btw

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2 3layer gasket which you take the second middle layer that you add to the first one.

 

the old hotcam stage 1 is the same as the new stage 2 (not available anymore)

the regular new hotcam(stage1) are a bit less aggressive.

 

but I doubt there would be a running issue having the new hotcam cam.

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Awesome thanks. Is there a reason you only went with the intake cam and not the exhaust?

I don't mean to hijack the question from maxpat82, but when I went higher lift and longer duration with just the intake cam I noticed big gains in the bottom of the rev range. Top end power is not a priority for me, so a more extreme cam on the intake side gave me a much more 'flightier' feeling down low. But that's just my observations.

 

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Awesome thanks. Is there a reason you only went with the intake cam and not the exhaust?

 

If you want more power overall use RHC 187's cams...they have same profile on In and Ex.....

I have tried Hotcams on a stroker....RHC are substantially better without question...

It's your call on what you want out of this configuration, just steering you towards the most power option

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Just a point of view / mincing words -

 

You don't actually NEED any of those other mods. They are only about A) making the most out of the new setup/parts, B) shaping the powerband, C) reliability upgrade by going to one-piece valves. But everything WORKS if you don't go all the way at the same time. And you ALWAYS add power. You never get a dip in power by not going all the way at the same time. (It's even the opposite - you even start losing a little at low RPM if you go further out at the high RPM range. That's a mild effect though afaik.)

 

There's one thing that's NEEDED:

If we make the stroke longer, then compression increases if everything else stays the same. So we need to take care of compression or we start to blow head gaskets. The most common ways are to raise the top end away from the bottom end by adding base gaskets - fix it in static compression - or with the RHC cams that are built to bleed a little bit of compression - we fix it in dynamic compression. Or some combo of cams/gaskets. (Or you can mill the piston. (And there are/were also special pistons? As far as I know not a cost-effective way or even easy to obtain anymore?))

 

The RHC cams and MRD exhaust do add some horsepower to the whole range, but are mostly about top-end. (Well, changing the exhaust is also about weight.) The 41mm carb basically only adds top-end HP [edit - and midrange! thanks for the correction Craigo!!]. Not sure about the valves, but I suspect they are mostly about top-end. (As a point of reference, almost all the 450 bikes use 39mm FCRs. I've ridden a Husaberg 450 - very oversquare, revvy motor with a loooong and hefty powerband. Revs to the moon and keeps building until redline. Amazing. Tons of fun. Still "only" a 39mm carb.)

 

Even if you change NOTHING else but add a stroker, then you still get more power almost everywhere. So those other mods are WANTS ... definite wants! ... but not NEEDS. And it's perfectly fine to do one at a time. It's good to strategize a bit about what to do in what order if you're splitting the cases, but the changes themselves do not call for it.

 

What do you use the bike for? Dirt, supermoto, street?

 

And do consider adding suspension work or parts to the budget!!! Myself I'd absolutely definitely tune the suspension before going beyond E-style cams, working the head for +1 valves, or dropping in a 41mm carb. I'd probably do the suspension before changing the exhaust as well. The first thing I'd do to an E bike would be the suspension actually! Even with the S model, I'd start by fixing the throttle response with the 3x3 mod or a new carb, and then go directly into the suspension. Power mods after. But I do ride dirt.)

Edited by Anthon Berg
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I pretty much agree with what Anthon says...Only with the 41 fcr on a stroker the power is increased in the mid range as well...

The cams is only part of deal that gets you an increase with  intake and exhaust gas flow..It starts at the carb and ends with the exhaust design ...

Larger valves and head flowing (straightening gas flow) are other parts of the equation....

 

And yes if your doing dirt , a 41mm shod fully blown stroker is going to be too much for all but a pro to ride to the limit of the engine ......

A lower state of tune would be advised here

Edited by Craigo
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I do not lust for any more performance out of the engine combo in my bike, even after hopping off my seriously grunty MT 09, the DRZ still surprises me, my DRZ is my dirt bike in summer, my road bike in winter so the engine is perfect for this split role, and it easily keeps 450's in sight the passes them when they run out of gears when the trails open up. Only thing on my wish list is an RHC 187 inlet cam, might be good for 1 or 2 hp but it will ease the cranking resistance for the starter. After 2000km of road and trail riding, the engine is still reliable, went with the 3 layer base gasket on my one because of NZ's poor fuel.

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Awesome thanks. Is there a reason you only went with the intake cam and not the exhaust?

the cam and FCR39 was the first mods I did on my bike...I did the BBkit and head rebuilt then(big oil consumption) and 1000miles later the crank went boom....so stroker and ACT while I was there.

 

I had just put enough money in my bike that year so it stayed like so....been going great since so no real need to dump another 500+$ into it.

 

Like fish_bait said: a lot of loww end..and get out of breath in the top end, but I don't care/used the top end much on my comute to work..hehe

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read my bike description. pretty simple to install the parts.

 

I might not be using all the engine potential..but it didn't cost me more then a new bike either.

 

I prefer to install the ACT while the case was splitted.  the cam and exhaust are easy to change later on.

 

What was the reason for the 4 layer base gasket mod? have you had this on a dyno?

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