WR Stroker build advice needed

As some of you may know my transmission has locked up ending my riding season for this year. Over the winter I will most likely be performing a full bottom end rebuild for the first time. I have never split cases before but I like to turn wrenches. I do not currently have a Factory service manual but will be buying one soon. (If anybody has a link to a pdf I could look over in the mean time I would appreciate it) I am currently trying to amass as much information as possible before the winter when I start dismantling the bike. This bike is only street ridden but I ride it hard and I ride it often so I need it to be reliable.

Motor mods as it sits:

*3x3

*MRD/SSW exhaust

*"E" cams and single layer base gasket

*Cylinder Works 434cc big bore

*39mm FCR

*SSW +1mm valve kit (led to believe it was the same as the RHC valves but I am not quite certain anymore)

*APE heavy duty valve springs

The big bore kit is only a few thousand miles old and the head was refreshed and new cam chain installed at the same time.

First thing I will be doing is rebuilding the gearbox and installing ACT wide ratio gears. While I'm in there I will replace the second gear bushing and most likely replace the countershaft. What other parts need replacing?

Since I will have the cases split I feel it is only logical to replace the crank and main bearings at this time. Looking at prices, it almost seems silly not to go with the +4mm stroker crank. This is not a race bike but you could always use some extra grunt. I understand there is no need for a cylinder spacer with the +4, does this mean I can use any piston? Specifically the piston that came with the CW kit and is already in my bike? Will the pin boss need to be clearanced? Will the counterbalancer shaft need to be clearanced? Should I go back to the 3 ply base gasket if I want to be able to run pump gas?

If I were to go with a stroker, what other parts will need to be upgraded? I am aware the cams won't cut it, but do I go with webcams or do I try and source some RHC187's? What's the real-world difference between the two? Will both sets "need" to be degreed ? Are my APE springs and SSW valves up to the task or will they also need to be swapped for RHC bits?

As for the carb, am I fine with the 39mm? From what I've read, the 39 makes more power down low but the 41 makes more up top. Since this is street ridden and I want it to be reliable I'm shooting for low end power.

Is it worth paying for a head port and polish? Who is the go-to now that Eddie is out of the question, FastHeads? If it will only gain 2-3 hp and there's no reliability issues I might skip it.

Ideally I would like to just rebuild the gearbox, toss in a stroker crank and cams, and go ride. Is this an unrealistic expectation? I apologize in advance for asking a million questions at once but it is hard to sift through all of the old threads filled with outdated information and suggestions like "just send it to Eddie and don't worry about it" and I want this to be as stone cold reliable as everybody else says their DRZ is (unfortunately I can't say mine fits that description)

I'm sure I will have many more questions before I am finished with this build but this seems like a solid starting point. I appreciate any help from anybody else who has gone down this path as I am tackling this with very limited knowledge and no experience with a bottom-end rebuild. Is there anything that I should be on the lookout for or that I am forgetting? Thanks

This is my mild stroker build

 

Cylinder works 434cc big bore kit,  11.3:1 compression

HotRods  +4mm stroker

New version stage 2  Hotcams

CVK40mm carb

E model header, S model muffler.

ACT Wide ratio gears.

 

I did not have to clearance the piston or the balancer.

(on a previous build with the old +5mm stroker I did have to clearance the piston and balancer)

 

  If you ARE NOT looking to build a race motor , and want to use the stock cams, or the new Hotcams etc.

you will need to use 5 base gaskets layers to get the compression back down to close to stock.

(buy a extra 3 layer S model base gasket and use the two black layers)

 

     I am running 5 base gasket layers, with the new version stage two Hotcams,,

and the bike runs great on regular pump gas.

Edited by warped

Shoot Ron Hamp a mail for a quote on RHC 187 cams, he posted in a previous post that he would make them again.

With the 187 cams, you can run a single or triple bottom gasket.

 

With a +4mm stroker, you can use the parts you already have fitted (- the cams, which you can sell)

You will not get full top HP with the 39mm fcr, but it will work better than other carbs ( - the 41)

Shoot Ron Hamp a mail for a quote on RHC 187 cams, he posted in a previous post that he would make them again.

With the 187 cams, you can run a single or triple bottom gasket.

With a +4mm stroker, you can use the parts you already have fitted (- the cams, which you can sell)

You will not get full top HP with the 39mm fcr, but it will work better than other carbs ( - the 41)

Will switching to the 41 cost me on the low end? I'd rather have it pull like a tractor down low than have it turning high rpm's all the time to make power.

Do you know offhand what sort of CR it would make with a single vs triple layer base gasket with the stroker crank? I need it to run on 91.

Edited by Gsxrstuntdrz

I think ive read just shy of 13-1. If it were my build, I would run a stock s/sm3 layer gasket. The consensus or the old one anyhow is the head gaskets leak after 13-1 sometimes. I wouldn't worry too much. I really thought about doing what your doing while I was in there, but I just bought s2 hot cams and didn't think they would cut it for swept cylinder volume. Plus I was ok with the power I had prior. When these gears blow im doing what ur doing. Wr470.

I have a 41mm FCR for sale ... Pm me

It's a Good used carb ....:devil:

Sent you a pm chooken :thumbsup:

I am in the exact same position... 434, cylinder works big bore with about 2500 miles, new hot cams and I lost the bottom end...

Rebuilding now and trying to decide if i should get the stroker crank...

 

What did you end up doing? stroker crank? haw about with regards to your base gasket?

 

Thanks

I am in the exact same position... 434, cylinder works big bore with about 2500 miles, new hot cams and I lost the bottom end...

Rebuilding now and trying to decide if i should get the stroker crank...

What did you end up doing? stroker crank? haw about with regards to your base gasket?

Thanks

Still pooling money honestly... Just about finished my semester and I'll probably get started as soon as I sell another toy.

Plan is +4mm stroker, 3 layer base gasket, ACT gears, RHC 187 cams and 41mm FCR. Need to sell another bike to fund it plus cams and carb from this bike.

I'll probably either update this thread or start a new one when I actually start the build, this is as far as I am now :

ImageUploadedByThumper Talk1417909471.094627.jpg

I'll probably either update this thread or start a new one when I actually start the build, this is as far as I am now :

attachicon.gifImageUploadedByThumper Talk1417909471.094627.jpg

 

Did you get your valve cover from masshole? because I got one from him like yours when I did the CW bb kit........

 

BlueValveCover010_zps1a8ac732.jpg

Did you get your valve cover from masshole? because I got one from him like yours when I did the CW bb kit........

BlueValveCover010_zps1a8ac732.jpg

I didn't, I saw his though and they looked awesome

I didn't, I saw his though and they looked awesome

 

Well, yours looks pretty damn decent too. You even did the water connector.....can't wait to read about the rest of your build.  :thumbsup:

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