Carltons Custom 155z crf70 build

[The_GDFP]

Carlts, per your PM request, I'll throw in my pair-O-pennies.

Riding style will make a minor difference in recommendations. Regardless, leave the clutch alone (for the most part) while riding and alter gearing and torque to suit corner exits. I run 2 of the 4 TB springs, as an intermediate measure. All 4 will have you ignoring the clutch altogether by the middle of the second moto.

If you prefer a revvy, top-end oriented motor, a V2 or +R head, Ti retainers, 25-35 cam and Tak rockers will suit you. That will bleed off some low end and move the hit a few feet down the straight where the bike is rolling and upright. The big cam/ small engine combo will have you floating valves without the retainers and rockers. That destroys the intake valve quickly. TB intake and a 28mm carb. AU seems to love the OKO, but I'm stuck on the genuine Keihin PE28 with a JFQ needle.

Tractor time: TB 64mm-177 or Wiseco 65-66mm, with a cleaned-up stock head. Same manifold and carb.

Run 250 intermediate class: 177-188 with the TB or Wiseco 64-65-66mm and a massaged +R/V2. TM 32mm carb softens the hit and lets it run out farther up top.

For a more brutal setup, add some stroke. I build a 215cc combo that seems a big hit with the half-dozen riders on them right now. You'll go through some clutch and trans parts, but those are cheap. Gear it tall and hang on tight.

I prefer the Tak decomp cams. No-touch, kick & roost. More money, but less hassle.

Wiseco piston kit (see Woggy's build) has smaller but still adequate valve reliefs and a thick enough dome to handle compression tuning. But, it's $100 more.

Opinions and results may differ but these are some options I've had good luck with.

Cheers!

Terry

 

[sean01]

for the clutch springs, you can also shim the original ones up with a washer.. 1mm washer would be heaps and like Terry has said you can use 2 or 4..

for tight mx tracks i recon the PE would be a better choice too, less aggression in power down low.. but iv also found that using the 30mm oko it levels the aggression off and adds a heap to the top..
the biggest down fall i think people do is use 1/8 and 1/4 turn throttles, they make it harder again on a pokey big block.. i run a standard turn (3/4 i think) throttle which at times can still be a handful..

end of the day Carlt's its your engine and you only really need to improve where you think your lacking.. if you think its lacking down low and seems fine or you never hit full noise then like Terry has said, alter the gearing a bit.. adding compression can be a big help too..

another problem i see all to much too is people trying to make a killer bike/engine perform both on the track and in the bush.. unfortunately this doesn't really exist.. you either build a track bike or bush basher.. bush bashers like speed which is tall gearing, track bikes need response and low to mid range power..

i think the easiest solution would be just going with the V2 or like Terry mentioned the +R, use the corresponding hi-comp piston, s25 decomp cam. if using the V2 then i would recommend swapping the rockers for the +R ones. iv personally seen heaps of these fail.. valve springs wouldn't hurt too, valve float is a killer in more ways than you could imagine.

 

[Carlts]

Thanks guys,

Just had a skim read then. I'm off to work now, but I'll have a thorough read tonight and get my head around it.

Thanks heaps,
Carlton

 

[Carlts]

KK I appreciate everyone's help.

Seems to be a much bigger and more confusing topic than I orginally thought.

Currently my bike has good top end in the bush and fairs well around the track. All I wanted was that mean acceleration, to give me a bit more go out of the corners. (I know I'm gunna get pummeled with people saying "It's just your riding style." - But yeah deal with it lol)

Looking at the options you posted Terry, the look sweet, but pretty expensive though lol. I originally thought it was slap a V2 head on and be done with it, but now I'm seeing I would be naive to think this any longer.

Seems I'm probably not gonna get a good power boost on a small budget, but I spose thats to be expected.

The 184cc kit seems cheap as, but I don't see anyone giving it any love? Is this because it doesnt improve noticeaby, or cuz it screws the rest of ya setup?

For now I shall continue to google all the options I've been told.

Cheers,
Carlton

 

[wogtaz ryder]

If you want "mean" acceleration like you said , my first setup z155 with v2 head/s35 cam the tb piston and a 26mm oko flatslide was a awesome setup!

Head was ported and had hd valve springs . but i really liked the power of it , was real quick out of the corners and had plenty of power up top.

 

[Carlts]

Cheers woggy! Well I've already got the oko 26 so if I could keep it that would save a hunk of doe. Thanks bro

 

[wogtaz ryder]

And if you decide you need more power down the road , just slap on a 64mm -177cc kit ,is only 200 bucks or something.

 

[DHZ_XR8cing]

Is the 177cc kit really worth it? My 155z combo is awsome. Im happy with the power the 155 produces.
The v2 is a must for sure.

 

[Carlts]

Just a quick question, does this kit contain everything I need (minus HD clutch springs and plates?):

Race Head V2 Upgrade Kit - GPX/YX150/160

Is that the best option or should I ask Terry about mixing and matching to a setup like yours woggy or one he recommends???

Also should I add a decomp button?

Cheers,
Carlton

 

[wogtaz ryder]

That seems to be everything , plus you will need to grab a TB manifold to suit the larger inlet.

Also a klx dress up kit , as the Z155 head covers dont fit.

Im sure Fpm can supply you all of that.

 

[Carlts]

Sweet bro, Im guessing TB manifolds and covers will be a bit of a cost ey lol but I spose what must be done ey

Shame I'll have to get rid of my Pitsterpro dress up kit

But yer if I can everything from the one source then I can be sure everything will fit, unlike my previous experiences lol

 

[wogtaz ryder]

Nar they shouldn't be to much , manifold is around $50 i think ?

And just a cheap set of covers.

 

[Carlts]

I'll probs try installing it myself, just for the experience and saved cash.

Is it a difficult job for a first timer, and will I need a torque wrench?

Oh and is porting worth it?

Ta

 

[wogtaz ryder]

Nar there pretty easy , as long as you set up properly for the job , and just take ya time .

Sean has a real good guide on here for the klx style topend engines.

 

[Carlts]

Nar there pretty easy , as long as you set up properly for the job , and just take ya time .

Sean has a real good guide on here for the klx style topend engines.

Haha time, I've got too much, that's why I'm still non-content with my bike lol

Yeah I shall have a search then for Sean's guide, CHeers

 

[The_GDFP]

If you are happy with the top end power, the 64mm kit seems ideal. It's a 184 on the YX, 177 on your Zonger. Heaps of low and mid range. Stock head isn't awful, and is a copy of the Kitaco SE, best thing going a few years ago. Then you keep your PP covers

Just plopping a V2 will give more up top, but no real outta-corner rip, without clutch fanning or keeping the revs up. You'll also find the revs up and valve float. Revs flex cranks, increase friction, heat and wear, on the Chinese engines. If you can hang on to a torquer, it will live longer. My 195 is done pulling at 8500 but will pull most tracks in just third gear.

If you wanted a single mod, to start with, I'd personally slip the TB BB kit on, $179 and you can add a V2 later, if needed.

A V2 with a Tak cam will need a cam cover that clears the mechanism. Stock KLX cover is $15 or less, new and works great. $700, for V2 head with Tak cam and rockers, adapter.

 

[Carlts]

KK so you reccomend the other way then.

SO if I go the 177 kit, will I need to upgrade clutch springs (2 of 4) and/or plates? and also will I need a decompression option to save my kicker gears???

Thanks mate

 

[The_GDFP]

Just my opinion, but if you like the top end, add bottom

The PP spark-plug decomp thingie is portable and works OK.

You can have your head machined for a button easily. There was a write-up a while back, on the Planet. No rocket surgery, just gotta find a decent machine shop or a brave lad with a drill press.

 

[Carlts]

KK, so all sounds good,

Then whats my best bet for say a $400.00 budget?

Could I just get a decomp cam instead of a button?

 

[The_GDFP]

KK, so all sounds good,

Then whats my best bet for say a $400.00 budget?

Could I just get a decomp cam instead of a button?

Unfortunately, the only decomp cams for the stock head are the $300 BBR and the Alibaba knockoffs. I might try one of the cheapies, but can't recommend them ATM.

BBK and the decomp would eat most of your budget.

http://www.miniriders.com/ask-tech-...uto-de-comp-race-cam-into-yx-160cc-motor.html

Ask Ken@DHZ to see how the cam has worked. Might be awesome. I truly hope so.
I'd suggest the Tak adapter, since there's nothing to guide the slider block on the Chinese engines.