Help!,how do I install a AUTO DE-COMP RACE CAM INTO A YX 160cc motor?

Pistelero · #1 (**permalink**) 05-06-2010, 01:22 PM

Hey yall,I have a several questions I hope some of the more mechanical minded on here could Possibly help me with,
I know this forum its a pool of wealth for info on here as I have learned a lot About fixing,pimpin' a pitty & have put it all
To good use,thank you for the info & tips .(its great to fix & mod your own bike,truly a special feeling.)
I checked the forums to find anything on changing cams properly & the info was scant at best,no real clear dedicated thread for it.
Yeah there was info on a head tear down that touched on some cam removal info but I don't want to tear down the head or remove it...
I want to change my cam.(if its possible with out taking the head off,I don't know)
No one has done a proper cam change thread with a clear simple step by step & good pics you can understand..I checked ok.
Specially for the yx 150cc or yx 160cc motor that needs a decomp cam swap, If this forum/site had that info it would have it all.

All I read was some paper thin answers ,,,one liners like...'loosen the tappets & the cam will slide out..WTF?

Or people arguing if it can be taken out with out head removal..I never really saw any clear simple straight up convincing info.
'id trust that info coming from the ogs,the masters - Thump*140,sagaone coolmodee01,dvdrip, you know the names...etc etc .....
Not some teenage emo zittheadz with 5 word vocab slang going on 5th hand info....so if you are newb emo zit head,I don't need your tips thanks...please don't clutter the thread with scant answers & ill informed info..
This thread is aimed for the pros/the veterans on here to help me/others with the same prob.
Ok so here my questions I really hope the pros can help me with,

QUESTION 1-
Any competent pit bike spanna heads in south Australia know how to install a AUTO DE-COMP RACE CAM into YX 160cc? Thump*140 maybe?

QUESTION 2-
If you do & can do it legit, want work on my motor?ill pay you to do it$.(or payment in grog if you want) I know its not a big big job & wont take very long.

(my motor in bike has done 90 mins run time on the hour meter,she is fresh & new,'has the upgraded cases',so I want my motor to last a bit longer,I don't want to risk it, prevention is my thought, so I'm thinking go the decomp cam)
I have worked on pittys for a little while & have done everything on a pitty ,bar take a head off/change cam,pull down-rebuild a engine..
If I could do the cam swap I would,but I think that installing a cam out of my mechanical skill range for now since theres is no LEGIT info on it on here to help me do it.,(maybe,but maybe not) I don't want to "STUFF IT UP" or risk it know what I mean....I know how to start the bike correctly to eliminate kick back but its ridiculous & takes to long,too much 'effing' around..I don't want to waste time & my afternoons carefully kicking a Chinese engine over..that's nuts...(yes valves are set correctly, the bike runs perfect..it hauls some serious anus....its tuned very nice etc etc)
If you can help me, disregard the other questions below,If no one can help me out with that,...then,

QUESTION-3
Can you hook me up with the info on doing it D.I.Y? (changing the cam on a yx 160cc) I know I could do it with the info no prob.
If no one can help me out with the proper info on that,...then,

QUESTION-4
Can you recommend a competent pit bike mechanic in Adelaide to me that wont rip me off ,that could install the cam for me?,I would greatly appreciate it if you could..
I know about retarding the timing,but I don't think I need to touch that hey,mine is fine as is,(don't fix want ain't broke,) & that doesn't really help kick back a great deal,or fix the prob from what I've seen & read on here,I think that's more like a band aid when it needs stitches,

QUESTION -5.(2 part)
I would like to know about the 'grinding the tab down', can be done on a IRK also?is it recommended?
I saw snitchys vid after he did the grinding down of the tab...i dont think he had the irk in it.but that motor didn't last long from what I read since the damage was done before he got to the tab mod,& I ride dirt tracks with jumps fairly aggressive for a old weekend warrior (25 ft jumps! lol),,so I want to nip it in the butt before the damage starts,so I'm not sure about grinding it down either if that trashes the bike...or doesnt fix the kick back prob,,just seems crazy to do that...& I don't really want to do that...it looks way dodgey.

Wrap up.
So I know the cam will def fix the prob...thats why they made the decomp cam & maybe it might give my motor a lil more bite/zing.
The cam might be very nice indeed...my bike has plenty of grunt for me & I'm 6ft - & a super heavy weight of 110 kg of pain..I'm thinking cam ,26 oko could be a real nice extra boost & thrill..

Many sincere thanks for any help you guys put out there,I'm sure it will not only help me but many other yx 150cc-160 cc riders thinking of the doing the decomp cam swap too.

bulldog93 · #2 (**permalink**) 05-06-2010, 01:40 PM

Page 3 tell you how to take the cam out:
- http://www.miniriders.com.au/mini-tu...mpletly-3.html

Yes you can change the cam with the head on. Thats as far as I read. Best bet is to PM Thump*140

sean01 · #3 (**permalink**) 05-06-2010, 02:17 PM

ok the link above will only help a little as you have a klx style head..

but to sum it up, yes it can be done with the head on...

ill give a quick run down but will do a thread up later as i been thinking about doing it for the klx anyways.

1. remove cam cover, magneto cover and valve covers.
2. turn the magneto by hand till the timing mark on the cam is at 9 oclock. note.. theres 2 timing marks on the cam gear, so make sure the valves arent opening and closing before and after the timing mark.. if they are then use the other timing mark.
3. remove the chain tensioner located on top of the barrel.
4. use a 14mm socket on the magneto to hold the engine still while cracking the 2 10mm bolts on the cam gear, remove the 2 10mm bolts without dropping them down in the engine.
5. remove the cam gear
6. behind the cam gear you will see a plate with 2 screws, you need an impact driver to remove these. then remove the plate.
7. loosen the valve adjusting nuts and unscrew then a little.
8. ok now the cam should come out without any drama's..

to refit the new cam obviously do the process in reverse.
but lube the cam up good with either assembly lube or what i use, moray's oil(it really thick.)

to refit the cam chain tensioner you have to remove the 10mm bolt from the middle and press the little button thing in and push the plunger up. fit it then put the 10mm bolt back in.

also it pays to double check your cam timing, so when you have it installed with the tensioner in place roll the engine around again (note.. the engine operates anti clock wise) and make sure your timing lines back up..

now for the magneto mod, which i recommend.
with the magneto removed and looking down at it with the bolt side facing upwards, you need to grind half of the little pickup strip off(left side to the middle)

and no this mod doesnt work for the IRK as the IRK is fully adjustable so you just retard it manually..

ok see how ya go with all this, but like i said i will be making a thread purely for klx style engine mods.
not sure when but it will happen.
also i will be including as many photo's and maybe even a video to help..

also if i have left anything out of the above it will be obvious what is needed to get to the next step..

Pistelero · #4 (**permalink**) 05-06-2010, 03:54 PM

Thanks a lot sean01,much appreciated for the awesome info your provided.
legendary stuff.

I'm totally confident i could tackle it myself with your info for sure,but at the same time i also think the only place that i might come 'unstuck' or 'loose my nerve' is getting the cam timing part of the process correct , & those extra little bits in the cam picture are
putting me off a little,im def not sure what they are..,you know the first time jitters of legitimately getting in there & exploring new frontiers hehe...so im still not sure if i should do it or could do it with out any drama...
if i cant find anyone in sa that can do it,i might need to sleep on this one for a while longer and balls up before i attempt to try it..

again,
thank you very much for taking the time to provide the info you did.
&

for the irk tip,...i couldn't find anything on it...& i have read this forum front to back many a time (unless i missed it) makes sense to not do it because on a irk you can set the timing...man that 1 kinda seems dumb now i asked...i guess i wasnt on the ball on that 1,my bad.

thump*140 · #5 (**permalink**) 05-06-2010, 04:01 PM

mate i reckon your best bet is to PM Thump*140....
He's known to open his shed for the purposes of pittie work, tuning etc, and is a hell of a lot cheaper than other bike shops, and unlike some bike shops, will actually work on pitbikes. come to think of it, he only works on pit bikes....
The guy is a bit of a wanker, and has too many bikes, but PM him, he's pretty good at finding time to repair minis....

Let me know mate, i've done a cam change here and there... Can probably steer you in the right direction for some other tuning tips and performance mods while we're at it...
I'll also tune the bike as well once parts are installed....

Cheers,

Thump*140

Pistelero · #6 (**permalink**) 05-06-2010, 04:39 PM

PM SENT,

VIVA LA thump*140

J3NNINGS_024 · #7 (**permalink**) 15-08-2010, 10:06 PM

I bought a de-comp cam for my yx but u dont know where the other little bits and peices go. Can someone please tell or show me where it all goes. cheers