Getting to the cam Valves

[JEEPRUSTY]

Can these threads not be chased and salvaged?
That would prevent a lot of excess effort.

The range of PSI noted looks like a stifled intake more than a bad seal.

[nickr234]

lol

Ya know, I was just reading about that old Q&A form post about giveing good information. It is funny when irony strikes


well before I started doing this project I had K&N pods and stock exhaust with 17.5 pilot 3rd clip on the needle, and 117.5 main. I got a new Exhaust system (mac 4 into 2 turnouts) and started to do plug checks. This is when my oops happened.


So I got a “new” head from eBay along with all the gaskets I needed (thanks Big T). I then lapped the valves and replace the oil seals, and then replaced the “old” head with the “new” one.


As for my intake I have replaced the boots and o-rings. The air box is sealed and I have not replaced the boots on the air box, but the boots are still ply-able and with a serious visual inspection I see no cracks or anything like that. The carburetors have been re-built just yesterday because I had some left over carb kits because they were really cheap and I needed the needle springs. so all of the gaskets and the springs and the jets are good. I used the new jets because even jets get “bored out” by the gas after 30 years.


As for the exhaust there are no holes at all, but the joints do leak a LITTLE bit of air. But nothing that would cause this. Just today I made sure the exhaust was sealing to the head, and there was a problem with the new screws that I bought because there was just a little too long and didn't get a tight fit to the head, but I remedied this and the exhaust is sealed up perfect (accept the joins).


I then took the bike out for a ride today and got it onto a highway so I could do a high end plug chop to make sure the mixture was good. The bike seems to have the most power in 3rd gear, and a good amount less in 4th, and WAY less in 5th (this is expected because 5th is the cruising gear and 4th is the “power” gear, but this was a BIG drop) then while still in 5th my RPMs went lowly down and then my exhaust started to crackle a little bit. So I shut the engine off and glided to a halt (with the clutch pulled of course). Then I looked at the plugs expecting to see a white plug because I heard crackling in the exhaust, but the plug was a perfect golden tan color (It was just about the best I have ever seen).


Also it seems boggy when I am going up hills, or if I open up the throttle when I am in a higher gear “than I am supposed to be” (like going about 25 in 3rd and opening it up to ¾ to open) and this never happened before.


I have read on here that sometimes this can happened if the timing chain is off. I know for a fact that there are 20 pins between mark 2 and 3, but maybe I disturbed the cams when I was putting on the caps? What do you all think.


Thank you all so much for everything,


Nicholas

[TheCafeKid]

Man sometimes I wish I could just zap myself from to somewhere and back.
So here's the deal. If youve put the stock airbox back on, and the exhaust is a Mac 4-2 still, (I'm assumig here) then 117.5 on the main is a little large. And what kits are you using?? I would advise only using Mikuni genyouwine jets. You have no idea how other companies measure their jet sizes and whether or not they're even accurate. (ex. DynoJet sizes are measured differently than MiC) ok so, all things being equal, your Mac exhaust should only flow slightly better than stock if any at all. Therefore with the stock box, etc you need to head back toward stock sizes. For one, the 15 pilot for sure. The main used to be what, 105? Stock. Maybe shoot for 107.5 if you're keeping the box on there. If you're going back to pods, which I wouldn't until you get it running good stock(ish) as it just complicates the diagnosing process, then hang on to your 117.5. Maybe get a set of 115 and 120 as well (Z1 sells legit Mikuni jets cheap). Set your carbs up:

Fuel screw 7/8 turn out
Air screw 1.75 turns out
#15 pilot
Main 107.5 (with airbox)
Clip in the middle slot.

Plug chops need to be done in circuits. Not RPms not gears.
Mark your throttle with tape. 0-1/8 throttle, 1/8-1/4, 1/4-3/4, 3/4-full. Do chops in each range. Examine plugs. Etc. It will also allow you to make note in which circuit the bike is running bad.
0-1/8 is pilot circuit
1/8-1/4 is pilot/needle transition
1/4-3/4 is needle
3/4-WOT is main.

[nickr234]

the stock jet sizes are 15 pilot and 102.5 main. right now since i put the airbox and the stock exhaust (i didn't throw it away) on i am using 15 pilots, 2nd clip from the top (this is how it came out of the factory. The PO was my father who bought it new.) and 102 main. the kits i used were keyster if i am not mistaken. i agree with the fact that im not sure if those kits had the right jets in it because they are not mikuni, but i would not get a perfect color plug chop if they were off if size. i have also used these jets from a previous carb rebuild that i did 2 years ago and they work perfectly.

sorry, i forgot to mention that i put the carbs back to factory settings.

i also had it at wide open throttle for that plug chop. and the 1/2 mark gives me a plug chop that is a little bit lite but the 3rd clip gives me a fouled plug.

sorry i need to get better at explaining what i am doing

also, lets say in the future sometime i am doing plug chop and the trasition between pilot and needle is off?. do they make new slide with diff cutaways to fix it?

[nickr234]

Thank you all

well guys i figured it out guys.

so after a couple more plug chops i figured out that my carbs are working fine. so that kind of started to worry me because that ment that it was in the engine.

So i took the valve cover off and turn the timing to TDC for the 1 and 4 pistons and low and behold my cam timing chain was off 1 and a half notches backwards (both the exhaust and intake).

So i timed it back up and got it all back together and it Wails like a banshee again.

WOOT!

Thank you all, i seriously could not have done it without you guys.

Nicholas Ryan Rasmussen.

[TheCafeKid]

Nice! Congrats. Nothing quite like the feeling of overcoming a problem with one of these bikes on your own, even if you got some pointers. That's what this place is here for and what makes it great

And to answer you question in your previous post about the pilot to needle transition. AFAIK there are no different slides with different cutaways but on the VM carbs you can tune the transition to be a bit smoother with the fuel and air screws. That's why I like tuning the VM carbs and find them easier to work with for mods because you have more control over the circuits on them.
With the CV type jet kits go a long way, but there are always compromises somewhere. The screws on those simply adjust the amount of a premixed air/fuel mix so they're IMO not as easy to smooth out any little hiccups.
But, the Jet kits pretty much get em as close as you can get, and for street riding that's close enough. I just get aggro over that little bit of bobbling you sometimes get on part throttle. If you tune it to where it takes the bike being fully warm go away, you have to wait on the bike to heat up. But if you tune it to where it goes away quickly, it will sometimes end up to wet when it does heat up. And couple that with ambient temp swings through out the day, it requires being accepting of a compromise, or sticking with the stock set up, which is ok, sometimes and for some bikes.... Etc etc