zed1015 wrote: Regardless of cam symmetry the lobe center timing method will get them degreed correctly every time.
You can use whatever checking height you like ( even negative figures) as long as you use the same ones in all your calcs .
You only need to locate true TDC on cyl 4 ( right hand , ign side, end cylinder) for cam degreeing .
This will cam time all cylinders unless the crank is twisted .
Thanks, this reinforces what I was thinking. So should I check the angle at 1mm lift (using negative lash) or just check it at max lift? If max lift, are my assumptions correct (IN: 105°ATDC - EX: 107.5°BTDC)?
Regarding the cylinders: I think I'll end up getting some JE pistons and getting the cylinders bored by a local guy. He does good work and if I have any problems I can just go round and talk to him. If I get the Pit Stop kit I'm stuck with it (assuming it really is from Pit Stop - the guy has the invoice but there's no way to be sure that the parts are actually the ones from the invoice).
Went to see the new engine guy today. The cracks in the head were a lot worse than they looked - he'd cleaned everything up so you could see exactly how far they went down the threads. Getting them fixed over the next couple of weeks. One of the plugs had been helicoiled as well but the helicoil was too short. It needs to come out anyway as there is a crack under it.
New plan for a nice street engine:
- 1075 Wössner pistons (or JE if he can't get Wössner)
- Stock valve sizes with seats bored out 1mm and bowls ported
- Yoshimura stage 1 cams
- No welding the crank, just check everything
The last point may cause a bit of a stir, but it just isn't worth the money (a lot more over here than it seems to be in the US). For the cost of doing it right I can almost replace the entire top end - no way I'm getting someone to weld the crank and not having it properly checked and balanced afterward.
The chances of a crank in good condition spinning with this setup is ridiculously low, especially looking at the pressure required to seperate them. I'll take my chances
What I found interesting is that almost nobody that I talked to in Germany recommended welding the crank, whereas pretty much everyone in the states did. Maybe you guys just don't trust japanese engineering
Have next week off to sort out the mini and get the Zephyr engine back in the frame. Will hopefully have some time to start planning what to cut off the frame....
I'm in the UK and almost any ground up built Zed motor that gets a decent power increase has the crank indexed and welded.
Even a stock motor can twist it's crank through a high speed missed gear or hooking up hard after a burnout.
The torque required to twist is much less than the poundage required to press the webs apart.
If you have ever seen a crank trued after being pressed up and clocked it is simply done by a highly skilled mallet technician.
Sounds crude but effective and a few sharp taps is all it takes.
Thanks zed. I realise there is a lot more leverage when twisting than when pressing apart. Still, consensus here seems to be that it isn't necessary under 130-140bhp - I figure I'll be hitting about 105-115 tops.
Also, although I can see myself missing a gear I'm not one for burnouts anymore - would rather spend my money on parts than rubber
Picked up the cylinders and pistons yesterday. Took a photo of one of the cracks in the plug threads before it gets repaired, after the head was cleaned up you could see the extent of the damage. I'll post a photo when I get it back after being repaired.
The worst crack in the head:
The cylinders - I went with Wössner pistons, had to go with German quality
Calum - those new pistons look great! It appears as though they apply some anti-friction coating to the skirts? Very nice.
And, just a suggestion if you haven't done so already - before installing those pistons, I would gently radius the edges of the valve relief pockets that are cut into the domes. This eliminates a potential "hotspot" and will lessen the chance of preignition. A small detail....
Good luck with your build.
Presently - 1980 KZ1000B4 LTD w/mild ported head, Megacycle cams, 1015cc Wiseco, Falicon Supercrank, R&D undercut trans
In a former life - KZ-based dragbike - CrMo car tire chassis, 1395cc, Hahn Racecraft turbo system, VP C16, Orient Express 3-spd auto, 7.80's @ 165-170.
Dragbike_Mike wrote: And, just a suggestion if you haven't done so already - before installing those pistons, I would gently radius the edges of the valve relief pockets that are cut into the domes. This eliminates a potential "hotspot" and will lessen the chance of preignition. A small detail....
Good luck with your build.
I’m not a professional builder but I agree. When I was building SBC street engines I’d grind and radius any sharp edges off.
Exciting project, everything does not have to be original. Very nice that you attach nice pictures of the project and progress at the same time as it is nice to have a building log for the owner and builder of the bike. Keep up the good work
Thanks. It's pretty slow going at the moment - the Zephyr is taking up too much time I have the shop cleaned up now and the Mini is out so things should start to pick up with hopefully a lot more pictures coming.
It's the slow periods that start to get under my skin with mine. For the first time since I started on mine it is under a cover. Looking like April at the soonest before I can get back to it. Keep up the progress, I really like where you are going with this bike!
'81 KZ-750 E2
'87 Suzuki Savage 650 Street Tracker
I hear you! It's been pretty frustrating working on everbody's vehicles but mine. Finally have some space though. Made myself a new workbench and laid down OSB over the tiled floor (don't ask me why anyone would tile the floor of a garage...).