Crankshaft questions & Piston recognition

The RC is for RC Engineering, thought ole APE Jay would've caught that one...the 3 horizontal grooves in the skirt are another RC trademark.Boy am I getting old, had a set of those style pistons in 1979 1132cc. tho.

wireman wrote:

i know wiseco has a W stamped on it,how about russ collins?

somebody was on that track!

Good info - now I am up another 60cc's but hey? what the hell huh??
I did some further thinking and snooping at the engine and it appears the bike has the 29mm carbs fitted as seen by the 17mm drain plug on the bottom of the carb bowl.
Should I go the way of the 1075 kit from APE; will these carbs feed the engine with a bit of dicking around with the jets?
What about the head - they recommend work there too. What would others recommend and how far should I take it before I decrease durability and reliability?
I prefer riding to fixing these days!

Post edited by: WTF!, at: 2007/03/10 05:38

Finished pulling down the engine today. I wanted to take a look at the crank bearings and see how hard it is to replace these.
So - how hard it it guys?

I have never stripped a bike engine this far before and its quite different to a modern jap car with its white metal bearing shells that drop out (similar to the Z1's cams)
It looks like the crank on the Z1E is pressed together?.

I know the limitations of a car engine for clearances and the difference between doing the job completely and just doing a 'patch up' job. EG: a jap engine at 200,000K needs only a head job, new rings and a hone and new B/E bearings to prevent the extra load from the new rings running a bearing during the break in period. The often don't need Crank bearing replacement until 400K +.

SO! what are the limits of the Z900 engine and what do the experienced hands out there recommend. With the new pistons and cams will the bottom end hold together on the basis of the measurements below or should I be doing more?

I measured the #5 bearing end play and the big end bearing clearances and came up with these #'s:

#5 - .15 thou / .38mm (max = .020 thou)

#1 BE = .015 thou / .380mm (max = .024"/0.6mm)
#2 BE = .011 thou / .279mm
#3 BE = .014 thou / .356mm
#4 BE = .016 thou / .406mm

Another question - what is a welded crank and where is it welded...

Cheers for the replies!

Post edited by: WTF!, at: 2007/03/13 19:20

according to mother kaw bigend side clearance on rods is .3 - .4mm standard and .6mm is the service limit.the pressed pin design of the cranks is one of the things that make these motors so strong by eliminating the weak link in the rods,the bolts.welding the crank is done on the outside edge of pin oppisite of rod where it meets counterweight to keep it from being twisted.its not complicated but you need to check crank for straightness before welding

Thanks Wireman. Can you check straightness at home or is it a shop job? I have to drop the head off anyway so perhaps I will get them to look at it.
Would you happen to have a picture of a welded crank?

you need a nice straight piece of rod same od as the id of rod small end,drill blank works good if you have access to one.i dont have a picture handy but if you look on oldkawmans site(:blink: :S :whistle: )he has a picture i think of one.

17mm Drill rod, available from Grainger, MSC, etc, or talk nice to your local machinist

Thanks Wireman, I'll drop on over to oldkawman and check it out. Maybe while I am there I will have a perv at his daughter...
:blink: :sick: