Another custom nice engine

[kirrbby]

I haven't re-read yet but...some comment/questions...
What a PITA with the cam chain! I know you'll have more to come on that, but, I can't believe that Yuminashi would have put so much...R&D? research and development...time and money, into producing a "kit" that doesn't work. If you can't buy their kit and use it as they claim it can be used...well...WTF? Is that what you're thinking? That there will be cam chain issues even if you use their top end kit on a stock Nice lower end??
Unless I've missed something, I think you're saying that this is a nice and good quality kit, that isn't going to work, long term, unless the cam chain problem is dealt with.

I'll have to spend some time thinking...how might I approach, balancing the "rotating assembly", if I were to need to do that job? Crank, oil spinner, flywheel, small primary gear...I think IS the rotating assembly. I'll think about it awhile, then maybe Google for info on similar jobs, then maybe ask how YOU approached it.

I've had issues on my black and red bike with getting fuel into the carb. I've monkeyed with the remote petcock placement, I've monkeyed with drilling out the petcocks fuel path...making it bigger. I've monkeyed with the fuel inlet barb on the carb, changing it to a 90°...to lower the inlet for better gravity feed. And I've checked and rechecked the air vents on the carb and tank cap.
The only thing that seems to work, every time, is if I burp the air bubble out of the fuel line before I ride...so I have solid fuel, no bubble, in the line. Sometimes the bubble returns as I ride, but that doesn't cause a problem when I've started out with solid fuel. ?
That bike is ALSO a bit of a fuel hog, for whatever reason.
Just sharing this I spose, since your problem sounds different than mine.

Wonder if maybe YOU need a petcock that operates on vacuum from the carb/engine..? Or maybe you need to open up, the smallest fuel passage, in your setup. You probably don't need much of a improvement...just ANY improvement might fix your problem.

 

[fatcaaat]

Kirby, before you buy the kit, allow me to be the guinea pig since I have another kit sitting here waiting for a couple of engine cores to ship out of Thailand...not sure when I'll get them, but they have been ordered and paid for. Based on my experience so far, I am going to predict that the cam chain thing will be an issue, but I cannot confirm that yet. However, I guess I don't consider it an issue anymore...I consider it something that would have been great if it were disclosed or understood rather than dealing with it as a discovery. The solve is easy and cheap, but it's just knowing whether or not you have to do it is all.

Balancing the assembly...i consider that everything attached to the crankshaft is that, outside of the piston. I say no piston because it would be impossible to fine balance it with a piston without having very specific equipment. Generally speaking, manufacturer's make parts within a tolerance and when you bolt it all together, those tolerances stack, but still need to be within a parameter. My approach was to improve each individual parts tolerances and balance, then assemble and mark, and balance the unit. That way, it can be put back on the same way it was balanced. But on my setup, the only things that can be clocked would be the crank drive gear and the mini outer oil sling. On a stock nice crankshaft, the only thing that can be clocked is the oil sling...so once you balance things, you just need to make sure the oil sling goes on the same orientation. balancing things is just slow and meticulous, and you can find videos on what you're looking for. For me, i only made adjustments to the flywheel and the crank ways, but if i were to balance a stock nice assembly, i'd assume i'd have to make adjustments to flywheel, crank ways, and the sling.

For fueling, i'm going to pull the tank and have a look to see what's going on.

 

[fatcaaat]

Well, of course another (minor) issue. Clutches slip above 8k. This is an easy fix but shows that the job is not quite done. TOok the engine out for the 20 mile loop and after getting it good and warm I started hammering it a bit, because...why not I thought? Well, once you get it above 8k in top gear, the clutches slip. I currently have 4 original trx90 clutch plates in it with two HD springs. I guess I'll reconfigure it to both HD springs and maybe 5 clutches...not sure I want to use my fancy 5-clutch setup on this or not as it was spare for my big 176cc motor but if it doesn't slip in that, it shouldn't slip in this.

Btw, i'm using Rotella T4 15-40 like I use in every one of my bikes. It's 93 degrees ambient temp today and the dipstick never exceeded 102C so I'm quite pleased with that as well. I think if the clutches slip it will overheat the oil so best I address it. Good thing is that the way this bike is setup is that I can be under the clutch cover in about 5 min or less and i'll just lean it right over on the side so I don't lose any oil.

 

[fatcaaat]

I did 30 trouble free miles on the motor today after adding all four hd springs. Clutch no longer slips. Also did a high speed run on the flat and achieved 67mph at 8800rpm. So out of power at that rpm, not out of gear. Its geared optimally for 50-55. Temps never exceeded 220f and mostly hovered around 200. Only heated up going 60 for 5 miles straight.

I can clearly tell that the exhaust is restricting it and would expect id break 70 with something else on there. Maybe the back pressure is what helps it off throttle. I might try something else just to see what happens