Detonation: An engines biggest threat

I will soon order a stage 2 kit from CRMachine for my PK 80 not so that I can break the sound bearer on my BICYCLE but rather because the products offered are good, solid quality products, I bought a modified piston for my Indian from CRMachine to in-hance the over all perfomance of the other quality components I've installed on the bike, now after seeing and using CRMachine parts first hand I'm hooked on the Quality and want more.
Sales pitch or not ? who cares??? the Man has done his research since the very first time he poked his head into the M/B world, that's good enough for me.
Thanks! Fred

Just to clarify, I was NOT hacking on crmachines products! Everything I have seen or heard leads me to think he makes great heads. I just don't agree with his statement about detonation being the main cause of ht failures.
I am done.
Sorry if you felt attacked cr...not my intention.

Sure would be cool if you just designed,built and marketed yer own engine Fred, I'm sure you thaught about it and it would probably look better too, you can do it I have no doubt! an early period correct 4hp 4 banger with all the modern day advancements.
I bet you could do some modern drive eccentrics as well.

I'd really love to see someone design a copy of the ht with japanese level performance and quality. Imagine RM 80 level performance on a bicycle! I know it would be pricey, but if it ran like a japanese motocross engine, I'd sell ALL my junk and build one instantly!
Why are there not more mills like the Morini/KTM?
I want it to mount and look like the china ht but run like it could with japanese reliability and excellent driveability. Smooth idle, no four stroking, good cooling, good seals and bearings, reed valve, tuned pipe, different levels of tune (daily driver, mild, race)
Steel sleeves, standard piston with oversizes available, forged piston and rod, standard good mikuni carb and air filter. MANUAL clutch (maybe with cent. option)
I'd like to see one of our machining wizards tackle this build.
Alas, I can drill, cut and weld, but the craftsmanship to make my dream come true eludes me.
* sighs*

Get a KTM..

Goat Herder said:

Get a KTM..

Click to expand...

I will
when they make a manual clutch for it.
I hate centrifugal clutches. Always have.
All my cars were manual, etc. I need the direct connection from the throttle to the power or it feels wrong to my instinctive lizard brain. It's like a deisel engine. I know they work great, but they just sound blown up to me.
I can't control it.

Get the Tomar clutch for it and it is heaven! Been loving mine more than any thing I have tried. Very easy to adjust too. Ive have had them set up to where they felt like they was gears. I mean the progression rate matched my habits perfectly.

Goat Herder said:

Get the Tomar clutch for it and it is heaven! Been loving mine more than any thing I have tried. Very easy to adjust too. Ive have had them set up to where they felt like they was gears. I mean the progression rate matched my habits perfectly.

Click to expand...

Really...I'm still skeptical. You had to finagle it daily to get that didn't you?
I understand tuning clutches from my RC days but it takes too much trial and error and it never holds a setting.
Does the Tomar stay set?

Stock 3 stone clutch finagling yes. Ayup..Tomar stays set and is easy to adjust!

Hmmm....I still need to feel one for myself. Too many years of broken hopes to overcome without concrete proof.

I will be riding



Now back to our scheduled program how about those new cylinder heads!!

Back on topic, no one is saying that the crmachine head doesn't cool better than the stock head. In fact, just from seeing pics of the crmachine head, I'm very inclined to believe that it performs much better than the stock head, in more ways than one. But it still does not PROVE that detonation is a LEADING cause of problems in ht engines. There are way too many variables with ht engines, ranging from how well any one engine was manufactured to the user's level of mechanical ability and a WHOLE LOT in between, to say that ANY one thing is the main cause of engine failures. Okay, so your research tells you that detonation is a problem. But that data still only comes from engines that you have personally studied. And you can't assume that when someone says this or that went wrong with their engine that detonation was the cause without personally studying that engine. Once an engine is blown, its not always easy to tell what the root cause of the failure was. Also I have no doubt that the crmachine head is winning races. But the only thing that proves is the performance of the head over stock. It doesn't prove that all stock heads have detonattion, it only proves that they cool poorly, something which is already known. And here is why this type of sales pitch is a problem. Your tactic is to get people believing that detonation is a serious cause for concern, and that your product will solve it. Now people that don't have this problem may buy your product not because they believe it will add performance, but because they believe it will solve a problem that may not even be present in their engine. Put a performance product in the hands of someone with limited mechanical ability, and they'll still have at least as many problems as they did before, if not more. No product that is out there today is foolproof. My dad used to say, as soon as you think you made it idiot proof, someone comes along and builds a better idiot. And I'm not calling anyone here an idiot, I'm merely demonstrating the point that people with limited mechanical ability may come to believe that a particular product is the cure-all, spend a lot of money on said product, and perhaps gain better performance but at unnecessary cost, or be no better off than what they were, and I don't think either of those outcomes are fair to the buyer. And in the ht bicycle engine market, I definitely support the buyer more than any vendor or manufacturer.

Just ordered yer Stage 1 PK 80cc Top end kit Thanks! Fred you can P/M me for some info and pic's of the build this kit is beiing used for, Might even need a little private school'n too! (LOL!)

Hey! Fred
When I replaced the stock head on my Indian (PK 68.5/80cc) with a Puch 70cc Hi Hi Comp head I replaced the wrist pin bearing and others with top quality products from Germany and Japan, when you provide the wrist pin needle bearing with the kit is it an up graded qaulity component or a stock Chinese part?

I had the exact same issues that Fred explained when I ran a stock RB80 on my old build. I have a GT5 engine on my current build. I completely tore it down when I got it, and matched the crankcase tranfer ports to those on the jug/cylinder. I have a high flow intake that was machined to match the stock port. I chose to use a 15mm Dellorto SHA carb. The exhaust is the SBP x-chamber. I sanded down the gasket-sealing ring on the stock head, and also sanded the top of the jug down until the piston edges were level with the top of the cylinder. Running it with the stock head, my engine was detonating badly and it got very hot. I'm no 2 stroke theory expert; all I know is that when I received my CR Machine head (6cc combustion chamber), the problem went away. It smoothed out dramatically, has much more power, and the speed of the bike is where it should be now. I know a lot of people run their engines in the stock configuration without problems. I'm not arguing against that. In my personal experience with Fred's cylinder head, everything that he has said has been absolutely true.

I bought Freds Stage 1 kit,cylinder,head,piston and intake manifold with all gaskets,tore down the PK 80 got the lower end together,painted and everything but just haven't had the time to devote to the bike as a whole,my thread is "Big Black Jack" lots of pic's bikes from old, as I said not much time to devote to the bike,it happens every time I start one but I will post on this thread as well when progress picks up again.