The Kamakazi - My "second" build

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Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Hey all,
So after my last engine failure and subsequent thread about deceptive practices of certain vendors, I decided to start another build thread. I am not quite a n00b as I was on my last engine so I will skip a little bit more of the basic stuff.
For this second build, I decided to name my bike, the Kamakazi. Since I already had a previous engine, this is what I am working with: Gary Fisher Capitola bike, Generic HT motor WITH needle bearings (magneto stamped 5/2011), NGK B6HS spark plug, magnacore wire, 36t rear sprocket, Worksman 415 HD chain.
Additional upgrades and addons that I have: I bought a wireless speedometer that didn't work when riding (what a surprise)gave that away and got a wired one and that works great. I still have a BGF Speed carb and I want to eventually get installed. I also bought a SBP pipe on sale during my downtime.

The possibly new motor I have looks, well like a china girl. I took her apart and checked everything out. The woodruff keys were a little beefier than my last engine. but everything looked well put together. I replaced the base gasket with a better homemade one, and greased all the bearings up with red grease. There were no glaring faults in its assembly. I had to do some work to get it mounted though. My old engine needed a mounting bracket with U bolts to get it one. This engine had a wider mount in the front. But it still was not wide enough for my bikes frame, so I had to take the Dremel to it. Once it was one I had it fired up and running within a few minutes.

I had a hard time with the clutch, though I kept on tightening the flower nut, and pedaled a bit before letting out on the clutch, the pads didn't last very long, so I ended up putting the clutch on from my first engine, re tightened and everything seems to be good.

This weekend for ****s and giggles I hooked up the SBP pipe, ran it high and strapped it down to the frame with a hose clamp and took it for a ride. DAMN, it really DOES make a difference. It really had a lot of get up and go. Of course stock setup with it is for low RPM power but it is still nice. I am having a hard time though trying to get it go into a lower mounting configuration. I have no weilding gear so I am just working with what they send. I am still reading and rereading the better posts on here on what others have done. But I have not seen one question asked "Can you cut the header pipe down without any major drawbacks?" And by "header" I mean the black pipe going into the chamber. Please correct me if I am wrong. If you look at the photo you can see I really can not ride with the pipe this low. :)

EDIT: Found my answer on the pipe. Problem with my bike is the pedal crack width. They are so close to the frame that there is no room for running the pipe between the crank and the rear tire. Have to look into that.
 

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maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
You might try running it high. Mine needed a guard or my inner leg got too hot on this version, but anything much longer can affect how the pipe works.

The longer version still gives a good torque spread but it made better power in the short version.
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Maniac,
I seriously thought about routing it high but already had burned the **** out of my leg once just testing the pipe. It looked cool too but at the same time made it look (and sound) too much like a dirt bike. So after spending a few frustrating hours over a few evenings looking at all the different ways of routing, I found the one way to get it between the crank without hitting either the pedals or the tire.
Barely, I have to thank you for your great picts you took of your bike, after studying them for a while I saw the best way of getting the pipe around. The best part is I only had to take of about 3 inches off the stock length to get it to work. Pretty much the perfect amount for the best all around perfomance.
And it does perform too! I am still early in break in, but it has FAR better acceleration through all ranges. I cruise about 20-24 at 1/3 throttle, and 30+ at WOT, though I am only doing short bursts for break in. I am not even going to try for top speed until it has a couple of hundred miles on it.
I just pray now this engine will outlast my previous by quite a bit.
 

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Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
So the good news, I put the speed carb on the Kamakazi and the performance is just incredible. The acceleration is terrific, and the ride is great! The bad news is I am developing clutch issues. I have been constantly tightening the flower nut and readjusting the clutch cable. At first I thought nothing of it, I thought that I was going through clutch pads fast and that my clutch cable was stretching.
Now I know that the countershaft is shifting. I was able to shift it back but when I reattach the cable and start screwing in the flowernut it just pulls through again. I need to do some reading on how to fix this. Any ideas?
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
It's strange, I can't seem to keep decent tension on the clutch cable. I have adjusted the cable and the flower nut but can't seem to find the perfect balance. It runs fine, just a little loose. I was going too tight on the flower nut so I backed it way off, roughed up the pads and plate a bit, and readjusted everything.

I invested in a couple of new things to play with. After getting through 35 of the 95 pages of discussion on Opti-2 I went out and bought a bottle. Even if it isn't all that and a bag of chips, for a little over a dollar a gallon, and no more black crap leaking out everywhere, it is still worth experimenting with. I also ordered an Iridium plug. Yes, that may be a waste of money, but again, a few bucks, something new to try perhaps make things a bit better, I'm game.

The engine still runs great so far, I have put another 35 miles on her or so. Will post some build picts once I get the new kickstand and get her wiped down from all the black crap she has been leaking with the 1 gallon of 20:1 Valvoline mix I ran. Hoping for some great things with Opti-2.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
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I usually park a new build with the clutch lever in the lock position to help get thru the cable-stretch period - that cable will usually stretch about a 1/4 inch before it settles in.
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Crass, thing is though this is the same cable I used with my previous engine, so it's had quite a while to stretch. If I unscrew the flower nut the cable is taut. When I follow the procedure HERE, there is too much slipage so I have to tighten it a turn more. Then the cable is a bit loose. On my previous engine the clutch would grab and hold quite well and the cable was always taut, but this one seems to slip no matter how tight I put the flower nut. Ehh. It still runs well, I just have to baby it more than before, that's all.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
the procedure you ref for adjusting the flower nut is right, except that I tighten the nut until rolling the bike makes the small drive gear try to turn, then I loosen the flower nut one notch so that rolling the bike lets the clutch spin freely

there can be other problems here tho
1) a bit of grease on the clutch surfaces will make it slip
2) clutch pads that don't fit the slots well will only touch outer plate rather than both plates and will slip a bit
3) the lock position on the lever may not be far enough back to give a good grab when released and will slip a bit (this is hard to fix and usually requires a new lever)
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
So like I said I decided to try Opti-2 and bought a bottle yesterday. I mixed a fresh batch of 100:1 and drained the last of my tank of the 20:1 valvoline mix I had. Poured about 2 cups in and took it for a short ride, I came back after about a mile to check the plug and the piston, and noticed the engine was quite hot. I let it cool down a bit and swapped my plug from a B8HS I was using to try to keep the carbon build up down while running the 20:1 mix to a B6HS to try to keep the heat down. I took it out for another run and ran for another mile, this time opening it up to see how she would handle. She did ok, but picked up a knock that wasn't there before. As soon as I heard it I immediately slowed WAY down and got back home. This time the engine was burning up. The carb was even getting hot! So I was done for the evening.

Today when I got home, I drained the Opti, pulled the head and checked the cylinder, everything looked fine, I didn't see any scoring. I put everything back together and put the 20:1 back in and took her out again for the same run I did yesterday. She ran fine but still had the knock from last night and she wasn't running hot anymore.

I am scared to try to run the Opti anymore. I was through my first "break-in" gallon with over 100 miles on it, and thought I would be safe but worried that the heat may have done some damage.

Call me lazy but I stopped reading the Opti-thread after about page 40. Did I miss some important info? Will it make a whole lot of difference if I mix it at a lower ratio? Should I burn through another gallon of regular mix before I try the Opti again?

Time to read the Opti thread for another hour or so and see how much further I get.
 
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Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Good Evening All!
So I discovered what my issue was with the OPti-2 and overheating. I had discovered that the intake manifold that Bikeberry had sent on the original replacement cylinder is a slightly bigger diameter than my original manifold so I swapped it out. The problem was that it was not sealing well against the carb and had a vacuum leak. Once I swapped back to the original, the temps dropped back to normal range. I am back to the Opti-2 mix at about 70:1 for now.

I have also swapped back to the stock NT carb. The Speed just wasn't feeling very "speedy" so I tried the NT on the same 12 mile run, and had no issues. Climbed hills like nothing. I may try the Speed again later, but losing confidence that it is any better than the NT.

Also got a NGK BPR6HIX Iridium Plug too. That coupled with the NT set one notch above the middle on the eclip is a great combo so far. The plug has a nice color, and everything is working well.

I do have one issue I would like an opinion on. When going uphill accelerating above 32 I pick up an awful knock that gets louder until the bike finally starts losing power and slows down to mid 20s. Downhill, she will go like a bat out of **** without any complaints, so I am just wondering why this would happen uphill. Any ideas?

Next week I am bringing her into work, I have a few coworkers who are interested in the concept. Now I just need to clean her up and make her presentable. Anyway have a good weekend everyone!
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
Sounds like detonation to me. You might try running premium gas or octane boost and see if the problem stops. If it does, you might be able to compensate somewhat by richening the mixture (raising the needle) which should help drop temps on uphills (more oil) at the expense of some power (more 4 stroking) If you are jetted aggressively, (lean) this can sometimes help.
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Maniac,
After doing more reading on detonation, that is exactly what it sounds like. Thank you for pointing me in the right direction. I will take your advice and look into what you suggested.
 

boofbike

New Member
Apr 5, 2013
11
0
0
Piute County, Ut.
Risingsunn,
Hey, I am a noob here and I just finished reading through both of the threads you started. IMHO. I truly think more people should do build threads and share their experiences like you have. I want to thank you because, I now have a handle on what to expect when I start my build. I may shy away from a China Girl though. The little "Morini" 2 strokes may be worth the extra bucks for me. I would rather spend more time riding than tinkering. Just my 2C. Please keep posting.
Best Regards,
~BOOF
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Well thank you very much boof, I am glad I could be of service. The china girls can be a handful, you may end up with a lemon or a 10k motor from one you get. I personally would not get a Morini. If I am going to invest that much for something motorized on 2 wheels I may as well just save up enough for a older model motorcycle. That's just me though.

I have set my needle to run richer, and though I haven't tried the "test" hill where I was having the issues, I still am having the knocking quite a bit. I took it out this weekend and it ran fine, even a little rich, but it started knocking a lot over about 28 mph even in the first 5 minutes of the ride. I popped the head and didn't see any sign of the piston hitting it, pulled the exhaust tightened all bolts and made sure it wasn't my teeth rattling so am wondering what it could be.
 
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boofbike

New Member
Apr 5, 2013
11
0
0
Piute County, Ut.
The China Girl 2 stroke engines are intriguing, A test of your ability to get one to run good and be dependable for say 10,000 miles shows everyone you got the pizazz, knowhow to do it. Kind of like the older Harley stigma. It took your constant attention to be a successful biker. Not for everyone, but an honorable challenge for sure. It's too bad nobody can get raw, un-machined parts and make everything to specs, get all the tolerances to optimum sizes. I bet if that could be accomplished you would have at least a good dependable power plant. Good quality Materials used in manufacturing the raw parts would also play a big part in the quality issues. I would say the China Girl aluminum castings are melted down old car pistons. All the best qualities used to be common place in this country when we manufactured these kind of things. Manufacturing has departed our dear 'OL USA and has gone overseas. Quality is treated like a bastard step child, kind of like our middle class over here. So, it's up to you (us) to learn what it takes to get one of these little power plants to run and be dependable like a good 'Ol Briggs and Stratton engine etc.. I guess there isn't a big enough market here for someone to do after market upgrades to the China Girl engines. Gosh, the old Go-Kart two stroke guys were 2 stroke magicians, Packing the cases, Pumper reed carbs, tuner pipes, on and on. Try to look up one of those guys, they will set you straight on trouble shooting a common 2 stroker. I hope you continue to keep us posted on your progress and adventures.
~Fred brnot
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Boof with your experience I am sure you could manage to squeeze every ounce of life out of one of these little china girls. But as it has been pointed out in these forums, what really do you expect for a sub $150 engine? If they were quality manufactured then they would be much more expensive, though probably well worth it.

Today I realized something, the reason I got one of these motors was to be able to enjoy putting around town without having to pedal like mad and to have fun learning about motors. Over the last few months, I had forgotten about that. It has turned into a drive to get the most out the engine, the rides, a test of the tweaks and changes. I haven't truly enjoyed a ride since my last motor died.

So it's time for me to remember why I started this hobby in the first place. Time to just ride and enjoy and stop trying to push the limits. I remember the first ride I took, the thing ran like crap but I was laughing my ass off, it was so fun! So I am just going to take it easy, no need for stressing when something does't go right or sound right.
 

boofbike

New Member
Apr 5, 2013
11
0
0
Piute County, Ut.
Boof with your experience I am sure you could manage to squeeze every ounce of life out of one of these little china girls. But as it has been pointed out in these forums, what really do you expect for a sub $150 engine? If they were quality manufactured then they would be much more expensive, though probably well worth it.

Today I realized something, the reason I got one of these motors was to be able to enjoy putting around town without having to pedal like mad and to have fun learning about motors. Over the last few months, I had forgotten about that. It has turned into a drive to get the most out the engine, the rides, a test of the tweaks and changes. I haven't truly enjoyed a ride since my last motor died.

So it's time for me to remember why I started this hobby in the first place. Time to just ride and enjoy and stop trying to push the limits. I remember the first ride I took, the thing ran like crap but I was laughing my ass off, it was so fun! So I am just going to take it easy, no need for stressing when something does't go right or sound right.

Risingsunn, You have a good point there. I may tinker with a China Girl before all is said and done. I really don't want a hot rod, Fun is the foundation to stand on in these endeavors. The last 2 stroke I had was a brand new 1972 Hodaka Ace 100 I bought for my wife a little over $300 bucks back then. I found an article in a motorcycle magazine that showed how to put a reed set up on the Hodaka to improve the performance. So I raised and enlarged the ports , milled the head. machined a custom intake manifold for a reed type carburetor, machined 2 windows in the little piston for the reed set up and made a tuner for it. Really fun & easy for me do back then, that's the beauty of 2 strokes. WOW! what a difference! a little rocket ship, the only thing, it was way too hot for my wife. So I went back and de tuned it for torque and took away all the top end power. As it turned out it was 10 times more fun to ride for my wife and me. Big lesson learned.
I guess with the China Girl, you have to learn from experiences on what to look for as far as what it will need to make them more dependable. With the right attitude it should be a fun learning adventure. Just keep us posted on your progress!
 
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Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
I understand now, I finally understand. I understand why the directions say to use such a large amount of oil to break in your motor, why Duane from Dax does not like 100:1 mixtures, and why I feel like such an idiot right now. Engines don't fail (often) from too much oil, oil keeps them cool. They fail from heat when they don't get enough oil. Which mine is. I knew it was running hot but didn't know HOW hot. I adjusted it richer but the damage was already done. Now my small knock is a big knock and the engine won't go above 25. Had I been running 25:1 homelite like I i was with my first engine, chances are the engine would have been fine. I am not blaming the oil, I am blaming myself. I didn't take it easy for a couple hundred miles and I didn't pay attention. to the signs. (Insert face palm here). So now I have to decide what to do next. I know I have failing bearings but I am not sure which. The engine seems to idle fine but when under load starts knocking. Could it be the piston bearings or perhaps the crank bearings? If I can save this motor I am going back to Homelite oil for at least another 200 miles before even thinking about anything above 25:1. And tuning? Not until I am 200% certain she is broken in.

Here I thought I was well on my way to being motorbike savy when I am really just an impatient novice. This is why motorbiking is not for everyone. Because it requires more patience and wisdom than it does money and mechanical skill.
 

Risingsunn

Member
Nov 24, 2012
191
5
18
Maricopa Arizona
Good Sunday Morning all!
Hope spring has brought some good biking weather to y'all! It has for me in Las Vegas. (btw is there any ACTIVE members in Vegas? I haven't seen any in a while).
Quite a bit has changed since my last posts, my attitude being the biggest thing. The engine that I last wrote about is sitting in a closet right now. It may be damaged, it may not. I just got too frustrated to deal with what I had done to it, so I set it aside. Now I am running the first replacement engine that BB sent me. And after roughly 200 miles of taking VERY good care of her, running 30:1 Homelite stock exhaust, normal plugs, and only bursts of full throttle, she is running like a doll, no knocks no pings, no issues. I am focusing on riding and ENJOYING my motorized bicycle experience instead of being anal about performance.

I am now trying out some minor changes. I ran the Iridium plug yesterday and she ran well, but no major performance boost. I have about half a gallon of Opti mix that I started testing last night. It seems that the opti mix plug the iridium plug doesn't like to idle very well. I swapped the plug back to a standard NGK 8 plug and she runs fine. I am going to try that for a while and see how she runs in the long term. The cleanliness of the oil is still a major factor for me. I may try my SBP pipe in a while but no rush. She runs well enough for me.

I might also try get the other motor running too, this time without all the upgrades. Stock pipe, standard plug, different oil. Perhaps some TLC will bring her back to life, we shall see.

I had a wonderful ride yesterday through the Lake Mead river trail, I tried recording a video by clipping my cell phone belt clip to my shirt but the video is too bouncy and you can't see more than 10 feet in front of me, so I am not going to post it. It's a shame, it was an AWESOME ride. Best I have had yet. A lot of people smiling at my bike. I even saw a baby desert tortoise. Definitely something I want record, so I will have to try it again with a better camera mount.

Anyway, have a good day all, happy bike riding!
 
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