Boy go fast/engine

[Skyliner70cc]

Note: After posting this, I went online and noticed that this vendor now sells engines with the locking clutch lever, roller wrist pin bearing, and bearing wheel tensioner. If clutch and paint issues are improved then my review may no longer be applicable. Please submit your experience with these engines!

I've had the opportunity to purchase two of his engines over the last 3 months.

Here are my general observations:

1. Quick shipping is a plus.
2. First engine was not properly packed and the plastic throttle assembly was (crushed) damaged. Vendor replaced it reluctantly but said he normally requires buyers to file a claim with the shipping company. Shipping company would not have honored the claim if I had. The box was not damaged on the outside.
3. Cheap older style clutch assembly. Yuk! These types NEVER work on amy of my bikes. They can't be depressed sufficiently to lock on my Skyliners or Searcher bikes.
4. Both engines start easily and are VERY smooth. Much less vibration than my older Dax engines. My only comment regarding the engine is that the engine is very sensitive to the choke setting and requires some fiddling with the choke while starting to get it to fire up. I drilled out the hole on the choke plate and opened up the airflow going into the engine. This solved the problem and engine now starts easily on full choke.

5. Clutch: BAD. Unlike Dax engines, the clutch cannot be adjusted properly. To this day, I cannot find an appropriate setting on the cable that allows me to have the clutch engage completely when released and NOT spin the wheel when it is locked into place. I have never had this issue with Dax or Kings motorbike engines. Also, the clutch setting seems to be tempermental and dependent on temperature. On colder days, releasing the clutch lever does not allow 100% positive engagement and clutch slips when starting. On warmer days the opposite is true and locking clutch does not completely allow disengagement. This is a deal breaker for me and the 75 bucks I saved in buying these engines is not worth it in my opinion.

6. Power: First engine power came on quickly with my normal break in procedure and was pulling 25 up hill on a 50 tooth sprocket. Second engine can only muster 17 mph. I'll let you know if things change.

7. Paint: Probably the worst paint quality I have seen in the almost 50 Happy time kits I've purchased over the past several years. If you value a decent paint job on your tank and chain guard, look elsewhere.

Overall comments: Value is offset by the clutch issue, need to buy locking clutch and a true roller bearing chain tensioner and lousy paint job. You get what you pay for.

 

[Skyliner70cc]

Sparky,
I didn't use the kwik JB weld. I use the regular stuff and let it set for 24 hours minimum. JB weld's specs are more than adequate for most uses:
Tensile Strength: 3960
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 500° F

I recently saved myself 100 dollars for a new radiator when I developed a crack in auto's radiator. I also stop drilled the crack and filled it in with JB weld. A perfect fit that isn't noticeable after I sanded the area and painted it to original color.

Used it last year to fix a crack in an aluminum oil pan. I figured if it was good enough for a multi-million dollar turbine engine, it would work for my daily driver.

I also used it to reuse a headgasket on a 17 year old Nissan. I was too cheap to buy a new headgasket and put a light coat of JB weld on both sides of the headgasket before I reinstalled the head. The JB weld and headgasket are holding up just fine and the vehicle has 198,xxx miles on it. Don't worry, if I sell this car, I'll let the buyer know that the head can't be removed

 

[hot70cc]

Sparky,
I didn't use the kwik JB weld. I use the regular stuff and let it set for 24 hours minimum. JB weld's specs are more than adequate for most uses:
Tensile Strength: 3960
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 500° F

I recently saved myself 100 dollars for a new radiator when I developed a crack in auto's radiator. I also stop drilled the crack and filled it in with JB weld. A perfect fit that isn't noticeable after I sanded the area and painted it to original color.

Used it last year to fix a crack in an aluminum oil pan. I figured if it was good enough for a multi-million dollar turbine engine, it would work for my daily driver.

I also used it to reuse a headgasket on a 17 year old Nissan. I was too cheap to buy a new headgasket and put a light coat of JB weld on both sides of the headgasket before I reinstalled the head. The JB weld and headgasket are holding up just fine and the vehicle has 198,xxx miles on it. Don't worry, if I sell this car, I'll let the buyer know that the head can't be removed

Correct, BUT it has to be applied correctly, It isn't steel it snaps lick a cracker. Apply a 1/8"thin layer 1"x3" let harden 24hours. Then put it in between both thumbs and fingers, and it snaps like a ritz cracker. I wouldn't recommend any high rpm motors to fix anything long term. IMO. I applied some to my rear bike rack when both bolts failed. As soon as i hit a pot hole both sides of the weld broke. Oh well what do i know, just from expierience. good luck

 

[rebelspirit]

Boygofast Engine Review

first-Please Personal message repair dialogue-this thread is to review boygofast engines and has become cluttered with off subject material. thank you.


OK-

Got my Boygofast engine on weds and it took my brother and I, both who are very mechanically inclined, 3 days to assemble. Bike is a Specialized Rock Hopper mountain bike.

Here is a list of problems and defects:

-Gas tank was rusted out and had metal shavings from the tapping proccess inside the tank (pic)! There is no question- ALWAYS put an inline fuel filter on your bike.

-Clutch lock was wrong size for clutch lever and had to be trimmed and bent to get it to work.

-Carb fuel inlet was smaller diameter than tank petcock and therefore the fuel line was not compatible for both uses-ended up getting a micro-hose clamp for fuel inlet after seeing that the fuel was leaking out of there.

-Gas cap leaks a lot.

-Universal clamshell/sprocket assembly not universal at all! It took us a whole day just to get this on and we still had to leave off two bolts and replace one with a smaller size to get it to fit through the spokes with out pulling the sprocket out of perpindicular to the axle. Total nightmare!

-Tensioner works, but is piece of junk to be replaced ASAP.

-Highly dubious that this engine is actually a 70cc engine. I am still breaking it in so no maxing out, but so far the performance is no better than my 43cc Go-Ped engine. This is definitely pedal assist.

Plusses?

-shipped quickly.
-New thumb press kill switch on throttle.

Final analysis:

Do not buy from Boygofast!!!!!

Only purchase from a reseller that inspects and guarantees the parts sent. Savings not worth the hassle and low quality. I mean-metal shavings in the gas tank?! Really?!

 

[Marktur]

Wow - just got done with my build...I didn't think of looking inside the tank. Thanks.

BTW: Is your throttle assembly junk, too? How much does it need to turn to go from idle for wide open? Mine goes about 1/4"...is that right?

Thanks,
Mark

PS, I will check the tank then run it tomorrow and let you know how mine worked.

 

[JosephGarcia]

i bought one the other week. The seller is in El Monte, CA. he is right next to me.. I asked if i can pick up the engine in person instead of paying 50 bucks to ship it 1 mile. no dice, but i did receive it the next morning.


quality seems good, nothing missing or broken, castings are good, nothing way out of size or shape.

The guy im building the bike for KNOWS the seller, he used to own a shop in arcadia, but now does internet only businesses. I can probably get this guy to update his quality for you guys, alert him of the rollerbearing failures.

anyways, the motor came and it was obviously started and run for a little bit before it came to me, so i know it ran at some point. the piston still slides and everything is good, a little tight from being new, but it all checks out.

im barely installing it on the bike right now and should have it started by sunday, ill let you know the progress then. we would have it started today but the chain came way too long, need to cut 3 links off.

 

[Marktur]

I can give you excellent first time buyer feedback for BoyGoFast. I built my bike last week...put 40 miles on so far. Everything works great! He shipped REALLY quickly - it went out the same day I paid for it, with no "rush" cost associated with it. All parts were there, well packaged, and I think it's the same exact thing everyone else is selling, too...I don't have experience with the other vendors, but I would have no problem purchansing again from BGF. In fact, I just left him awesome feedback on Ebay 2 minutes ago.

If this is the last thing stopping you from motorizing your bike, go ahead and spend the money and do it. Too much fun!

Good luck,
Mark

 

[nobody_21us]

I have to agree with Marktur; although, I have only purchased a single 48cc engine from boygofast. Overall I’m pleased with my purchase, and I have 1300 miles on the little thing. He also emailed me the instructions while I was still deciding on the purchase. His shipping was fast, and it arrived with no damages. Started right up after installation. I can’t really compare this engine to others as it was my first build; however, I did have a few problems with it. Mainly my fault sure, but I wish I would’ve taken the head off and inspected the gasket first…

I blew the head gasket because of the poor design of the head and cheap head pins; although, looking at the blown gasket it appeared smashed more than blown. What happened was a head pin snapped and the others bent a little. A quit mill job, a meter of M6 all thread, and some gasket material and I was back in business. He gets a mark against his customer service because he couldn't get replacement head pins; otherwise, he’s been willing to answer all my questions. I also didn't use the supplied clutch lever, and the throttle was cheap.

I'm working on buying two more before the week is out too My dad just has to have one now. Of course this time, I'm going to do the head job before I blow it :">

 

[Marktur]

Yeah, I'd buy from him again...I'm using both clutch and throttle, and they both work just fine...on the clutch, I won't "lock" but in all honesty, I don't see myself riding THIS bike for exercise anyway...

Well...I just went to ThatDax.com to look at his 4-stroker. It says 12 days before it gets shipped...which means about 3 1/2 weeks before I see it. Ugh...big deterrant. I also think the price has gone up, but I can't remember...I just thought it was about $100 more than the 2 stroke motor...not any more

My BGF Bike sold for $455, so I'll be ready to go as soon as I get the money from the buyer...I broke even, so I'm happy, and I know the buyer will be REALLY happy, too.

I didn't have any issues with the motor...and I took the time to Loctite everything, and no loose screws anywhere. I just rode it up to work (1 last ride), and it's great! New tires are not blowing tubes, and the motor is really happy! I was doing a nice 23mph, which is the speed that the motor "clears out" and gets on the pipe, and riding steady there, I still have an easy half-throttle more that I can turn! Way faster than I feel comfortable on this beach cruiser. 20mph is just fine for me -- maybe I'm extra worried about popping tires, I dunno...no need to speed, though....if I wanted to go at the speed of the traffic, I'll pickup a scoot...which I may still do.

OK, TTYL
Mark

 

[eljefino]

Agree on the fuel tank shavings, cheezy "russian clutch lever". Had to tighten clutch daisy nut slightly more than 1/2 turn. Took opportunity to add a little grease to gearcase, though there was enough in there.

The little holder screw on the outermost end of the (motor end of the) clutch lever is garbage; I stripped it out accidentally and put in an on-cable cable stop like most other chinese motors seem to have.

The question of both boygofast and HT engines in general is how much free tinkering do you want to do for a cheap product?

 

[spunout]

I asked if i can pick up the engine in person instead of paying 50 bucks to ship it 1 mile. no dice,

that would have stopped me right there