How Many Miles Did You Get On Happy Time before the times became unhappy ?

[linnix13]

I agree Mountainman but it would entail telling whoppers. Like the comment above that implies the motor sits on 50 km\hr for 4 hours a day since time immemorial yet the engine has only done 3000 kms. That sort of use would put 2800 kms on the clock in 14 days! Is it any wonder I'm cynical about a claim like that. I've ridden 18,000 kms on HTs and the best I got was about 4800 kms out of a Grubee Skyhawk 48cc with an engine rebuild and plenty of other fixing along the way. I break every engine in gently but the lifespan of these motors is NOT good and if you ride them a lot you should stop to cool down every 20 mins. I also know that anyone who can get 50 km\hr out of an ordinary HT without additions needs to check the calibrations on the speedo. Also at that speed the motor WILL NOT LAST LONG. Why tell whoppers on a forum that knows about these things. It's so preposterous it is funny.
Good luck Hybriped I believe everthing you've written and I've seen the videos of your bike. You have a good motor and you ride it with respect for it and it will serve you well but 3000 kms is not much for a motor and I'd like to know the final mileage when it eventually breaks a top or bottom bearing. My guess is 5500 kms because you treat it so well. 6500 tops.

hahah well what i meant was that i CAN and HAVE done 50kmh for 4 hours once or twice but the engine does have 3000km on it.

 

[HybriPed]

I'll only build HTs for people who want to do small distances and who ride really slowly. They are good for that sort of use but it's all 4-strokes these days because people can see them on the roads around here and they love what they see.

Gday IJ

I've been off the forum while I sort things out.

I gotta say that I agree with your position - HTs are ok for small distances and slow rides. However, I do believe that there is a future for HTs as a lightweight engine that is used sparingly in conjunction with pedals.

However, if HT quality is questionable, it is because there has been hardly any R&D since the Cultural Revolution (except for Japanese bearings) and everyone has been predicting the demise of 2-Strokes for decades, meaning that noone has wanted to throw cash at them. However, direct injection HTs are feasible and all it requires is for someone to throw $$$ at the problem.

Before we chuck out 2-Strokes, I believe that we need to explore their saving graces; (1) there is nothing in them and (2) their light weight.

 

[Irish John]

Gday IJ

................However, direct injection HTs are feasible and all it requires is for someone to throw $$$ at the problem.
..............Before we chuck out 2-Strokes, I believe that we need to explore their saving graces; (1) there is nothing in them and (2) their light weight.

You are right Hybriped I have long said that these motors are a beautiful little design that would be just fantastic if they were made in Germany, UK, USA, or Sweden or anywhere with a reputation for quality. But it's the quality of them that I have a beef about. The fact that the ports are the same size on the 48cc, 55cc and 66cc and that the pistons are not a similar shape to the cylinders and all the other depressing details concerning them that show just how little care is given to these otherwise lovely little engines. As far as I have been able to ascertain the bearings are NOT Japanese. That is a marketing myth invented by some greedy capitalist. If the bearings had been Japanese then they would surely have been installed on my first Grubee 48cc that actually was of a quality that leaves anything else that has come out of China since 2005 dead. It had needle bearings but they weren't japanese I can assure you. That engine wasn't great and seized eventually but it was the best one of many many I've had since. I was robbing it today for parts and I noticed how vastly superior everything that's left of it is compared to current Grubee or Zbox kits. The throttle reel is alloy and the throttle tube is alloy - not the nylon they now use. I was genuinely shocked to see the huge quality differences in the old motor and the new ones. The whole clutch assembly is different - everything is better right down to the tank and pet cock.

 

[linnix13]

You are right Hybriped I have long said that these motors are a beautiful little design that would be just fantastic if they were made in Germany, UK, USA, or Sweden or anywhere with a reputation for quality. But it's the quality of them that I have a beef about. The fact that the ports are the same size on the 48cc, 55cc and 66cc and that the pistons are not a similar shape to the cylinders and all the other depressing details concerning them that show just how little care is given to these otherwise lovely little engines. As far as I have been able to ascertain the bearings are NOT Japanese. That is a marketing myth invented by some greedy capitalist. If the bearings had been Japanese then they would surely have been installed on my first Grubee 48cc that actually was of a quality that leaves anything else that has come out of China since 2005 dead. It had needle bearings but they weren't japanese I can assure you. That engine wasn't great and seized eventually but it was the best one of many many I've had since. I was robbing it today for parts and I noticed how vastly superior everything that's left of it is compared to current Grubee or Zbox kits. The throttle reel is alloy and the throttle tube is alloy - not the nylon they now use. I was genuinely shocked to see the huge quality differences in the old motor and the new ones. The whole clutch assembly is different - everything is better right down to the tank and pet cock.

so there arnt any that have goon bearings? the one i got said it had japanese bearings in it. arnt any bearings better than bushings and how long do the bearings usually last? how many kn before i should begin to wory about changing the bearings. i have close to 3000km on my engine that i got from powerking.

 

[Irish John]

so there arnt any that have goon bearings? the one i got said it had japanese bearings in it. arnt any bearings better than bushings and how long do the bearings usually last? how many kn before i should begin to wory about changing the bearings. i have close to 3000km on my engine that i got from powerking.

It's a close call between bushings and bearings I've tried both and not noticed any difference although my brain tells me needle barings must be better. Mind you the bearing contact surface on a bushing is greater so maybe it's better. They all break soon if you gun it and not so soon if you creep about carefully and keep the revs down on long trips.

 

[linnix13]

It's a close call between bushings and bearings I've tried both and not noticed any difference although my brain tells me needle barings must be better. Mind you the bearing contact surface on a bushing is greater so maybe it's better. They all break soon if you gun it and not so soon if you creep about carefully and keep the revs down on long trips.

ok and when it does fail how does it fail and does that mean the engine is junk or can i limp it home? will the motor just stall or what will happen? thanks
i usually cruse at around 45kph on a 44t sprocket. its a 80cc engine, is that ok?

 

[ozzmonaut]

happytime vs. everything else

I can see that which engines to buy has come up in many forums. However, I myself have never owned an HT, but have been extremely tempted to buy one. The simplicity of the installation is what almost has me hooked into doing it. I was thinking that for the low cost and minimal time investment they might be worth a try. But so far I have only built friction drives which can also be low cost and minimal time, but then you end up looking for ways to safely mount them. Right now I am working with a 56cc chainsaw motor. But chainsaw motors can be very unpredictable and I kind of want this to be a "surefire get up in the morning and crank up reliably " kind of deal. Now I am torn because the HT was the backup , in my previous line of thinking anyway. What do you guys think?

 

[Irish John]

ok and when it does fail how does it fail and does that mean the engine is junk or can i limp it home? will the motor just stall or what will happen? thanks
i usually cruse at around 45kph on a 44t sprocket. its a 80cc engine, is that ok?

45 kph is wide open throttle (prob with a boost bottle) and the motor is totally maxing at that speed. When the top bearing goes the piston jams in the port and the bike totally locks up. When it happened to me I was slowly going along a quiet road looking out to sea for whales and doing about 25 kph and the next second I was over the front and in the ditch. Because the rear wheel locks up the bike goes to the right. I didn't have time to get the clutch in and I use a twist clutch so my hand is always on it. 3 minutes earlier I was on the Pacific Highway - a 6 lane motorway - if it had happened there I'd have gone under a truck and been killed almost certainly.
In my opinion the kits should have to include a rear freewheel sprocket as standard so engine seizure doesn't lock the rear wheel up. I believe that without a rear freewheel you will always be risking death and at 45 kph your engine will not last. That I can promise you. If it's the bottom end that goes it's not so bad but I'm only speaking from my limited experience of massive failure - once it was top end and once it was bottom end. Top end was much more catastrophic. Both times it was with the best of my many HT motors and it was the one I kept going the longest with because I didn't know much back then. Here's a picture of the exact bike and motor that seized and nearly killed me.

 

[linnix13]

45 kph is wide open throttle (prob with a boost bottle) and the motor is totally maxing at that speed. When the top bearing goes the piston jams in the port and the bike totally locks up. When it happened to me I was slowly going along a quiet road looking out to sea for whales and doing about 25 kph and the next second I was over the front and in the ditch. Because the rear wheel locks up the bike goes to the right. I didn't have time to get the clutch in and I use a twist clutch so my hand is always on it. 3 minutes earlier I was on the Pacific Highway - a 6 lane motorway - if it had happened there I'd have gone under a truck and been killed almost certainly.
In my opinion the kits should have to include a rear freewheel sprocket as standard so engine seizure doesn't lock the rear wheel up. I believe that without a rear freewheel you will always be risking death and at 45 kph your engine will not last. That I can promise you. If it's the bottom end that goes it's not so bad but I'm only speaking from my limited experience of massive failure - once it was top end and once it was bottom end. Top end was much more catastrophic. Both times it was with the best of my many HT motors and it was the one I kept going the longest with because I didn't know much back then.

45 is not full speed. i can push it up to 50 but it vibrates allot. if i keep pushing the engine screams and gets really smooth and does 60kph. 45 is the speed at witch the engine runs smooth and doesn't scream nor vibrate

 

[sparky]

In my opinion the kits should have to include a rear freewheel sprocket as standard so engine seizure doesn't lock the rear wheel up. I believe that without a rear freewheel you will always be risking death and at 45 kph your engine will not last. That I can promise you.

If only all kits came with a freewheel for the engine chain... then maybe everybody'd ride MBs.