Mini Twister

[papa_smurf49319]

mmmmmmmmmmmmmmmm baby ruth

[dajogejr]

15K posts, like I said, get a life.

 

 

Thanks JD. I didnt "start" anything and shouldnt have to explain every little thing I see. I guess some people are simple that way tho. (Not you)

 

Thanks again for replacing that grille for me a while back. Youre a great guy and do great work.

 

I call a spade a spade, and a fat douche a fat douche. The shoe fits ass clown, and you're wearing both of them.

 

All you did was try to poke at Fast, you know it, we know it...your bluff was called.

You couldn't explain the difference between black and white, moon and stars...BigRed's nut sack and his taint...

 

Just because I can type fast and speak clearly, and am willing to help people...oh well, I guess you wouldn't understand.

 

Somewhere, there's a box of Twinkies with your name on it...get to it.

Nom Nom Nom Nom...mmm...good.

 

Good to see BigRed come around and eat his words too. All he did was talk about how SLOW that FAST motor was, and the truth finally comes out. A drag bike is a drag bike...purpose built. Of course it had a narrow powerband...that's how you make the most power. It's not rocket science...

 

It's a wonder both of you can tie your shoes and function.

[bada450r]

is this going to be a 100 page worthless post?i was hoping to learn something here guess not,my expectations were to high.

the problems that i have had with my motor are

1.ive broken 2 second gears on my tranny 1 regular and one robinson billet[worthless]

2.the nut on the clutch side holding the gear the turns the water impellar shakes loose no mater if i tighten the shit out of it or not, i have even put 2 new nuts with washers see if it works.

3.i broke a crank bearing from the stator side

4.i have broken fith gear also

for some reason this thing shakes really hard and it also produces alot of torque

so much torque that i have geared it 17/42 and it takes of like a bat out of hell with out reving the the crap out of it.am running 12 padlle haulers on it right now[hillshooting]but i thing there the wrong tires for it and that i would benifit from a more agresive tire without sacraficing top end.the fastest this twister has gone up any hill with a 240 pound rider[me]is 78.8 on my buddy tonys radar gun which in my mind is pretty fucking good,i think after having this motor for over a year am finally stating to get it to run with the fastest 10mils out here.the other thing is it loves shearer pipes over cpi the shearers pulled harder alltheway...cpi just did not feel right.

hope this helps some of you that are looking for some info on the twister cylinders.[mine was drag ported by the way].

[BigRed350x]

I call a spade a spade, and a fat douche a fat douche. The shoe fits ass clown, and you're wearing both of them.

 

All you did was try to poke at Fast, you know it, we know it...your bluff was called.

You couldn't explain the difference between black and white, moon and stars...BigRed's nut sack and his taint...

 

Just because I can type fast and speak clearly, and am willing to help people...oh well, I guess you wouldn't understand.

 

Somewhere, there's a box of Twinkies with your name on it...get to it.

Nom Nom Nom Nom...mmm...good.

 

Good to see BigRed come around and eat his words too. All he did was talk about how SLOW that FAST motor was, and the truth finally comes out. A drag bike is a drag bike...purpose built. Of course it had a narrow powerband...that's how you make the most power. It's not rocket science...

 

It's a wonder both of you can tie your shoes and function.

Rabble Rabble Rabble Rabble!

 

All I am doing with this twister build is offering a shop for greg to work in. He's doing the work himself, and building this bike on his own. I don't have any association with it daj. Just so you know... He's just using my shop as a place to work.

 

Not all drag bikes have a narrow powrband though. The engine in the bike firehead built that I have does not have a narrow powerband at all. And a narrow powerband doesn't necessisarily make the most power, its area under the curve that gets the job done. Useable power. It just happens that these engines tend to make peak power in a narrow powerband from their two-stroke deisgns. BUT an engine can be designed to make the same peak power without the narrow powerband, which is what firehead did the engine he built in my twister bike.

[BigRed350x]

With all the rabble rabble aside, can you give any good solid suggestions for what greg can try or do to help it run better in the future? I know you have a lot of very informative knowledge that could help his build, and help the other readers on the forum learn from threads like this. Why don't both of you guys take the rest of the rabble rabble to the flames and fights section or whatever its called, and make this thread more informative for anyone who reads it. Help others learn from gregs mistakes and maybe help other do-it-your-selfers in the future.

 

I know there are builders out there who can and would do a better job than the garage warriors of the world, but we all know there are a lot more of the garage warriors out there, and its sites like this that get them through each project. Daj, you've helped me with a lot of things in the past that I was totally stumped about. I know you could do the same here for greg, if you can both get past crap from the past, this thread could turn into a great resource for anyone who is trying to do a build like this at home, and who might not be able to afford to use a builder. I know I would love to send business to a lot of the builders out there, I just can't afford it, so I try and teach myself and learn from my mistakes.

 

The guy who put this engine together (which was not greg or myself) made quite a few mistakes, which came out after the transmission exploded. Like the clutch basket missing cushions, the backing plate not being tightened down good, the spacer washer between the inner hub and basket missing, etc. So, why don't you guys take the rabble rabble to the other section and use the things that are wrong with this engine to help other people learn and maybe figure out their own problems? There are a lot of people out there who enjoy working on their own stuff and probably can't afford to use a professional builder. So why don't you put some of the effort you are putting into bashing on eachother into helping the other folks out there. You have helped me in the past daj, and I know you can help greg and the others reading this thread.

 

- Jared

[gregrob]

Thanks for the input bada.

 

This one shakes pretty good too

[dajogejr]

You definition of narrow power band and mine may differ.

The bigger the motor, generally speaking the more torque which makes a narrow power band seem less noticeable.

 

Bada...

First thing I'd look for in your bike is the cases and the crank.

It's possible the bore is out of align or sloppy for the crank and/or the tranny.

It don't take much wobble or clearance to start shitting 2nd gears out.

 

I know their full billet trans eats shift forks like a fat kid on a cupcake. I've not heard....however, that the billet 2nd alone will do that.

A bad shaft, fork or worn case could be the reason 5th got eaten too...

Or a poorly cut tranny (not accusing, just throwing out ideas.)

 

Now, everyone thinks the billet 2nd gears are drop in, they're not. They have to have the matching/mating gear backcut to match. That could be a problem??

 

I'd also look at your crank. Have someone that knows what they're doing, perhaps crankworks or twister, check the balance on it.

 

Most of the time, you get it to within .003 to .005 of being true, weld it, done. Truing the crank does not check balance. That could explain the violent shaking, etc.

[BigRed350x]

is this going to be a 100 page worthless post?i was hoping to learn something here guess not,my expectations were to high.

the problems that i have had with my motor are

1.ive broken 2 second gears on my tranny 1 regular and one robinson billet[worthless]

2.the nut on the clutch side holding the gear the turns the water impellar shakes loose no mater if i tighten the shit out of it or not, i have even put 2 new nuts with washers see if it works.

3.i broke a crank bearing from the stator side

4.i have broken fith gear also

for some reason this thing shakes really hard and it also produces alot of torque

so much torque that i have geared it 17/42 and it takes of like a bat out of hell with out reving the the crap out of it.am running 12 padlle haulers on it right now[hillshooting]but i thing there the wrong tires for it and that i would benifit from a more agresive tire without sacraficing top end.the fastest this twister has gone up any hill with a 240 pound rider[me]is 78.8 on my buddy tonys radar gun which in my mind is pretty fucking good,i think after having this motor for over a year am finally stating to get it to run with the fastest 10mils out here.the other thing is it loves shearer pipes over cpi the shearers pulled harder alltheway...cpi just did not feel right.

hope this helps some of you that are looking for some info on the twister cylinders.[mine was drag ported by the way].

 

 

Have you tried any other billet 2nd gears, besides the robinson? I've heard of a couple guys on planetsand who don't like the robinson ones. Maybe try stealing 2nd gear out of another similar transmission (RZ, RD, etc) and see if it holds up better for you.

 

Have you tried using blue loctite on the nut on the crank? Are you sure you have the spring washer the correct way? Its spring so it acts like a lock-washer. If you have it flipped over the wrong way, it will act like the opposite of a lockwasher and try and push the nut off all the time its running. Make sure the washer is the right way, and I'd try a little bit of blue loctite on clean threads and torque it down good. (I use an air impact on a lower setting for my flywheel nut, clutch basket nut, and the nut you are talking about.

 

Have you tried a maxload bearing on the stator side? I read in a thread on planetsand that the TZ bearings and stock bearings are not the best to have on the stator side with higher HP/TQ engines. Maybe try a maxload if you haven't already.

 

Maybe look into a complete billet trans if you're breaking more than 5th. Is your current trans cryo treated or hardened beyond what the factory does? I know firehead made the gears in my big block twister himself. They've held up good so far. Maybe buy a whole new transmission and start from scratch with cryo treating and new bearings all the way around, billet 2nd, etc and see what happens?

 

When was the last time you had your crank trued and welded? What crank is it? If it vibrates excessively, it could be a balance problem. I've been talking to a guy in nebraska who has a 24mil twin saber setup that vibrates so bad its causing him problems with his upper rod bearings and wrist-pins. He even went as far as to have the crank balanced by falicon and it didn't help. Kim at K&T told me that his vibration problems were from the spread bore and the wrong bearings on the crank.

 

Hope some of that helps, or gives you some ideas.

- Jared

[dajogejr]

With all the rabble rabble aside, can you give any good solid suggestions for what greg can try or do to help it run better in the future? I know you have a lot of very informative knowledge that could help his build, and help the other readers on the forum learn from threads like this. Why don't both of you guys take the rest of the rabble rabble to the flames and fights section or whatever its called, and make this thread more informative for anyone who reads it. Help others learn from gregs mistakes and maybe help other do-it-your-selfers in the future.

 

I know there are builders out there who can and would do a better job than the garage warriors of the world, but we all know there are a lot more of the garage warriors out there, and its sites like this that get them through each project. Daj, you've helped me with a lot of things in the past that I was totally stumped about. I know you could do the same here for greg, if you can both get past crap from the past, this thread could turn into a great resource for anyone who is trying to do a build like this at home, and who might not be able to afford to use a builder. I know I would love to send business to a lot of the builders out there, I just can't afford it, so I try and teach myself and learn from my mistakes.

 

The guy who put this engine together (which was not greg or myself) made quite a few mistakes, which came out after the transmission exploded. Like the clutch basket missing cushions, the backing plate not being tightened down good, the spacer washer between the inner hub and basket missing, etc. So, why don't you guys take the rabble rabble to the other section and use the things that are wrong with this engine to help other people learn and maybe figure out their own problems? There are a lot of people out there who enjoy working on their own stuff and probably can't afford to use a professional builder. So why don't you put some of the effort you are putting into bashing on eachother into helping the other folks out there. You have helped me in the past daj, and I know you can help greg and the others reading this thread.

 

- Jared

 

Other builders have put bigger bores and bigger strokes on stock cases with stock trannies.

 

Who did the machining on the cases? Did they use mixable expoxy (2 parts mixed together to harden) or pour in? Or did they weld the cases? If so, were the cases heated up prior to welding?

 

Stock transmissions are strong if left stock. They also just shift like shit under power.

Do you have an engine stay, solid motor mounts or a center bearing support?

 

If you still have it together, try and pull up on the chain. Does it cause the motor to shift in the frame?

Are you using a chain tensioner? Are the forks in good condition? Did you break the tranny down and inspect the shafts for wear? Spin the bearings? Check the drum for any rough spots? Make sure all sliders on the gear work and engage/disengage? Any other mods on the tranny?

[BigRed350x]

You definition of narrow power band and mine may differ.

The bigger the motor, generally speaking the more torque which makes a narrow power band seem less noticeable.

 

Bada...

First thing I'd look for in your bike is the cases and the crank.

It's possible the bore is out of align or sloppy for the crank and/or the tranny.

It don't take much wobble or clearance to start shitting 2nd gears out.

 

I know their full billet trans eats shift forks like a fat kid on a cupcake. I've not heard....however, that the billet 2nd alone will do that.

A bad shaft, fork or worn case could be the reason 5th got eaten too...

Or a poorly cut tranny (not accusing, just throwing out ideas.)

 

Now, everyone thinks the billet 2nd gears are drop in, they're not. They have to have the matching/mating gear backcut to match. That could be a problem??

 

I'd also look at your crank. Have someone that knows what they're doing, perhaps crankworks or twister, check the balance on it.

 

Most of the time, you get it to within .003 to .005 of being true, weld it, done. Truing the crank does not check balance. That could explain the violent shaking, etc.

 

Very true on the power/torque thing. I might be confusing power with torque in how I'm thinking about it. Good call.

 

I read on PS from a lot of guys who say the robinson's are clunky and stiff.

 

I didn't think about the gear lash issue with the billet 2nd. That's good to keep in mind, and makes pretty good sense.

 

I also didn't think about the case being worn that could be causing the problem. This might have also been the problem with greg's build. If the cases were worn, it would allow the transmission to wobble a little (talking thousands of an inch) but at high rpm and engine load, it doesn't take much like you said, to cause catastrophic problems.

 

Does anyone happen to have the measurements for what teh bore should be on a brand new set of cases for where the bearings all ride in the trans section? Do you happen to have that info daj?

 

The guy with the mushroomed wristpins on PS lives right over in nebraska, not to far from me and he and I have been talking a lot about his vibration issue, which we've pretty much narrowed down to a bad crank balance combined with the fact that its a spread bore that's causing his problems. I think greg's problem and maybe bada's are both in the transmission areas from the what I saw on gregs engine when he was taking it apart and from what bada is describing.

 

Lets keep this going. This is good stuff, and definitely more informative for the other readers...

[dajogejr]

I run a TZ on the PTO side and OEM on stator side. I run stock helical cut gears.

If you run a TZ on both PTO and stator side, you really should have straight cut gears.

 

I honestly don't believe in straight cuts for smaller motors. But you guys are probably at the point they'd help with reliability if you don't already have them.

 

I've run stock bearings on stator side the life of my 10 mil. You're fine with OEM on motors of this size...PTO is where I'd go at least maxload if not TZ.

 

I don't believe in cryo treating a trans either. mainly because not many people do it correctly.

There is a process that "shot peens" the trans I've always wanted to try....but I've never had a trans problem on my bike...so, why fix what ain't broke.

I can not remember what the name of the process is called, but it basically kinda shot peens the metal and makes it stronger.

[dajogejr]

 

 

Does anyone happen to have the measurements for what teh bore should be on a brand new set of cases for where the bearings all ride in the trans section? Do you happen to have that info daj?

 

The guy with t

 

No, but I'm fairly certain Clymers does. If not...Tim from Titan can probably rattle off the measurement from memory.

 

Keep in mind there's a LOT of flex in stock cases with this kind of power as well. That flex leads to give and clearances that aren't supposed to be there.

 

Did anything else in the motor let go other than the trans? Crank bearing, rod bearing? How did the pistons look? The bore? The head? Any scaring or rubbing going on?

[BigRed350x]

Other builders have put bigger bores and bigger strokes on stock cases with stock trannies.

 

Who did the machining on the cases? Did they use mixable expoxy (2 parts mixed together to harden) or pour in? Or did they weld the cases? If so, were the cases heated up prior to welding?

 

Stock transmissions are strong if left stock. They also just shift like shit under power.

Do you have an engine stay, solid motor mounts or a center bearing support?

 

If you still have it together, try and pull up on the chain. Does it cause the motor to shift in the frame?

Are you using a chain tensioner? Are the forks in good condition? Did you break the tranny down and inspect the shafts for wear? Spin the bearings? Check the drum for any rough spots? Make sure all sliders on the gear work and engage/disengage? Any other mods on the tranny?

I did the machining on the cases, but I did it prior to chase (the previous owner of the twister before greg) put it all together. I just had the cylinders and the top case half. I bored the case for the cylinder, and did the case port matching myself, and had some tips on where/how to match the ports from firehead that I followed.

 

I used a pour-in epoxy that was recommended to me by firehead for filling the heat chambers around the cylinder bore prior to boring and case porting. It is made by 3M and requires a hazardous materials handing liscense, which I had to order through work to get. Firehead used the same stuff on my big block twister. I don't believe the epoxy to be an issue with what happened on gregs engine though.

 

No, we do not have an engine stay on this particular bike. Do you think it would be a good idea to add one, even with the smaller size of the engine?

 

Factory front and rear mounts were used on gregs setup. I can remove the mounts on the under-side and weld in some solid mounts, but I don't think he'd go for that since he has a really nice powdercoat job on that frame that came from the previous owners. I'd hate to ruin it too, but if its necessisary to keep the engine from destroying itself, we will do it.

 

Its still together, but the cases are cracked from 1 side to the other across the top case half. Crack starts right at the 12-oclock position at the sprocket bearing and go across the top towards the clutch basket. In the shape its in right now, if we pull up on the chain, it will just lift the whole rear transmission shaft and opent he crack in the cases more. I'm sure you can picture what I'm saying in your head.

 

Thanks for the ideas. A bearing support is definitely in gregs plans for this bike when he can afford it. I think the damage that happened already is going to take a little funds saving to get all fixed. I've got a set of cases I'm going to give to him to get it fixed, but I'm pretty sure we are going to need a transmission. =(

[BigRed350x]

I run a TZ on the PTO side and OEM on stator side. I run stock helical cut gears.

If you run a TZ on both PTO and stator side, you really should have straight cut gears.

 

I honestly don't believe in straight cuts for smaller motors. But you guys are probably at the point they'd help with reliability if you don't already have them.

 

I've run stock bearings on stator side the life of my 10 mil. You're fine with OEM on motors of this size...PTO is where I'd go at least maxload if not TZ.

 

I don't believe in cryo treating a trans either. mainly because not many people do it correctly.

There is a process that "shot peens" the trans I've always wanted to try....but I've never had a trans problem on my bike...so, why fix what ain't broke.

I can not remember what the name of the process is called, but it basically kinda shot peens the metal and makes it stronger.

Greg has helical gears on the twister, but I know he's got a set of stright-cuts on his dune bike. Maybe we swap gear sets between the two bikes and see if it helps.

 

I also ran helical gears on my 10mil cub when I had it and never had any problems with it. I agree with you on that issue. The straights definitely help, but are over-used a lot of the time when they aren't really needed.

 

I believe gregs crank has stock style bearings on it, but I don't think the crank was the issue with this last carnage. Something definitely bound up int he transmission and blew everything all to hell. We haven't split the cases yet, but are going to try this weekend if the weather is ok.

 

Thanks, good ideas!

[BigRed350x]

No, but I'm fairly certain Clymers does. If not...Tim from Titan can probably rattle off the measurement from memory.

 

Keep in mind there's a LOT of flex in stock cases with this kind of power as well. That flex leads to give and clearances that aren't supposed to be there.

 

Did anything else in the motor let go other than the trans? Crank bearing, rod bearing? How did the pistons look? The bore? The head? Any scaring or rubbing going on?

 

 

I'll give titan a call tonight, or greg can. I was thinking about him as well.

 

As far as I could tell from what little greg got dissassembled so far, it looks like 1 or 2 things that happened. Soemthing in the trans is defintely toast. The case is exploded upwards directly above the rear gear cluster, like a gear exploded and bound up or something and there were a LOT of metal shavings in the oil when we drained it and in the clutch compartment.

 

The crank all looks good. Still feels right and solid. No issues on the top end or in the crank department. Compression was and still is 185 on both cylinders before and after the tranny went. I believe he checked cylinder clearance and it was about .004" on one cyl and .003" on the other.

 

The only other issue I saw in there was there were no cushions on the clutch basket (the billet basket was installed by the bikes previous owner). I wouldn't think that missing cushions would cause the trans to explode, but you never know when everything in there is spinning that fast with a heavy load on it.

 

He should have gone through and torn the whole engine down and checked everything when he first got it from chase, before running it. Excitement got the better of him and he ran it "as-is" when he got it after we put bigger carbs on it. He learned the lesson the hard way this time around, but at the same time, it will give him the opportunity to go through and do things right this time, with good parts, and also document the build for others here looking to do the same thing.

 

What do you think happened from the description so far? I'm going to take a LOT of pics of everything this weekend if we do split the cases and we will update this thread as he goes along with the rebuild.

 

Thanks for the input. This is a lot more of what I hope people are looking for in threads like this.

 

I've got to get back to work, but I will check back here tonight for sure.

 

- Jared