Ok all the sensible people, take a deep breath, count to ten and bear with me.
I am going to convert my shaft drive xz400 to chain drive. I know, it's higher maintenance and all that but I just want to. Haven't done anything like this before so if I pull it off it should give me a sense of achievement, that's reason enough to me. Oh and I blew the money for my tig welder (for frame mods) on a couple of old bikes. Anyone know if there is a "bike collectors anonymous" program anywhere I can sign onto?
I have the general idea of what to do but because I'm pretty new to engineering I have question.
An outer housing seems the way to go but I'm a little unsure how to measure accurately so the bearing in said housing lines up exactly with the output shaft from gearbox. If you guys have seen a chain conversion or picture of one this should make sense hopefully. I saw some pics in the ROV newsletters so I'm assuming most will know what I'm on about. Please assume I'm clueless and give me the basics or a link to an appropriate site. :-[
There are pics and descriptions of John Clemens' chain conversion on this forum
Once you get the chain conversion done, find an XS400 Seca (82-83) rear wheel to match the Vision front... It was chain drive!
Quote from: the oldstuff on October 23, 2013, 02:44:49 AM
An outer housing seems the way to go but I'm a little unsure how to measure accurately so the bearing in said housing lines up exactly with the output shaft from gearbox.
I'd drill the housing and fit the bearing first, fit on to the shaft, then transfer punch to locate the drilling spots on the engine casing. I love transfer punches as they pretty much always give accurate results. You can make your own out of old drill bits, bolts etc by sharpening in your lathe - or even a drill
Ah it's just like you said the other day POD, there will be an easy way to do. The way you describe makes good sense, I was thinking from "inside the box" i suppose. So I'll locate on shaft, transfer punch, probably dowel and maybe use studs in the casing, then mill outrigger bearing housing to shape. All sorted in my head now, just need to get down to business.
I think I will be going for alloy rims and spoke wheels for weight saving and looks but also good to know about the 400 seca wheel.
We need to collaborate on the spokey wheels
To make the chain conversion the "middle gear" on the end of the counter shaft is machined and fitted with a sprocket. There is no need to be adding bearings and shafts etc. This has been done several times some years ago when the XZ was raced ( John Clemons, Eddy Wilbanks, and our own motoracer8, among others) The Eddy Wilbanks XZ was made into a 750, but that required changing the stroke of the crank as well as larger bore. More usual is just boring the cylinders to 650 and opening the top of the cases so the larger cylinder sleeves fit into the cases.
Here's John's post about chain drive conversion
http://ridersofvision.net/rovforum/index.php?topic=11572.msg104853#msg104853 (http://ridersofvision.net/rovforum/index.php?topic=11572.msg104853#msg104853)
The thought of a 650cc vision gets me wet. What a shame no-one itemised the changes needed.
Removed the shaft drive from parts bike today. In excess of 6kg, mostly rotating mass. Maybe there is hope for the 400 yet eh?
My goal is to have my 400 whip a stock 550.
John Clemons (I think?) once said that 650cc Vs were "all bore, no stroke". I'm thinking that no replacement cylinders or liners were needed. Just bore the stock cylinders to max bore needed to get the 650 displacement. Getting the correct pistons and rings is the hard part.
Interesting chain conversion on an XS - with pretty pictures
http://www.xs11.com/forum/showthread.php?t=35862 (http://www.xs11.com/forum/showthread.php?t=35862)
Need new cylinder liners to get to 650cc, as stock ones would be too thin after boring. Also need to enlarge the holes in the cases where the liners slip in. It means taking the motor all apart to bore the cases. It's quite feasible to make it a 650 if you want a larger motor, but making it a 750 is considerably more work and expense.
I talked to John 12 years ago about the procedure needed to go to 650 cc and Fret has it right. Jefferson referred me to a fellow who had raced 750 cc Visions. The cranks were custom made by a foundry in his town. there were 3 total. he had one left and it was in his race bike , which sat on his show room floor and had not been run in years. He wouldn't sell the bike either.
He used special JE piston and rings , which have long been out of production .
Jeez that's not going to leave much material in the barrels of my 400. Are water jackets really necessary ::)
What about using 550 barrels as a starting point? That would be far more sensible.
Ok, now where would I get a couple of those? Ready to do a deal on those injuns?
Maybe I could bring my empty frame around and trial fit one to be sure...
I'm reluctant to get rid of any bits till I'm up and running
We can take measurements though
Long time - no action. I've been busy gathering tools and getting side-tracked learning how to use them.
Today I removed outer gearbox bearing where shaft comes out. The 4 countersunk screws holding the retainers in place were a bugger to get out. They are dot punched to lock in place and a large torx head which I don't have tool for. Not that it would matter, these were probably done up with a rattle gun, which I also don't have. I drilled a suitable hole in head of screw/bolt and used a screw extractor/ezi-out. May have to make those screws down the track..
Anyway it's not what I expected in there. Photo:
I should have shown photo of side of bearing seen from outside, it looks like an open bearing but I turned it to show the back(inside) because I didn't expect it was like this. There's two steel rings still in place behind bearing. What purpose do these serve? There is also an oil hole in side of bearing housing. Does a gearbox need to breathe or is it safe to seal these holes up which seem to lubricate the bevel gears?
I have a couple of pics for you showing my proposed new swingarm. It is very similar in all dimensions/angles (yam xt250 '81?). Now question time. The vision swingarm has wide mounts for obvious reasons compared to the new one. What I'm wondering is do you think the narrower mounting (bush area) will have any adverse effect on handling perhaps due to extra twisting force (guessing)? Any suggestions regarding modding in this respect?
Does it fit in the XZ frame?
I've had thought of adapting a different swing arm to incorporate two shocks, like motorcycles are supposed to have. Several models use the same SA bearings and parts, just different swing arms. I think it's rather important to have a good fitting swing arm, with adequate support from the frame so things don't become all wiggly under stress.
Yes it fits ok, except will have to weld different bush mounts? to the frame. It's a starting point to continue the conversion.
QuoteThere's two steel rings still in place behind bearing. What purpose do these serve?
The steel rings may be thrust shims to achieve proper bevel gear teeth engagement?
Rather than trying to fit a chain drive model's swinging arm into a Vision frame, it may be easier to fit the Vision engine into a chain drive frame. An SV650 may be a good candidate. I could take this line of thinking one step further but I won't. I don't want to be accused of discouraging someone's dream. :)
Thrust shims, Ok I'm learning all the time and that's what this is all about for me. I'm sure you guys have mostly come by your vast knowledge by repairing or modifying things when it would be quick and easy to just buy something else. This project is definitely a budget build using only what I have or can obtain very cheaply.
"definitely a budget build using only what I have or can obtain very cheaply."
Just regular Life, it's the way things go. You use what you have. In my younger days (before I was married) I had a bike rather than a car for my transportation, and had to make things work or walk. One learns a great deal out of necessity. I learned to get a car. Actually my preferred vehicle other than the bike is a pick up or a van., so I can haul the bike if necessary.
Perhaps budget was the wrong term. I just don't want to spend much on it. I have plenty of other bikes to soak up the larger amounts of money. Here's another mock up with a CB250RS wheel. Would rather use alloy dirt bike wheels with disc brakes, but would have to use two back wheels (have to match) which in use as a front would be too wide? Thoughts? Don't know much about (anything!) wheels/tyres/handling.
Quote from: dingleberry on May 12, 2014, 07:59:44 PM
Thrust shims, Ok I'm learning all the time...... I'm sure you guys have mostly come by your vast knowledge by repairing or modifying things........
I've never had the middle drive gear apart, I looked on the part fiche and deduced the shims were what you described. :P
I have recently developed an interest in classic/vintage trials so I have started converting an old Yamaha AG200 to a trials bike. I don't think this bike was available in the US but it is a farm version of an XT200 (AG for agriculture I believe). So I was eying up to swap out the swing arm with a DT200 I have and realized this is the same as the XT250 one in pictures above, except it is of square tube like the Vision swing arm. So, there is an ideal candidate for swing arm swap if anyone wants to do chain drive conversion and keep the same look. Just thought I'd mention for any reference value. And no, I'm no closer at getting mine converted as I am very easily distracted.
Why don't you do a trials XZ400. First of a kind !!!
Ha ha. Or I could just buy a trials bike and bolt 100kg of concrete to it. Maybe I could saw off one of my legs as well so I don't have an unfair advantage ::)