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View Full Version : Yamaha TRI-Z single rear wheel



luke
12-03-2007, 02:21 PM
Here is a view of the complete bike, I dont have a rear fender for this ( any one have one they would like to ship to UK ? ;) ;) ) . After taking the swingarm off the bike it looks to be a home made set up :wondering However i have seen pro built kit for sale in England that also had a pro fabricated rear fender. At the time i couldnt afford it , and it was only 20 min drive from my house :crazy: :crazy:

luke
12-03-2007, 02:48 PM
Close up of each side of the swing arm. It has a small 3mm plate on the right holding the caliper in place over the disc, the disc is bolted to the hub in the original location.
Pictures also show th swing arm conversion, showing the strengthening work. The plate steel used looks to be over 5mm but it's hard to tell with all the edges welded up. It's substansial though ! However the way it has been made is very simple and could be coppied.

Bryan Raffa
12-03-2007, 03:09 PM
how does that sprocket hook up?

luke
12-03-2007, 03:15 PM
Sorry for the delay , i'm having to resize all the pictures as i go.
Here is a close up or the complete set up, with the wheel in place.

luke
12-03-2007, 03:23 PM
The wheel will run almost in line with the engine sprocket, these show how much offset i put on it to get the chain straight. This was done by eye. The shims and long (tube) spacers i used came from the local tractor dealer. I cut them to length myself, it was a bit of trial and error as these parts did not come with the kit when i bought it.

luke
12-03-2007, 03:38 PM
This is the extended hub, The new part is alloy, milled to size and shape. It looks to have been completed before being welded on, as the weld has clearly not been milled. However i suspect it was a blank and centered and drilled out for the bearing after it was welded on. It also looks like the sprocket has been riped off on more than one ocasion, as there are 8 extra (damaged) holes in the end behind this sprocket. It has been well made though and up close looks to have been better made than the swingarm :wondering If these could be made at the right price i would think these kit's would be easily made , ther isn't much to extending this swingarm. There was no sprocket with the parts when i got them, so i went to my local bike shop with the hub and bought one to size. What you cant see very well in the bicture is the small lip the sprocket sit's on to locat it. I put a 47 tooth on it as it was a good match to the bolt hole's and the lip on the side of the hub.

luke
12-03-2007, 03:51 PM
Finally, the extended side has an oversize bearing (altough the original bearing will still fit deep inside) The new bearing still fits on the axle the same size but is 52mm outside.

cr480r
12-03-2007, 03:56 PM
So the rear tire is not inline with the frame?

luke
12-03-2007, 03:57 PM
Not quite, it's out by about 9mm. It looks more in the pictures.

tri dee
12-03-2007, 05:02 PM
thats a :crazy: ride & i like it, can you do anything to pull the wheel over to centre?

luke
12-03-2007, 06:21 PM
thats a :crazy: ride & i like it, can you do anything to pull the wheel over to centre?

It will go to DED center but the chain run's on the p1ss between the sprocket's :cry: However, it's only out a little and at a glance you cant see it. I set the spacer tubes on each side to run the chain true ( with the wheel just off ) . Didnt i buy a crank from you recently on Ebay ???

cr480r
12-03-2007, 08:14 PM
However, it's only out a little and at a glance you cant see it.

Is it noticable while riding? It seems like it would turn funny like that..

250rfan
12-04-2007, 12:21 AM
It will go to DED center but the chain run's on the p1ss between the sprocket's :cry: However, it's only out a little and at a glance you cant see it. I set the spacer tubes on each side to run the chain true ( with the wheel just off ) . Didnt i buy a crank from you recently on Ebay ???


Luke,
Am i right in thinking, in order to line up the 2 sprockets perfectly, you would either have to

1 - make the rear wheel THINNER.

2 - Extended the front sprocket outward - 9mm to 10mm

Cutting and re welding the rim might be a hassle but i have seen it done.

You could get a special front sprocket made which would sit out further from the engine casing, this would allow you to put the rear wheel back into a central position.

I cant remember how much clearance there is between the top of the chain and the inside of the frame around the front sprocket area, but you may be able to steal a few millimeters or so, possibly you may have to re figure mounting the sprocket guard if you wanted to run one.

Cool piece tho, and in the UK:Bounce , am sure if you can engineer a solution to this, well done.

G.

cr480r
12-04-2007, 12:46 AM
How much clearance is between the chain and the tire? If there is adequate clearance some material could be removed from the face of the spocket flange on a lathe...

RedRider_AK
12-04-2007, 02:11 AM
An easy way to bump the front sprocket out some would be to drill some holes in 2 different sprockets and bolt them together with some sort of spacer in between.

cr480r
12-04-2007, 02:50 AM
I dont really like the idea of extending a front sprocket unless it is supported with a pilot bearing... but it could work...

tri dee
12-04-2007, 03:35 AM
the last crank i sold went to Scotland, did you have the lighting rotor & loom? if you need any parts or help give me a shout

luke
12-04-2007, 01:52 PM
Luke,
Am i right in thinking, in order to line up the 2 sprockets perfectly, you would either have to

1 - make the rear wheel THINNER.

2 - Extended the front sprocket outward - 9mm to 10mm

Cutting and re welding the rim might be a hassle but i have seen it done.

You could get a special front sprocket made which would sit out further from the engine casing, this would allow you to put the rear wheel back into a central position.

I cant remember how much clearance there is between the top of the chain and the inside of the frame around the front sprocket area, but you may be able to steal a few millimeters or so, possibly you may have to re figure mounting the sprocket guard if you wanted to run one.

Cool piece tho, and in the UK:Bounce , am sure if you can engineer a solution to this, well done.

G.

Much easier than that :p , and need to extend the front sproket from the engine.
Here are two pic's of the wheel with the sprocket. In the second picture you can see the space between the outside edge of the wheel and the inside edge of the sprocket, this is 22mm. so the hub could be put in a lathe and taken down to suit the wheel centre mesurement without the chain touching the rim or tyre. New outside spacers would have to be cut to move the wheel to the left, but thats the easy part.

luke
12-04-2007, 02:03 PM
Is it noticable while riding? It seems like it would turn funny like that..

I had the kit for about a year before i put it together and on to a bike. There were no bearings or spacers and no axle. I had to guess it all (but there's no way it would work any other way than this) You cant tell the wheel is off centre as it's only a few mm, but also the bike is so heavy by comparison to a YZ250 that once youve been on it for 10 min's you get a feel for it an forget about the little niggle's it has :p

It's not on a bike at the moment as i only had one TRI-Z left and put that back to standard. Otherwise i'd take some video and put it on YT for every one to watch :rolleyes:

luke
12-04-2007, 02:08 PM
This is the axle with the spacers set up how i had it on the bike. The only ajustment to these would be to make a longer one for the disc side and cut some off the sprocket side.

rydetriz
12-04-2007, 08:46 PM
that is one crazy setup to convert it must be scary to ride