Yamagama 100

[Yow Ling]

could you just bore the gudgon pin holes in the piston a bit bigger, or is that dicing with death?

[TZ350]

um, yeah so this could convert a piston with a big pin to a smaller pin for a rod bearing combo. . . .But the problem here is that the rod wants a larger pin for the bearing that the rod uses as std.

Ok so you are just being picky now, right!.

Why do you need a cage? many roller bearings run without them. Many old British singles big ends used crowded rollers and no cages.

I have not seen this done, but could you fit lose rollers with two retaining washers either side like you see in a RGV250.

Assembly should not be a problem, I would use a short dummy pin that held the washers and rollers in position and which gets pushed out as the piston pin is pushed through.

So really the question is, can a crowded roller work in the little end of a 2-stroke.

.

[F5 Dave]

Argh!!! a short dummy pin is a stunning idea. Wish I'd thought of that!

Kevin Cameron (urgh, maybe it was Gordon Jennings) had written somewhere that it worked well but he had seen "strong men weep with frustration" attempting to assemble an all roller no cage bearing. So the only concern would be is the diameter difference lucky enough that is makes for enough rollers not to be sloppy?

But I'm still a bit uncertain how these would go in a high speed engine. I mean the problem is they all need to roll in the same direction but under load the closest ones would be pushed apart a little but that would crowd the ones opposite to the load & they want to drive each other in opposite directions. This isn't a problem with a cage. Maybe it is ok.

[TZ350]

But I'm still a bit uncertain how these would go in a high speed engine. I mean the problem is they all need to roll in the same direction but under load the closest ones would be pushed apart a little but that would crowd the ones opposite to the load & they want to drive each other in opposite directions. This isn't a problem with a cage. Maybe it is ok.

I am not sure either. but old British singles used crowded rollers in the bigend. But I think high peformance ones like the Manx went to cages.

Also its an oscillating action in the little end compared to a rotating + oscillating action at the big end.

So not sure realy,

But if it was me I would give the crowded roller a go before using an automotive/industrial caged needle roller in the little end.

People have forgotten how unreliable motorcycle little end cages were in race bikes in the early days.

.

[Mrs Busa Pete]

my barrel is ready to be paid for now the tecnition that does rotorys and 2 strokes said it should go like a basted . the cage roller bearings that i got dident quiet do it have to give it to the work shop at work to do something with it then it only leaves the head

[jasonu]

try 021552488 ask for eric he had 12 sets of them $100 od for piston and barrel he is located in wiuku near glen brock. i cut the barrel up to try and save money on a sleeve didnt work it was to small for the job.

Is that $100 for one barrel and piston set or $100 for all 12 sets? (just being hopeful)

[jasonu]

You know, I wonder if you did carefully weld some fins on your stripped TZR barrel & then rebored it if that would be effective cooling. That would be a great starting point for a 125. Don't think anyone has tried that yet.[/QUOTE]

Most likely no one has tried it because it is a seriously backwards move

[Pumba]

Is that $100 for one barrel and piston set or $100 for all 12 sets? (just being hopeful)

I can answer that because I know, it is only for 1 barrel and piston.

Christ if it was for all 12 I dont think they wouild of hung round for long

[bucketracer]

Dad's figured out how to air cool a RGV cylinder without a lot of modification, next years project after Taupo apparently.

[Mrs Busa Pete]

I have hade the head welded up and the team from work mashined it back to suit of to get head gasket tomorrow then just fit the pipe to the frame . Do i have to get the sleaved barrel verafied or do i just have to present the print out from the reconditioners .

[F5 Dave]

My advice, Get a witness who is known in the racing circle so if it comes up "yup Johno saw it & it was 50mm or whatever".

[Mrs Busa Pete]

My advice, Get a witness who is known in the racing circle so if it comes up "yup Johno saw it & it was 50mm or whatever".

so if i get john conner to check it im ok then

[Mrs Busa Pete]

[QUOTE=F5 Dave;1129354279]I think his pin size is the same, but the Rod is for a bigger bearing. Bearing will need to run on a plated surface.

Hmm I wonder if you got a 1mm precision sleeve if you could run that over the pin (ie inside the Bearing ID) & use the std TZR bearing? Would have to be a tight fit on the pin & would be a pig to insert/remove the pin.


this is what we have done will see how it goes for the first 5 hours and asses when we change rings

[F5 Dave]

Let us know how that works out, should be fine.


Re JC, can't see anyone questioning him if he says he's seen it, but anyone like DaveD or Rob or Keith would be as fine.

[Mrs Busa Pete]

took the barrel and head and botem end to mt wellington last weekend showed john he said he has never dune this before may be he should be anyway hes happy with it gave me some advice and sent me on my way.
put it together on the sunday and started to fit it to the frame sorted out the position and hunted through my bits and found a ysr mount for the lower rear fixed it at work and cut a spacer on friday .
took the mounts of the mc22 rolling frame that i got for a bucket frame and used them for the top head mount will have to get them welded on or can i bult them through the frame need to cut spacers for here allso may use threaded rod with nylocks for this top bult or get one made at work.
had to cut out the top rear mount so the carb and top of motor could fit will see how it goes as to puting one back in the area .
just a case of the chamber now angles and length and clearance that sort of thing i realy wont to use the wobbly one i all ready have with a new front section .