2 Strokes Down Under

DOC03 wrote:Thanks Lozza.
Hey in relation to the 400 crank, can they be made ot fit the 350 ?
Ive seen one in the state pretty good nick and can get it relatively cheap ???

I suppose they could but went through this with fitting LC cylinders to the RD bottom end. Which is the best option BTW.
The problem is that the RD cylinders are 6mm longer than the LC, 3 of which needs to be at the base of the cylinder, the 3 that need to be on the top of the cylinder is the problem. You can put 6mm spacer under the cylinder but the port timing is something like 220deg on the exhaust which isn't ideal.
Options are to make another sleeve with a 3mm ali plate welded to the top of the LC cylinder before a new cast iron liner is installed. A sneakier option is for an aluminium bronze(same material as det rings) would save a bit of work and the ring would run over it just fine.
Other than that I can copy the RD balnce factor over to the LC no problems.
The air cooled RD rods have a 28mm big end eye with 18 rollers stock LC/RZ has a 29mm eye (14 rollers)they are the best rods (same as TZ's) cylinderical roller bearings handle the high loads and axialy locate the crank better

90 deg crank..does this mean there is no cross over..so a single pipe could be used on a twin with success???

No, the waves are still going to affect each other even if they aren't 180 apart.

ahh there goes my reverse cylinder single pipe idea..lol

single pipe needs 180 deg firing

It's still not going to work as well as separate pipes though.

Well ANt, was gonna do the 90deg Crank but have to get modified Zeel with Dual pick ups and I cant be bothered just now. Might have to wait till next time shes apart...or the spare motor.
On another note, Steve at TwoStrokeShop has got some sweet Banshee cranks he had specially made to drop straight in the RD case... Hmmmmmm

Cheaper to get a hot rods crank and mill the outside main bearings, thats what I did in 94.

Still good to this day!!!!

I guess Im not all that confident in my ability and thought it might be easier if they are ready to just drop in.
I have had a look but the Hot Rods are still around US$400 I thought ??
With shipping and I have to get pay someone to mod etc its getting up near steves price.

He quoted "Our brand new RZ cranks modified to fit RD-LC cases are US$630 each. (These have the load-carrying advantage of the 1mm wider RZ big ends ...) We can also supply new fully balanced +4mm stroker cranks to fit RD-LC - these start at US$830 for cranks with 7-ball mains throughout, or if you want the 11-ball max capacity or roller outer mains, that adds $75 to the price.

Yep, just had another look - new USD $369 plus 100 for shipping.. about A$550 landed plus mod. But thats new, not used.

Your cheaper option is to rebuild a Lc crank ,then you can use Tz big end bearings even better than the 1mm wider Rz ones.Main bearings can be purchased off the shelf from all bearing shops just make sure they are C3 clearance.

Not sure how those stroker cranks would perform in a Lc.

Ant

C3 clearance.
i tryed to get rz500 bearing years ago .
got a basic bearing with no pin the guy said they where the same just no pin .
got a few & checked the tolarance =all over the place.
ask about clearance . never said a word about c3.
he knew whot they were used for .
use to by a lot of bearing & seal & thought he new his stuff.
so should ask for c3 clearance .are there an ofther thing to keep in minid when buying bearings

cherrs peet

Next you might delv into 7 ball and 11 ball races, then what brand you want to use it goes this way China,Jap,German I use jap Narchi never had a prob with them.

You can get the grooved one easy enough clutch side on a Lc the others with the locating dowels are unobtainable from a bearing shop.Dowels are there as a precaution to stop the bearing spinning in the cases.
My crank builder informed me that when the cases are bolted up the bearing shouldn't spin anyway so I dont bother buying the bearings with the dowels I just add a small smear of bearing lock to each side of the bearing then bolt it up.

Never had a problem with a spun bearing yet and Im on crank no2.

Steve at tss sells them if your chasing some however more expensive.

Pinned many bearings at home myself. It's a snack just a straight flute drill and a roll pin.
The pins are there for a reason

There is one downside to the 90deg crank. It happens to be sound. Or lack of sound. With the 180deg, you get that great 2stroke wail that everyone loves. With the 90deg, not so much. IMHO, It is a little dull sounding.