ESE's works engine tuner

[Frits Overmars]

I opened that MSG I can't see PNGs without opening them in a new tab.

I could not post PNGs here for a while, but the problem went away somehow. Anyway, I converted the above PNG to a JPG; here you go:

[marsheng]

that should work out for Wallace than as I think the rod he has is about 2mm wider so deleting the washers might work out for him.

As I said I need to measure the whole arrangement - East German manufacture.

From my rough current measurements, I only have 0.7 between the crank and cases. I may then have to shorten the big end pin by 0.6 mm to give the 1 mm

The old rod was roughly 17 compared to 20 so I will need more than 2 x 1.1mm washers.

Why I like copper washers is all things being equal, they will turn at best only 1/2 the speed of the cage. If the oil friction is the same on both sides of the washer, then it will be 1/2 speed.

Pressed in washers will be running against the cage at full RPM.


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I have a damaged crank with slogged out big end pin holes. I think I read in Eric Gorr's book to TIG weld them up with a SS rod and then re-machine. I was thinking on a rough bore and then ream to finished size. Any ideas ?

[husaberg]

As I said I need to measure the whole arrangement - East German manufacture.

From my rough current measurements, I only have 0.7 between the crank and cases. I may then have to shorten the big end pin by 0.6 mm to give the 1 mm

The old rod was roughly 17 compared to 20 so I will need more than 2 x 1.1mm washers.

Why I like copper washers is all things being equal, they will turn at best only 1/2 the speed of the cage. If the oil friction is the same on both sides of the washer, then it will be 1/2 speed.

Pressed in washers will be running against the cage at full RPM.


****************************************

I have a damaged crank with slogged out big end pin holes. I think I read in Eric Gorr's book to TIG weld them up with a SS rod and then re-machine. I was thinking on a rough bore and then ream to finished size. Any ideas ?

Hopefully Frits will post the full story but my understanding is by deleting the washers big end life improves as it allows more lubricant to flow intothe big end bearing. From Frits post above it seems you can spray bronze on for better results.
You should also aim for at least 1mm clearance all around the crank to minimise drag.

[Muciek]

Thanks guys for many replies. I have made a list and passed it to friend who's bike it is. Now we will try to fix it. In earlier post I have made a mistake forks are from GN125 not 250 they are looking like regular forks not leading axle. Thanks again for help.

[peewee]

I purchased 2 YZ250 rods. The ProX has a w cage and the HotRods has a plain cage. Guess I'll use the HotRods one.

Cheers Wallace

Why not use the hotrods bearing in the prox rod as its japan , where as hotrods is taiwan. Better yet maybe you could get a honda bearing for your prox rod. Ive always tried to avoid hotrods when possible

[seattle smitty]

Older-generation racing outboards, such as the Konigs I had, used narrow hardened-steel washers on either side of the rod small-end to center the rod. Worked fine for us at the time, but was improved by slotting the small end or carefully notching the outer edges of the small end in a couple of places, to give much better access to lubrication and vent heat. I don't know how the latest motors locate their rods, but since they are manufactured by men from GP bike racing backgrounds, I suppose they locate from the big-end.

In searching this thread (thanks to those who showed me how!!) I saw a reference to other engines that located from the small-end, as above, but used aluminum thrust washers. It was reported that neither the use of 7075 nor hard-anodizing kept these washers from failing. Nothing was said about any sort of slotting or other modification of the rod small-end for lubrication. Obviously slotting would weaken the rod, perhaps to the point of trading one problem for another.

[Grumph]

Older-generation racing outboards, such as the Konigs I had, used narrow hardened-steel washers on either side of the rod small-end to center the rod. Worked fine for us at the time, but was improved by slotting the small end or carefully notching the outer edges of the small end in a couple of places, to give much better access to lubrication and vent heat. I don't know how the latest motors locate their rods, but since they are manufactured by men from GP bike racing backgrounds, I suppose they locate from the big-end.

In searching this thread (thanks to those who showed me how!!) I saw a reference to other engines that located from the small-end, as above, but used aluminum thrust washers. It was reported that neither the use of 7075 nor hard-anodizing kept these washers from failing. Nothing was said about any sort of slotting or other modification of the rod small-end for lubrication. Obviously slotting would weaken the rod, perhaps to the point of trading one problem for another.

Overhead guidance is possibly an option on Wallace's Maico as it probably won't be called on to do the prolonged very high RPM which seems to destroy the alloy top spacers. I suspect that bronze spraying the rubbing areas of the crankwebs may not be available local to him and I. Steel, zinc and aluminium spraying, yes, Bronze, probably not. I've dealt with the local mob who do it and they are not helpful generally...
Last time I had to use thrust washers fixed to the crankwebs was a vintage Triumph 4T single which had very badly worn crankwebs where the rod had rubbed. It's still running so it seems to have worked...

[FastFred]

Overhead guidance is possibly an option...

Older-generation racing outboards, such as the Konigs I had, used narrow hardened-steel washers on either side of the rod small-end to center the rod. Worked fine for us at the time, but was improved by slotting the small end or carefully notching the outer edges of the small end in a couple of places, to give much better access to lubrication and vent heat.

TeeZee has often posted pictures where you can see the RGV250 thrust washers he uses, The rod is located by hardened steel washers on the piston pin, just like you described and the bigend bearing by thin steel washers that can be seen in the second picture.

[TZ350]

Been helping Chambers dyno his 50 which is running a 24mm Tillotson pumper carb.



13+ rwhp so far.

[F5 Dave]

My word that's got some revs on it Rob. My 50s never touched 14 ever. Mind you the crank is still fine on the RG for ten years so it was clearly conservative with Yamaha parts.

[TZ350]

My word that's got some revs on it Rob. My 50s never touched 14 ever.

If rev's could win races we would be champions. Not sure what needs changing but it should be able to make more hp than it does and like you say, below 14K rpm ...... No doubt the answers are buried in this thread some place, I will have to start digging .....

[marsheng]

Overhead guidance is possibly an option on Wallace's Maico as it probably won't be called on to do the prolonged very high RPM which seems to destroy the alloy top spacers. ..

The inside of the piston does not have parallel to conrod faces so washers here may be an issue. I'll stick to machining the webs and copper washers.

On the other and hand I'm re-building a Konig 350 cc and they are spaced inside the piston, so any info on this is a real plus. The motor had rusted and badly machined spacers and I will be making new ones. Not sure on the clearance required in the little end but the big end is really sloppy.

[husaberg]

The inside of the piston does not have parallel to conrod faces so washers here may be an issue. I'll stick to machining the webs and copper washers.

On the other and hand I'm re-building a Konig 350 cc and they are spaced inside the piston, so any info on this is a real plus. The motor had rusted and badly machined spacers and I will be making new ones. Not sure on the clearance required in the little end but the big end is really sloppy.

If you are going to run washers aim to use the silver plated washers though Wallace.
If you read up on Jennings two stroke book which is on the net he explains the top end guided.

http://www.google.co.nz/url?sa=t&rct...ozRZ9VqG6aC7UQ

[seattle smitty]

The inside of the piston does not have parallel to conrod faces so washers here may be an issue. I'll stick to machining the webs and copper washers.

On the other and hand I'm re-building a Konig 350 cc and they are spaced inside the piston, so any info on this is a real plus. The motor had rusted and badly machined spacers and I will be making new ones. Not sure on the clearance required in the little end but the big end is really sloppy.

For the Maico piston, maybe you could fit a reverse-spotfacer to make the faces parallel, if you want to use washers there.

With the Konig, when you figure out what all you need you can PM me and I'll get you in touch with people who still work on those. Give me dims for the spacers. It might be that Konny is making many parts you can use. They only build 500s and 700s, but these are essentially the same as the 350s, same crank, rods, etc.. What's more, since all these versions had the 54mm stroke, to make a 350 required an extra-thick sleeve. This is a good thing if you happened to want to modernize this engine with improved porting; starting with new, thick, blank sleeves, you can make your own porting and have a real stomper. The manufacturing tolerances were pretty sloppy on the old Konigs (we in the States had a strong feeling that we got the junk and the Europeans got the better-made motors), but if you buy a complete new Konny crank, as I hear it you'll be getting good workmanship.

[peewee]

TeeZee has often posted pictures where you can see the RGV250 thrust washers he uses, The rod is located by hardened steel washers on the piston pin, just like you described and the bigend bearing by thin steel washers that can be seen in the second picture.

is that epoxy filling the cheek holes ? i have one with similar holes but didnt bother to plug them. wished i would of but at this stage it would be alot of work to take the engine back apart