ESE's works engine tuner

[koba]

Although the cases do look significantly different to an MB50.

[husaberg]

Although the cases do look significantly different to an MB50.

"SQUINT HARDER" Then

Well I guess it would be a lot easier for me, being Asian and all

Definitely cousins. I think anyway, The MR50 was pre reed Mini Elsinore. Points ign Has no balancer and not many gears
i think.

Pics are MR50 MB5/H100 and Air Cooled CR80.
PS I never noticed the CR80 clutch set up was different to the MB/H100 and I have a Cr80 AC motor bits in the shed.

[wobbly]

E15 bearings are "magneto" shaft units that slide apart - yes they are angular contact.
Used in electric motor shafts and in some bikes as tripple tree steering head bearings, they need some form of end float adjustment.

Thanks for the links - great to have info like that on so many parts

[husaberg]

E15 bearings are "magneto" shaft units that slide apart - yes they are angular contact.
Used in electric motor shafts and in some bikes as tripple tree steering head bearings, they need some form of end float adjustment.

Thanks for the links - great to have info like that on so many parts

Yes they looked a little like the bearings Suzuki use in some steering heads But What is the advantage as a main over a std Bearing, less Fiction?
I couldn't figure out the magnetic bit So its (Magneto Bearing) I guess that Google translate got a bit lost in Translation from Swedish.
Had you heard of this Guy Wob?
Your Right there is some neat stuff and info there.
He obviously makes great use of his long winters.
The MB disk Valve seems available as a kit too.
Here is a forum he is on.
Best of all he seems to speak English too, by the look of it.

http://50iniepoca.forumfree.it/?t=43987929&st=75

[wobbly]

Had a look at the forum, his crankcase stuffing looks like the RGV100 im doing.
Wierd, he says its best to have as short a RV inlet as possible - I agree, but then he bolts on a poxy old round slide Mikuni.
Maybe in the rules??.

The angular contact bearings have the least friction - as they have a very small contact patch, and maybe this is an issue in a high rpm 50cc,but they also need real precision setup with shimming or a threaded end float arrangement.
I would use Microblue treated C4 radial balls, much easier, as I have dyno'd these as worth nearly 2 Hp in a 50 Hp 125.

[husaberg]

Had a look at the forum, his crankcase stuffing looks like the RGV100 im doing.
Wierd, he says its best to have as short a RV inlet as possible - I agree, but then he bolts on a poxy old round slide Mikuni.
Maybe in the rules??.

The angular contact bearings have the least friction - as they have a very small contact patch, and maybe this is an issue in a high rpm 50cc,but they also need real precision setup with shimming or a threaded end float arrangement.
I would use Microblue treated C4 radial balls, much easier, as I have dyno'd these as worth nearly 2 Hp in a 50 Hp 125.

Yeah I did see that with the crankcases, the carb is a period rule thing.
Those angular contact bearings. Didn't Ducati used them in the 851/916. But they need Preload in the cases as well. Is that right?

The water pump control and the ignition are interesting too.Very Jarcar/Dicksmith.

Ps what did you think about the Phil Irving book Gudgeon pin mod.The YZR500 was I thought a good article YAmaha were very generous I will post a Swiss auto writeup later I never knew they were that light.

[TZ350]

Been playing with a friends nearly stock MB100 tonight, modes were pipe, razed compression, reed and carb.



Dialled it in best we could with ignition and jetting but suspected it was a bit over compressed so we put a gauge on it, 195psi cranking, Blue line.

A quick bit of machining and 180psi Red line. (My own bike is 160psi at 13.5:1 uncorrected)

And even more skimmed out of the combustion chamber 130psi Green line.

Interesting to see how the power changed with compression.

Next move is to check the port time areas and pipe TL as it looks like there is a bit of a missmatch somewhere and cc it properly for around 14:1 and dial the CR in using the dyno.

I have often used a dyno to dial in the ignition and main jetting but have never thought of actually dialing in the compression ratio on the dyno by making small adjustments to the CR untill I have found the CR sweet spot .... but its an obvious thing to do realy.

[ac3_snow]

I have got a little bit done this morning. Fitted the crank up in my 'lathe' and polished it with emery cloth so the bearing now slides on with hand pressure.

Then got stuck in measuring everything up, was interesting. One question regarding the crankcase volume.... There is space between the piston port/reed block and the carb, I would consider this area to be the intake manifold. Is this part of the measurement when calculating crankcase volume? If so then it changes things considerably.

What I ended up with was...

Primary compression ratio (not including intake manifold) 1.37

Compression ratio 14.67

My thoughts are that the PCR is about right.. and compression ratio is not too bad, think from memory it gives me about 160psi. Only issue is the squish I think is still 1mm, will have to check this out once I do the final assembly, and perhaps reshape the head to reduce the squish and not up the compression.

Other pic is my plug after melting the piston

[F5 Dave]

I have often used a dyno to dial in the ignition and main jetting but have never thought of actually dialing in the compression ratio on the dyno by making small adjustments to the CR untill I have found the CR sweet spot .... but its an obvious thing to do realy.

Not everyone has a lathe in the dynoroom.
re above, so did you find the best ignition timing for each CR? it can change quite a bit for each head shape (although power can stay the same -can not will). A change in baffle cone may affect your 'sweet CR spot'

[wobbly]

Everyone uses the chamfered pin with plain clip now - but for years we had to cut the inner leg off TZ clips and add the chamfer to prevent the clips from popping out.
Dont know if Irving was the instigator of the idea, but it works a treat.
The angular contact bearings I dont think are a good idea for mains - as any side float will translate into vertical slop as well, so they must be run with preload.
Sort of the reverse of floating the crank - and thats worth easily replicated free Hp.

Primary com of 1.37 would be about right for the average transfer duct and port geometry being run.
If the descending piston compresses the volume, then its part of the case compression if its connected when the piston port is closed.
That plug looks way too hot for the application as well.

[ajturbo]

could this be sleeved down to 150cc????

http://www.asphaltandrubber.com/news...-learner-bike/

[Yow Ling]

could this be sleeved down to 150cc????

http://www.asphaltandrubber.com/news...-learner-bike/

I think you could get a special exemption to leave it at 250cc, cant see it even bothering a mighty FXR

[husaberg]

Everyone uses the chamfered pin with plain clip now - but for years we had to cut the inner leg off TZ clips and add the chamfer to prevent the clips from popping out.
Dont know if Irving was the instigator of the idea, but it works a treat.
The angular contact bearings I dont think are a good idea for mains - as any side float will translate into vertical slop as well, so they must be run with preload.
Sort of the reverse of floating the crank - and thats worth easily replicated free Hp.

Primary com of 1.37 would be about right for the average transfer duct and port geometry being run.
If the descending piston compresses the volume, then its part of the case compression if its connected when the piston port is closed.
That plug looks way too hot for the application as well.

With the Holed piston I suppose it would have made it easy for snow to measure the comp ratio so something good will come from the blow up I guess.
I think snow had mentioned the plug was a NGK 6 rather than a 9 which I would have thought would be more suitable for a tune such as Snows

The chamfer on the gudgeon.
I understand pretty much every pin is like that now. I just never knew that was why. I just thought it was for easy assembly and sress relief.
I never would have guessed that retaining the circlips was what it was for.

I mains were a bit of a surprise, but I think he said somewhere thay were worth a hp on a 50 but I don't know what bearing he compared it to.
With a the floating crank one think I have never been able to get my head arround is why wouldn't that cause problems with the disk valve clearances?Or is it not done on that side of the crank on a RV.

On his site it also says to use long bits of solder in a cross pattern for the squish checking. I always used to use 4 bits of short but his way is far neater and probably more consistent results not to mention easier with a angled cylinder like a MB100.

RE the Harley they would be hard to pass as they take interesting lines and are very wide I guess the 250 would go better than a stock EVO though.

Last pic is that an Airbox for a disk valve motor? If not what is it?

[teriks]

If you hand me the text in Swedish I might be able to translate it to something more useful

[wobbly]

Re the floating crank,in all the race engines I have done the RV floats on a boss thus any movement of the crank has no effect.