With the ever increasing need for "new" Penton parts, I took it upon myself to reproduce the 6B 125 rod kits. These kits are made to a much higher standard than original, and carry a retail price of $110.00.
The rod itself is "I beam style" for greater strength all around, and allows you "high RPM/speed freaks" to increase HP without sacrificing reliability. The kit includes: rod, upper pin, upper bearing, lower pin, lower bearing and thrust washers. Kits are in stock! Dealer inquires welcome.
Thanks
Marc Biro
Builder of the 125 "METTCO Replica"
(http://www.pentonusa.org/forum_images/misc/sachsrodkit.jpg)
Marc,
Would it be possible to get a kit with a shorten lower pin? What would is cost to have that done? Having a pin shortned localy with out damaging the polish on the bearing surface and keeping the ends square is not easily done for most.
How thick are the rod thrust washers?
The reason i ask is that this rod would work in 100/125 A , B and 175 engines. The 175 uses a thinner thrust washer .025 as apposed to the 125's .053 but the same rod as the 100/125 and the A rod a shorter pin buy about .060 to .065 as the kit you show.
The 175 rod kits are very hard to find.
Thank you for you efforts,
John D.
John D,
I had taken into consideration all the issues you mentiond prior to making the rod kits for the 6B motor. The actual lower rod pin length in my 6B rod kit measures 54.5mm allowing it to be used for either the A or B motor. With the 54.5mm length pin used on the 6B crank, it is 0.75mm shy from flush on each end of the crank halves, and do not cause any problems such as crank halves rotating out of balance. SACHS new what they where doing when they designed the pin/crank with a taper allowing for a very snug fit! I have run my kit on my personal bikes with great success. I am about 2 weeks away from receiving the 0.75mm thrust washers that you are requesting.
Thanks
Marc Biro
Quotequote:Originally posted by Marc Biro
John D,
I had taken into consideration all the issues you mentiond prior to making the rod kits for the 6B motor. The actual lower rod pin length in my 6B rod kit measures 54.5mm allowing it to be used for either the A or B motor.
Thanks
Marc Biro
Mr. Brio,
You are a credit to Pentonkind.
Tony
Marc,
I've E-mailed you. Have you gotten it? How do we get these kits and how do we pay for them? Credit card? Money Order?
Thanks
Lew Mayer
How does the weight of the new rod kit compare with the original stuff? Will it be necessary to rebalance the crank,rod,piston assembly?
Now we need a good supply of the main bearings.
Thanks, Mark
Mark
You can get the M-20 main bearings through Applied Industrial Technologies. It is a standard 3 piece magneto bearing available at roughly $40 per copy the last time I looked. I am sure that other bearing jobbers can get the same;)
Mark,
I will weigh the kit tomorrow and advise.
Thanks
Marc B.
Kip,
I think they have an office fairly close to me. Do you have their stock number or some other ID number they may recognize. Last time I tried to get a guy to look up a M 20 "magneto bearing" all I got was a blank stare.
Mark
Mark,
I don't think you would need to worry if the rod is a little heaver than the NOS ones.
Here is what we found out from the 175 conversion on the 125 Sachs lower end.
The Sachs and Penton engine repair manuals have a balance factor of 80 to 83 % listed as the thing to shoot for.
Knowing the 175 Piston was 1 and 1/2 ounces heavier than a Sachs 125 piston we thought that weight would have to be added to the A crank we used. We contacted Falicon and went through what we had and what we needed. They recommended that a 60 to 70 % be used when building our a crank. That is a very big difference so we double checked with Martijn in the Netherlands on what his 125 Sachs Road Racer was balanced at. He confirmed what Falicon had told us. He is using a 66 to 70 % balance factor.
We went with the balance factor Falicon recommended. Over 2 and 1/2 years the crank has worked fine. No difference in vibration over the stock 125 Sachs or the 175 KTM engine in my sons Piner.
Anyone else that has more experience with cranks or some better idea's Please offer what you know here. Doug , Ron, Bobby , Kip , anyone please chime in here. This is an important Bit of knowledge that everyone will gain from.
John D.
John,
I will see if I can find my notes on the reed valve engines and other pistons that I have drilled. I had to change to a B crank assy on the cut pistons(for port timing) due to cutting weight off the piston(making it lighter). When I get time I will look it up, but I thought mine was around 72 to 74%(with the lighter crank)?
Ron Carbaugh
Mark when looking for the M20 Bearings it is best to tell the bearing supplier it s a "Consolidated M20 " Consolidated is a bearing importer that always have them in stock ... Manufactures like SKF and FAG dont seem to keep inventory on these low use bearings . If you order a Consolidated you will probably end up with an FAG brand .
Brian Taylor ( OP MGR Canadian Bearings )
Brian Taylor
Mark,
The weight of the new "I beam style "125 rod is 4.8 oz. Stock rod is 3.6 oz. Weights of all other components are the same. Once the kit is installed I true the crank assembly with a crank trueing jig that incorporates a dial indicator. Hope this is helpful.
marc
Marc,
It looks like you have done your homework. I hope to install one of these soon on the next race bike that needs a rod kit. Thanks for all the hard work. I will try and keep you updated on any feedback. Thanks.
Ron Carbaugh
Ron,
I've got one coming for a 5a motor. I'll let you know how it works.
Lew Mayer
Lew,
I am also looking forward to finding out how how the kit works on the 5A motor. I have installed my kit on a 5A (aluminum rod)crank and found that pin/brng/thrust washers fit fine. Width of crank assembly remained the same, as well as lower brmg to thrust washer tolerance which is .018 or .457mm. Now I just need to put it in a chassis and run it!
Marc Biro
I want to be perfectly clear on this: this rod kit fits KTM 175s as well? Or does it fit Sachs 175? $110.00 with top pin and bearing is a super deal and I need a Jackpiner rod kit. Thanks Dan Pagel
1975 250 Cross Country, 1974 175 Jackpiner, 1975 125
Dan,
I do not know if it will in fact fit the 175 Jackpiner. maybe somone out there can enlighten us both? I have been told yes, but not sure as I have been a SACHS 100/125 guy for many years. I will however be cracking open a Jackpiner motor I've had sitting around for some time now. As soon as I get to it, I will have an answer for you.
Thanks
Marc
Marc,
Was the NOS rod you weighed knife edged or an I beam? Most B rods I have seen were the I beam style. I have a knife edge A rod I can weigh for comparison.
Dan,
We did some comparisons back 3 years ago and it looked to us like the rod and pin for the 175 Piner KTM were the same as a B engine Sachs. The difference in the rod kits were the 2 bronze thrust washers. The 175 Kit used 2 thin washers about .025 in thickness , the 125 B Sachs Kits had 2 bronze thrust washers about .053 in thickness.
Euro Rod confirmed this and was at one time trying to find the thin thrust washers so they could offer a 175 rod kit.
John D.
John,
The 6B rod I used when comparing weights was the knife style. I have yet to see an I beam style rod in a 6B motor, and did not even realize they where used in the 6B motor. I have rebuilt quite a few of them, only to find the knife style. I am assuming the I beam style rod is found in the later production 6B motors?
Marc
Marc,
I dont know when the I beam rods came in. All the B engines we got as parts donors in the last 2 years were I beam rods. Doug might know when the I beams came in.
I can press a bad crank apart and weigh the NOS I beam in the next few weeks. We have another Hurricane about to pass this way tomorrow.
Thats 4 this year so far . Man will I be gald when it's November!!!!!!
chuckle chuckle.
John D.