pmk

This week, my riding buddies new rear shocks arrived. These were OZO Pro Trials Rear Shocks from InMotion. The version he got were the silver colored ones with Shrader valves on the end cap. My question, and he has not heard back from InMotion yet, does anyone know how to alter the size of the mounting setup in regards to diameter. I have not personally tried to work on them, but he mentioned the oem spacer will pivot and rotate, but does not seem to want to be pushed out. Obviously asking before causing damage. The shock eye mount diameter is too small.

Gordo, were you able to get the info you needed about the Rickman? If not, there is a dedicated crew on ADVRider that post in the Forum Section “Olds Cool” in the topic “All things Rickman”. A couple of the guys have the Rickman books, and in them, there are pages listing frame numbers and build quantities. Jaglite, one of the guys there helped me identify my Rickman Yamaha. All the best with it.

4130 Chromoly sheet is ordered. Footpeg kit is here. So the process begins maybe mid next week to make some cuts. So much info shared here has been awesome and very helpful. Now it becomes a matter of putting ideas to results. I ordered bar risers for my own MAR. I will share more on that when they arrive. Essentially, nothing crazy planned, merely bring the modern Renthals to about the same height and position as what the MAR was when new. My bike will have stock location footpegs with the KX pegs vs the tiny MAR things. Thanks everyone, great discussion.

Been window shopping for bar risers for my own MAR. If I can locate longer 7mm bolts, I have risers off a vintage KTM that are 1”. Time will tell what I ultimately decide upon.

Woody, any chance I can ask for a couple more photos of those peg mounts. AND...how much bar riser do you install? Your words of down only is what was decided yesterday, seeing your photo indicates it is about at axle height based on a quick check today on his sister MAR. being about the same height and experienced with the MAR for a while is a huge help. As for all the numbers and math, sorry.

Appears they moved footpegs back and down, but also moved the bars back also? When I asked about Micks height before, the numbers were all over the place.

In the process of sourcing bar risers and 7mm bolts. At a guess, I want the bars up a similar amount if only to bring them closer to stock MAR bars in the stock position. No plans to redo my footpegs at this time. I currently run KX pegs on stock frame mounts. i am 5’10” tall with as some tell me stumpy short legs that are an inseam of 30”. Can you share how tall you are for comparison on raising the bars. Also, KT bars, any idea on how tall they are? Footpegs willl be redone on my friends bike, and he does run bar risers as I mentioned before.

In regards to the yokes (tripleclamps), the 2” you mention, was that fork tube offset or bar position? If bar position, was that 2” up or 2”” forward only with no height change? I realize you said forward in the post. Learning as much as possible.

On my bike, being resto mod it would certainly defeat keeping the theme of looking somewhat original, but no doubt would give mounting options. Yes, the 7mm bolts that secure the bars, well mine currently remain 7s, but I may convert to 8s if need be. What we have found, on EBay, are Honda 50 and clones Pitbike bar risers from China that can work. Does require finding longer bolts though. I may simply find the bolts, get a few lengths, then fabricate risers from flat material. Your setup certainly can be fine tuned. Curious, when you stepped up to 8mm, did you install the HeliCoils for added strength, or was there another reason.

The bike getting the footpeg mod, the owner has had several back surgeries, so any bending over forward is not comfortable for him. As for me wanting to raise the bars some, trying to find oem height bars the same as original MARs in something other than steel has been impossible so far. Currently running Renthal bars, the tallest trials 7/8 bars they offer. Still a bit lower than oem. So the modified bike will get footpegs lowered, and bar height reset for the riders comfort.

Actually, 51.5” is what I measured and that matched what feetupfun measured a few years ago. Not the shortest nor the longest, but does match what someone else posted that Miller, I assume Sammy Miller, apparently says 51.5” is optimum on the older bikes. Regardless, this is quite the learning lesson prior to making some cuts to the frame.

Yes, ratios are being determined, this morning with fresh eyes and brain, I am double checking my late night efforts I posted earlier. His bike already has bar risers. Pulled the bars foward slightly also. You mention a taller rider wanting the pegs down and aft. What is your opinion on moving them aft for the tall rider? Increased room or some other factor being changed? Months ago, on another website I asked if anyone knew how tall Mick Andrews is / was back when the MAR was designed. Simplya curiousity to have an idea of how tall the target rider for an MAR was back when they were new. Sadly, his height, posted by others, varied a bit. Regarding the use of the clutch. The sections in our local events, some certainly require use of the clutch to get the bike to corner tightly, while other times, the sections seem more old school where you simply ride using throttle control, balance, and turning skills. I will say, that while accomplishing all this research, and since I am modifying his frame, I remain curious about my own MAR and me as a rider shorter than my friend. Pretty certain I am either making or buying some risers for my handlebars. Not interested in lowering my forotpegs just yet since my frame is recently powdercoated.

Greg, yes. Prior to your post, I decided that on the MAR, the front / rear location seems somewhat optimized as delivered back in the day. For my friend, that is tall, the footpegs are being moved downward. How much is unknown at this point, but is the next variable to decide upon. Another post mentioned to lower them to the height of the axles. Next will be running a string from axle to axle and seeing how much change this creates and if the position is too low, too high still or possibly appears good. I have been looking at various photos of many OSSA MARs with relocated footpegs. The most extreme is 50mm down and 50mm aft. The owner mentions his goal was modern bike feel, and says it is now that way. My current though is as I mentioned simply downward with no change front to rear.

Yes, I messed up posting swingarm. It was late and I had both this topic and the one I linked open. Thats_A_Five posted swingarm length and it was on my brain when it should not have been. My measurement and calculation was as you described, actually using your posted formula. This morning I found the variation between your 26.2% and my 27.2%. Your numbers were likely taken on an MAR with oem stock footpegs, on stock mounts. Those footpegs were small overall and certainly not a large platform front to rear. This morning, I went back out and remeasured. My current setup has oem mounts on the frame, but uses Kawasaki KX footpegs. Last night I measured from the center of the footpeg, the KX peg, to rear axle. That came in at 14”. Remeasuring this morning, as if oem MAR footpegs were installed, the length decreses to 13.5” from footpeg center to rear axle. That 1/2” difference accounted for a 1% change. This became an eye opener when seeing where another person stated 29% was a good base number. Granted there is some minor measuring errors since the measuring was done directly with a tape measure vs obtaing the true dimension by dropping plumb bobs to the floor. Essentially, the tape meaure is close enough. Overall, as a general guide in helping to determine where to mount footpegs, all the info has been a huge help.

Refrencing the linked topic. In regards to the wheelbase and footpeg locations, has anyone got a reference to the front to rear weight bias on these vintage bikes. Not critical, more curious about it.

Footpegs on my buddies and my MAR have been swapped to Kawasaki footpegs. Position remained the same. My buddies MAR is going to be modded. He currently runs bar risers, guessing about 1 1/2” maybe more and slightly forward. Certainly noticable compared to my MAR with no risers. We both run the tallest Renthal bars. Lowering the footpegs is primarily to accomodate his tall height.

Feetupfun, the topic I linked, do you recall the MAR you measured. Maybe remember what year it was. I ask, since your dimensions measured a wheelbase of 51.5”, same as mine, but doing the math based on swingarm length, I came up with 27.2% vs your 26.2%. Any chance it was a typo mistake, or do you think they had different length swingarms while retaining the same wheelbase? Even though you posted that info years ago, thanks, it was very insightful.

This topic I found gave some insight into footpeg location front to rear.

The mention of setting the height based on the axle centers is great info. Easy to check, and guessing the MAR footpegs are above that reference line. For whatever reason, this IPad is not accomplishing searches here, but I plan to keep gathering more info until we start cutting.

Aftermarket footpeg location brackets and do it yourself footpeg relocating certainly is popular on vintage bikes currently used in competition. In general, how or what criteria determines the best footpeg front to rear location? Is the lowest possible position that kerps the fert safe best? While researching this, one company mentioned that going rearward with footpeg mounts is not always a benefit, it can reduce weight on the front tire and creates steering issues. Being specific, we will be modifying the setup on my riding buddies 72 OSSA MAR. The internet has many photos of these machines with footpegs anywhere from stock to 50mm x 50mm down. As a rider, he is 6’3” and about 200 pounds with gear on.

Simple report. Installed Tubliss system. Installed onto a 2.15” wide vintage Akront rim that was laced onto the existing oem OSSA MAR rear hub. As per Tubliss instruction recommendations, I went with a new rear tire to ensure no or minimal leaks possibly from a previous rim lock scarred area. Even following instructions, the Dunlop 803 was a tough challenge to seat the bead of the tire onto the rim. Even once seated, I deflated the tire, and the Tubliss to allow the Tubliss bladder to settle into position. Immediately, the Dunlop fell off the rim bead seat area on both sides with simply being deflated. Reinflated, bead seated and Tubliss inflated. Wheel was reinstalled and tested at 3 psi in the yard. Bead stayed seated. Had an event Sunday. Rode the entire event at 3 1/2 psi, tire never dropped off the rim towards the center. Being a lower class rider, with far less experience than all of you, the lines I rode were mostly rolling with no hops. The rear certainly found more than enough grip, and felt more stable. After the event, I rode my buddies MAR, same rear tire and pressure. Granted, his rear damping is firmer, but it did seems my bike had more grip. Advertising mentions it is the added ability of the tire to flex because of no tube. Maybe, but honestly, it could be we used two different gauges when setting up, or me running the 2.15 and him the 1.85 rim.

My riding buddy and I had a discussion about the Twinshock vs Vintage topic riding home from the event yesterday. Our local group runs the classes of Vintage B and Vintage C. We both have OSSA MARs. Mine a 73 and his a 72. As others posted, we ride for fun. We are honest with our score and winning is not the most important thing. In regards to the Hondas, obviously, the TL series is vintage, but what is the opinion on the later Honda twinshock bikes. I asked, based on curiousity. How much better are the 80s Honda Twinshocks.

I doubted this was possible as did my friend with the issue on his MAR. He drilled the rim and installed screws. A bit upset that the screws apparently were not holding the tire, he removed the wheel, and unseated one bead to reposition the tube. He noted there was no torn or elongated rubber on the tires bead, simply the spots where the screws had held the tire.

Guessing, probably order two Tubliss setups, and install them, one in each MAR. My MAR has so much rear grip it sometimes catches me off guard. If I run the rear with Tubliss and no tube then it can seriously mess with my head... Who knows, maybe I should polish that 2.15” rim, lace it up, run Tubliss in it with no tube and a Dunlop. Just is a tight fit already between the swingarm with 1.85”, but it would be cool to do and simply adds to my resto-mod built MAR.

I suppose, but for $95, the Tubliss setup seems pretty cost effective and retains the vintage look of the rim while adding a level of safety and reliability. FWIW, my riding buddy was having issues with what was thought to be the Dunlop tire slipping on his MAR with an Akront rim. For whatever reason, his tire does not drop towards the center, but constantly he would see the valve stem getting that lean to it. He added screws to the rim in tne bead area to stop the tire from slipping. The ironic part, even with screws securing the tire, the valve stem still tilts with use of the bike. He removed the tire to correct the tilted valve stem, and found the screws marks were not stretched or elongated. He determined, with the low pressure, he runs, the tube is walking about inside the tire casing and over time, with the tire flexing the tube moves enough to tilt the valve stem tight against the edge of the hole and is trying to tear the valve stem out.