XR100 Heavy Duty Connecting Rod??

[TechGuy]

Hi Guys,

I was wondering if anyone makes a stronger connecting rod for the xr 100s? Today I received a used XR100 that I bought on Ebay with the Powroll 150 stroker kit installed. The small end of the rod was badly worn out and Powroll told me to expect only about 1 year of riding out of the stock Honda rod they use on the stroker crank. Before I take the time and $$$ to rebuild with the stock rod again I thought I would ask to see if anyone knows about an alternative to the stock Honda rod.

Thanks

[enduro4231]

iwould the Wiseco HotRod be classified as "heavy duty"? Ive never used one so i dont know. I only looked at one site, but they didnt have it for the 100. MOst likely though, they make one for your bike.

[ACS]

minifig-phil might best answer this but a 150 stroker has a "shrunk" stock rod. It has a lump in the middle. You are going to have to get one done from powroll or elsae you will have the piston go up to far and back down too far.

[minifig-phil]

The problem with the Powroll stroker crank is the angle of the connecting rod at mid stroke is much steeper than a stock crank with a longer rod. This is very hard on rods.

I would like to try to use stock length rod (spacer inder the cylinder) but how do you lengthen the cam cain that much and what do you do with the tension blades?

[R_Little]

Can't they make a piston with a higher piston pin hole, in order to use a stock rod? I guess there is not enough room to the piston crown to do that?

[minifig-phil]

If you can find one it would be great!

I longer connecting rod has many advantages one being the geometry of the rod through the stroke and the other being the amount of Dwell time at TDC and BDC when you need it most to fill the cylinder and time for fuel to burn. With this extra time you also get the piston to move faster in it's stroke to help with the velocity of the air moing through it.

[socalxr]

No they can't a piston with a higher hole, because Powroll don't make their pistons. They machine a pre-existing pistons to work. That's why the 120 kits that different people make all run a little different. Since everybody machines them slightly different according to their own preferences. The only company that makes their own piston is Wiseco, Kitaco, Takegawa and may some other Asian companies that don't sell stuff here. I've ridden both the long rod and short rod strokers and the long rod is by far Superior. As far as making a longer cam chain, I'm pretty sure they just pressed the pin out and installed a extra link, then pressed it back in. Spike from Spike racing had one and Dave from DMC. It was a long time ago, but remember riding their bikes, thinking, "This just isn't fair." Eventually we all went to 120's because, we all were breaking gears all the time. I remember Spike breaking a kick start gear almost every week!!

[minifig-phil]

I haven't broke one yet but I'm aware it can happen and am very careful.

I had a TZ250 that had a long rod motor and I couldn't believe the difference.

[bianese]

I have been building long rod engines for several years and just as the above posts states, they are superior to the shorter rod. The rod ratio is a part of engine building that gets completely overlooked, just like degreeing cams and setting squish tolerances. You would be surprised at how much free power is never tapped. BTW, long rod engines are superior regardless of whether it is a stroker crank or stock. Clint

[PowerFiend]

Carillo should be able to custom make a rod and cp pistons can do a custom piston, if you can tell them the exact geometry. Expect to pay $500+ for the pair though.

[bianese]

Another free mod is to grind smooth and casting marks on the sides of the rod and poilish it smooth. Chevy does this to their performance rods and called them "pink" rods. It makes them less likely to break if there are no scored marks or casting lines. Clint

[socalxr]

Actually, I've been riding built xr100 motors for 16 or 17 years and I've never seen a rod go bad. (unless there was an oil problem) I've broken cranks, trannies, and valves, but not rods. And there used to be a bunch of us riding them. Although, after seeing some scarry stuff from ebay purchases, I don't put it past some people.