ok i whent threw 3 conectiong rods in this year. the first time 4 races in my brother was racing with a 76 mm crank stock bore and snapped one took out the cylinder. we thaught it might be from getting spun around and whent backwards. so didn't think anything about it. we got his engine back by the next wecent fully repaired the second time was my 8th race on the motor it blew up durring the heat race chipped a peoce off the piston and we rebult it to go out for the feature then worked my way from the back up to 3rd going for second snap crack snapped another took out the jug and came out the bottom of the cases and locked up the engine. we figured it was from the stock piston we were using and that we broke the chip off of the top durring the heat maby some parts fell down into the crank. so we borrow and engine for my brother and i took his 76mm that was repaired 5 races ago it is our 9th weekend this last saterday i was running ok got the jets right leading by a strait all feature 4 laps to go locked up and slid up the track luckely it slid off the racing line and not into the wall. after we got off the track I saw the spark plug wire got jerked off and the peice that holds the torsion arm onto the birdcage snapped from the jerk of getting locked up. water was porring out the engine looked under the carb to see that there was a hole right were the plate case and jug comes together. we took the head off and the engine looked perfect no burning anywere not on the edge not in the center couldn't look better. what is going on?!!!?!!!?!!! that is 3 cylinders and 2 sets of cases in half since the begining of the season all from connectiong rods. the shock of the 3rd rod was almost enough to park the 270 and forget about the points and put some money to get the 600 ready. but some people told us it was just a bad batce of rods and our engine builder is ordering a nother batch from another supplier. has anyone else had this problem? what do you think it can be i was told the rods and cranks are indistructable. i already fount one person that said this happend to him. so i have 3 and someone i talked 2 has 1 how many other people had this problem due to a bad conectiong rod?

what kind of clearances are you running for the pistons? too much and piston can bind and get stuck. snaps rod and puts hole in cases

we are using a vary respected engine builder that has been doing this for more than i have been alive I am 14 so i don't think that is a problem but thanks for the sugestion. so knowone has been having this problem?

what kind of clearances are you running for the pistons? too much and piston can bind and get stuck. snaps rod and puts hole in cases

I haven't had any issues w/ my rods, but I would defiantly check the clearance! You want around 40 thousandths. It almost sounds like the wrong dome or something if you keep having the same problem... Does the dome have any marks on it like the piston came up and hit it.?. If your dome is alright, I would say that your engine builder isn't balancing the crank properly... I use RTS to rebuild my cranks and then I do the rest myself. I would consult another engine builder and ask them about it...

ok thanks for the advise i will look at the dome and how do you check the clearance? i dnon't have much specialty tools besides a digital caliper and fealer gauges.

ok thanks for the advise i will look at the dome and how do you check the clearance? i dnon't have much specialty tools besides a digital caliper and fealer gauges.

Its real easy to do, get a piece of solder that is fairly thick... The stuff I use is is about .060", you can buy it at any hardware store. Take about a 3 inch piece and bent it in a "L" shape... Stick the solder into the cylinder through the spark plug hole. Try to make sure the solder touches the side wall of the cylinder and is align w/ the wrist pin of the piston. Now crank the motor over by hand until the piston squishes the solder, then measure what that is. Should be about .040" on your calipers... You should do this on both side of piston where the wrist pin goes through the center of the piston...

I was not really thinking about clearance from piston top but from piston side in the cyl wall. some of the builders I ran across in the past would use a stock piston in a overbore cyl. use the next size rings to fill gap at top and spread the bottom of the piston out. makes great power with little drag but doesn't last long at all.

ok i wikk check the clearance at the top and we have stock borem pistons and I checked them they are the right ones.

If you are using the stock Honda rod that would be your problem. You need to be using an aftermarket high preformance peice such as a Hotrod. They are built to handle the stress, the stock part is not.

Make sure you are turning off the fuel when stopped. You could be filling up the cylinder with fuel and bending the rod when you start the car.

If you are using the stock Honda rod that would be your problem. You need to be using an aftermarket high preformance peice such as a Hotrod. They are built to handle the stress, the stock part is not.

Actually i heard that the honda rod is the best rod for a honda...heard that pro x and hotrods, wiseco, are made of softer metal. And also heard the best piston is a stock honda.

Actually i heard that the honda rod is the best rod for a honda...heard that pro x and hotrods, wiseco, are made of softer metal. And also heard the best piston is a stock honda.

I agree Derek,There is absolutly nothing wrong with stock Honda rods.