1973 xlh project
alright trying to find new pistons and rings. My jugs iner diameter is 3.197 is there a way too determin piston and rings by that measurment. Thanks for any help

 

Yes there is. I do not have the experience to give guidence on this. Best to have the factory service manual 99484-78, study the appropriate section, re-measure, then take it to a machine shop. There is a specific measuring technique. Without the manual you would most likely have not done it correctly.

You could go direct to a trusted machine shop but, in any case, it is best with this type of work to go in knowledgeable. You may have to be firm and give specific directions as many do not have experience with vintage engines. Many machine shop guys are resistant to the customer knowing more than do they.

You should also have the factory parts catalog 99451-78B.

Widely available from a local indie bike shop, HD dealer, J&P Cycles, and various eBay and internet sellers. Just put the part numbers into the Google and eBay searches.

 

stock is 3.188 i believe, needs to go to a shop and be checked for roundness and whatever pistons you buy have to be " fitted" a cast piston has to be fitted looser than a forged piston, should never just buy a set of pistons and throw them in if you want it to last, take them to a good shop and let them tell you what piston you need, you will be alot better off

 

+1

The machine shop will tell you if the cylinders need to be bored or honed [or neither], and what size pistons will be needed. Then they will bore/hone each cylinder to a specific piston.

 

Thanks for all the help guys figured out the jugs are good so i need standerd pistons and .010 rings

 

Nope! You cannot do that. Must use standard rings with standard pistons.

As already mentioned, you must have and study the factory service and parts manuals, and you must consult with a reliable machine shop to do this kind of engine work. Look for a shop with experience with vintage, cast iron engines. This is no place for a new guy to be guessing and deciding on his own.

I take all of my potential machine shop work to my local indie motorcycle mechanic, and i let him choose the machine shop and supervise the work.

 

oh boy i hope you listen i will hate to see another ironhead dead!, not only does the bore dia. have to be with in spec, it has to be round, and not taperd, take them to a good machine shop, they will tell you what you need, and it wont be standard pistons with anything other than standard rings,if the cylinders will accept .010 rings and you use standard pistons they will slap themselves right into the scrap pile!

 

If it's a matter of trying to save money you'll do better with a good machinist in the long run. Ask a bike shop you trust which machine shop they use. Then cut out the middle man and deal with the machine shop directly. It saves dollars and you'll meet a bunch of guys who love bikes and give great advice, like best way to break in your newly rebuilt top end. A properly rebuilt top end is better than a new one because the metal is done flexing so much from hot/cold cycles. So once you restore "round" even with a good honing, your bike will be much tighter and last much longer.

 

Just an update that info came from the local harley shop after they measured them. I have now found a vintage shop with some realy great guys not 4 secounds from my work who would have guesed. But dont worry there helping me sort it out now. There was no need to worry i have a rule when it comes too anything mechanical ( allways get a 2 3rd and 4th opinion). Thanks for all the help yall have been im trying too get some befor pics and build pics up asap