'74 WR250 Low Compression?

I had someone helping me go over everything to get my bike quieted down, there is still lots of engine noise, did a compression test, got about 100 PSI, this seems really low to me. I suspected it was low since it can be hard to start but I can't seem to be able to find what it is supposed to be at. What is the proper PSI for a 1974 WR250?

should be at least 160 psi..are you kicking it with the throttle held fully open until the gauge wont read any higher? if so that is for sure too low. other later air cooled hoosk 250s i have rebuilt were 180 psi when assembled. perhaps 160 would be ok?

100 seems too low , Id say anything under 125 needs a rebuild then it would be a basic rebuild too . When you wait too long it cost more.
my 250's are in the 175 range just to give you an example.

ok, thanks. I just could not find the specs for compression anywhere. I know there is a wide range of what is acceptable depending on the specific engine. I got a Haynes manual, it says "check compression" but not what it needs to be at. And yes this is with the throttle wide open, at least a dozen good kicks.

pour about 2TSP of motor oil down the sparkplug hole let it sit sit for a few minuets stroke it thru a few times then put the gauge to it be-sure to hold it WFO and KICK IT if it comes up its time to order parts

I was looking on ebay at piston kits for my '74 WR 250, seems to be many available, but I found it really strange they were all listed as fitting '74 - '84 , I thought the '74 engine was the same as the early '70s bikes? Is this the right part?

Yes, that is correct, 74-84 air cooled.

Are you going to hone it over size?

I have the gear driven adjustable hones with coarse, medium and fine stones. I can open up any cast iron bore to any size.

But make a note I find the older husqvarna sleeves are harder to hone probably because of the higher nickel content in the cast iron. The Swedes never skimped on quality.

I just got done taking everything apart and packed it all in a box. I'm going to take it down to my local shop and see what they think, I've never done this before so I really don't know what it will need. The boring/honing part is beyond what I can handle myself.

i highly doubt she would want to go through the trouble of honing it the whole way to the next bore size, if thats all it needs. most like to take it to a machine shop that can assure its straight. my local shop has an old sunnen cylinder king, only costs 45 dollars labor. and thousands in tools to do it right.

take them a list of the available piston sizes and they will bore your cylinder till its round again, then let you know which piston will be needed. after they get the piston in hand, they will do the final hone to the piston manufacturers clearance spec or yours if you specify something different.
at least thats how ive always had it done.

and remember the bigger the piston the more it will expand so you need to up the clearance if it was me i would ask for a loose .002

I don't claim to be a 250 Husky expert, my knowledge is in the big bores but I believe that the 74 250WR is the older porting technology with one transfer port in the piston skirt instead of two like the 74 250CR and later models. With that said any piston for sale that says its for 74 - 84 will not work. Check your application before buying anything.

Agree with Crashaholic, measure twice cut once. I. Don't buy anything without checking part numbers myself and validating comparability. Plenty of good places in the states from which to buy as well.

Both retailers below sell the same Wossner pistons. As you can see Husqvarna-parts clearly states this works for the 1974 WR250. If your piston does not look like this regarding the transfer ports, then I would call or email. Of course pictures posted here of what you have always help in people providing advice.

http://www.hva-factory.com/crankshaft-top-end/husqvarna-250-piston-kit-1974-1984
http://www.husqvarna-parts.com/catalog/item/3736875/3452728.htm

I had a portable gear adjustable sunken hone. I just purchased a new one. Well actually two, one for big bores and another for small bores. The coarse stones cut very quickly to the next bore size. It holds the cylinder perfectly round. There is no taper in the bore too. These gear driven homes aren't the cheap spring loaded hones. I been doing automotive shop work since I was in trade school. That's over 50+ years ago. I do all my own work.

Only one port in the piston skirt. I had a feeling that was the wrong one. It seemed odd that it would be like the late '70s bikes when nearly every other part is identical to the pre '74s

Search the net and ebay I seen the one port husky pistols somewhere.
Does weisco offer one?

This single port piston could be a mid production year upgrade to the double port piston?
There is the double transfer port cylinder and head on eBay can you upgrade?

I can't seem to find one... would think this is a part that should be available as aftermarket, can't seem to find anything from Weisco. Anyone have a good source? I would like to get the whole piston kit and new gaskets too.

have you tried calling vintage husky?
http://www.vintagehusky.com/
your year should be in his wheelhouse, and he should likely have anything you need. i dont deal with them much as they deal mostly with older stuff..

http://www.husqvarnavintage.com/Husqvarna_250_piston_kit_wossner/p792576_3797510.aspx
In England!