Yes sir, $30 bucks for a drum and follower.
Made a lowball offer on a minty starter lever as well and the seller accepted. Starting to put together a nice collection of starters and clutch covers, I just wish I’d have started it 15 years ago before someone decided there was gold in them.
Tonight was.... you guessed it, input shaft night.
No surprises other than realizing the LGI aka Last Guy In (Remember that, I plan to use it in the future) used silicon to seal the cases
Having time to spare I decided to debur and buff up the crank before I take it in to PG Racing.
Cost me part of a thumb nail, but it was worth it to feel the adrenaline slowly oozing into my bloodstream as I realized I’d lifted the nail off my thumb about 1/8” in from the tip and not just nicked it like I first thought.
Started prepping the cylinder today. First step was to match the cases to the transfer ports.
The left side was a little trickier. Because the dowels are on the right side cases I had to remove the locating dowels on the cylinder, bolt the cylinder to the left hand side and then slide the right side cylinder out so that I could access the left side.
No intention of modifying the power band on this engine, but in the event that something has to be changed for whatever reason I’m going to try and lean towards adding to the bottom end rather than the top of the power band.
Only did one side today. Looks like it could use a few spots of epoxy in a couple places, but because this is the last bore on the cylinder I probably won’t bother as a new sleeve would displace all the questionable spots.
Last edited by El Camexican; 01-28-2020 at 11:54 PM.
^^^^ No me gusta
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Ouch! Seeing that are you leaning toward resleeving?
- 1985 Honda 250SX
- 1985 Honda 350X
- 1985 Honda 350X
- 1986 Honda 250R
“I Love The 350x. It’s So Bad”
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Na, I’ll try it like that. The sleeve isn’t cracked and the amount of aluminum in that areas is about 3/8” wide and 1/8” thick, so it isn’t like that’s a structural area.
All my Kawasaki KZ 900 and 1000 had cracks running from the valve seats to the spark plug holes. Freaked me out until I found out they all did that. I would not be surprised if many of these Yamaha power valve cylinders of the same year have similar fractures, but if it blows you guys will be the second to know
Almost forgot about this thread.
Amongst a zillion other projects I’ve been dicking with this off and on, but it’s been one step forward and two steps back as of late.
Came to find out that someone attempted to surface the base of the cases with a grinder and jacked them up so bad I was able to slide a .005” feeler gauge between the cylinder and the cases with the cylinder fully torqued down.
So after spending two nights filing and leaping the cases I noticed that the LH case half was cracked. Wanted to cry, but it was my fault for working the parts before cleaning them, so shame on me.
Fortunately I had some spare case halves and found two that bolted up nice and let the crank spin free, so they are being put into service.
On the first set of cases I had to remove a fair amount of material to match them to the cylinder, so on these I decided to build up the low spots with epoxy instead of removing material as the removal method leaves very little surface for the base gasket after it’s trimmed.
Last edited by El Camexican; 07-08-2020 at 11:14 PM.
Today I worked up the nerve (took only 3 beers) to add a second boost port to the cylinder. This one is a little trickier than the Tri-Z cylinder because the intake is angled to the left. Eric Gore says to drill a 1/2” hole on this cylinder and I’ve seen the mod. Frankly it looks stupid, so I decided to get a little more creative.
Attachment 263535
Attachment 263536
One small hole as a reference
Attachment 263530
Then another
Attachment 263531
Attachment 263533
Unlike the Tri-Z that’s prone to cracking after this mod I don’t think I have anything to worry about. There seems to be more material in this area on the YZ cylinder and the mounting base seems to be thicker as well. Time will tell.
And there it is.
Attachment 263532
Attachment 263534