Build thread and some thoughts on progress

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Yeah when I assemble it I'm gonna take some deck height measurements, might either shave the head or run with a thin/no jug gasket. If the compression drop is only from 10.5 to like 10.3 I ain't worried out it
 
Actually I'm sure I'm not the first, anyone know off hand the compression bump from skipping the jug gasket? I remeber seeing an old thread where weston did it and have heard the idea thrown around a few times
 
I measured the leftover one I had and it's only .020" thick. Quench area is also a thing to look at. From my research, I think it's better to shave the head down instead of moving the jug down. Unless your piston flat area to deck(quench) is more extreme.

The cam timing is also affected when you move the head closer towards the crank. I think this should be factored in decisions. It's why I abandoned the idea of doing chamber work to my head. Yours should be fine since you didn't do any large amount. Could always cc check the head with a piece of acrylic or lexan. You can get a cheap syringe from tractor supply or another equilivelent store.
 
Might measure the cc change for shits and giggles but I'm telling myself the power from an increase in flow will more or less offset the tiny loss in compression.
I got my jug back and a shipping date for my cam, so I decided it's time to break the motor the rest of the way down to seal the case leak that it's had for a few years.20240808_183441.jpg I found the key for my flywheel all blown out and the mating surface on the crank and flywheel all chewed up. If I had to guess the timing chain was collateral damage.
Gonna have to take a good look and see if I can polish up them mating surfaces and save the crank, but either case there's a bit of bad news; I'm not gonna be running in time for the pa meetup.
 
I've seen this on a couple other motors I tore down. The flywheel is held in place by the taper in the shaft with the correct torque on the bolt. The key is to locate it, not hold it.

Picture of the crankshaft damage?

You might be able to take the damage around the keyway out with fine files. Obviously need a new key and another flywheel.

Edit

The heads chambers vary slightly on these. So if no huge difference from your grinding, you won't notice it.

And the timing chain could have been damaged by a flywheel slapping back and forth. It's a small chain. Wasn't ment to take hits back and forth.
 
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Mildly chooched but I can get it right with a little emery cloth, keyway is undamaged. 20240809_105233.jpg
Hard to get a picture the but flywheel is about the same, though I might change it out anyways.
Found a good chunk of the key and the problem cones from it being the wrong size, too thin to seat right and rolled itself back and forth till it broke off
20240809_105806.jpg20240809_105759.jpg
 
I use valve lapping compound on cranks that look like that. It cleans it up real nice even if there`s a few imperfections left or any little divots it will be fine.
 
I like that idea, keeps the taper right and it so happens I have a ton of valve compound left over
 
That old key an offset key to adjust timing. They are thin in the middle. Someone probably didn't torque the bolt correctly. It doesn't really help performance as the ignition on these is already very advanced. The crank looks very usable. Just make sure the flywheel bore isn't scored, screwed up, or out of round. I'm sure used flywheels aren't expensive. It has to be from the same year range. If I remember right, there are 3 or 4 different ones. 87-88 are unique, and I know the Raptor ones added another pick-up sensor.
 
Nah the old key wasn't some weird offset one, it was just wrong lol.
 
"I use valve lapping compound on cranks that look like that. It cleans it up real nice even if there`s a few imperfections left or any little divots it will be fine."
This was a brilliant bit of advise and it worked awesome, thank you.
Got the motor assembled and almost ready to install. Test fit the carb to see where everything landed and its looking pretty gnarly. I decided a little fresh black on the head and jug like factory and just scrub the rest the best I could and it looks pretty enough. Best in show isn't what I'm trying to win if you know what I mean. Got a few small things to button up, and need to weld in a bung for the wideband into my old exhaust for tuning but with any luck I'll have it running sunday20240814_183837.jpg
 
Yeah rock run sadly isn't in the cards, life does what it does and things pop up.
I did meet my goal of having it running though. I ran out of time to get too involved but over the course of this week I'm going to be doing some tuning and trying to make some kind of temporary airbox adapter. According to my meter I'm running pretty rich but I'll take that over lean. Between the carb cam and head work this thing revs quick as hell, can't wait to throw a leg over it and go for a proper test rip
 
PineyPower said:
Yeah rock run sadly isn't in the cards, life does what it does and things pop up.
I did meet my goal of having it running though. I ran out of time to get too involved but over the course of this week I'm going to be doing some tuning and trying to make some kind of temporary airbox adapter. According to my meter I'm running pretty rich but I'll take that over lean. Between the carb cam and head work this thing revs quick as hell, can't wait to throw a leg over it and go for a proper test rip
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Hell yea buddy that's great it's running better
 
I just got off my first proper test rip. I have a little fine tuning yet but its veeery close. Sadly my wideband 02 crapped the bed shortly after the first bout of idle tuning but it at least gave me an idea where to start.
Got to ride it at full potential and I'm quite happy to say this thing makes awesome power, especially mid and high rpm. Throttle response is quick and pulls hard all the way to redline, the motor doesn't feel choked out anymore. Once I get it the rest of the way dialed in I'll probably do a few small write ups with what I've learned and what I did, cause although reading there's alot of people running similar setups there is still alot of basic stuff that'll catch you off guard
 

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I don't see the vent tubes. You'll want to install them to make sure dirt and dust doesn't get in where you don't want it. I used the exact same Uni filter for test and tuning. Made it way easier to loosen and tilt the carb for jet changes. You have to rip it hard a bit, shut off before letting it idle, and take the plug out for a plug chop to really see how close you are.

In my experience, the FCR is not necessarily a very hard carb to tune, just a learning curve. I'm still glad I switched to it.

Can't wait to see what you have found. Most people never follow up.
 
Yeah I wanted to keep the tubes off and out of the way for tuning, same with this filter it makes it super easy. I might end up building my own air box around it honestly, I like how much free space the setup makes.
Made some small changes and went on another longer ride this evening, it's getting closer and closer. High load low rpm it'll hiccup if I whack it too hard but otherwise it's about perfect. I can't stress enough how happy I am with how this came out.
Got some other work to do but late next week I should be able to bring it into work and finally get my shock mounts made up (hey, this thread mentions early how progress doesn't always go like you hope)
And it's all fiddly tuning stuff, cosmetics, and basic matinence from there on out.
 
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