Author Topic: New guy, first build (Read 57204 times)

grcamna2 · « **Reply #50 on:** May 18, 2014, 05:14:14 AM »

Beautiful Job on the polishing P.abrera

Make sure you've got enough braces on that Dexion homemade engine stand;that Dexion steel shelf stuff is real strong 'up & down' but not much sideways.I look forward to seeing what your engine looks like.
The images you have posted lately look a lot more clear that the old ones,Nice.

P.abrera · « **Reply #51 on:** May 18, 2014, 07:33:01 PM »

Thanks grcamna2. Slow goin but ill just keep pluggin along.

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P.abrera · « **Reply #52 on:** May 27, 2014, 05:10:17 AM »

Some progress. Got my carbs sorted with new jets, needles and gaskets.

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grcamna2 · « **Reply #53 on:** May 27, 2014, 06:01:03 AM »

I know those carbs must have been a big job,good to see them ready to install

P.abrera · « **Reply #54 on:** June 03, 2014, 04:31:01 AM »

Got to work pulling the head. Ran into some trouble with the tappet covers. One broke off leaving the threaded end stuck in the valve cover and a couple rounded off. PO cemented everything shut with gasket sealer! Some heat and a pipe wrench persuaded them to come off and and chisel spin out the left-over thread. Valve cover over saved.

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P.abrera · « **Reply #55 on:** June 03, 2014, 04:37:08 AM »

Stuck at pulling the cam sprocket off cause it wont turn from the cam or the crankshaft, rings must be rusted.
Flooded the cylinders with oil from the sparkplug holes and hope they loosen up after a soak. Will apply some heat to the outside of the cylinders via heat gun to thin the oil in hopes it penetrates better. On the bright side. Camshaft and valve stem/springs look tidy despite the grotty state of the case on the outside.

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P.abrera · « **Reply #56 on:** June 03, 2014, 04:38:22 AM »

The points and condensers are a different story though. They arent exacy looking thier best

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calj737 · « **Reply #57 on:** June 03, 2014, 05:14:43 AM »

If you're planning on splitting the cases, cut the cam chain and pull the cam, sprocket and chain out.

Make sure you use the 14mm bolt under the left side to turn the engine over, and NOT the larger bolt under the points assembly.

I had to barbecue my jugs for 4 hours after a 6 month soak of alternating fluids and pent rants to get them freed from my rusted rings. Even then, propane directed at the bottom edge of the sleeves was required to free the rings in #2/#3 and free the cylinders from the lower end.

grcamna2 · « **Reply #58 on:** June 03, 2014, 05:20:38 AM »

Quote from: calj737 on June 03, 2014, 05:14:43 AM

If you're planning on splitting the cases, cut the cam chain and pull the cam, sprocket and chain out.

Make sure you use the 14mm bolt under the left side to turn the engine over, and NOT the larger bolt under the points assembly.

I had to barbecue my jugs for 4 hours after a 6 month soak of alternating fluids and pent rants to get them freed from my rusted rings. Even then, propane directed at the bottom edge of the sleeves was required to free the rings in #2/#3 and free the cylinders from the lower end.

That sounds like it was an 'All Day' effort Calj

calj737 · « **Reply #59 on:** June 03, 2014, 05:28:32 AM »

Actually, it was a true 6 months. Soaked, soaked, soaked. Turned the bolt again and again. No budge. Flushed more stuff through the cylinders than you can imagine. Kept seeping past leaving me convinced, "Finally I'll get it to rotate now". Wrong!

Best part was, it was about 12 degrees and spitting sleet that final day, so standing about a bonfire in my jugs was pleasant enough.

Bores required an overbore from 56.5 to 59. Rust had wormed itself into the sleeves pretty deep.

Proof to the adage, The most expensive bikes are free to a good home

P.abrera · « **Reply #60 on:** June 03, 2014, 06:02:33 AM »

Argh! I hope i dont have to go that far. Hoping not to have to split the case. Well see. Fingers crossed...

Thanks for the advice, hope i dont have to use it tho

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calj737 · « **Reply #61 on:** June 03, 2014, 06:06:28 AM »

Yeah, I can't imagine the devastation if it got to 12 degrees and sleeting in the Phillipines. A stuck motor would be the least of your worries

P.abrera · « **Reply #62 on:** June 03, 2014, 07:52:07 AM »

Haha. Not too far fetched with the unpredictable weather these dsys

Well like i said, hopin for a easy break on this first build. Progress is gonna be slow but will keep you guys posted. Thanks!

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P.abrera · « **Reply #63 on:** June 06, 2014, 03:50:00 AM »

Two bolts showing! Rings broke free after a 3-day oil soak and 20 monites with a heatgun

the journey continues!

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P.abrera · « **Reply #64 on:** June 06, 2014, 11:14:51 PM »

Heads off! Found some scoring on piston 1 and matching cylinder though

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P.abrera · « **Reply #65 on:** June 06, 2014, 11:17:25 PM »

Also some damage on the cam sproket. Think it'l affect functionality?

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calj737 · « **Reply #66 on:** June 07, 2014, 04:08:41 AM »

I see a re-bore in your future. And a new cam sprocket. Best to include a new cam chain with that purchase too. If you can, do evaluate the primary chain and sprocket while you're at it. The chains are cheap, having them fail is not.

P.abrera · « **Reply #67 on:** June 07, 2014, 06:01:08 AM »

Quote from: calj737 on June 07, 2014, 04:08:41 AM

I see a re-bore in your future. And a new cam sprocket. Best to include a new cam chain with that purchase too. If you can, do evaluate the primary chain and sprocket while you're at it. The chains are cheap, having them fail is not.

Ya, definite rebore. Hopefully next oversize up. What's the story on the piston scoring? Don't the rings hit the cylinder wall before you get piston rub?

Have to do a bit more reading on replacing the cam chain, can it be done without splitting the cases?

70CB750 · « **Reply #68 on:** June 07, 2014, 06:07:05 AM »

Piston scoring is normal. If its not too deep you can polish it out with sand paper but only in the direction of the lines.

grcamna2 · « **Reply #69 on:** June 07, 2014, 06:17:47 AM »

Quote from: P.abrera on June 07, 2014, 06:01:08 AM

Quote from: calj737 on June 07, 2014, 04:08:41 AM
I see a re-bore in your future. And a new cam sprocket. Best to include a new cam chain with that purchase too. If you can, do evaluate the primary chain and sprocket while you're at it. The chains are cheap, having them fail is not.

Ya, definite rebore. Hopefully next oversize up. What's the story on the piston scoring? Don't the rings hit the cylinder wall before you get piston rub?

Have to do a bit more reading on replacing the cam chain, can it be done without splitting the cases?

I Hope you DO split the cases(it's the only way to replace the cam chain)and replace the Primary chain and sprocket as Cal says.

calj737 · « **Reply #70 on:** June 07, 2014, 06:19:50 AM »

Scoring is not "abnormal" but it can also indicate other problems, beyond just wear. Insufficient lubrication, worn wrist pins, worn crank bearings or out of spec rods. I don't see that particularly from the photo, but all these need to be checked-off as you rebuild.

If you bore, new pistons are required, so don't fret with cleaning those up. May need to go second over due to scoring on the cylinders, but let the machinist dictate that after micrometer readings.

grcamna2 · « **Reply #71 on:** June 07, 2014, 06:40:46 AM »

Quote from: NobleHops on March 27, 2014, 03:13:47 AM

Cool thread, subscribed.

Don't care for the instagram style filter on your photos, makes it hard to see and help. Save that retro patina effect for when it's done maybe? My $.02 - everyone else probably loves it.

Bottom of your fork = fork leg

Thinner chrome part of your fork = fork tube

Welcome!

I agree w/ NobleHops that many times the pictures you post are difficult to clearly see. Can you change the setting of your computer so they are more clear please ? !

P.abrera · « **Reply #72 on:** June 07, 2014, 07:37:17 AM »

Haha, sorry guys, im grabbing hipsterific pics from my instagram.

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P.abrera · « **Reply #73 on:** June 07, 2014, 07:39:45 AM »

Cylinder

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calj737 · « **Reply #74 on:** June 07, 2014, 07:45:53 AM »

If you're looking for input on what might have cause the scoring on that cylinder, I'd suspect ring failure. Perhaps the rings are too close (not enough end gap) or are somewhat seized to the piston due to crud/corrosion. This might have allowed the piston to slide up and down in a "canted" angle.

Doesn't really matter at this point. New pistons, rings, and bore are in order.

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Author Topic: New guy, first build (Read 57204 times)