Author Topic: Cheap 836 kits back on ebay...$110! *Update! (Read 109840 times)

Garage_guy_chris · « **Reply #350 on:** February 06, 2015, 12:51:47 AM »

Quote from: Garage_guy_chris on January 18, 2015, 08:38:23 PM

I wouldnt worry i bet the guy is just feeling out the market. he is probably looking to increase his prices a bit, notice the thread tittle is "$110" last kits were $120. the next cheapest kit is the Cycle X 2nd (0.50) and 4th (1.0) Over Piston Kits @ $199.95 or for big bore, Cycle X 849 kit @ $249.95 i bet they come back at $130 or $140 this year

Both listed as 10+ available buy away...

http://www.ebay.com/itm/69-77-HONDA-CB750K-836cc-65mm-BIGBORE-PISTONS-KIT-W-HEAD-GASKET-CI-CB750KBB-/131421590213?pt=Motorcycles_Parts_Accessories&hash=item1e995652c5&vxp=mtr

http://www.ebay.com/itm/69-77-HONDA-CB750K-836cc-BIGBORE-PISTON-KIT-W-GASKET-/131421590215?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item1e995652c7

ekpent · « **Reply #351 on:** February 06, 2015, 04:57:38 AM »

Quote from: Stev-o on January 21, 2015, 03:02:50 PM

Update....they are $119 now....

http://www.ebay.com/itm/Honda-CB750-750-69-78-836cc-65mm-Big-Bore-Pistons-Kit-10-25-1-compression-ratio/141542941855?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D28796%26meid%3D50d545ca2efa472e9ce5bcdddc3f1cb5%26pid%3D100011%26rk%3D2%26rkt%3D10%26sd%3D141538985630

His add says 10:25 comp ratio but I think it is lower than that due to the flat piston design.

Garage_guy_chris · « **Reply #352 on:** February 06, 2015, 12:37:33 PM »

they are manufactured based on the standard compression design of 9.0:1 but because of the bore increase the compression ends up at about 9.5:1 with no other modifications.

alacrity · « **Reply #353 on:** February 08, 2015, 04:21:55 PM »

I have 5000 miles on one of these kits and the only problem is a leaky right side cyl head o-ring that I am gonna fix with a mls headgasket and/or better o-ring (per hondaman).

http://www.ebay.com/itm/Honda-CB550F-CB550K-600cc-Bigbore-Piston-Kits-Head-Gasket-CB550FBB-/131242443087?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item1e8ea8c14f

Brantley · « **Reply #354 on:** February 12, 2015, 01:02:33 AM »

Report #2: This week marks 10k miles on the cruzinimage 836 kit.

01Thomas · « **Reply #355 on:** February 12, 2015, 01:49:31 PM »

:-)

Quote from: Brantley on February 12, 2015, 01:02:33 AM

Report #2: This week marks 10k miles on the cruzinimage 836 kit.

Sgtpepper67 · « **Reply #356 on:** February 13, 2015, 10:32:55 PM »

I got a set of these a week or so ago, they look good but one piston had a flaw. The seller Sent me a replacement without hassle.

Garage_guy_chris · « **Reply #357 on:** July 01, 2015, 12:17:26 AM »

Hey guys, im finally getting around to building the engine.... Another thread on here has made me double think my choice for ring position. Initially I put the black square ring closest to the face and the silver / chrome beveled ring in the middle groove.

Now after a couple searches and a quick review of engine theory Im pretty sure the silver / chrome beveled ring goes in the top groove and the black square ring in the second groove. Luckily I haven't installed the pistons or cylinders yet so it should be easy to fix if im wrong.

Also a quick note about ring end gap after going through the crappy CB750 service manual, checking for service bulletins, and Hondamans book the most information i could find was a service limit of 0.0276" for end gap on all rings. this is NOT a specification for a fresh build! After searching around on here and some general guidelines i used 0.012" - 0.014".

After fitting everything I found a bunch of the rings were too tight (filed to fit) and 2 oil rings that were too big (almost service limit) Luckily i bought an extra set of rings so everything got fitted in perfectly.

Phoenix · « **Reply #358 on:** July 01, 2015, 03:58:53 AM »

Is anyone having a problem iinstalling the three part oil ring? I'm having a hard time fitting them all in the groove. As far as the rings, most of the first and second ring gaps are coming in at about .014. The two outside oil seals are coming in at about .005. My reading on the minimum gap is it should be .10-.012. Anyone have any comments?

BTW, be carefull. I broke two 2nd rings. I'm sure it's my fault.

Powderman · « **Reply #359 on:** July 01, 2015, 11:06:59 AM »

Quote from: Phoenix on July 01, 2015, 03:58:53 AM

Is anyone having a problem iinstalling the three part oil ring? I'm having a hard time fitting them all in the groove. As far as the rings, most of the first and second ring gaps are coming in at about .014. The two outside oil seals are coming in at about .005. My reading on the minimum gap is it should be .10-.012. Anyone have any comments?

BTW, be carefull. I broke two 2nd rings. I'm sure it's my fault.

Are you sure those numbers are correct? .10-.012

Garage_guy_chris · « **Reply #360 on:** July 01, 2015, 03:06:51 PM »

Regarding ring end gap:
A zero would have been forgotten it should be 0.010 - 0.012"

generally they say 0.004" x bore in inches (2.560") = 0.010"

Alternately generally the service limit is about double the ideal clearance so 0.028" halved = 0.014"

so in my mind 0.010 - 0.014" seems about right and the forums seem to back this up in multiple threads. Mine is going together with 0.012" throughout.

Regarding the order of the rings:
which there seems to be a little confusion ( maybe just me) it seems:

1st groove = chrome beveled rings
2nd groove = black squared rings
3rd groove = oil rings

We should put a sticky together with all the pertinent information regarding these kits,

Phoenix · « **Reply #361 on:** July 01, 2015, 04:45:58 PM »

My problem is the width of the three part oil ring. It seems too large for the groove.

madmtnmotors · « **Reply #362 on:** July 01, 2015, 06:20:25 PM »

Quote from: Phoenix on July 01, 2015, 04:45:58 PM

My problem is the width of the three part oil ring. It seems too large for the groove.

The "waffle" ring goes in first, then the two "scraper" rings, one above and one below. There is a ridge on the inside edge of the waffle ring that the scraper rings bear against. If you stack the rings with the scraper rings resting on top of this small ridge then they will be too thick. The scraper rings do not "bottom out" in the groove.

Garage_guy_chris · « **Reply #363 on:** July 21, 2015, 10:05:59 PM »

Well over the last few days I have been building my engine. Its been going together good but I have had a few surprises.

Like a number of people have encountered, My pistons came out 0.011" above the cylinder deck. this isnt a huge issue as the head gaskets are thick at about 0.060" so they provide sufficient space between the head and the piston face. (In my case i measured 0.048" with the solder method)

Yesterday I was working on setting up a Kenny Harmon D grind and checking valve to piston clearance and I came upon some issues. I degree'd the cam in within about 2 deg i put the rockers into the towers for cyl 2 then adjusted the valve lash to 0.005" and rotated it through a few times. Upon dis-assembly I measured my clearances again and got 0.047" on the intake and 0.035" on the exhaust.

My research indicates 0.065" intake and 0.080" exhaust are about as tight as you would want to run.

If the pistons had the proper deck height at 0.016" - 0.020" below the deck or in the hole the clearances probably would have been borderline or OK as this change would have provided an extra 0.027" - 0.031" of clearance increasing valve to piston clearance to 0.047 + 0.027 = 0.074" intake and 0.035 + 0.027 = 0.062" in my case.

For me i think the Kenny Harmon D grind is gonna be a no go, im gonna dial it back to an F2 cam i was initially gonna use.

So the moral here is if your adding a cam to these pistons know your deck height and carefully check valve to piston clearance with clay or plasticine!

If anyone has successfully checked clearance and successfully ran a performance cam please share the details
-Im still considering something milder, like a webcam #41 , #41a or a Megacycle 125-00

Terry in Australia · « **Reply #364 on:** July 22, 2015, 03:05:21 AM »

Hmmnn, the thing to remember about using any performance cam is that they were not designed to be run with stock pistons. (or pistons of stock design, like these) When I had my first K1, in 1983 I bought an Action Fours SS-2A, but I had to return it, because the valve to piston clearance was non existent. I could have had the valve pockets on the pistons enlarged by having them "fly cut" on a mill, but as I'd already buttoned up the top end without breaking a ring, I wasn't going to risk pulling it apart again.

I took it back hoping to get a milder cam, and the only cam that the dealer would recommend with stock (2nd oversize) pistons was an Andrews "A" grind cam, which was excellent. An F2 cam will be OK clearance wise, even though they are not a great cam, and you'll need to think about heavy duty valve springs if you haven't already. I used stock springs with the A grind cam, with no issues. Cheers, Terry.

Garage_guy_chris · « **Reply #365 on:** July 22, 2015, 06:32:05 AM »

The kenny harmon d is supposed to work with stock pistons but becuase of the deck height issue some people are having it makes the d grind too tight. I was considering fly cutting the pistons but at this point i want to finish the bike rather than work on it for another month. Im just posting so people are aware.

Terry in Australia · « **Reply #366 on:** July 23, 2015, 04:32:24 AM »

Yeah, no worries mate, but if you can find a better cam than an F2 cam, even better.

HondaMan · « **Reply #367 on:** August 16, 2015, 11:40:31 AM »

I have used the Megacycle 125-00 with the 836 with good results.
The Webcam 41a in a recent 836 engine (4 years ago) kept knocking some of the valve adjuster nuts loose, eventually breaking one of the adjusters as well. I pulled the head and found smiles in the intake grooves of the pistons, even though there was .058" (clay-measured) clearance. It's a cafe' bike, rider said he had some issues with making 2nd gear reliably from time to time, due to having tennis shoes on when riding.

koendd · « **Reply #368 on:** August 16, 2015, 02:10:11 PM »

might have been said before but do these fit a K7 engine?

madmtnmotors · « **Reply #369 on:** August 16, 2015, 02:41:17 PM »

Quote from: koendd on August 16, 2015, 02:10:11 PM

might have been said before but do these fit a K7 engine?

Yes, the dome on the k7/k8 is so slight that the compression loss from the use of flat tops is nearly offset by the increase in compression as a result of the overbore.

Loctite77 · « **Reply #370 on:** August 21, 2015, 08:16:56 PM »

Looking at this kit. http://www.ebay.com/itm/Honda-CB750-750K-SOHC-1969-1978-836cc-65mm-Big-Bore-Pistons-Kit-w-Head-Gasket-/141749170041?hash=item2100e8af79&vxp=mtr

Does it seem to be the same one discussed here? Will it work on my 76F model?

Powderman · « **Reply #371 on:** August 22, 2015, 12:57:01 PM »

Quote from: Loctite77 on August 21, 2015, 08:16:56 PM

Looking at this kit. http://www.ebay.com/itm/Honda-CB750-750K-SOHC-1969-1978-836cc-65mm-Big-Bore-Pistons-Kit-w-Head-Gasket-/141749170041?hash=item2100e8af79&vxp=mtr

Does it seem to be the same one discussed here? Will it work on my 76F model?

Not the CruzinImage discussed here, but similar. CruzinImage has a good rep for their kits. Your kit says it's for 69-78, I think 76 falls in there somewhere. The list I checked showed a different part # for the piston on a F and a K.

Loctite77 · « **Reply #372 on:** August 22, 2015, 02:22:56 PM »

Quote from: Powderman on August 22, 2015, 12:57:01 PM

Quote from: Loctite77 on August 21, 2015, 08:16:56 PM
Looking at this kit. http://www.ebay.com/itm/Honda-CB750-750K-SOHC-1969-1978-836cc-65mm-Big-Bore-Pistons-Kit-w-Head-Gasket-/141749170041?hash=item2100e8af79&vxp=mtr

Does it seem to be the same one discussed here? Will it work on my 76F model?
Not the CruzinImage discussed here, but similar. CruzinImage has a good rep for their kits. Your kit says it's for 69-78, I think 76 falls in there somewhere. The list I checked showed a different part # for the piston on a F and a K.

I thought they would be different as well the k and F. But the Weisco kits are the same for the K and F model for these years so I thought it would be the same.

Yeah Son!

Retro Rocket · « **Reply #373 on:** August 22, 2015, 03:28:38 PM »

75/76F models share the same type of pistons as all the K model bikes, they have the 392 head, which is the same head as the K7-K8's. K model pistons are fine in the early F model bikes, the F2-F3 have the 410 head which is completely different, hence the different pistons for that model...

Powderman · « **Reply #374 on:** August 22, 2015, 08:08:22 PM »

The different part # piston I was referencing were both for 1977.

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Author Topic: Cheap 836 kits back on ebay...$110! *Update! (Read 109840 times)