Author Topic: Anyone tried the $120 CB550 big bore kit yet? (Read 41162 times)

FastCB550 · « **Reply #100 on:** September 23, 2013, 09:51:24 PM »

Just a quick update on my Big Bore Kit.

About 150 miles so far on the fresh build and she is running like a sewing machine. Just still trying to find the right jetting. I feel I'm getting a little lean from 3/4 throttle to WOT.

I'd recommend these kits to anyone looking to do this modification. You will come out cheaper on the kit (pistons, rings, wrist pins & head gasket) but have a bit more cost in machine work compared to a standard .25-1.0 step up.

Duke-Nukem-Dan · « **Reply #101 on:** September 24, 2013, 12:52:29 AM »

If you live near the central coast of Cali, the shop i mentioned is Rural Machine. Guy sounded like he knew what he was doing, said he had to have the pistons in hand before boring. So that's comforting.

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Tews19 · « **Reply #102 on:** September 29, 2013, 02:35:16 PM »

I ordered my set about 2 hours ago.. I will post updates when the time comes

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Duke-Nukem-Dan · « **Reply #103 on:** October 03, 2013, 03:47:46 PM »

For anyone that cares. My replacement ignition plate works great. So my old martek 440 was, in fact broken. I also got my adapter for compression testing, will post my readings tomorrow. Will also be trying my new homemade carb synchronizer, does ATF fluid work well?

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Tews19 · « **Reply #104 on:** October 03, 2013, 05:07:01 PM »

Quote from: Duke-Nukem-Dan on October 03, 2013, 03:47:46 PM

For anyone that cares. My replacement ignition plate works great. So my old martek 440 was, in fact broken. I also got my adapter for compression testing, will post my readings tomorrow. Will also be trying my new homemade carb synchronizer, does ATF fluid work well?

Sent from my Nexus 10 using Tapatalk 4

I knew it wouldn't need to have the cylinders redone. . Congrats.

KrautKoffin · « **Reply #105 on:** November 17, 2013, 07:50:51 PM »

Anyone else got some input? I'm pulling the trigger on this tomorrow.

FastCB550 · « **Reply #106 on:** November 17, 2013, 09:27:35 PM »

Quote from: KrautKoffin on November 17, 2013, 07:50:51 PM

Anyone else got some input? I'm pulling the trigger on this tomorrow.

I got about 1000 miles on mine so far and there running great.

Hasenkopf · « **Reply #107 on:** December 03, 2013, 08:35:38 PM »

Mine just needs to have the head installed....and the whole bike put back together, but so far, so good.

KrautKoffin · « **Reply #108 on:** February 15, 2014, 11:38:30 AM »

What's the total cc's on these kits with the 63mm pistons and stock stroke?

bwaller · « **Reply #109 on:** February 15, 2014, 06:43:21 PM »

These are 61.5mm unless I missed something. Works out to just a tad over 600cc.

alacrity · « **Reply #110 on:** February 15, 2014, 07:45:18 PM »

I hate to jinx it. 200 miles and it's pretty quick (compared to normal cb550).
I have cb650 cam in it too

calj737 · « **Reply #111 on:** February 16, 2014, 04:58:56 AM »

Quote from: bwaller on February 15, 2014, 06:43:21 PM

These are 61.5mm unless I missed something. Works out to just a tad over 600cc.

I think your math is off:

PI r squared x stroke x cylinders(4)

Over bore with 61MM = 3.14 x 30.5 x 30.5 x 50.6 x 4 = 592 (rounding up from 591.207)

the stock 550 bore is 58.5 = 544

Psychonaut · « **Reply #112 on:** February 16, 2014, 05:22:57 AM »

Quote from: Duke-Nukem-Dan on October 03, 2013, 03:47:46 PM

Will also be trying my new homemade carb synchronizer, does ATF fluid work well?

Sent from my Nexus 10 using Tapatalk 4

I know, old post but ATF is too thin. I used gear oil. I did a write up on making a home made sync.

Duke-Nukem-Dan · « **Reply #113 on:** February 16, 2014, 05:31:04 AM »

It was pretty thin, and I sucked up a little into the cylinders because of that. But damn I've got those things synced really close. There was a tear in one of the Pre carb boots so after replacing it they were WAY out of sync.

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bwaller · « **Reply #114 on:** February 16, 2014, 06:40:15 AM »

Quote from: calj737 on February 16, 2014, 04:58:56 AM

Quote from: bwaller on February 15, 2014, 06:43:21 PM
These are 61.5mm unless I missed something. Works out to just a tad over 600cc.

I think your math is off:

PI r squared x stroke x cylinders(4)

Over bore with 61MM = 3.14 x 30.5 x 30.5 x 50.6 x 4 = 592 (rounding up from 591.207)

the stock 550 bore is 58.5 = 544

61mm =592....but if you check the original post these pistons are 61.5mm.

underachiever · « **Reply #115 on:** February 16, 2014, 08:06:40 AM »

Quote from: calj737 on February 16, 2014, 04:58:56 AM

Quote from: bwaller on February 15, 2014, 06:43:21 PM
These are 61.5mm unless I missed something. Works out to just a tad over 600cc.

I think your math is off:

PI r squared x stroke x cylinders(4)

Over bore with 61MM = 3.14 x 30.5 x 30.5 x 50.6 x 4 = 592 (rounding up from 591.207)

the stock 550 bore is 58.5 = 544

Works out to 601.22.

or thereabouts.

alacrity · « **Reply #116 on:** February 17, 2014, 07:19:47 PM »

Did a really fun 200 mile ride yesterday. It definitely FEELS like 601cc.
;-)

pdq for an old bike, that's for sure.

KrautKoffin · « **Reply #117 on:** February 18, 2014, 05:07:29 PM »

Aren't they 3mm over, making them 61.5?

RAFster122s · « **Reply #118 on:** February 18, 2014, 05:32:48 PM »

The overbore pistons which are the topic of the thread are 61.5mm whereas the Henry Abe kit piston is a 61mm. Either are possible overbore candidates and both leave thin liners. They are adequate. The HA kit is known for bad rings. For the HA kit, Widen the oil control ring slot and use std cb750k rings and they give a trouble free solution.

The cb500 requires a set of cb550 cylinders for the HA overbore or the HA cylinder liners are used with the stock cylinders replaced and bored.

Ensure your machinist align bores the cylinders.

P.abrera · « **Reply #119 on:** June 24, 2014, 09:06:35 PM »

Digging up an oldie.

How do you determine correct ring end gap on the 61.5 kit?

Any associated overheating concerns with running big bore kits? Adding an oil cooler kit would help yes?

Tews19 · « **Reply #120 on:** June 25, 2014, 05:43:43 AM »

The kit comes with everything you need in regard to pistons. Rings and pins.

P.abrera · « **Reply #121 on:** June 25, 2014, 06:08:47 AM »

Quote from: Tews19 on June 25, 2014, 05:43:43 AM

The kit comes with everything you need in regard to pistons. Rings and pins.

So end gap is set already?

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Tews19 · « **Reply #122 on:** June 25, 2014, 06:55:42 AM »

Yes. I had mine balanced when the head was done.

P.abrera · « **Reply #123 on:** June 25, 2014, 03:43:36 PM »

Balanced? How you doin in terms of managing temps? Does it in fact run hotter?

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bwaller · « **Reply #124 on:** June 25, 2014, 05:29:40 PM »

The rule of thumb is 0.004" end gap per inch of bore. 0.010-0.012" should be good.

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Author Topic: Anyone tried the $120 CB550 big bore kit yet? (Read 41162 times)