Author Topic: CB550 Big bore planning (Read 6513 times)

akabek · « **on:** November 10, 2012, 04:44:17 pm »

I currently have a CB550 with a 650cam, CR29, MAC 4-1 header, cone engineering reverse muffler and electronic ignition, coils and wires. My head gasket is leaking so it is time to tear into the motor. My plan is to go for a big bore 61mm Dynoman piston kit, port, polish and valve job. Is it worth while going for a 3 angle valve job? I have a complete gasket set but what else should be replaced while I have it all apart? I have read it is good practice to replace the cylinder studs. Should I upgrade the clutch plates and springs?

turboguzzi · « **Reply #1 on:** November 11, 2012, 03:18:02 am »

kevin camron says in his book that he's seen, bikes with 3-angle, no angle and what-have-you valve seats, all in the winners cycle, so until i see (one day....) flow testing of a 500/550 head with 3 angle being better, i'd say just do normal maintenance/ basic port cleaning.

Theres no evidence that polished ports flow better either, even the opposite, i like to leave them rather coarse. no doubt polished ports look cool in pictures, if the air particles like it is another matter

At this point you'll ave to tell us your info sources

why change studs? where did you read that? steel is not a material that has a fatigue limit...

would wait with the clutch until you see that its slips under power, the stock one is pretty good, all i often do is add washers under the springs to preload it more by 1-2mm

and would go with mrieck's mls head gasket....

akabek · « **Reply #2 on:** November 11, 2012, 07:41:54 am »

At this point you'll ave to tell us your info sources

why change studs? where did you read that? steel is not a material that has a fatigue limit...

would wait with the clutch until you see that its slips under power, the stock one is pretty good, all i often do is add washers under the springs to preload it more by 1-2mm

and would go with mrieck's mls head gasket....
[/quote]

I read on this forum references to the bolts stretching but than some have reused the bolts with no issues.

I thought Mrieck's MLS head gasket is from Dynoman. When I place my order for the Dynoman 61mm bore kit I was going to ask them for the MLS gasket.

turboguzzi · « **Reply #3 on:** November 11, 2012, 08:04:39 am »

in order to get studs to stretch, you'd need to overtorque them and go into the plastic deformation range.... IMHO at least but maybe it just never happened to me

interesting, what do other engine meisters here say? do/can studs stretch (i.e. unreversible plastic deformation) under normal loads - meaning torqued within their elastic range?

FunJimmy · « **Reply #4 on:** November 11, 2012, 11:34:32 am »

Quote from: akabek on November 11, 2012, 07:41:54 am

I read on this forum references to the bolts stretching but than some have reused the bolts with no issues.

I thought Mrieck's MLS head gasket is from Dynoman. When I place my order for the Dynoman 61mm bore kit I was going to ask them for the MLS gasket.

If memory serves me, the Dynoman pistons come with a MLS head gasket.
I'm going the HD stud route too. Might not be necessary, but I've already pulled the factory studs.

akabek · « **Reply #5 on:** November 11, 2012, 02:03:40 pm »

I figure I should show a pic of my work in progress.

Johnnie · « **Reply #6 on:** November 19, 2012, 09:23:14 am »

Quote from: akabek on November 11, 2012, 02:03:40 pm

I figure I should show a pic of my work in progress.

Very nice!

What rearsets are those?

Sara · « **Reply #7 on:** November 19, 2012, 10:33:49 am »

I think they are from Tardozzi, have the same.

Sara

akabek · « **Reply #8 on:** November 19, 2012, 12:38:19 pm »

Sara is correct

turboguzzi · « **Reply #9 on:** November 19, 2012, 12:55:07 pm »

a cafe job that has some proper performance mods and no heat wrap on the pipes?

WOW, kudos you man....

akabek · « **Reply #10 on:** November 19, 2012, 02:53:48 pm »

Quote from: turboguzzi on November 19, 2012, 12:55:07 pm

a cafe job that has some proper performance mods and no heat wrap on the pipes?

WOW, kudos you man....

I know there are apparent benefits to wrapping the pipes but I am going for a clean look and a sleeper.

singedebile · « **Reply #11 on:** November 22, 2012, 02:58:35 pm »

Quote from: turboguzzi on November 19, 2012, 12:55:07 pm

a cafe job that has some proper performance mods and no heat wrap on the pipes?

WOW, kudos you man....

my pet peeve exactly, you see these 5-10k builds with NOTHING done for performance,... stock brakes and engine.

akabek · « **Reply #12 on:** November 22, 2012, 04:10:52 pm »

Quote from: singedebile on November 22, 2012, 02:58:35 pm

Quote from: turboguzzi on November 19, 2012, 12:55:07 pm
a cafe job that has some proper performance mods and no heat wrap on the pipes?

WOW, kudos you man....

my pet peeve exactly, you see these 5-10k builds with NOTHING done for performance,... stock brakes and engine.

I am not sure if you are referencing my build with your comment but since when were there rules you have to follow? Granted my brakes are stock, they have been upgraded to dual disc. My motor will have a higher displacement, 650 cam, porting and Keihin CR29 carbs with stacks. The suspension is upgraded with Ikon rear shocks and Race Tech emulators with new springs. I understand the benefits of wrapping the header but I prefer a cleaner look for my build. At the end of the day it is personal preference which is what makes every bike on this forum unique. This is a 40 year old street bike

singedebile · « **Reply #13 on:** November 23, 2012, 01:08:25 pm »

I was complimenting your bike, ..i was saying it is refreshing to see someone focus on more then just the way the bike looks and to me that is a real cafe racer.

akabek · « **Reply #14 on:** November 23, 2012, 02:23:23 pm »

Quote from: singedebile on November 23, 2012, 01:08:25 pm

I was complimenting your bike, ..i was saying it is refreshing to see someone focus on more then just the way the bike looks and to me that is a real cafe racer.

My apologies and thank you for the compliment. I am aiming for some performance but a clean/vintage look...not show room.

turboguzzi · « **Reply #15 on:** November 24, 2012, 01:16:58 am »

it was a compliment from me too. the amount of "all pose no go" sohc's out there is just amazing, your's is pretty remarkable in that sense.

akabek · « **Reply #16 on:** November 24, 2012, 05:50:46 am »

Thanks again. I guess that is what makes bike builds so interesting. Some want show bike quality, some are looking for performance and others want both. Originally I had no intentions for a big bore, cam and 4-1 exhaust but after the build I wanted more street performance. So far I am impressed with the bike although I have never ridden a stock CB550.

FunJimmy · « **Reply #17 on:** November 24, 2012, 11:48:04 am »

Quote from: akabek on November 24, 2012, 05:50:46 am

Thanks again. I guess that is what makes bike builds so interesting. Some want show bike quality, some are looking for performance and others want both. Originally I had no intentions for a big bore, cam and 4-1 exhaust but after the build I wanted more street performance. So far I am impressed with the bike although I have never ridden a stock CB550.

It's an addiction.
Better get used to it.

bwaller · « **Reply #18 on:** November 24, 2012, 01:49:35 pm »

It's an addiction.
Better get used to it. [/quote]

Hah, +1 to that!

Kemp · « **Reply #19 on:** November 28, 2012, 09:35:29 am »

Check out Funjimmy's post with the CR26's. That might be of help with the issues you've been having with your CR29's. Again, you really can't beat a big bore for performance. Even with your mild CB650 cam, the dynoman 10.5 591cc kit will make your bike rock!! A side benefit is that the 650 cam allows you to keep the torque that the big bore allows. I noticed quite a difference btw 650cam and Web B grind on my 591. The web gave more HP but really hurt the low down torque and mid range acceleration whereas the 650 cam would straighten your arms when you got hard on it at 6000 rpm. The Web would hit hard at 7500 but torque was gone and you needed to ride it like a road race engine, on the boil from 8000 to 10,000 to keep the acceleration strong and momentum up. I road raced a lot of different TZ models in a past life and the web cam reminded me of those 2 stroke machines, peaky!! I think the 650 cam, as it has just a bit more duration than a stock 550's, is a really effective street cam for everyday use.

akabek · « **Reply #20 on:** November 28, 2012, 05:15:44 pm »

Hi Kemp, I spoke with Jimmy already. We had similar stories with our CR carbs although mine is the CR29. I am sticking with my 650 cam as I prefer the low end torque for street use. My jugs and head are currrent at the shop so I should be all set for next summer.

akabek · « **Reply #21 on:** March 13, 2013, 01:32:48 pm »

I recently rebuilt my motor with a big bore kit but I want to hold off on starting it up for another month when the weather is warmer. Is there anything I should do to get the internals lubed before I put gas in and start it up for the first time? I did apply oil to the rings and cylinders during the installation but the motor will have been sitting for approximately 6 weeks before I start it for the first time.

FunJimmy · « **Reply #22 on:** March 13, 2013, 03:19:43 pm »

Quote from: akabek on March 13, 2013, 01:32:48 pm

I recently rebuilt my motor with a big bore kit but I want to hold off on starting it up for another month when the weather is warmer. Is there anything I should do to get the internals lubed before I put gas in and start it up for the first time? I did apply oil to the rings and cylinders during the installation but the motor will have been sitting for approximately 6 weeks before I start it for the first time.

You shouldn't have any issues as is.
Let us know how it goes.

Cheers
FJ

MRieck · « **Reply #23 on:** March 13, 2013, 04:10:00 pm »

Jimmy has a hell of a kit too. His bike is going to be fantastic and fast.

akabek · « **Reply #24 on:** March 13, 2013, 04:20:56 pm »

I am looking forward to see how it all comes together: 592cc (10.5:1), Keihin CR29, ported head with 3 way valve grind and CB650 cam. It should make the bike nice and peppy...maybe I will take it to the track this summer and see how she goes.

MRieck · « **Reply #25 on:** March 13, 2013, 05:49:32 pm »

Quote from: akabek on March 13, 2013, 04:20:56 pm

I am looking forward to see how it all comes together: 592cc (10.5:1), Keihin CR29, ported head with 3 way valve grind and CB650 cam. It should make the bike nice and peppy...maybe I will take it to the track this summer and see how she goes.

It will be fun. If you don't mind me being nosy who did the porting?

akabek · « **Reply #26 on:** March 13, 2013, 06:55:03 pm »

Quote from: MRieck on March 13, 2013, 05:49:32 pm

Quote from: akabek on March 13, 2013, 04:20:56 pm
I am looking forward to see how it all comes together: 592cc (10.5:1), Keihin CR29, ported head with 3 way valve grind and CB650 cam. It should make the bike nice and peppy...maybe I will take it to the track this summer and see how she goes.
It will be fun. If you don't mind me being nosy who did the porting?

I had a friend of mine do it. He has done head porting before and he was familiar with vintage bike porting. On top of that the price was right.

akabek · « **Reply #27 on:** March 31, 2013, 04:16:21 pm »

Yesterday I completed the bike. It took a few cracks on the starter but she came alive. Since jetting my carbs last fall I now have a 592 big bore, ported head and I added BBR filters to my Steel Dragon velocity stacks as the bike is for street use. I took a short ride around the block to get a feel for it and although I could not whined it out (with the new big bore kit) it did seem to be peppier.

For the break-in I will keep the RPMs down below 5500 and change the oil around 1000 KMs. Any other suggestions for the break in period?

The CR29 carbs were dialed in pretty good before the motor mods except it ran rich during idle. If I drop the floats down will that help with the idle richness?

I will post some pics when I have her running good and add some finishing touches.

turboguzzi · « **Reply #28 on:** April 01, 2013, 07:43:56 am »

Quote from: akabek on March 31, 2013, 04:16:21 pm

Any other suggestions for the break in period?

dont baby it at all. i try to run in motors in the dyno and start aplying full throttler right away

10 runs up to 6K + 10 runs up to 8K + 10 runs up to 10K , done

if not find a really quite open road where you can do similar "pulls" that last about 10 seconds in 4th-5th gear

akabek · « **Reply #29 on:** April 01, 2013, 08:43:42 am »

Quote from: turboguzzi on April 01, 2013, 07:43:56 am

Quote from: akabek on March 31, 2013, 04:16:21 pm
Any other suggestions for the break in period?

dont baby it at all. i try to run in motors in the dyno and start aplying full throttler right away

10 runs up to 6K + 10 runs up to 8K + 10 runs up to 10K , done

if not find a really quite open road where you can do similar "pulls" that last about 10 seconds in 4th-5th gear

Good thing I asked or I never would have thought to use this approach. I live near a highway so I will break it in there. After each run should I bring the bike to a complete stop and go again? I guess I could get on the highway, run the bike up to 5th gear and get off at the next exit and come back the other way. Should I let the bike cool after a couple of runs? The weather is still on the cool side right now.

akabek · « **Reply #30 on:** May 05, 2013, 05:35:06 pm »

Well I believe I have my CR29s jetted the best they will get. I need to keep it idling over 2K after it warms up or it dies on me. I can hammer on the throttle and she goes but it is running rich. Now I am thinking I should pony up for the CR26 and sell the CR29s. Will this be a more fitting size carb? Some stores match the CR29 with the CB550 and others suggest the CR26. The acceleration is great but my tail pipe is black. Will my CR29s fit a 750 or would it need new brackets to re-align the carbs for a 750?

mazen0822 · « **Reply #31 on:** May 19, 2013, 08:51:56 am »

Any updates on the bike.

akabek · « **Reply #32 on:** May 19, 2013, 01:52:51 pm »

Quote from: mazen0822 on May 19, 2013, 08:51:56 am

Any updates on the bike.

I was chatting with another member that has a CB550 modified similar to mine and he said the CR29 worked better for him than the CR26. I have the bike running well but my next plan is to sync the carbs. My carbs have not been synced since I made all the engine mods so hopefully that will bring my idling down. I should find time in the next few days to sync my carbs and I will post an update.

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Author Topic: CB550 Big bore planning (Read 6513 times)