Topic: Stock connecting rods with an 836cc???

[Zev Fisher]

Hi,

This is my first-ever post on the SOHC forums!!! Yes!

My question is this:

I just dropped my 1975 CB750K engine off with my engine builder to have a Wiseco 836 kit, a cam (.370 / .282) and some porting and polishing work done.

I am wondering what everyones take is on stock connecting rods. The builder told me that if I wasn't going to be racing the bike (which I am not) that I shouldn't worry about it as it would (at the very least) double the price of the rebuild.

While the bike is probably never going to see a race track, the motor will probably see 8K rpm from time to time  and I would really be sad if one of my stock connecting rods decided to jump ship and explore life outside the engine case.

The Falicon rods are a grand and the bottom end rebuild would be another grand easy. I REALLY don't have that kind of money, but I also don't want to do this twice...What do you guys think?

[Sweep]

Hey I'll be first to reply on this one too.  I went with Carillo rods and IMO stronger rods is the way to go if you're building for power.  If I was just rebuilding the motor as stock I wouldn't have bothered.

My bike has 1k miles so far and has seen 8k+ quite a few times 

If I had it to do over I would have invested even more in getting my gears cut and getting an aftermarket cam tensioner.

Make sure you have your mechanic go over your gearbox and measure everything per the manual for wear including gear drum and shift forks.

[MRieck]

 It's the bolts that are the weak link. Upgrade to the later F2/3 bolts/nuts. They are stronger.

[Gregorymoto]

Ya i agree change the bolts, and have each piston and rod set up balanced.
Do no not In my opinion use Aluminum rods unless you are going to race and do not mind replacing them every 5000mi or less. If you are riding it hard all the time it will stretch0-out the rod over time.

[Zev Fisher]

Hey Mike, have you had any experience working with Rick over at Harry's Machined Parts in Northborough MA? I was looking online and I saw a couple of Dyno run results from there with your name on them and I didn't know if you knew of the shop....not even sure if you are from this area or not...

This may also be a dumb question, but can they do both the top and bottom (crank and piston) rod bolts with a top end rebuild, or would they have to break open the lower case for the crank bolts?

Thanks...I appreciate your help!

[754]

Generally rods are advised if run hard. You could shotpeen your rods and use stronger bolts if you can find them, or as they said the F rods are stonger?

I ran stock rods in an 836 for a long time, with a fairly hot cam & carbs I usually ran it to 10K or +, nearly everytime I rode it. Bracket raced it as well, a lot. probably hit 10K or better at least a thousand times.. and it held up fine.

But if I had the big bang, I could not say  that I would not have expected it.

If you are not going to race or rev it out constantly, you will probably be fine.

 As for paying 1K to get rods put in, I think that is high. And second I must ask, why would you do what you are doing to the topend without at least looking at the lower end?

[Zev Fisher]

To answer your last question, To be honest, it makes me a little uneasy.

The builder basically talked me out of opening up the bottom end, saying that if I wasn't going to be racing that it would really not be needed.

The guy has a great reputation in my area and has done a ton of race sohc 750's over the years, so I am trying my (very) best to just let him steer me in the right direction for the type of riding that I am going to be doing.

What do you think?

[754]

I think it is 30 yrs old, and looking at it wont hurt..

 If eveything checks out it wont cost much, good peace of mind..

 Do you want a great motor or a marginal grenade?

 You will get out of it, what you put into it..

[MRieck]

Hey Mike, have you had any experience working with Rick over at Harry's Machined Parts in Northborough MA? I was looking online and I saw a couple of Dyno run results from there with your name on them and I didn't know if you knew of the shop....not even sure if you are from this area or not...

This may also be a dumb question, but can they do both the top and bottom (crank and piston) rod bolts with a top end rebuild, or would they have to break open the lower case for the crank bolts?

Thanks...I appreciate your help!

I've known Rick for quite a while. He is a very, very smart guy. I'm in Ashland...not far from Rick's place. You need to split the cases to get to the bolts. You should be ok, as Rick said, with the stock bolts if you install a rev limiter and don't beat the piss out of it. The F2/3 bolts are good insurance but the cost will go up a good bit if you split the cases. You can tell Rick Mike Rieck (pronounced "Rick") says hello.

[andy750]

Zev do a search on the Forum for Mikes name and you will see that HE is one of the best SOHC engine builders around and hes here in Boston! (well close enough) - then do a search for Sparty and you will see HIS engine that Mike built - its a hotrod that has few competitors (except for Mikes own F of course  ). Anyway sounds like you are in good hands but if it was me Id have Mike do it.

Good luck
Andy (also in Boston)

[Sweep]

I'd #1 build it myself and since you're asking all of these detailed questions you're not really leaving it to the pros.  Take your time and learn every aspect.

Barring that I'd definitely have Mike build my motor and having him endorse the other guy is a consolation prize for not choosing the first two options.

Split those cases...I never got the point of taking the motor out of the frame and not splitting the cases, getting the motor in and out is the hardest part!

[Zev Fisher]

So Mike...

...Any interest in building another kick A$$, rock solid 836? I would really love for you to be involved with the project and to do it the right way.

I only just dropped it off at Harry's this week and he is super busy over there, so I'm sure they haven"t done anything with it yet...

I would (of course) not mention why...

What do you think?





 

[scondon]

  Since you're paying good money to have the work done it's completely up to you as to whether you want to pay another  $xxxx.xx to add insurance to the bottom end. I've been sticking with the stock f2 rods/bolts with two seperate 836 motors that spend more time above 7000rpm than below and believe in the "if you're not going to race it, don't worry" addage. One motor I left the bottom end untouched and the second I added a lightened crank and new bearings,chain, etc..   Both motors have had numerous brief stints above 10,000rpm.

     How many miles the motor already has on it is my determining factor as to whether to split the cases. A 60,000+ motor is gonna get the cases split so I can look at the bearings, and while I'm in there I might as well do whatever I can afford or needs doing. A 20,000+ motor will get split if there's an obvious problem or if my bank account is ready to let me have anything I want

[scondon]

So Mike...

...Any interest in building another kick A$$, rock solid 836? I would really love for you to be involved with the project and to do it the right way.

I only just dropped it off at Harry's this week and he is super busy over there, so I'm sure they haven"t done anything with it yet...

I would (of course) not mention why...

What do you think?





 

    I would think you couldn't find a better choice. Proven record and solid work/advice

[MRieck]

So Mike...

...Any interest in building another kick A$$, rock solid 836? I would really love for you to be involved with the project and to do it the right way.

I only just dropped it off at Harry's this week and he is super busy over there, so I'm sure they haven"t done anything with it yet...

I would (of course) not mention why...

What do you think?





 

Thanks very much for the offer Zev but I'd rather not get in the middle of it. You commited to Rick and rest assured he'll do a perfect job. I hope you understand. If I can help you out in the future ....tuning etc....please let me know.
   Mike

[mystic_1]

So, any good sources for conrod bolts?  Honda seems to want US$9.00 for conrod bolts and US$2.50 for the nuts, but they look like they're unavailable?  CMSNL wants €7.50 and €6.50 respectively.  Ouchie!

mystic_1

[754]

mystic, dont look further..
 cuz you are not going to like the price of real hi-po rod bolts...

[mystic_1]

Heh, I gathered that. 

How about just a source of OE bolts?  My build is more or less stock.

mystic_1

[Gamma]

My 836 was a standard low mileage F1.  I have reused the original rods, unfortunately I was unaware of the stronger F2/F3 bolts.  And I have no intention of re-splitting the cases.  I also have no intention of mincing about on this bike.( I'll try not to miss gears)  We shall see 

[scondon]

So, any good sources for conrod bolts?  Honda seems to want US$9.00 for conrod bolts and US$2.50 for the nuts, but they look like they're unavailable?  CMSNL wants €7.50 and €6.50 respectively.  Ouchie!

mystic_1

   Mystic, I got the part #'s from cmsnl and ordered the bolts/nuts from servicehonda.com. Best prices and service I have found in the U.S. so far for OEM Honda parts. I've also heard many good things about westernhillshonda but have not checked them out. Prices are less than list and in some cases MUCH less

[mystic_1]

Yup, the Honda prices I was looking at were from Servicehonda.  List price on the bolts is US$11.89 each.

Thanks for the info, everyone.

mystic_1

[Jerry Rxman Griffin aka MuthaF'er]

I've had the original rods (except for 1  ) in my 75 750F0 since new. It has had a 810 Yoshi kit and cam for 25,000 miles and it visits 10,000 rpm quite frequently. I do like the idea of opening it up and at the least using new f2/f3 bolts and nuts. Don't even check with ARP for prices on their bolts !!
More expensive than Honda rods.