Topic: Hot Street Motor on a Budget

[stikman]

If you know how much , it helps..usually done on fixture in a mill.
But if its a very slight amount, some have done them with a dremel

Ahh k, perfect.  It's good getting confirmation on this stuff.

Did it for OS intake valves. I think the cam was a 41 or 41A.....it was 3 or 4 years ago.

Right on, good to know!

I currently have the CI pistons in my auto along with the 41 (341-CX1) cam, I do not have any work done on the pistons.

Now Stikman I would like to refer back to your original post/question. You are wanting a *budget* semi hot motor for the *street*, that is going in a *chopper*. Those are key words I focus on when giving my opinion. In the last 35 years of building racing engines for people, the first thing anyone giving advice needs to understand when putting a combination together is what the person wants and to know what is needed to get there.

Yeah Turbo, I guess "budget" is subjective.  I basically mean I don't have the deep pockets for the shiniest of goodies on this motor to give guys a relative idea how far their suggestions can go.  But I do want to push er as far as I can.  All the info is much appreciated.

[stikman]

I hope this helps to answer as to which "stock" cam will make the most power.***

Why no lift specs?

[BPellerine]

"vintage guys are the worst"simply playing with these old bikes kind of makes us all "vintage guys no?bill

[TurboD]

Stikman generally the shop manuals list a high and low spec, its not clear cut like a aftermarket cam card. The stock cams are all pretty close when it comes to lift. Also when it comes to lift, small differences in total lift with similar lobe profiles has very little bearing on power. The time spent at full lift is very brief (only a few degrees). Although all factors play roles when it comes to cam specs, changes in openings, closings and ramp speed have the greatest impact on changes in power output.

Bill If you are quoting me, I said "vintage bike guys" :

[stikman]

Fair enough, if the lift specs are close.  I've seen the lift numbers for most of the years and models but not the later ones.

[PeWe]

The kit cruzinimage 836, 41 cam is a good budget...springs will not add that much more. open cases to change the chains and tensioners?
HD cam chain? Old Tsubaki no more available. DID is, maybe stronger?
http://www.ebay.com/itm/371657444845?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
It is very easy to be taken by the upgrade devil, beware!!

EDIT:
Note! The cam chain in the link above is an OPEN version with link. Maybe for those in need of a new chain and not need to open case and lift crank.

Yamiya sell closed HD chain they call Yoshimura type. Stamped DID 219 FTS. For use that open cases lift crank shaft and swap chain(s).
http://www.yamiya750.com/index.php?main_page=product_info&cPath=246_21_249_68&products_id=2151

[BPellerine]

one thing that should be noted is that most of the tuning and mods for these engines is for higher rpm work from what I have seen,big bores seem to be the way to get low end perf,that and gearing.bill

[PeWe]

Big bore w higher CR to compensate for lost low torque with a hot cam.

I think it is difficukt to keep the budget very low on a 40 years old engine. The bottom must be in need of new parts as chains, tensioner, bearings, oil seals, clutch.
Why not new rubbers inside the primary hub?

You must be an enthusiast that love these old CB's. You get a much better modern bike with plenty of horses for the same money it cost to restore and upgrade an old CB. I have understood in later years that I married my bike when I saw it for first time January 1979. I had to restore what I did to the poor bike in early 80's

Honda CBR1100XX Super Blackbird from 1997 -2005 in a good shape with good looking fairings for $3500-5000 US here in Sweden. Really much bang for the $. I would like to have one beside my CB750. Wife has to bless me and enjoy travel on holidays first....that can be tricky though...
My engine mods in my CB750 that will be in next season cost MUCH more than that! If I add all mods spended so far, double it.... Engine only...then add new tank, side covers, 4-4  exhaust, NOS seat, NOS fenders, new fork.......

 I have a complete extra engine for left over parts...Just to assemble it when everything is on my shelves and floor in the garage. That is tuned too, 836, ported head w std valves, hot cam, Smoothebore carbs if used in another rolling chassie.

[BPellerine]

yeah pewe,you are really dedicated to your bike,and you have fun with it.I learned a few things from your build.bill

[PeWe]

yeah pewe,you are really dedicated to your bike,and you have fun with it.I learned a few things from your build.bill

That sounds good. A lot of my knowledge has been found here on these forums or inspiration to find out elsewhere, except for my findings the hard way..

[stikman]

I'm finally making some decisions after much deliberation.  Going to go with the Wiseco 836cc kit, as Bill P has offered me his spare set.  And looking to go with a DP 295 cam, or an MC 125-60, and HD springs if anyone happens to have any spares they'd be willing to part with.  I have a new in the box WebCam 41 (341, CX-1, whatever you want to call it) that I'd be willing to trade or sell to help fund things.  Thanks again for all the input so far, fellahs!

[TurboD]

I would use the 41 cam, It will make the same or more top end power over the 295 while having a stronger bottom.

A street bike is always much better with good throttle response and more low end power, I will give up a possible 2 HP on top for a better performing low and mid range any day.

I corrected my post above, I have the CX-2 cam in my automatic.

[stikman]

I would use the 41 cam, It will make the same or more top end power over the 295 while having a stronger bottom.

A street bike is always much better with good throttle response and more low end power, I will give up a possible 2 HP on top for a better performing low and mid range any day.

I corrected my post above, I have the CX-2 cam in my automatic.

Interesting.  The 295 has higher lift, longer duration, and tighter lobe centers than the 41 but I assumed from what I've read that it has alot of torque down low and gains throughout the whole rpm range.  The auto guys swear by it, and the autos are all about that torque.  Does it affect them differently?  I'm also all about that low and mid power over high end.

[madmtnmotors]

I'll be swapping the F2 cam for a CX-1 (Webcam 41) in my Street E/T dragbike posted earlier and will be able to post results. Current best ET is 13.38 at 97mph. I'll try to do the comparison before any sprocket changes. I'll be switching sprockets to try and get 5th gear on top end since I'm currently hitting my shift point in fourth gear right at the stripe.

[stikman]

I'll be swapping the F2 cam for a CX-1 (Webcam 41) in my Street E/T dragbike posted earlier and will be able to post results. Current best ET is 13.38 at 97mph. I'll try to do the comparison before any sprocket changes. I'll be switching sprockets to try and get 5th gear on top end since I'm currently hitting my shift point in fourth gear right at the stripe.

That will be very interesting for sure.  If you end up with the 60ft number comparison too, that would be awesome.  When are you planning to test your changes?

[madmtnmotors]

I'll be swapping the F2 cam for a CX-1 (Webcam 41) in my Street E/T dragbike posted earlier and will be able to post results. Current best ET is 13.38 at 97mph. I'll try to do the comparison before any sprocket changes. I'll be switching sprockets to try and get 5th gear on top end since I'm currently hitting my shift point in fourth gear right at the stripe.

That will be very interesting for sure.  If you end up with the 60ft number comparison too, that would be awesome.  When are you planning to test your changes?

Hopefully before the end of the year. We just finished the season in Valdosta over the weekend, so it's time for wrenchin'! Current 60' numbers are right at two seconds.

[TurboD]

Wilber I think you will be happy with the CX-1, it is nearly every bit as good as the CX-2. The CX-1 actually shows better numbers all the way up the RPM until around the 7500 mark (if my memory is correct), then the CX-2 makes a few more HP on top up to the 10:5 range. With a little cylinder head work the CX-2 would also make for a super street-strip combo.

I have the CX-2 in my auto, It pulls good from 2400 (all I can get from my stock converter) all the way to 11,000 which is where at shift and where it goes through the traps. The autos rely greatly on torque, in my case with a stock converter I leave at 2400 RPM and with a low gear ratio that is basically between 2nd and 3rd on a manual shift (5 speed sohc). After only a handful of outings at the track it has managed to run 13.4 at 105 with a 2.15ish 60 ft. The 2400 launch flat kills the ET.

[BPellerine]

turbo,at what point do you feel the cam coming on?interesting that you are getting 11000 rpm.up to what cc do you feel this cam is good for?bill

[PeWe]

The cam data make difference even if the data of different cams look similar on the paper. The shape of the lobe is not specified, only max lift and duration. Not how long time/degrees at higher lifts (lobe shape).

My Action Fours SS-1 cam has specified data as 0.360" lift. 28/62, 62/28 duration. I could verify the lift in my engine, actually a little bit more 0.361". Duration at 1mm lift (0.04") 22/55, 56/24
This modest cam did not add anything after 9500 rpm.  The data on paper look close as Webcam 41A.

Another thing with Megacycle 125-20 (Micky Mouse ear lobes) that had no respect at all for my tachometer that felt tuned. The needle gladly passed 10500 rpm and into the green area after the red! I got a bonus wheelie when WOT up to +10.000 on 2:nd gear and slammed in the 3:rd. I instinctly reduced throttle a little to avoid serious problems with that wheelie angle. I never checked max rpm with that cam. Before Ape ultra crank with Cariillo rods.

I have a RC295 copy that has better power from low and all the way up to around 9500 too. Slightly better then the AF SS-1.  I used the CX-7 during a short time too. I had carb /ignition issues and old Smoothbore 29's. TMR32 work different.
This cam however, was a very loud in my engine, really screaming one and sudden power around 6500-7000 rpm. Rather boring for street.

My new favourite is the DP315. A really good cam for street! It has better idle than all the other cams, SS-1 included. The APE ultra crank might make a difference too. That cam has no heavy sudden power as the other cams (turbo feeling). It has good power from low and it has nice response up until I shift. This with 4-4 exhaust, Yamiya HM300 replica without diffusers. 836 and 900cc last summer

I'll check more coming season with bigger bore (71.25mm) and pistons ordered for 24.4cc chambers to get CR 10.5.
The cam was rather thirsty last time, despite lean jetting. +1-2dl/10km in highway speed compared with SS-1 and RC295 copy

125-20 and CX-7 consumed much more fuel as expected.

I'll use an AF meter and measure while driving in constant speeds, city as well as highway. Dyno runs usually check WOT only which can hide a super lean at low lift. Too rich acc pump can trick too.

I have a WegoIII kit. 4-4 exhaust with a sniffer instead of diffuser make it possible to measure and jet  all 4 carbs individually. Billet block has no air vents between cylinders so 2-3 might need richer mixture. An Action camera can record the AF gauge while driving so speed and rpm will be visible at the same time. How the throttle was twisted too to understand the effect of the acc pump.

I use my bike as a street bike only.

[TurboD]

turbo,at what point do you feel the cam coming on?interesting that you are getting 11000 rpm.up to what cc do you feel this cam is good for?bill

It starts pulling good around 4500, having a little wider lobe separation the power is smoother through the entire power band. Strong low end while still having a good top end. The auto is one of the most demanding setups to try to go fast on, especially with the stock converter.

[754]

I would think with the converter, you have to he careful with cam choice.

Stikman, I can remember racing my 836 at the first Prince George Bike Drags... ..... Many moons ago.

[stikman]

Stikman, I can remember racing my 836 at the first Prince George Bike Drags... ..... Many moons ago.

Oh no way, nice.  Probably don't have any video of it eh?  Let me know if you ever plan to come back up this way.

[TurboD]

I would think with the converter, you have to he careful with cam choice.

Stikman, I can remember racing my 836 at the first Prince George Bike Drags... ..... Many moons ago.

Yes the cam is very important if wanting to fast with a auto. I would say that the auto is one of the most demanding bike projects I have worked on, in terms of parts selection and getting a good combo working together. The very low launch RPM and only having 2 speeds requires a lot from the engine.

[stikman]

I appreciate the help and info from you lot.  I've made some decisions on the route I want to take this build.  Bill P sold me a Wiseco 836cc piston set he wasn't using, and I'm going to go with the WebCam 41 that is sitting unused on my shelf.  I'll do the port and chamber work myself and I've got some roundtops to go with it.

So I just tore the top end apart a couple days ago, what a mess to say the least!  This motor obviously had some bad leaking judging by the thick coat of dirty/sandy oil on everything, and the PO was very hard on it (as in riding it on a dirt track with v-stacks... I know right  ).  I've honestly never seen a worse top end rebuild than whoever did this one before.  The cylinders were clearly not honed last time, with glazing, pitting, and still have grooved markings showing it was at least partially seized at some point.  The 3 piece oil rings were lined up with each other... on all 4 pistons!!  Whoever rebuilt it had no clue what they were doing and obviously figured it made sense to line up the oil rings.  In fact, the 2nd ring was also lined up with the 3 oil rings on #1, and #2 had a broken top ring and what looks to possibly be a bit of piston melting right above that.  The piston skirts all have beautiful brown blow-by markings.  The carbon buildup in the chambers is incredible.  I checked the valve lash before pulling the rockers and found too much on all of them, .005" to .008" here and there... up to 0.012" on one of the exhaust valves.  Two valves have pretty hammered heads, no doubt from the lash numbers.  What else?  Oh, the o-rings around the underside of the piston sleeves were rock hard, and all 6 of the the nickle seals under the cam towers were wet with oil on the underside lips.  The cam lobes are all worn, which smacks of low oil and/or irregular oil changes.  The motor is a K4 but the cam is stamped "K8" on a flat spot, which I've never seen before.

At any rate, the head and jugs went out yesterday to get hot tanked. So I should be able to get started on the port work soon and get the cylinders bored once the pistons get here.  Based on the rest of the bike, I had already dubbed it the Toilet Plunger (K4 motor in a Canadian D5 plunger frame).  Now having torn into the motor I find it never ceases to live up to its name.  Here's a few pics for your viewing pleasure.

[MRieck]

Broken rings...there's a story