HMB Cams

[czakky82]

It looks like HMB has a cam package designed for bikes with VHB/PHF30s. Anybody have experience with this cam?

Trying to weigh improvements of this cam vs PHF36s plus cam.

Thanks
Bill

[Antietam Classic Cycle]

This one?

https://hmb-guzzi.de/Valve-drive-Kit-HMB-K-77-mechanical-drives

A claimed 8 ps (7.89 hp?) increase. But $700+? 

[czakky82]

This one?

https://hmb-guzzi.de/Valve-drive-Kit-HMB-K-77-mechanical-drives

A claimed 8 ps (7.89 hp?) increase. But $700+? 

Yessir that one. Could you effectively do a 36mm carb upgrade with porting, cables, manifolds, etc for less?
Which offers more return?

[Frenchfrog]

You need to add cam followers to the HMB set too....I'd get a P3 from agostini and yes it really livens the bike up.In combo with the 36 's even better...

[moto-uno]

  Do you mean professionally porting the heads, or simply opening the outside of the intake to fit the larger carbs ?
  Proper porting is not for the weak of pocketbook :( . But it sure can liven things up . Peter

[czakky82]

You need to add cam followers to the HMB set too....I'd get a P3 from agostini and yes it really livens the bike up.In combo with the 36 's even better...

I was under the impression that you should replace followers with a new cam.
I’m trying to do this somewhat cheap, just trying to see if it’s worth it.
Why the P3?
Thanks for the response.

  Do you mean professionally porting the heads, or simply opening the outside of the intake to fit the larger carbs ?
  Proper porting is not for the weak of pocketbook :( . But it sure can liven things up . Peter

Is that all there is to it? A guy with a dremel could do it?

[blackcat]

 "Do you mean professionally porting the heads, or simply opening the outside of the intake to fit the larger carbs ?
 
Is that all there is to it? A guy with a dremel could do it?"

I never got around to tapering the intake on my 81 CX with 36mm carbs but it runs fine and it's been that way for about 15 years  But it's due for a valve job and I'll do the tapering then.  The cam that I installed on the Lemans I was a P3 cam and I highly recommend it. The CX has a mild cam that isn't stock and I should have installed a better cam but that will be up to the next owner, but I did install a Milich lightened flywheel.

[Rough Edge racing]

 Tapering ports and or port matching has become debate with mant top car engine builders.. Some claim  the step in the port makes no difference on some engines...
  If you need cams and headwork is an easy decision, do you often run the engine 5000 rpm? If not, just spend your money on a quality valve job..And try to find a shop using a valve machine like a Serdi or Newen...

[guzzista]

Hard to say how the HMB cam comperes to a P3 as I did not see any specs.
In any case it's a matter of combinations . If some actual porting on a flow bench operated by a specialist, combining port matched PHF36, any cam improvement including a B10 or better ( P3 an excellent choice) and some careful squish band adjustment , results will be very good, at least in how the engine responds in real world  conditions ( but not a revelation on the Dyno , just to be clear)
but if we are comparing for return on  dollars spent, even tapered intakes, and PHF36'S  will be a  nice return for the $
Or, another option , B10 regrinds (such as from Delta Cams in Tacoma or equivalent) combined with resurfaced lifters can be a inexpensive  bang for the buck by itself a as long as you don't expect too much with stock carbs and no port work.
All  can be done in  progressive steps   based on mechanical  location/ convenience so you don't have to break the bank all at once, and while  people  may claim that one thing will be the most important, it is the complete recipe that makes the cake imo

[fotoguzzi]

What motorcycle will you be spending all that money on?

[John A]

See the vid I posted under educational vids labeled hot rod stuff, it’s about the basics of porting. You need at least a basic understanding of the principles before you screw up a good pair of heads

[czakky82]

Hmmm. I’ll check that vid out.

@foto, a T3 mostly stock.

The other side is I kinda want to keep the VHBs…

[moto]

This reminds me of the Alfa GTV 2000 I once had. The PO told me it "had a cam." After selling the car, I tried to find another one in better shape. But the responsiveness of the stock engined ones I drove was by then really disappointing.

I have a T3 with just-rebuilt VHB 30 carbs, and was out for a ride today. I spent a lot of time accelerating between 5,000 and 7,000 rpm because the motor is not too powerful but produces its best power in that range. I bet the suggested HMB cam would be just the thing to pep it up a bit while keeping the same carb.

[Frenchfrog]

Agree...the standard cam is a bit lazy to say the least. The P3 is an awful lot better than anything the factory turned out and at 450 euro not a bad deal compared to the HMB which is simply an exchange regrind.I'm sure the HMB is good though.Personally I'd go the full 9 yards if you can afford it : better cam, bigger carbs,lighter flywheel.The trouble is that all that investment will only give you a relatively modest performance increase compared to buying a modern bike.

[czakky82]

I’m sure out and out objective performance is the goal of anybody tuning an old Guzzi. It’s just fun! You wouldn’t want to know how much I’ve spent transforming my old Yamaha R5 from 30hp to a whopping 55hp! But I dare you to not ride it and either swear off motorcycles or laugh hysterically!
Plus I just like the old bike!

[czakky82]

@Moto, you doing the Crud run tomorrow? I see you’re from Madison. I’m in Mineral Point.

[Gliderjohn]

My T-3 has a 1,000cc kit, the old V7 sport cam, 36mm carbs, heads ported and polished (not at flow bench level but by someone that was skilled and experienced), K&Ns and cheap Emego mufflers. Makes a great street riding combination. Here is a RW measured dyno chart.



GliderJohn

[moto]

@Moto, you doing the Crud run tomorrow? I see you’re from Madison. I’m in Mineral Point.

Yes. Look for you at Pine Bluff around 9:30?

[Rough Edge racing]

My T-3 has a 1,000cc kit, the old V7 sport cam, 36mm carbs, heads ported and polished (not at flow bench level but by someone that was skilled and experienced), K&Ns and cheap Emego mufflers. Makes a great street riding combination. Here is a RW measured dyno chart.



GliderJohn

That big dip in power around 3200 rpm, was that noticeable on the road? It's usually because of exhaust system tuning and or inlet manifold length..

[czakky82]

@ john, thanks for posting. BTW who messes around below 3200 RPM?

@ Moto, the plan is to meet at my house around 830 and head out the twisty way…. So likely closer to 10. I’m looking forward to it though!

[moto]

I'll keep an eye out for you.

[czakky82]

I’m pretty sure I’ll be on my Guzzi. Black T3, bald dude.

[Gliderjohn]

From RoughEdgeRacing:

That big dip in power around 3200 rpm, was that noticeable on the road? It's usually because of exhaust system tuning and or inlet manifold length..

The dyno operator shut the throttle at that point and then cranked it, don't know the reason. On the road it is about as linear as one could asked for.
GliderJohn

[ratguzzi]

I personally don't understand the effort. I bought a 2002 Stone for $1000. I sold all but the driveline for around $800. I put an 1100 motor in my 75T with equal power to what you all want to do for $200. And it will easily go 200k with zero work.
Just saying....
JB

[Gliderjohn]

From RatGuzzo:
 personally don't understand the effort. I bought a 2002 Stone for $1000. I sold all but the driveline for around $800. I put an 1100 motor in my 75T with equal power to what you all want to do for $200. And it will easily go 200k with zero work.
Just saying....
JB
Totally understand, but hey, it worked out great for me. I'am happy with what I have so I am happy!
GliderJohn

[Rough Edge racing]

From RoughEdgeRacing:The dyno operator shut the throttle at that point and then cranked it, don't know the reason. On the road it is about as linear as one could asked for.
GliderJohn

ah, jut operator error...The shop I use makes  bike owner/rider do the dyno riding..

[moto]

I’m pretty sure I’ll be on my Guzzi. Black T3, bald dude.

Black T3 for me, with Wixom bags. Gray hair and beard.

[Turin]

Ratguzzi makes a really good point. A well tuned 1100 cali motor is good for 65 RWHP.

My 850 runs a megacycle X-9 / Norris S cam, ported heads, stainless valves, lightened lemans flywheel, 36mm carbs, and a mistral exhaust.

End result is a nice riding bike with a meatier powerband.

My quota is still faster.

[Scout63]

My T-3 has a 1,000cc kit, the old V7 sport cam, 36mm carbs, heads ported and polished (not at flow bench level but by someone that was skilled and experienced), K&Ns and cheap Emego mufflers. Makes a great street riding combination. Here is a RW measured dyno chart.



GliderJohn

That’s what I want.  I have the 949ccs and a pair of 36’s in a box.  I’m a little nervous about handing the heads off to someone.  Maybe just pick up a spare pare.  This is an interesting thread.

[Scout63]

I don’t know whether to blame John or the forum generally.  I just ordered a P3 from Stein Dinse.  $460.00 shipped.  It’s going to go on the special part of the shelf that has the PHM’s.