CMB .91

[rocky]

I know these motors are built differently. I know the stroke is a little different.

Can anyone tell me the plus or minus of these 2 different motors?

Does one of these motors have an application that the other doesn't?

Help a rookie out.

Rocky

 

[dr gary turner]

I am a fan of the R/S 91. It is a little harder to work on. It is a strong motor and is vary durable. I run two of them in my twin and Mark Bullard has two in his twin. I run 60% nitro and a 13cc Mack pipe and we have not found a prop that it would not turn.

We have tried v967, 2167, 1967, piched up 1667 and have settled on H50's for heat racing. We actually could stand more pitch in the H50's. We have yet to try 2267. GTT

 

[dr gary turner]

BTW I run the 101 which is the same as the R/S 91 except for a bigger bore, in my Crapshooter 90 hull and it is like driving a BLOWN NITO FUNNY CAR!!!!!!!!!! Fastest boat I have had in 30 yrs of boating. GTT

 

[glenng]

I know these motors are built differently. I know the stroke is a little different.Can anyone tell me the plus or minus of these 2 different motors?

Does one of these motors have an application that the other doesn't?

Help a rookie out.

Rocky

Hi Rocky, I'm just a rookie boater too, but from what I've heard the RS(racing special) has more torque(low end HP) than the HR and is better suited to heavier boats. I saw a twin outrigger w/.91 HR's run today-very impresive but the owner told me if he had it to do over again- he would use the RS. Take this advise with a grain of salt. I,m sure others smarter than me will reply

 

[rocky]

I know these motors are built differently. I know the stroke is a little different.Can anyone tell me the plus or minus of these 2 different motors?

Does one of these motors have an application that the other doesn't?

Help a rookie out.

Rocky

Hi Rocky, I'm just a rookie boater too, but from what I've heard the RS(racing special) has more torque(low end HP) than the HR and is better suited to heavier boats. I saw a twin outrigger w/.91 HR's run today-very impresive but the owner told me if he had it to do over again- he would use the RS. Take this advise with a grain of salt. I,m sure others smarter than me will reply

Thanks for the comments Gary and Glenn.

Hey Glenn, it sounds like you got to see some racing this weekend. The Evansville, In. race is next weekend and I can't wait to go down to watch and try to learn a few things from some of the guys.

The way it sounds is that both the RS and the HR can be used in the same application. The RS is just a newer and maybe a little better design. CMB does still make parts for the HR from what I can tell.

Unless someone chimes in and tells me different, the HR is still a strong durable engine.

Rocky

 

[Don Ferrette]

The way it sounds is that both the RS and the HR can be used in the same application. The RS is just a newer and maybe a little better design. CMB does still make parts for the HR from what I can tell. Unless someone chimes in and tells me different, the HR is still a strong durable engine.

The RS design has actually been around for a long time with it's direct predecessors being the Evo2000, Evo2mk2, Evo2, etc. A tough as nails motor that makes plenty of power, hard to go wrong with choosing one. B)

 

[aaron alberico]

i run 2x HR91's in my twin sgx, it is awesome fast,

with awesome rev's and good bottom end,

regards Aaron

 

[Daniel's Racing]

Love my CMB 101 RS in CMDI Eagle SG. Fast and a real blast.

 

[dr gary turner]

Love my CMB 101 RS in CMDI Eagle SG. Fast and a real blast.

Like a blown nitro funny car!!!!!!!!!!! Gary

 

[SayMikey]

I know these motors are built differently. I know the stroke is a little different.Can anyone tell me the plus or minus of these 2 different motors?

Does one of these motors have an application that the other doesn't?

Help a rookie out.

Rocky

Hi Rocky, I'm just a rookie boater too, but from what I've heard the RS(racing special) has more torque(low end HP) than the HR and is better suited to heavier boats. I saw a twin outrigger w/.91 HR's run today-very impresive but the owner told me if he had it to do over again- he would use the RS. Take this advise with a grain of salt. I,m sure others smarter than me will reply

Thanks for the comments Gary and Glenn.

Hey Glenn, it sounds like you got to see some racing this weekend. The Evansville, In. race is next weekend and I can't wait to go down to watch and try to learn a few things from some of the guys.

The way it sounds is that both the RS and the HR can be used in the same application. The RS is just a newer and maybe a little better design. CMB does still make parts for the HR from what I can tell.

Unless someone chimes in and tells me different, the HR is still a strong durable engine.

Rocky

Hey Rocky oppss better not gp there. What the heck be sure to look me up i will be the one on the stand looking like Bullwinkle.......Are you racing?

 

[rocky]

I know these motors are built differently. I know the stroke is a little different.Can anyone tell me the plus or minus of these 2 different motors?

Does one of these motors have an application that the other doesn't?

Help a rookie out.

Rocky

Hi Rocky, I'm just a rookie boater too, but from what I've heard the RS(racing special) has more torque(low end HP) than the HR and is better suited to heavier boats. I saw a twin outrigger w/.91 HR's run today-very impresive but the owner told me if he had it to do over again- he would use the RS. Take this advise with a grain of salt. I,m sure others smarter than me will reply

Thanks for the comments Gary and Glenn.

Hey Glenn, it sounds like you got to see some racing this weekend. The Evansville, In. race is next weekend and I can't wait to go down to watch and try to learn a few things from some of the guys.

The way it sounds is that both the RS and the HR can be used in the same application. The RS is just a newer and maybe a little better design. CMB does still make parts for the HR from what I can tell.

Unless someone chimes in and tells me different, the HR is still a strong durable engine.

Rocky

Hey Rocky oppss better not gp there. What the heck be sure to look me up i will be the one on the stand looking like Bullwinkle.......Are you racing?

Hi Mike,

No Racing for me, I'm not ready for that yet. I have a lot to learn. I am thinking of joining the club. A few guy from up here in Haubstadt are starting to learn boats and have been running on local lakes. We are all airplane guys and still learning about the boats. I am sometimes frustrated with the boats trying to tune on them and getting them to run right. I have been over to St. Wendle to a father and sons garage to talk with them. I can't remember their names ??? but they were very good guys and answered any questions I had. This is why I am going to try to learn as much as I can this weekend at your event.

I have a modded Bandit tunnel this week that I want to run as much as I can this fall. I have a Carbon/Fiberglass Youngblood Rigger I want to finish this winter. Maybe I could run it next spring. I have a lot to learn. I have a racing back ground as I worked for Tom Helfrich back in the 80's and travel all over the country working on his cars. I think I have a little ability and knowledge.

I hope I can talk with you this weekend.

Rocky

 

[Tofastformellow]

heres my latest 700$ paperweight.

its a 2007 offshore rs... hmmm.. didnt make its first race start.

i bought a hr91 and a rs91/101 ,at the same time . i would say get the hr .

at least the hr91 runs strong...

i just got a bad motor , you get one now and again ., part of the hobby , burning 700$ on new parts left and right ....

Jason

 

[Akiuk]

heres my latest 700$ paperweight.
its a 2007 rs ... hmmm.. didnt make its first race start.

Jason

The "dimple" on the case sides is cute.... what you want for the hunk of junk?? seriously want to sell it?

 

[Mark Bullard]

heres my latest 700$ paperweight.
its a 2007 offshore rs... hmmm.. didnt make its first race start.

i bought a hr91 and a rs91/101 ,at the same time . i would say get the hr .

at least the hr91 runs strong...

i just got a bad motor , you get one now and again ., part of the hobby , burning 700$ on new parts left and right ....

Jason

New motors just don't do that unless they are not check or prep. The K motors are the only one that could be run right out of the box but head deck clearance should be set to your liking. I have found little things in Pico's, OPS's, CMB's, and other motors over the years. So it always a good idea to go thru a motor before running it.

 

[Ray Sametz]

K&B motors definitly blew up, if not checked and run right out of the box. :lol: :lol: :lol:

 

[Tim_Duggan]

it always a good idea to go thru a motor before running it.

Unfortunately, not everyone is competent or capable of doing this - and in reality they should not have to on a "race" engine. Those who need to have someone else do it for them have to spend even more money just to ensure the new engine is safe to run, which can't be doing good things for the manufacturers reputation.

I'm glad I pulled down the new RS101 I bought last year before it went anywhere near fuel. The engine seemed to be rather poorly assembled in my opinion (after having Kalistratov's for years..... I guess I just got spoiled after knowing what those engines look /feel like new). The piston would push right up thru the sleeve top, the carb didn't line up with the disk plate sleeve ports rough etc.etc.

This engine is also going in an Eagle SG when I finally get around to building it! One day!

 

[rocky]

heres my latest 700$ paperweight.
its a 2007 offshore rs... hmmm.. didnt make its first race start.

i bought a hr91 and a rs91/101 ,at the same time . i would say get the hr .

at least the hr91 runs strong...

i just got a bad motor , you get one now and again ., part of the hobby , burning 700$ on new parts left and right ....

Jason

New motors just don't do that unless they are not check or prep. The K motors are the only one that could be run right out of the box but head deck clearance should be set to your liking. I have found little things in Pico's, OPS's, CMB's, and other motors over the years. So it always a good idea to go thru a motor before running it.

Hi Mark,

Thanks for the input. I am going to end up buying a NIB Picco .90. Give me some ideas of what I need to do when I get this motor.

I'm a newbie, I don't know s**t.

Nitro % & oil during brake in?

Head deck clearance?

anything else you can think of?

Your information would be greatly appreciated

Thanks

Rocky

 

[Mark Bullard]

heres my latest 700$ paperweight.
its a 2007 offshore rs... hmmm.. didnt make its first race start.

i bought a hr91 and a rs91/101 ,at the same time . i would say get the hr .

at least the hr91 runs strong...

i just got a bad motor , you get one now and again ., part of the hobby , burning 700$ on new parts left and right ....

Jason

New motors just don't do that unless they are not check or prep. The K motors are the only one that could be run right out of the box but head deck clearance should be set to your liking. I have found little things in Pico's, OPS's, CMB's, and other motors over the years. So it always a good idea to go thru a motor before running it.

Hi Mark,

Thanks for the input. I am going to end up buying a NIB Picco .90. Give me some ideas of what I need to do when I get this motor.

I'm a newbie, I don't know s**t.

Nitro % & oil during brake in?

Head deck clearance?

anything else you can think of?

Your information would be greatly appreciated

Thanks

Rocky

Don't buy the Pico. Parts will be hard to find. Go ahead and get a CMB. And I would go with the RS. They are a bullet proof motors. There are more RS's, EVO's and whatever other motors were called of this style motor running than any brand. If you get the 91rs make sure that it has a ABC piston & sleeve. We can them for you along with a few other people on this board. I could also race prep your motor for you. I only charge $60.00usd for the service and it will be ready to place in a boat.

 

[Tofastformellow]

it always a good idea to go thru a motor before running it.

Unfortunately, not everyone is competent or capable of doing this - and in reality they should not have to on a "race" engine. Those who need to have someone else do it for them have to spend even more money just to ensure the new engine is safe to run, which can't be doing good things for the manufacturers reputation.

I'm glad I pulled down the new RS101 I bought last year before it went anywhere near fuel. The engine seemed to be rather poorly assembled in my opinion (after having Kalistratov's for years..... I guess I just got spoiled after knowing what those engines look /feel like new). The piston would push right up thru the sleeve top, the carb didn't line up with the disk plate sleeve ports rough etc.etc.

This engine is also going in an Eagle SG when I finally get around to building it! One day!

going thru a motor , voids warranty , so my dealer tells me . i haven't seen the inside, i will send it back and ask for a please explain .

something failed and it failed in the first 6 litres...ran it in for four , and started leaning it off a little for 2 more... just got the hull trimmed out and it starting to pipe , and lock up ...at 1/2 throttle. on 25%.

most of my many 91/101s i have owned over the years have been pretty good... went for 3 or 4 years before doing this. its tough to swallow.

bearing the cost of this ... i wont , if its not fixed as a manufacturing failure , than thats it for cmb for me.

thats 125$ a litre it cost to run .

Jason

 

[rocky]

heres my latest 700$ paperweight.
its a 2007 offshore rs... hmmm.. didnt make its first race start.

i bought a hr91 and a rs91/101 ,at the same time . i would say get the hr .

at least the hr91 runs strong...

i just got a bad motor , you get one now and again ., part of the hobby , burning 700$ on new parts left and right ....

Jason

New motors just don't do that unless they are not check or prep. The K motors are the only one that could be run right out of the box but head deck clearance should be set to your liking. I have found little things in Pico's, OPS's, CMB's, and other motors over the years. So it always a good idea to go thru a motor before running it.

Hi Mark,

Thanks for the input. I am going to end up buying a NIB Picco .90. Give me some ideas of what I need to do when I get this motor.

I'm a newbie, I don't know s**t.

Nitro % & oil during brake in?

Head deck clearance?

anything else you can think of?

Your information would be greatly appreciated

Thanks

Rocky

Don't buy the Pico. Parts will be hard to find. Go ahead and get a CMB. And I would go with the RS. They are a bullet proof motors. There are more RS's, EVO's and whatever other motors were called of this style motor running than any brand. If you get the 91rs make sure that it has a ABC piston & sleeve. We can them for you along with a few other people on this board. I could also race prep your motor for you. I only charge $60.00usd for the service and it will be ready to place in a boat.

Hey Mark,

I know a guy on here that has an older CMB .91 (purple head) It has been modded and some blue print work done to it. It hasn't been run since gone through.extra piston and sleeve comes with it. It was a back up motor. 450.00 with pipe and header. Not a bad deal.

what do you think?

Rocky