K+B .67's / 11cc... any good / competative

[yamaha74]

Are the K+B .67's any good ?... what are some noticeable mod's ?

 

[Joe Wiebelhaus]

Are the K+B .67's any good ?... what are some noticeable mod's ?

As long as you have at least a dozen...............or so............

B)

 

[Tim Kish]

Are the K+B .67's any good ?... what are some noticeable mod's ?

As long as you have at least a dozen...............or so............

B)

Man ain't that the truth :lol: ..

Tim K

 

[Dan_Cousin]

Are the K+B .67's any good ?... what are some noticeable mod's ?

What they are saying is that they will run like hell for a few races then will invariably break in a variety of places.

These can be strong light motors but the reliability has been an issue.

 

[Don Ferrette]

Well in years gone by we actually made them survive life in a scale boat. A couple things we did-

1- raise the middle third of the exhaust port in the sleeve .030", notch the case to match if it blocks the notch in the sleeve.

2- set the head clearance at .017" & don't run over 50%

3- if it's a disc motor set the disc clearance. Most of the time they were way too loose. I would take 2 strips of a new piece of notebook paper & slide under each side of the disc for setting the clearance that seems to work well. The later drum set up works well.

4- if it has the stock dogbone style rod toss it in the trash. They were hollow inside and would break real easy. We ran either the old style I beam rod or a rod from RPM or Aeromarine.

5- spend an evening in front of the TV with some rags, the piston & sleeve & a can of WD40 hand lapping the piston. Almost every bigger K&B had a horrible fit out of the box. Used to watch guys trying to start a new one turning the motor past TDC with a wrench on the collet so the starter motor would maybe spin it over, not a good thing.

6- if you can still find one run the old style carb with the interchangeable velocity stacks. Never did like that new style carb with the goofy disc on the side. Or better yet put Geraghty carb on it if you can find one.

Or take the easy way out & send it to Rod Geraghty. He can make those K&B motors work.

 

[SayMikey]

Well in years gone by we actually made them survive life in a scale boat. A couple things we did-

1- raise the middle third of the exhaust port in the sleeve .030", notch the case to match if it blocks the notch in the sleeve.

2- set the head clearance at .017" & don't run over 50%

3- if it's a disc motor set the disc clearance. Most of the time they were way too loose. I would take 2 strips of a new piece of notebook paper & slide under each side of the disc for setting the clearance that seems to work well. The later drum set up works well.

4- if it has the stock dogbone style rod toss it in the trash. They were hollow inside and would break real easy. We ran either the old style I beam rod or a rod from RPM or Aeromarine.

5- spend an evening in front of the TV with some rags, the piston & sleeve & a can of WD40 hand lapping the piston. Almost every bigger K&B had a horrible fit out of the box. Used to watch guys trying to start a new one turning the motor past TDC with a wrench on the collet so the starter motor would maybe spin it over, not a good thing.

6- if you can still find one run the old style carb with the interchangeable velocity stacks. Never did like that new style carb with the goofy disc on the side. Or better yet put Geraghty carb on it if you can find one.

Or take the easy way out & send it to Rod Geraghty. He can make those K&B motors work.

The real problem is the motors like to break during heat racing. If you want to race get a greenhead,if you want to work on motors and get pissed cause you almost fifished a heat use the k/b

 

[Don Ferrette]

The real problem is the motors like to break during heat racing. If you want to race get a greenhead,if you want to work on motors and get pissed cause you almost fifished a heat use the k/b

Well I'd rather help someone who might not yet be up to affording a CMB or MAC but might have that K&B be able to run as opposed to scaring them into not even getting their boat wet...... <_<

I ran the snot out a K&B .67 in my first scale boat & never broke it.

 

[dannyual767]

Not to hijack this thread from Yamaha who started it but I've got a question: I own two ebay purchased K&Bs (.67 and .82). I don't race at all and have absolutely no plans to start. I'm just a "run for fun" type of rc boater. If I keep my nitro levels low (~25%) can I expect to get some good life and running out of these engines?

My .67 is brand new and it has the older style carb that Don was talking about.

My .82 is used (well used PS :unsure: ) with the new style of carb that Don said isn't so good.

My buddy has a K&B .67 outboard and he's had good luck "fun running" the thing.

 

[Ron]

And one more thing, do all you folks have the same opinion about the 3.5 K&B, or are those okay to race as they are and we're just talking about the 7.5 & 11cc engines only?

Thanks,

Ron

 

[SayMikey]

Not to hijack this thread from Yamaha who started it but I've got a question: I own two ebay purchased K&Bs (.67 and .82). I don't race at all and have absolutely no plans to start. I'm just a "run for fun" type of rc boater. If I keep my nitro levels low (~25%) can I expect to get some good life and running out of these engines?

My .67 is brand new and it has the older style carb that Don was talking about.

My .82 is used (well used PS :unsure: ) with the new style of carb that Don said isn't so good.

My buddy has a K&B .67 outboard and he's had good luck "fun running" the thing.

If you have a handful of motors its one thing,if you dont its another. If you pop a k/b 67 its going to need a p/s rod and bearings, how many sets can you buy before you spent enough to buy a good used greeny? A guy in our club ran good with a k/b but so many dnfs and when the motor starts to sour you dont figure it out till your so upset your ready to sell the boat. He did and i bet if he started with a greeny hed still be racing that boat instead of someone else enjoying it my 2 cents

 

[Don Ferrette]

If you have a handful of motors its one thing,if you dont its another. If you pop a k/b 67 its going to need a p/s rod and bearings, how many sets can you buy before you spent enough to buy a good used greeny? A guy in our club ran good with a k/b but so many dnfs and when the motor starts to sour you dont figure it out till your so upset your ready to sell the boat. He did and i bet if he started with a greeny hed still be racing that boat instead of someone else enjoying it my 2 cents

OK one more time.......... but louder

IF A K&B 67 IS ALL SOMEONE HAS TO WORK WITH FOR NOW HELP GET THE GUY RUNNING RATHER THAN SCARE HIM ENOUGH TO WHERE HE WON'T EVEN TRY TO RUN IT!!

Did you hear me that time? <_<

If you prep one right you can make them live a while. If you try to run them straight out of the box they will most likely expire rather prematurely. Yes the greenhead is a great motor but what if someone ain't got almost $500 to spend on a motor & header? Running for a while with what one has is still better than not running at all. I know a number of people who did just fine few a few seasons on K&B motors until they could afford the step up. At least if you pop a K&B you can get parts for it, unlike some of you who still run Piccos........

 

[Tim Kish]

And one more thing, do all you folks have the same opinion about the 3.5 K&B, or are those okay to race as they are and we're just talking about the 7.5 & 11cc engines only?

Thanks,

Ron

3.5 outboard is a very good little motor that can be very fast and from what I have seen very reliable.

My sons B mono has the inboard and although it is not fast it has not had any problems at all.

Tim K

 

[SayMikey]

And one more thing, do all you folks have the same opinion about the 3.5 K&B, or are those okay to race as they are and we're just talking about the 7.5 & 11cc engines only?

Thanks,

Ron

3.5 outboard is a very good little motor that can be very fast and from what I have seen very reliable.

My sons B mono has the inboard and although it is not fast it has not had any problems at all.

Tim K

Yo Don ole buddy where did it say he had one ? I think he would better be served by a used greeny. I bought a pair for like $250 a piece. Id just look around and be patient till i found a good used one. Being in this hobby a long time i remember how much grief a motor can give and if he is a newby laps mean a lot. Broken motors or tired motors tend to chase more guys off than an extra $100.00 heck a couple cards of plugs can kill a new guy now........... PEACE Mikey

 

[Don Ferrette]

Hey Mikey it's cool, I'm just thinking that out of almost 3,000 members here that there just might be a few looking to make the K&B's live a little longer.

 

[yamaha74]

Since i'm the guy that started this thread.... i would like to throw my 2 cent's in on the subject, lol. First off, thank's to everyone who put in thier input, positive or negative, it's all good ! I'm kind of new to model boating, - owned a couple mono's before - and was actually lucky enough to win an ebay auction for a 1/8 scale 93 T-Plus built by DPS Racing Hulls. I also bought a sport 40 to do some "practice" on ! But if the K+B is supposed to rated as an underdog motor, i'm all in ! I've been around motor's, and "trying to make thing's work better" all my life. I spent quite a few year's making something / anything faster and better, instead of buying "off the shelf" power.

 

[Steve Sutton]

If you have a handful of motors its one thing,if you dont its another. If you pop a k/b 67 its going to need a p/s rod and bearings, how many sets can you buy before you spent enough to buy a good used greeny? A guy in our club ran good with a k/b but so many dnfs and when the motor starts to sour you dont figure it out till your so upset your ready to sell the boat. He did and i bet if he started with a greeny hed still be racing that boat instead of someone else enjoying it my 2 cents

OK one more time.......... but louder

IF A K&B 67 IS ALL SOMEONE HAS TO WORK WITH FOR NOW HELP GET THE GUY RUNNING RATHER THAN SCARE HIM ENOUGH TO WHERE HE WON'T EVEN TRY TO RUN IT!!

Did you hear me that time? <_<

If you prep one right you can make them live a while. If you try to run them straight out of the box they will most likely expire rather prematurely. Yes the greenhead is a great motor but what if someone ain't got almost $500 to spend on a motor & header? Running for a while with what one has is still better than not running at all. I know a number of people who did just fine few a few seasons on K&B motors until they could afford the step up. At least if you pop a K&B you can get parts for it, unlike some of you who still run Piccos........

As much as I hate to admit it I have to agree with Don on this one, as I raced K&B engines for several years (89 thru 97)and had good luck with them. They were very competitive in the classes I ran in (D Tunnel, 1/8 Scale, D Mono, and E mono) I did replace the stock rods in them with RPM rods or the older style "I" Beam K&B rods. which increased the life of the motors. I also ran a little extra oil in my nitro fuels which helped a lot and I learned this trick from Mr. Finch. When K&B ran into production problems and finacial issues I switched up to Picco & CMB engines. I gotta say I had a lot more problems with the Picco 45 & 80 than I had with any of the K&B engines I owned. I switched up to CMB engines and found them to be the most reliable engines which made good power. Now after taking some time off from racing I have gotten into racing in the GAS classes and have really enjoyed them. I would say if you have a K&B motor and want to run it do so, just check the set up and do the proper maintence and the engine should work well.

 

[Steve Sutton]

And one more thing, do all you folks have the same opinion about the 3.5 K&B, or are those okay to race as they are and we're just talking about the 7.5 & 11cc engines only?

Thanks,

Ron

Ron,

The 3.5 is a good little engine and a good solid performer at least the earlier 89 thru 95 models where don't know much about the newer engines. We did change the rods and set the head clearance as well as lap in the piston / sleeve fit prior to running the motors. I started out with a little 3.5 K&B on a Dumas tunnel boat and the engine ran very good for 3-4 years. I changed the front and rear bearings every year and the PTO bearing every other year. Good little engine.

 

[dannyual767]

S Sutton, thanks for your words of experience as well. I've got these two K&Bs and I hope to just get some good, reliable fun running with them. They'll probably never see more than 25% nitro and I'll most likely add a touch of extra oil. I've got an unopened bottle of castor h34r: . Now I just need to get my Dumas Miller American 1/8 scale built !