Ryobi 31 @8000 RPM (18X8)
05-13-2002, 10:18 PM
#1
Senior Member
Thread Starter
My Feedback: (34)
Join Date: Mar 2002
Location: Gilbert,
AZ
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
Guys,
I just replaced my rigs with frank Bowemans after market rings. My Ryobi 31CC conversion went from 7200 to 8000 RPM with a MAS 18x8. Anyone even come close to this? This ring cover the "pin" increasing compression by 30%.
I just replaced my rigs with frank Bowemans after market rings. My Ryobi 31CC conversion went from 7200 to 8000 RPM with a MAS 18x8. Anyone even come close to this? This ring cover the "pin" increasing compression by 30%.
05-14-2002, 03:38 AM
#3
Senior Member
Thread Starter
My Feedback: (34)
Join Date: Mar 2002
Location: Gilbert,
AZ
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
The pinned rig lets a LOT of compression out. Yes, I opened the caby, manafold, and made a new reed, but I would not do it again.
The Ring in your engine now is pinned so it can not spin in the slot. Stock, this makes a 4 MM gap that leaks. What you do is press this pin 1/2 way into the slot a replace the ring with one which will cover the pin. MY GOSH. I went from 7300 RPM to 8000, and a lot more torque. Drop a mail to [email protected] (Frank). It is a great 9 dollar investment.
Tim
The Ring in your engine now is pinned so it can not spin in the slot. Stock, this makes a 4 MM gap that leaks. What you do is press this pin 1/2 way into the slot a replace the ring with one which will cover the pin. MY GOSH. I went from 7300 RPM to 8000, and a lot more torque. Drop a mail to [email protected] (Frank). It is a great 9 dollar investment.
Tim
05-15-2002, 11:38 AM
#8
Senior Member
My Feedback: (1)
Join Date: Jan 2002
Location: Sault Ste Marie,
ON, CANADA
Posts: 758
Likes: 0
Received 1 Like
on
1 Post
Ryobi 31 @8000 RPM (18X8)
Anything that will raise the anemic compression ratio of the stock Ryobi (within reason!)will help starting.I have found as you accumulate time on a stock Ryobi the compression improves somewhat and hot starting can be done by hand,although rather than fight the engine I use a standard 12 volt starter all the time.
I too ordered one of these rings as the theory makes a lot of sense of sealing the ring gap at the pin.
I too ordered one of these rings as the theory makes a lot of sense of sealing the ring gap at the pin.
05-17-2002, 10:37 PM
#9
Member
Join Date: May 2002
Location: Eldon, MO
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
I have converted a couple on these enginges and are turning 18x6 @ 7200. I will have to try a ring I always thought the engine would run much better with more compression.
05-20-2002, 09:58 PM
#14
Senior Member
My Feedback: (23)
Join Date: Jan 2002
Location: Houston, TX
Posts: 3,227
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
Yap, I bought a couple of Frank's rings some time back and I got very similar results with a MAS 18x8. I was going to order a Synchrospark module for the CH ignition and up the CR as per Pe Reiver's(sp?) instructions, but other projects got in the way and put the Ryobi on hold.
Glad to see others having good luck with Frank's rings. Very nice fellow to deal with.
Glad to see others having good luck with Frank's rings. Very nice fellow to deal with.
05-21-2002, 06:37 PM
#15
Senior Member
Thread Starter
My Feedback: (34)
Join Date: Mar 2002
Location: Gilbert,
AZ
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
My RPMS dropped to 9750, with an 18X8 with about 1/2 gal. However, my trust is up about 20% after flying my spacewalker.
This has worked out well. I have a feeling it will get even better with more run in.
BTW... this idles much, much better with the impoved compression. Not bad for a 55 dollar engine.
Tim
This has worked out well. I have a feeling it will get even better with more run in.
BTW... this idles much, much better with the impoved compression. Not bad for a 55 dollar engine.
Tim
05-21-2002, 07:01 PM
#16
Ryobi 31 @8000 RPM (18X8)
Boy, 9,750 rpm,
That's really turning up there for any Ryobi with an 18-8?
Maybe I better send my TNC tach in and get it checked?
That stamped steel connecting rod may let go at that rpm?
Don't be standing in line with the prop.
Enjoy,
Jim
That's really turning up there for any Ryobi with an 18-8?
Maybe I better send my TNC tach in and get it checked?
That stamped steel connecting rod may let go at that rpm?
Don't be standing in line with the prop.
Enjoy,
Jim
05-21-2002, 09:02 PM
#17
Senior Member
My Feedback: (23)
Join Date: Jan 2002
Location: Houston, TX
Posts: 3,227
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
Yes, sounds like you'd better prop it up a little more. The Ryobi 31cc is $50 for a reason. Both Frank and CH Ignitions warned me about the stamped steel conrod when I described my hop-up plans to them. Plus the flywheel is made from several stamped steel plates riveted together. I'd prop it to run at 8000rpm max.
05-22-2002, 04:27 AM
#18
Senior Member
Thread Starter
My Feedback: (34)
Join Date: Mar 2002
Location: Gilbert,
AZ
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
stop the bus! I mean 7950 RPMs from 8000. I should check my typing!
However, after flying this, I am still pushing it. I bet I could go to a 18X10 and have better response. Man, the new ring really does the job.
cheers
Tim
However, after flying this, I am still pushing it. I bet I could go to a 18X10 and have better response. Man, the new ring really does the job.
cheers
Tim
05-22-2002, 11:07 AM
#19
Senior Member
My Feedback: (1)
Join Date: Jan 2002
Location: Sault Ste Marie,
ON, CANADA
Posts: 758
Likes: 0
Received 1 Like
on
1 Post
Ryobi 31 @8000 RPM (18X8)
Im looking forward to delivery on one of these rings and Ill post the results .I think we all should remember these are really cheap little engines that were not designed for the RPMs some of us are turning,and grenade city is always a possibiliy.Another weak point is the reed valve.A friend of mine wound his up tight on a test stand one day,the reed fractured ,or the mounting screw pulled out of the plastic backplate,but in any case the engine ate the valve,and instantly destroyed itself. 
05-22-2002, 03:38 PM
#20
Senior Member
My Feedback: (23)
Join Date: Jan 2002
Location: Houston, TX
Posts: 3,227
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31 @8000 RPM (18X8)
You know, after I had a chance to compare the Ryobi 31cc with a "professional-grade" weedie engine, my enthusiasm for it dropped substantially. It just looks, well, cheap compared to the other dual ball-bearinged, dual counterweighted, precision machined engines. With as much as moeny and work as I've put into it so far, I'd have been better off getting a better grade weedie to start with.
I still think the Ryobi is a very good motor for RC conversion. When I convert another one, though, I will just do the new ring and standard CH ignition, and forget trying to hotrod it.
I still think the Ryobi is a very good motor for RC conversion. When I convert another one, though, I will just do the new ring and standard CH ignition, and forget trying to hotrod it.
