Topic: My JMR ported F2 836cc engine is assembled!

[CB750R]

It’s been a long time coming but I can finally say I have my engine back in one piece!

I can’t thank Mike Rieck enough for the awesome head he built, and the parts he supplied and all the advice given along the way.

Big thanks to all of the forum members who’ve helped answer questions or make helpful posts on this forum, it’s a constant resource for information!!

A partial list of everything in the engine:

JMR F2 Portrd head,
new valves, hd springs, new retainers
Megacycle Cam
JE F2 836cc pistons (dynoman kit)
Carillo rods
APE lightened and balanced crank
APE clutch kit
Oil pump rebuild
HD studs and nuts
All new bearings, new HD primary and cam chain, new tensioners
All air passages hand filed to remove flashing/improve airflow.


Etc…

[RAFster122s]

Nice! Congratulations

[Jerry Rxman Griffin aka MuthaF'er]

Looks great. Hope it runs as good as it looks.

[Finnigan]

So cool, what's JMR?

[Leino]

So cool, what's JMR?

James Michael Rieck

[CB750R]

So cool, what's JMR?

Our friendly neighborhood superhero “MRieck” on the forum.

[Sam Green Racing]

CB750R, he built one for me and it wouldn't even top 165mph despite it putting out 98rwbhp.
Here's a link to a video of it, if it will play on here.
https://www.facebook.com/579151338763550/videos/695993873745962

[CB750R]

CB750R, he built one for me and it wouldn't even top 165mph despite it putting out 98rwbhp.
Here's a link to a video of it, if it will play on here.
https://www.facebook.com/579151338763550/videos/695993873745962

Sounds pretty quick!!

Of course first thing I had to do was test fit the sweet new Hindle system!

Ohhh man I can’t wait to fire this thing up!!

[Sam Green Racing]

CB750R, don't worry mate, you are in safe hands with Mike.
I was just having a laugh when I said it wouldn't top 165mph, it probably would if geared to do so.
The bike was geared right down for quarter mile drag racing with 16/52 sprockets, and stock, the bike was the slowest of all CB750s, it being a CB750A, better know as the Hondamatic, it only had 2 gears.
Mike helped me out a lot on my first build for a friend, although he didn't build the motor, he supplied some parts and a lot of useful info of what to do and what not to do.
When the bike was finished, He even came over to the UK to see it run, sadly the weather didn't play ball and we had to give up.
Here's a picture of my team with Mike in blue and the bike he helped build.

[richmagee7]

Congrats CB750R
I concur that Mike is a wealth of information, great advice, parts connections as well as incredible engine work.  I finally have my CB500 land speed bike together per Mike's head work and recommendations and just hoping the salt is dry this year so I can do him proud.
Rich

[CB750R]

CB750R, don't worry mate, you are in safe hands with Mike.
I was just having a laugh when I said it wouldn't top 165mph, it probably would if geared to do so.
The bike was geared right down for quarter mile drag racing with 16/52 sprockets, and stock, the bike was the slowest of all CB750s, it being a CB750A, better know as the Hondamatic, it only had 2 gears.
Mike helped me out a lot on my first build for a friend, although he didn't build the motor, he supplied some parts and a lot of useful info of what to do and what not to do.
When the bike was finished, He even came over to the UK to see it run, sadly the weather didn't play ball and we had to give up.
Here's a picture of my team with Mike in blue and the bike he helped build.

Haha thanks Sam, I figured there was a bit of sarcasm in your first post! I sweated the details assembling this engine, I did my best both skills and budget when I built the last motor for this bike, but with so many $$$ parts in this build I definitely had some trepidation assembling it myself. I guess we’ll see how I got on when I fire it up!

[CB750R]

It’s a runner!!
Link to short video of its first warm up. I am so so happy to hear this thing fire up again. It’s been 3 years since I pulled the motor and started on this full rebuild of the bike.
Can’t wait to button it up and test ride it!!

https://youtube.com/shorts/9Zm2yTJNaYg?si=S-6gnFbAfbpzoURZ

[Jerry Rxman Griffin aka MuthaF'er]

Nice!! Congratulations

[CB750R]

Nice!! Congratulations

Thanks!

[newday777]

It’s a runner!!
Link to short video of its first warm up. I am so so happy to hear this thing fire up again. It’s been 3 years since I pulled the motor and started on this full rebuild of the bike.
Can’t wait to button it up and test ride it!!

https://youtube.com/shorts/9Zm2yTJNaYg?si=S-6gnFbAfbpzoURZ

Wahoo!!! Sounds good 👍

[CB750R]

Thanks Stu! I still need to put the synch gauges on,  I think I got pretty lucky on “out of the box” setup on the carbs! Also got lucky with where I set the timing plate!

[MRieck]

Congratulations Grant. Sounds good and oil pressure looked real good. Don't let it idle to long and put a fan in front of the engine when synching the carbs.
 It will be fun to see the bike on a dyno!

[CB750R]

Congratulations Grant. Sounds good and oil pressure looked real good. Don't let it idle to long and put a fan in front of the engine when synching the carbs.
 It will be fun to see the bike on a dyno!

Thank you, good tip on the fan, I’m waiting for oil cooler parts, and some parts to make my Tintop “anti pod” filter setup work. I have a local customer with a Dyno I can hopefully get some time on to confirm AFR and dial things in after I get my butt dyno tuning done!

I’m glad to see 60psi start up, I’m using Motul 10w40 break in oil (jaso ma2) I gave the bearings and everything moving a slather of assembly lube or assembly grease when putting it all together so I think after some heat cycles and carb synch I will dump the oil and put more fresh oil in.

[Sam Green Racing]

Nice one Grant, it sounds awesome with that Hindle silencer.

[MRieck]

Nice one Grant, it sounds awesome with that Hindle silencer.

That engine is going to be great Sam....all the best parts...for sure. It's going to run hard for a long, long time.

[CB750R]

In the break in and tuning stage, I am happy to report the Mikuni RS34 out of the box from MikuniOz have been really good and easy to work on.

I have the pilot screws 1 turn out, 17.5 pilot jet, 125 mains I have raised the needle to the second lowest clip position, and so far the bike runs awesome. I haven’t explored tuning the main jet yet as I’m not ready for any WOT runs yet but it’s idling, cruising and accelerating all very well so far. No lean pops on deceleration no surging, no hanging idle… I have been fearing how hard it would be to set up an aftermarket set of carbs having struggled with the PD carbs in the past.

I did an oil change after my first day of running it in, which was a few warm ups in the shop, including getting the carbs synced and timing set. And 60km of total riding with several stops to cool down in that 60km.

Last night on fresh oil I did another 30km or so and bike is responding really well. I varied load quite a bit and putting a bit more load on the engine through 4-6k rpm, the motor is very smooth and really wants to spin up! I am extremely pleased how it feels so far!

[scottly]

Did you get the slipping clutch sorted?

[CB750R]

Did you get the slipping clutch sorted?

Yep… I was overly afraid of breaking another clutch lifter and under tightened the bolts. Snugged it all up used a bit more torque and it feels great. Was looking at my history on here and 19years ago I had similar problems. I guess when I’m mid 60’s I’ll be wondering why my clutch is slipping on install for the 3rd time…

[CB750R]

Working on my filter/intake setup.

I have one of the filters I believe Tintop made several years ago using an ITG filter/plate and had rubber intake boots.

The RS34 have a much larger intake so the old rubber ones wouldn’t work, I ordered some Chinese velocity stacks so I could modify the intake plate and plan to use some silicone hose to mount the plate to the carbs. I used my mill and a single point fly cutter as a “boring bar” and I shortened the velocity stacks by removing the mounting flange they came with. I thought rigid mounting this whole setup would be challenging at best and with vibrations not likely they’d stay on.

Due to the bellmouth size I had to hand file the edges to prevent them from over lapping. Happy to have my idea taking shape and glad to be able to continue using the filter setup that has worked so well for me so far.

[CB750R]

As usual it’s been a busy summer, I’ve had several full day rides on the 750 now and feel like I have it pretty dialled in.

I am really happy with how the engine feels! It pulls nicely and the Hindle sounds awesome! Really enjoying having my “Old girl” back on the road!

Really disappointed with Duplicolor engine paint adhesion. Aside from that I’m very happy with how this rebuild has gone and is functioning.

I keep grabbing the keys for the Honda instead of my KTM Duke 890r which says something!

My rebuild helped inspire my good friend to dust off his Yamaha Fazer 750 and get it running again and we’re doing a short road trip this weekend with a Royal Enfield 650 and a Honda 919, will be a fun group of bikes and guys to ride with, will post up some photos after the trip!