Topic: Blackfin CB750 F1 BLASTER

[Blackfin5]

Don & Cal - thank you for the BOTM nomination.  Very cool just to be nominated by you guys.

Technically, the bike is not finished. The headlight rim was PC in gloss black.  Picking up today and will install rim and headlight this afternoon and post new pics.  Was going to install a truck LED headlight, but I can't because it won't fit in the OEM style bucket (switched to metal but same shape) with the wire bird nest.  I have to wait until I find extended headlight ears to fit a larger, Triumph-like, cone bucket.

I really, really like riding this bike - stable and fast, even if I can't throw in into the corners like my suspension upgraded 550.  But it handles VERY well for an old girl.

Bit concerned about oil temp.  Can you guys recommend an oil cooler which fits well and works for these 750s?  I also want to pick up a motor mount oil temp gauge.

Cheers!

[SOHC4 Cafe Racer Fan]

Kevin,

An oil cooler can't hurt.  I am running a Setrab on my new bike, but my Nine Lives K7 is cooler-less. 

Check out Seth Hawkins' Pro One cooler on his 750 build (page 5) -- http://forums.sohc4.net/index.php?topic=131294.100
It's a trick looking cooler with a thermostadt built in. 





A pressure gauge is a good call, too.

[Blackfin5]

I run Maxima 20/50 Syn blend.  Thanks for the cooler suggestions.

[Blackfin5]

These may be last pics for a little while.  Headlight in and working.  Need to focus on completing the 550.

[SOHC4 Cafe Racer Fan]

Kevin,

How far are you from Julian?  I ride up to Palomar and Julian a couple of times each year.  The mountain roads are tight up one side and fast sweepers down the back side (to Palomar) and then we head to Julian for some late lunch.

Don

[Blackfin5]

I'm right there - on Hiway 78E near the junction of Hiway 79 going to Palomar.  About 4 miles west of Dudley's Bakery.  Ride to the Apple Restaurant for breakfast almost every weekend.

[Blackfin5]

I think the Seatrab 107 (50-107) is the correct cooler for this bike but it doesn't appear on the web site.  If I can't find a 107 should I go with the most compact available?  They list by HP and even the smallest is for 70-100 hp.

[SOHC4 Cafe Racer Fan]

If memory serves me correctly, I bought the 1 series:
http://www.setrabusa.com/products/oilcoolers/engine/index.html
100-150 50-119-7612 8.27 5.75 2.2/2.6 13,000-17,500

[Blackfin5]

Thanks, Don.  Looks about perfect.

[Blackfin5]

Did the Ton this morning on the Blaster on a long straight on my back roads.  A couple observations:

1.  Bogged a bit hitting about 7000-7500 rpn then cleared.  May be the needles?

2.  Very stable.  Impressed with the BT-45s.  Glad I went with 110 ftont and 130 rear.

3.  Braking is weak, spongy even with rebuilt MCs front and rear and SS brake lines.  Need to put some thought in here.

4.  Some popping on decel - not too bad.  Makes sense with the gpmotowerks pipes (stock airbox).  Seems lean and hot running.

Other than that, can't wait to drop in an 836, JMR head and new cam for better acceleration.

Cheers!

[brandEn]

Nice. That's a great feeling isn't it?

[Blackfin5]

Yes - it - is !   Was riding to breakfast at an inn out in the country.  It felt great.  Even after hitting 100, I still wanted to go faster.  Still a big 550 homer but liking this bike.

[Blackfin5]

Will going up 1 or 2 mm in the front MC improve braking noticably; or just minimally and really only make the brake lever firmer?  I would like to stay with the OEM caliper but I kind of know I will need to go with a dual piston set up.  Are there any bolt on conversions using my stock forks?

[SOHC4 Cafe Racer Fan]

Hi Kevin,

There's one sure fire conversion that will leave you period correct, yet improve braking power.  Swap the front forks, triples, brakes, rotors, axle from a 1975-77 GL1000.  Something you might want to consider for the future, at least.  You can find bargains for the complete front end and then do a direct swap. 

However, given the amount you've put into your existing front end, and that you've just completed it, I would not do that anytime soon.

Another option is to swap out your existing stock MC for an aftermarket that can push some additional fluid.  That said, I went with a slightly larger and radial MC on my 550 and it still felt spongy until I added the second caliper.

The third option is what you have going on with your 550 -- add another caliper and rotor from Goddfrey.

Don

[Blackfin5]

Option 1 definitely in the future, but as you said, just finished and want to enjoy riding for a while until I commit to the 836/JMR Phase 2.
 
Option 3 is do-able now.  I just ordered a 2nd 550 dual disc package from Godffrey for my mate's black bike.  So I may as well have Jeff include a  dual kit for the 750 at the same time.  Will still need to upgrade the MC.

Thanks, Don!

[SOHC4 Cafe Racer Fan]

Option 1 definitely in the future, but as you said, just finished and want to enjoy riding for a while until I commit to the 836/JMR Phase 2.
 
Option 3 is do-able now.  I just ordered a 2nd 550 dual disc package from Godffrey for my mate's black bike.  So I may as well have Jeff include a  dual kit for the 750 at the same time.  Will still need to upgrade the MC.

Thanks, Don!

If you go dual stock disc, yes, I would still recommend upgrading the MC. 

If you really want to flaunt the classic, period looking MC, then this is bad-a$$:
http://www.apracing.com/product_details/motorcycle/classic_range/classic_master_cylinders/front-cp2215-90.aspx

[brandEn]

Or use a MC from an F2-F3 or a early Goldwing. Dual discs on both my bikes and I am happy with the stopping power...(when they are running,heh)

[SOHC4 Cafe Racer Fan]

Yeah, at $544 for the AP Racing MC, that's insanity -- you can already buy a Brembo 19RCS, almost two of them!!!

The GL MC should work well, as it's designed for larger dual piston brakes - and it IS period correct.  If modern doesn't bother you, you can also pick out a Nissin radial MC cheaply.

[MRieck]

Yeah, at $544 for the AP Racing MC, that's insanity -- you can already buy a Brembo 19RCS, almost two of them!!!

The GL MC should work well, as it's designed for larger dual piston brakes - and it IS period correct.  If modern doesn't bother you, you can also pick out a Nissin radial MC cheaply.

I have one of those sitting on my shelf Don
http://www.apracing.com/product_details/motorcycle/master_cylinders/pull_type_adjustable_ratio_master_cylinders/variable_ratio_type-cp4125-26.aspx
It will probably end up on the CB. I traded it for some work.

[brandEn]

Wow those are pricey. Are those MotoGP quality or something?

[SOHC4 Cafe Racer Fan]

Wow those are pricey. Are those MotoGP quality or something?

AP Racing parts are very high quality.  The Classic line is not so much high performance by modern standards but much improved over classic parts and the design is from period pieces made by AP back in the day.  Like these old calipers:


The performance braking parts that they make for modern bikes are excellent -- on par with modern Brembo gear.

[Blackfin5]

Nice options.  Definitely worth consideration when I go with the 836/JMR next phase.  Once my 550 is finished, I may start sooner than I anticipated.

[SOHC4 Cafe Racer Fan]

Wow those are pricey. Are those MotoGP quality or something?

Kevin,

The GL front end swap provides great bang for the buck.

[Blackfin5]

I bled the SS line after a bunch of riding.  No air bubbles at all.  I'm thinking some air must be trapped in the splitter.  My orange 550 with OEM lines stops better and feels firmer.  Tapped on splitter and pushed fluid up thru the bleeder too.  Same.

[Buxcustoms]

Hey, I'm fairly new to this forum.  I just bought a 76' cb750.  I really enjoyed reading thru your build! I will definitely use this as a reference for parts and info.  I hope Jazzy made a full recovery!!