Topic: Stronger starter options for high compression or big bore motors

[Elan]

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[01Thomas]

Thanks DR

Any starter from a 1980-1983 DOHC will work.  This includes the 900 and Cb1100f.

[Don R]

 I drilled my stock cover and put a rubber grommet where the busa power lug sticks through. I'll have to get a picture. I was working on one bolt in a stock hole.

[PeWe]

I found a CB900 Hornet starter motor (Mitsuba SM-13) for a good price (28 Euro with shippping) so I had to check it in my CB750 K2 case waiting for internals and covers, everything is missing
I cut the mounting flange a little for easier fit. I cut one a little bit more than needed.

I guess I can drill a 3:rd hole in the middle of the 2 bolt holes on the motor.
A bracket is needed, about 5mm thick over the mounting holes in case, thicker where the motor will be mounted for good threads.

2 issues to solve:
1.) Pinion has 9 teeth only, the next gear must be found. HONDA CB600  HORNET has SM-13 motor too, gear look smilar as CB900 Hornet sc48. Need some machining to fit  I guess. Found a 14£ gear with shipping.
I hope the pinion will fit the CB750 starter gear I still not have, yet.

2.) 12V wire. It would be fine if I can route the cable as the OEM starter inside case and sidecover. Modified motor cover with more space for the connection that must be possible to shorten.

[gschuld]

Just an update.  I will be using Paul Cashio's well recommended services.

http://www.danddexhaust.com/dealers/paul-cashio-engineering

 Just sent two starters down to him to turn them into his "super starters".

Will give a full report when they are put into use.

George

[MRieck]

Just an update.  I will be using Paul Cashio's well recommended services.

http://www.danddexhaust.com/dealers/paul-cashio-engineering

 Just sent two starters down to him to turn them into his "super starters".

Will give a full report when they are put into use.

George

Paul is a nice guy to deal with and really knows his stuff. He did a 2 battery starter for Juha's GS for me.

[gschuld]

I agree.  Paul and I had a nice little conversation on Friday and he was kind and patient enough to answer my questions.  A no nonsense straight shooter, my favorite kind of guy!  We went over a few things and though his 24volt system is definitely what he recommends for the real big stuff, as in like 1500cc 13:1 compression ratio dragbikes, he admits it becomes much less important once you get "down" to 1000cc 10.5:1 compression motors.  He said that a proper capacity single 12v battery will be more than enough for what I'm doing, especially since I will not be running a total loss electrical system.  This way, single 12v battery, factory intact charging system, simple wiring.  Almost caveman like .  Basically, the 24volt system gives even more turn over rpm than his starters on 12v, which is supposed to be easier on the starter clutch in the long run.   

Anyway, I have read MANY glowing reports from first hand knowledge owners of his super starters, and basically ZERO complaints, so that's hard to say no to.  

Mike, I'll have a few things in the mail to you in the morning

George

[MRieck]

That's cool George. I finally got an oil pump in very good condition to put in the engine. The rotors on the one that came with engine were wiped out. I also found a later model output shaft (not the 77/78 piece with the larger bearing....that original 1 row would not live long.
 Just got the brown mains I needed...crank is in and things should go fairly smoothly (I hope).

[Elan]

Just to add for anyone looking to do this. If you are looking for a cb900 starter online, you'll notice they are listed as the same starter for the dohc 750.  As stated earlier, some are 800 watts and some are less.  They are the same Honda part number and same Mitsuba number : SM-220.  It came in 700w and 800w.
Most of the 750's seem to have the 700w version, and all the cb900 starters I came across were 800w.

Yes, they say in small casting letters what size they are but you can't really see that when browsing on eBay. Luckily, the 800w version has a big "438" cast into it. It also has a larger cylindrical shape that the 438 sits on.  It also has the fine print curved around the cylindrical shape. See pics below:

Standard sohc cb750  SM-226 (600w or 0.6kw)
- small cylindrical center
- straight fine print



Dohc cb750 79-82  SM-220 (700w or 0.7kw)
-same small cylindrical center
-same straight fine print aside from the wattage



Cb900-1000-1100 c/f  SM-220 (800w or 0.8kw)
-larger cylindrical center( probably because of larger inner bearings)
- fine print curved around center
- large "438" stamp


As for the reduction gear:

Sohc 750 has 16 teeth on the small gear and 47teeth on large gear.

Dohc 750-900-1000-1100 all have 15 teeth/46teeth.

Don't think about goldwings, shadows, or cbx as they allegedly spin the other way 

[Old Scrambler]

Elan...........Thanks for the info

So the CB900 starter not only has more wattage.........but a 6% gear-ratio advantage for the CB750 sohc motor. 

[PeWe]

0.7kW version is an upgrade too?

I noticed that most of the CB900 DOHC starters sold on eBay are the 0.7kW version.
I found a good looking CB900 DOHC -81 0.8kW version marked 438 complete with cable. Most of them are without cable.