Topic: Newish rider upgraded to CB750K8

[MattCB750K8]

Been reading articles on here for a while, but without a CB seemed useless to join.

Been riding my 09 Suzuki TU250X for several years and decided it was time to step up to a little more road capable bike.

I have been considering a 500cc + bike for a year or so, I love the vintage look. I considered a 70's CB550/750, Triumph Bonneville T100, Royal Enfield Classic.
I originally was looking for 50,s bikes like AJS/Matchless Twins or Vintage Norton Commando and Triumph.
My dad convinced me to think of a slightly more modern bike, with electric start, modern type controls and a disc brake.
He rides a couple of newer Bonneville's (And he is 83) and in the past had a 1948 Triumph Speed Twin, CB550, BSA Royal Star, so I trust his advice.

I Hmmmed and hawwed a lot on the Royal Enfield Classic but the idea of another thumper kind of soured me, although it had the looks. Newer Triumph T100's have kind of the look I like.

I bought a nearly unmolested 78 CB750K8, everything original ( Except the 4 into 2 exhaust) and runs perfect, all electrics work and rode nicely.

I have decided to put a few hundred dollars and time into maintenance, new tires, rebuilding the brakes, etc.

The PO had the carbs rebuilt and synced. Kicks the first time even cold, idle rises after a few minutes. He had it idling a bit high, so I adjusted it to idle about 1050 when warmed up.

The tires where VERY old continentals 3.50/4.50 that had dry rotted badly, the front brake is hanging a little bit causing drag on the nose.

Today I ordered everything to completely rebuild the front and rear brakes, MC, Hydraulics, fluid change. also a new oil filter kit etc.

For tires I ordered the Metzler Lasetec's, mostly because the front is the correct 3.50-19 instead of the 100/90-19 which in my research is not even close to a 3.50-19 and I was able to match it to a 130/90-17 which is very close to original size. Both have the correct sidewall profile and are approved for the 1.85/2.50 rims.

I plan on keeping her stock as she is now. If I do like her a lot I may look for a CB550 or an earlier CB750, this is after all dipping my foot into the larger bikes.

Just want to say there is definitely a wealth of info here and I thank all that contribute their knowledge.

Matt

[MD]

Welcome from MN,

Remember that other members like to see pictures of your bike.

-MD

[MattCB750K8]

Ahh yes the all important photo op.

CB750k8 and pops 09 Bonneville in the background.

[Stev-o]

Welcome from Texas.  I had one just like that but mine had the original exhaust.

BTW - pretty sure the OEM front tire was 3.25-19", but 3.5 will be fine.  I run a 100/90mm on my K4....

[MattCB750K8]

I spent a few days researching the front tire. in 77 they gave the CB750k a bump from 3.25 to 3.5, my manual also states the tire is a 3.5.....your right either are fine though as its the same 19" 1.85 rim as the k6 and earlier.  The funny issue is though, a 100/90-19 is supposed to be equal to the 3.5, but all the manufacturers data says the 1.85 rim is not approved for it and a 2.15 is the minimum. Its probably not a big deal though as I have read most run the 100/90 with no issues.

[flybox1]

Very clean K8 
Welcome from Seattle....

[Desert-SOHC]

Howdy...78's are the fastest......

If you want to get rid of those pipes...I call dibs!

[BobbyR]

Greetings from NY. K8 owner also.

[Desert-SOHC]

I run 100/90 on the front and a 130 on the rear.

[mt-ac]

I spent a few days researching the front tire. in 77 they gave the CB750k a bump from 3.25 to 3.5, my manual also states the tire is a 3.5.....your right either are fine though as its the same 19" 1.85 rim as the k6 and earlier.  The funny issue is though, a 100/90-19 is supposed to be equal to the 3.5, but all the manufacturers data says the 1.85 rim is not approved for it and a 2.15 is the minimum. Its probably not a big deal though as I have read most run the 100/90 with no issues.

Thanks for posting about tire sizes, this is something else I definitely need to replace on my 77'.