Topic: What’s Wrong with my Honda cb750K8?

[BenelliSEI]

There’s a very nice looking K7 on BAT this week. It will be interesting to see where it gets vs the $8-12 the earlier bikes have been hitting regularly.

[denward17]

It is a clean example, be interesting to watch.

[Stev-o]

Years ago, I picked up a K8 for a song, it was one of the last ones manufactured. It was totally stock and in great condition, always ran great, never an issue.  But to me, I found it just a little too "vanilla", didnt love the shape of the tank and especially the exhaust, way too quiet [my other bike at the time was my 836 K4 with Action Four exhaust, sounded awesome]. 
I found myself not riding the K8 so put it up for sale, sold for $2500 to the parts manager of the local Honda dealer.

[BenelliSEI]

Steve….they are quiet. My buddy Gary bought a new replica set for his and that’s what we noticed the most. Beautiful pipes and they cost just about 1/2 what the HM300’s sell for. Go figure.

[HondaMan]

They are quiet!
I still have a set of 3 mufflers (1,2 & 3) with an extra #3 muffler from a 'blind purchase" I did some years ago for 2 'full sets' of the mufflers for a K8 I was restoring. If anyone needs some nice mufflers, except #4, or maybe has 2 bikes that need a #3, they are for cheap...

[rotortiller]

I have a 77K with 55,000 miles and the original untouched engine. It does not burn oil but now I am wondering what the valve guides might be like since it has been suggested that they fail after 10,000 miles or so. If this is the case I would think I am well past my 'best before date' and should be seeing some physical symptoms of being well beyond wear limits? Or is it just another thing that gets blown out of proportion? Instincts and CDF say keep on riding.

[BenelliSEI]

No smoke, no fire. Ride it! I did the guides and valves (pistons and rings too) at 36,000 miles and only because I had it on the bench.

[PeWe]

Bad guides will smoke.... Sooty plugs.
If tire smokes, throttle with care
Ofreen's bike has done many miles without head job.
Not too thin oil and without overheating.

[denward17]

BAT bike (K7) went for 7K......that's good money...

https://bringatrailer.com/listing/1977-honda-cb750k-14/

[HondaMan]

I have a 77K with 55,000 miles and the original untouched engine. It does not burn oil but now I am wondering what the valve guides might be like since it has been suggested that they fail after 10,000 miles or so. If this is the case I would think I am well past my 'best before date' and should be seeing some physical symptoms of being well beyond wear limits? Or is it just another thing that gets blown out of proportion? Instincts and CDF say keep on riding.

Rotor: if you got one with the Stellite guides (there were some that came from the F0 leftovers) they can last for over 100k miles - my Stellite guides went 131k before they got to the wear limits. It's the simple cast-iron ones that Honda used to cut costs in the later bikes that wear out so fast. It usually starts by showing oil around the exhaust pipe headers, next to the 'flower' clamps. Soon after that the front of the engine starts showing greasy spots, and then it just gets wet and messy. I have seen Stellite guides in K7 and K8 heads, but they are not common by any stretch. They have a unique color, a sheen-like dark grey. They are brittle: I've seen many of the original K0/1/2 versions with chips on their tops when there were no seals on the exhaust guides. Even my own (I think it was #3 exhaust) had a chip on the inner edge of it.

[spotty]

my 'trailbike' K7 that is getting ever nearer completion has solved many of the original problems that the bike suffered from

i'm not using any of the original bodywork, so it's not as ugly as a monkeys arse anymore

i've replaced the p1ssweak front brake with a 300mm wavy disc and 4 pot caliper

the forks have been replaced with longer stronger ones

its got 'fatbar' mx bars on

much simplified (and modern) electrics including gps speedo so i don't have the unsightly cable, tacho is gone for that matter

i could go on but modesty prevents me....

someone here in melbourne ( in carnegie to be precise, are you out there mystery K7 lover ) as i sold another rolling K7 with both sets of bodywork to one guy

[BenelliSEI]

Spotty…… are you suggesting your K7 is now a “thing of beauty”?

[spotty]

Spotty…… are you suggesting your K7 is now a “thing of beauty”?

maybe not 'of beauty' but i sure do prefer it, and i'd like to think i'll get less old farts coming over to talk about the one they had that was just like it when they were younger

[BenelliSEI]

Spotty…… are you suggesting your K7 is now a “thing of beauty”?

maybe not 'of beauty' but i sure do prefer it, and i'd like to think i'll get less old farts coming over to talk about the one they had that was just like it when they were younger

Good point! How’s it coming along?

[spotty]

got the shocks i wanted ( koni alloy bodies ) and a new delkevic exhaust, new and better fitting seat, major jobs still to do are paint and electrics, talked to my tame bike auto elec the other week and he doesn't want to do it the way i want to ( remote battery isolator, led lights, gps speedo, no elec start etc ) so i may have to seek a more amenable sparkologist. paint i want to try myself before admitting defeat and paying to get it done at work ( toyota dealership with a paint and body shop)

i did get a pair of new 18" akront alloy rims at a swap meet so i'm looking forward to killing the road/trail knobbies quickly and then converting ( the wheels at least ) to supermotard specs

[RAFster122s]

I think my sit bones are wider as a bicycle std seat kills me ... I put a cushie Schwinn wide saddle seat on the bike and the more upright riding I set the bike up for it is very nice...
But the right hip won't let me ride a bicycle the past few years...

[madmtnmotors]

Spotty…… are you suggesting your K7 is now a “thing of beauty”?

maybe not 'of beauty' but i sure do prefer it, and i'd like to think i'll get less old farts coming over to talk about the one they had that was just like it when they were younger

Nope, still happens everywhere I go with the K8.