Topic: 1976 CB750K6 - Time to Re-Tire

[jchilper]

I'm wondering if anyone has ever tried to remove the rear tire on a CB750 (with four into four exhaust) that was oversized? The PO put a 130/90/18 on it and ground clearance is pretty tight when the bike is on the center stand. I recall (from a long time ago) when I removed the front wheel I had to remove the rear shock lower bolts and slide them to the rear just to get the front forks clear of the front axle. So I'm thinking of parking the center stand on a piece of 3/4" plywood to get a little extra height. Anyone ever tried this?

[PeWe]

My bike is parked on sidestand.
Under right foot peg, a jack stand it will land on when pumping up the left side with a jack under the foot peg.

Careful to not hit engine case or gear shifter. Ensure that jack stand is propery placed while pumping up on left side so it will land on footpeg, not hitting the exhaust.

Photos here on my K6 with 4-2-1.
I have done this when bike had 4-4, several times.
When lifting front it need a wooden plank pressing engine up, rear wheel down.

A wide tire as 130 need the drive chain case removed before.
The brake stopper arm is probably bent or mounted sideways on the under side of swingarm to avoid the rear tire.

If you use stock 2.15-18 rim, use stock tire size 4.0-18, nothing wider, it does not work well.

If you like 120 tire, go wider on rim. I'll do that on my K6 build, see my link to project forum.

[jchilper]

I should have mentioned I'll be replacing that 130 tire with a stock 120/90/18 on a new rim. Interesting leverage method.

[PeWe]

120/90 is not stock, too wide for CB750 stock 2.15"  rim which you will see when it will be flatter earlier with horrible handling in curves. My worst example got bad handling after 3500km, replaced at 4500km.

4.0 is stock and will last longer with better handling until time to change.
I have tested and verified it on different brands.

Also read what others have written about it.
120/90 need minimum 2.5", 2.75" as recommended rim width.

[jchilper]

Sorry - I "really" did mean the 4.00 x 18. It'll be a Dunlop D404. I put those on my 550 last year and really like the ride.

So - another thought to getting that old fat tire out is to remove the rear fender - the chrome part including tail light and grab bar.

PeWe - I also did notice the brake drum stay was bent to accommodate the 130/90/18 tire on there now. Why do folks always want to fix what's not broken? Hopefully I can bend it back without too much difficulty.

[PeWe]

I use a jack and pump up rear as much as needed. Chain guide to remove.
Maybe I had to remove the 2 bolts holding fender to frame hoop, so it could be tulted upwards when releasing the 2 orher a little. Fender not off.

Bending that rod was very common here in the 70-80's.  I guess worldwide!
As wide rear tire as possible

130 needed to make brake stay to not touch the tire. I also bent mine.
I learnt much later that mount it at the side of the swingarm mount did not need any bending.

Problem to fit chain guide too with 130 tire.

Use the stock tires on stock rims is also late for me. I have read about better handling with stock tires.
But it took a while for me to admit it. Boring when handling become bad early, before rear tire is worn out.
4.0 does not look silly slim either

I have now used a few 4.0-18 and seen that handling stays OK until it is worn out.
As the old farts have written for years on Honda, Kawasaki, Ducati and BMW forums using stock tire sizes on stock wheels, especially BMW.

My last 120/90 bought last year just to test that tires dual compound, harder rubber in the middle and if it will stay better longer.

[Jimcg]

John, let the air out of the tyre before trying to remove the wheel from the bike might help. Maybe you already tried that or it didn't make a difference.

/Jim

[Stev-o]

John, let the air out of the tyre before trying to remove the wheel

+1....let air out, that will reduce the width of the tire.  And use a 2x4 instead of plywood, that will give you a 1.5" height increase.  No problem!

PS. I run 120/90 on my K4 without issue

[andy750]

This is a very timely post for me as Ill soon remove the 130-90-18 Bridgestone Accolade tire I put on my extra wide Buchanan rims on my stock K2 (4-4 pipes). All great ideas I will also follow!

thanks
Andy

[PeWe]

An old tire not fun to remove from rim.
My old Metzeler ME99 130 tire had to be cut off after 20 years. I used a saw...