Honda NT1100

[halfSpinDoctor]

I've said it before, but I'll say it again for those new to the 1100 Unicam motor.
The 1100 is a nice enough motor, but be prepared for large maintenance costs when it comes to valve inspection.
The exhaust valves are adjusted by screw and nut, just like the NC750.
But the intakes are direct cam action with shimmied adjustment.
If the intakes need shimming, the exhaust side rocker arms must be removed in order to remove the single cam for shimming.
That isn't all that crazy, but the fairing, gas tank, and radiator must be removed to access the cylinder head.
On the Africa Twin, there's 2 radiators to remove. But it looks like only 1 on the NT1100.
Valve adjustment is scheduled every 16k due to the rocker armed exhaust side.
If using a dealer, this would be an expensive valve inspection, and if adjustment on the intake side is necessary, be prepared for a very large bill.
This is just an FYI post, not looking for any arguments.

I was just having a convo with my friend and fellow NC700 rider and we were not sure if the valves were screw-style or shimmed on the AT. Given exhaust is more likely to get tight over time, this is at least a somewhat okay compromise.

 

[brb]

New Concept really means shared components what the Auto Mfgs have been doing forever. With all the different models we have with the 700/750s it looks like Honda is doing the same with the 1100 twin now. Not really cutting edge just altered to appeal to a more riders. I think Ill wait for the NC replacement. 850 engine? Direct Injection? Turbo?(come on Honda you did that in the 80s with your CX500T/650T). Just dont forget the Frunk that really was a game changer.

 

[the Ferret]

Is the seat comfy? Haha. I read that as a rhetorical question.

I'm pretty sure it could be the most comfortable seat in the history of motorcycles and half the people would still say they can only ride on it for 50 miles and want a custom seat. Same goes for the windshield and suspension components, any of which replacing would " transform the motorcycle"

 

[bigbird]

Sure, there is more service time involved with checking and/or adjusting them compared to stone age screw & lock nut tappets but the advantages of shim under bucket valve trains far outweigh the disadvantages. That's why valve trains like that of NC are an anachronism in 2021.

That's funny.
Did you know that Honda still uses stone age screw and lock nut tappets on their inline 4 and V6 3.5L automotive engines?
In fact, it's the identical method used in the NC750; a SOHC with 4 valve head.
That V6 still uses a timing belt, not even a chain!

My 4 cylinder Subaru Boxer engine is DOHC and uses shim adjustment.
The nice thing abut the Subaru is that no valve inspections or adjustments are necessary for the life of the engine.

It makes me think Honda cheaped out on all their automotive engines when they could have gone the DOHC with hydraulic adjustment route like Toyota did with every one of their engines.

 

[dduelin]

That's funny.
Did you know that Honda still uses stone age screw and lock nut tappets on their inline 4 and V6 3.5L automotive engines?
In fact, it's the identical method used in the NC750; a SOHC with 4 valve head.
That V6 still uses a timing belt, not even a chain!

My 4 cylinder Subaru Boxer engine is DOHC and uses shim adjustment.
The nice thing abut the Subaru is that no valve inspections or adjustments are necessary for the life of the engine.

It makes me think Honda cheaped out on all their automotive engines when they could have gone the DOHC with hydraulic adjustment route like Toyota did with every one of their engines.

Cars and motorcycles place different demands on engine design and component packaging. Many cars, including late model Hondas, still use screw and lock nut tappet valves but we were discussing motorcycles here.

 

[bigbird]

Cars and motorcycles place different demands on engine design and component packaging. Many cars, including late model Hondas, still use screw and lock nut tappet valves but we were discussing motorcycles here.

Thanks for pointing that out.
I thought we were discussing stone age Honda NC750 valve actuation technology and the stone age half of the NT1100's valve actuation technology.
Silly me.

 

[brb]

Yes the price we pay for high tech is high price, buying and maintaining. The great thing about buckets is the valves do not get side loaded that wears out valve guides. The 80s Honda had shims above the buckets(no pulling cams). They even used hydra. fulcrums in the Shadow and Nighthawk models. When you want to save weight and size (don`t forget about friction losses) those design parameters out way maintenance costs.

 

[BFair]

Great evaluation of valve operation and wear. I can attest to replacing many valve guides on BMW airhead and one CB350 motor. The bigger 2 valve motors are prone to wear as does the valve rocker arm tips. Not so much on 4 valve heads unless lubrication issues exist.

I'm not aware of any roller rocker setups on a motorcycle, which have their own failure issues in attempting to combat frictional losses.

 

[dduelin]

Great evaluation of valve operation and wear. I can attest to replacing many valve guides on BMW airhead and one CB350 motor. The bigger 2 valve motors are prone to wear as does the valve rocker arm tips. Not so much on 4 valve heads unless lubrication issues exist.

I'm not aware of any roller rocker setups on a motorcycle, which have their own failure issues in attempting to combat frictional losses.

The NC 700/750 engine has a hybrid sort of rocker arm - the lifter riding on the camshaft has a roller bearing to combat friction loss.

Perhaps BMW airhead valve guide wear was more a product of metallurgy rather than design. The later 1100, 1150, & 1200 twin cylinder engines don't seem to have valve, valve seats & guide wear that airheads had during the early years of lead free gasoline. My 1981 R100 required the valve seats replaced as well as 1 of the needle bearings in a rocker arm. The valve seats were recessing by 75,000 miles. After all that was replaced the valve clearances stayed remarkably stable for the next 45,000 miles. My 1200cc boxers have been much the same. Though the valves require checking every 6,000 miles it's often 18 to 24,000 miles before an adjustment is needed.

 

[wheel_of_steel]

I've said it before, but I'll say it again for those new to the 1100 Unicam motor.
The 1100 is a nice enough motor, but be prepared for large maintenance costs when it comes to valve inspection.
The exhaust valves are adjusted by screw and nut, just like the NC750.
But the intakes are direct cam action with shimmied adjustment.
If the intakes need shimming, the exhaust side rocker arms must be removed in order to remove the single cam for shimming.
That isn't all that crazy, but the fairing, gas tank, and radiator must be removed to access the cylinder head.
On the Africa Twin, there's 2 radiators to remove. But it looks like only 1 on the NT1100.
Valve adjustment is scheduled every 16k due to the rocker armed exhaust side.
If using a dealer, this would be an expensive valve inspection, and if adjustment on the intake side is necessary, be prepared for a very large bill.
This is just an FYI post, not looking for any arguments.

Experience and a stubborn attitude means I like to fix my own stuff at home.

My old yamaha trx850 had a shim-under-bucket 5 valve head. That experience has put me off shim-type valvetrains for good. The constant camshaft removal, shilly shallying measuring, calculating, swapping, and sourcing new shims, and then subsequent carburettor balancing was a dreary and tedious millstone around the neck of the home mechanic. The TRX was renowned for valve seat recession and mine was no different - by 40k miles I was down to the thinnest available shims on the intake, next stop head rebuild.

By comparison, my NC has the same mileage now, and the screw-and-locknut valvetrain has only needed the occasional 1/16th of a turn on the adjuster, the plastics and electronics will crumble long before this cylinder head wears out.

I'm sure the 1100 is fine in the same way an old lexus or a 777 is fine: well made and unlikely to break, but come overhaul time, hand your wallet to the nice mechanic in the embroidered labcoat for authorised service.

 

[dduelin]

Experience and a stubborn attitude means I like to fix my own stuff at home.

My old yamaha trx850 had a shim-under-bucket 5 valve head. That experience has put me off shim-type valvetrains for good. The constant camshaft removal, shilly shallying measuring, calculating, swapping, and sourcing new shims, and then subsequent carburettor balancing was a dreary and tedious millstone around the neck of the home mechanic. The TRX was renowned for valve seat recession and mine was no different - by 40k miles I was down to the thinnest available shims on the intake, next stop head rebuild.

By comparison, my NC has the same mileage now, and the screw-and-locknut valvetrain has only needed the occasional 1/16th of a turn on the adjuster, the plastics and electronics will crumble long before this cylinder head wears out.

I'm sure the 1100 is fine in the same way an old lexus or a 777 is fine: well made and unlikely to break, but come overhaul time, hand your wallet to the nice mechanic in the embroidered labcoat for authorised service.

Metallurgy has come a long way in 25 years and experience does not always carry across motorcycle brands. Shim under bucket valves in various Hondas I've owned from 2003 on are remarkably stable over time. In 180,000 miles my ST1300 only had one valve stray from allowed clearances and in 105,000 miles my Goldwing valves are all still in spec.

Modern machines are moving in the direction of special tools and equipment requirements not often owned by the DIY owner. The only way to avoid it is to stay with older machinery or new vehicles that continue to use older technology. Myself I think I could handle checking the valves on the NT engine and based on experience they are not likely to need attention other than checking for a long time to come.

 

[wheel_of_steel]

Modern machines are moving in the direction of special tools and equipment requirements not often owned by the DIY owner.

That's the truth - industry and customers place too much focus on first ride reviews, showroom appeal, and gee-whiz doodad marketing. Holistic long term ownership has gone out the window.

I don't know about goldwings, but I've personally done the valve adjustments (with shims) on the following bikes and cars; it was a needlessly bad experience every single time:
-Kawasaki klr 250
-kawasaki z800
-kawasaki ninja 250
-suzuki tl1000s
-suzuki gs500
-suzuki gsxr 125
-honda vtr 250
-triumph sprint st 955i
-yamaha trx850
-suzuki alto 1000
-daihatsu sirion 1000
-toyota echo 1300

I avoid shim-type valvetrains like the plague, even worse is the new trend of the integrated shimbucket, featured on the alto and the echo, and most subarus. You cannot buy a ~$100 hotcams shim kit, each shimbucket needs to come from the dealer, which might be a 3 month wait due to covid + JIT supply chains.

I certainly wouldn't buy an nc750 with a unicam head.

 

[the Ferret]

Metallurgy has come a long way in 25 years and experience does not always carry across motorcycle brands. Shim under bucket valves in various Hondas I've owned from 2003 on are remarkably stable over time. In 180,000 miles my ST1300 only had one valve stray from allowed clearances and in 105,000 miles my Goldwing valves are all still in spec.

Modern machines are moving in the direction of special tools and equipment requirements not often owned by the DIY owner. The only way to avoid it is to stay with older machinery or new vehicles that continue to use older technology. Myself I think I could handle checking the valves on the NT engine and based on experience they are not likely to need attention other than checking for a long time to come.

The exact reason all the most of the major players, Honda, Suzuki, Kawasaki, Yamaha, Triumph, have gone to the shim under bucket valve arrangement. They rarely need adjustment, unlike the screw and nut valve adjustments which needed adjusting frequently. Sure it's harder to do the shims but rarely do the cams have to come out.

 

[bigbird]

I certainly wouldn't buy an nc750 with a unicam head.

I wouldn't buy anything other than a Goldwing with a Unicam head.
On the Goldwing, the intakes will very rarely if ever require shimming, and the screw and locknut exhausts are a piece of cake to access and adjust.
The NT1100 or AT, not so much.

 

[mzflorida]

Regardless of any of the designs, I am really hoping that this comes here to the USA for me to consider as the new baby. It just looks like a nice bike that may be even more enjoyable to me than was my VFR.

My two daughters are both on their own now; one in Orlando and one in Miami. Looking forward to some weekend rides to visit with them.

 

[davidc83]

The exact reason all the most of the major players, Honda, Suzuki, Kawasaki, Yamaha, Triumph, have gone to the shim under bucket valve arrangement. They rarely need adjustment, unlike the screw and nut valve adjustments which needed adjusting frequently. Sure it's harder to do the shims but rarely do the cams have to come out.

Really, my 2013 Honda NC700x has 62,000+ miles and every valve inspection, the valve clearance is in specs....in the middle-no, but within specs (just checked at 60,000 miles). My 2007 Suzuki C50 Boulevard (also screw and nut), has 102,000 miles and the valve clearance has never been adjusted....Checked every 3,000 miles (following Suzuki's recom...) up to 27,000 miles, always in spec....I went from 27,000 to 100,000 miles without checking,,,checked at 100,000 miles,,,,still within specs (not in the middle but within specs)..... the 2009 BMW G650gs, the cam had to come out and it was a frigging PITA....never will I buy another bike with shims....So the nt1100 is off the check list....

 

[670cc]

Really, my 2013 Honda NC700x has 62,000+ miles and every valve inspection, the valve clearance is in specs....in the middle-no, but within specs (just checked at 60,000 miles). My 2007 Suzuki C50 Boulevard (also screw and nut), has 102,000 miles and the valve clearance has never been adjusted....Checked every 3,000 miles (following Suzuki's recom...) up to 27,000 miles, always in spec....I went from 27,000 to 100,000 miles without checking,,,checked at 100,000 miles,,,,still within specs (not in the middle but within specs)..... the 2009 BMW G650gs, the cam had to come out and it was a frigging PITA....never will I buy another bike with shims....So the nt1100 is off the check list....

You make an excellent point about your screw and locknut motorcycles never requiring valve clearance adjustments. You also mentioned the BMW being a PITA to adjust, but did the BMW need adjustment or not need adjustment?

 

[the Ferret]

I worked in the mc industry from 1972-1989 when screw and nut valve adjustments were the norm and we adjusted lots of valves. Maybe better materials and machining have made it so they don't require adjustment as frequently. That's good, since this is my first screw and nut adjustment bike since my XS 650 Yamahas. Some I had before my last few bikes were shim on top of bucket but for some reason the mfgs got away from that system. I know with shim under bucket my ST 1300 110,000 mi, my FJR 38,500 mi or my CB 1100 63,000 mi, none of them have ever needed a valve adjusted.

I know with Beemers flat twins a supposed selling point was it was a simple job to adjust the valves (screw and locknut). I wonder what BMW uses on their K 1600 and XS 1000 models

There must be SOME reason why almost every mfg uses shim under bucket now? I'm sure someone smarter than me could explain why.

 

[670cc]

I worked in the mc industry from 1972-1989 when screw and nut valve adjustments were the norm and we adjusted lots of valves. Maybe better materials and machining have made it so they don't require adjustment as frequently. That's good, since this is my first screw and nut adjustment bike since my XS 650 Yamahas. Some I had before my last few bikes were shim on top of bucket but for some reason the mfgs got away from that system. I know with shim under bucket my ST 1300 110,000 mi, my FJR 38,500 mi or my CB 1100 63,000 mi, none of them have ever needed a valve adjusted.

I know with Beemers flat twins a supposed selling point was it was a simple job to adjust the valves (screw and locknut). I wonder what BMW uses on their K 1600 and XS 1000 models

There must be SOME reason why almost every mfg uses shim under bucket now? I'm sure someone smarter than me could explain why.

My guess, and it's only a guess, is that shim under bucket reigns because it is compact and light weight. It takes up less space than screw/nut rocker arms, has fewer moving parts, and the lower mass enables higher speed valve actuation.

I had shim over bucket on my old Suzuki GS series bikes. It required no cam removal to change shims. But, compared to shim under bucket, it was bulkier and heavier.

 

[dduelin]

My guess, and it's only a guess, is that shim under bucket reigns because it is compact and light weight. It takes up less space than screw/nut rocker arms, has fewer moving parts, and the lower mass enables higher speed valve actuation.

This is my understanding.