cam chain tensioner

[PhillipLarsen]

Thanks Phil, will go with sealant as you recommend. Any particular type you would suggest?

[Lucky Phil]

1 hour ago, PhillipLarsen said:

Thanks for the info Pete. The issue I am having is with the blade off the base / pin, when I go to place and bolt the base in place I cannot as it cannot lay flat due to the difference between the plane the base mounts on and the case pad under the aft end of the pin. About 4.5mm difference. 

This might help

https://wildguzzi.com/forum/index.php?topic=104650.30

[PhillipLarsen]

Thanks for the link Phil. That is exactly the issue, and although they show an older model Guzzi where the original tensioner pin attaches to that pad and the newer 2004 v11 the tensioner pin just rests against that pad, the pad needs to be relieved 4.5mm plus 2.0 mm for the end of the new tensioner pin. 
Looks like a lot of dremel work. 
I am going to check if the other aftermarket tension would avoid the need to remove material from the case. 
If I end up doing the surgery it will be like when getting an eye lens replaced, with complete sealed protection covering and enclosing the timing case area with only the area of work exposed to avoid any material contaminating the engine. 

[PhillipLarsen]

Update, I contacted HMB. They sell both types of tensioners, their beefed up version of the MG one and the blade style. They recomend their beefed up one, but also say the other works as well.

They said that the HMB design fits exactly as the original and no case machining or grinding required.

I am ordering one to see what it looks like and will decide which way to go once I have both on hand in about 10 to 14 days.

Thanks Phil and Pete for your expertise.

Will post the outcome in a few weeks.

[pete roper]

Looking more carefully at the pics posted I can see the problem. It looks as if by the time your crankcase was made they had started using the newer pressure die cast moulds for the crankcases. I thought the change over happened at the time of the CARC bikes but obviously it predated that. Now I’m not sure, I’ll have to check, but that annoying boss on the case might be a there for the oilway drilling for the under piston sprays on the 8V motor, (As I’ve mentioned before, a lot of modifications are put in train many, many years before model launches.).

 

I have an 8V case on the bench in the old workshop, I should pick it up anyway. I’ll have a squizz over the next few days. The ‘Honeycomb’ structure of the casting also suggests the casting method of the case changed at this time.

[audiomick]

16 hours ago, PhillipLarsen said:

...HMB....

Will post the outcome in a few weeks.

Looking forward to you thoughts. HMB enjoys a very good reputation in the German Guzzi community. I'm interested to hear what you think of their tensioner.

[Lucky Phil]

17 hours ago, pete roper said:

Looking more carefully at the pics posted I can see the problem. It looks as if by the time your crankcase was made they had started using the newer pressure die cast moulds for the crankcases. I thought the change over happened at the time of the CARC bikes but obviously it predated that. Now I’m not sure, I’ll have to check, but that annoying boss on the case might be a there for the oilway drilling for the under piston sprays on the 8V motor, (As I’ve mentioned before, a lot of modifications are put in train many, many years before model launches.).

 

I have an 8V case on the bench in the old workshop, I should pick it up anyway. I’ll have a squizz over the next few days. The ‘Honeycomb’ structure of the casting also suggests the casting method of the case changed at this time.

This was the theme of my comments relating to the clutch slave cylinder Pete. It's amazing the small and generally unnoticed subtle changes that the manufacturers do in the production run that even at times proceed the actual incorporation of things for later model. 

Just when you think you have a handle on what was produced when you get a curve ball. Ducati crankcases are a myriad of such production variations. Most don't have a major implication for engine assembly but some do. 

Phil

[PhillipLarsen]

Thanks Pete and Phil, the additional information is great to know. I sure don’t want to go grinding out anything before knowing if there is something important in there.
While I am waiting for the new HMB tensioner I have been looking at the original one closely and it seems to me that if the spring had somewhere around 3/8 to 1/4 less coil is would provide a lot more resistance to the tensioner pad.
By shortening the spring and re-bending the end that could be accomplished, but not sure how it would affect the fatigue life of the spring. Looks like Chuck and the Engineers Handbook would provide the answer. A real solution to the weak spring on the later Guzzi Tensioner maybe a redesigned spring and continue using the Guzzi Tensioner, kind of like the gear selector spring issue. 

[pete roper]

I seem to remember that Valtech actually produced a ‘Blade’ type tensioner that fits the *Newer* crankcases? I’ve not laid eyes on one but despite my memory being less than perfect nowadays I’m pretty sure I’ve seen pictures of one?

[Pressureangle]

FWIW rather than dremel clearance, flinging tiny chips everywhere, I'd locate the contact point between case and bracket with layout dye, or even a sharpie and some care. Then centerpunch your point and use a drill, somewhat larger diameter than the pin to sink the clearance. A bit of grease on the drill bit and some care in the work area guarantees you don't get swarf in the engine. 

[PhillipLarsen]

Thank but unfortunately it is not just the pin but the whole pad area that need to be relieved 4.5 mm and then an additional hole for the pin.

 

[PhillipLarsen]

I recieved the HMB Tensioner today which HMB had assured me would fit directly with no interference problems of the Millepercento tensioner.

Enthusiastically I went to work on it, only to discover the same interference issue with the pad and no way to modify the base of the HMB tensioner as the interference is where the pin is attached to a countersunk screw that holds the pivot pin to the base.

The HMB tensioner does not fit ($ 248 Cdn for tensioner, shipping and import tax)

So I now have two new tensioners on hand, neither which are useful with out removing about 4.5 mm from the entire pad area and in the case of the Millepercento an additonal hole drilled into the lowered pad to accomadate the protruning back side of the pivot pin.

The tensioner arm that rubs against the chain and the spring look to be the same dimensions as the original tensioner so I am considering to use those peices of the HMB unit on the original tensioner base. I have advised HMB of the issue and will see if they have any solution.

 

 

[PhillipLarsen]

Update. I did not hear anything back from HMB after I advised them that the cam chain tensioner does not fit my 2004 Ballabio. 
Wanting to take advantage of the riding season I went ahead with using the HMB tensioner wear pad and spring on my original tensioner base. The pad is near identical and the spring as well The HMB spring had a little more resistance than the original, likely because it is new. They look identical. 
I reassembled the bike, using new metal gasket on timing case, hoping to again have an oil tight bike. 
Ran the bike, checked spark scatter at idle and the 1750 to 2000 rpm range. Very slightly less scatter but maybe 20% less.
Took bike for a test ride. Same issue of popping back into air box at that rpm range whether riding or in my stand. 
I am now convinced this is not the issue causing misfire / popping into air box.
I set everything back to Decent tuneup setting 157mv, balanced TBs, CO =0, air screws 1 turn out, idle 1250. 
Extensive test in stand ( use my Hartzel dyno cooling fan) and riding showed missing and popping back into air box in the 1500 to 2800 rpm range (larger range than previous), plugs showing white / very lean indication. 
Also ran test in stand on left cylinder only and right cylinder only. Same problem both sides. 
There are no leaks on intake or exhaust. 
All sensors are new, plugs, etc. 
In desperation I decided to see if increase TPS setting would help.

i did it initially in large increments to see if changed. Without going through all the steps which was spread out over 2 days I found as I increased the TPS setting the range of rpm where missing and popping got tighter until it was only at 1950 RPM. One more increase and it was gone. I then worked back down until it started and went up in small increments until it stopped. Took numerous rides attempting to get it to pop or miss. It doesn’t now, no matter what I try. 
The end setting that makes it run so nice  with as low as I can set it with out inducing popping is 

TPS 285 mv, balanced TBs, air screws 1/2 out, idle 1250 RPM. Plugs show medium tan at various rpm runs. 
It doesn’t make sense to me that this works. 
Could it be fuel pump pressure? Or injector condition?

I am very pleased to have it running so fine, and not worrying it may pop and stall when making a left turn across traffic at low rpm, but would really like to understand if something is not correct  

I have put on about 300 km now and it continues to run perfectly. Will be checking fuel consumption to compare to previous levels. 

I would really appreciate input from others that may have any ideas. 
 

[Pressureangle]

53 minutes ago, PhillipLarsen said:

Update. I did not hear anything back from HMB after I advised them that the cam chain tensioner does not fit my 2004 Ballabio. 
Wanting to take advantage of the riding season I went ahead with using the HMB tensioner wear pad and spring on my original tensioner base. The pad is near identical and the spring as well The HMB spring had a little more resistance than the original, likely because it is new. They look identical. 
I reassembled the bike, using new metal gasket on timing case, hoping to again have an oil tight bike. 
Ran the bike, checked spark scatter at idle and the 1750 to 2000 rpm range. Very slightly less scatter but maybe 20% less.
Took bike for a test ride. Same issue of popping back into air box at that rpm range whether riding or in my stand. 
I am now convinced this is not the issue causing misfire / popping into air box.
I set everything back to Decent tuneup setting 157mv, balanced TBs, CO =0, air screws 1 turn out, idle 1250. 
Extensive test in stand ( use my Hartzel dyno cooling fan) and riding showed missing and popping back into air box in the 1500 to 2800 rpm range (larger range than previous), plugs showing white / very lean indication. 
Also ran test in stand on left cylinder only and right cylinder only. Same problem both sides. 
There are no leaks on intake or exhaust. 
All sensors are new, plugs, etc. 
In desperation I decided to see if increase TPS setting would help.

i did it initially in large increments to see if changed. Without going through all the steps which was spread out over 2 days I found as I increased the TPS setting the range of rpm where missing and popping got tighter until it was only at 1950 RPM. One more increase and it was gone. I then worked back down until it started and went up in small increments until it stopped. Took numerous rides attempting to get it to pop or miss. It doesn’t now, no matter what I try. 
The end setting that makes it run so nice  with as low as I can set it with out inducing popping is 

TPS 285 mv, balanced TBs, air screws 1/2 out, idle 1250 RPM. Plugs show medium tan at various rpm runs. 
It doesn’t make sense to me that this works. 
Could it be fuel pump pressure? Or injector condition?

I am very pleased to have it running so fine, and not worrying it may pop and stall when making a left turn across traffic at low rpm, but would really like to understand if something is not correct  

I have put on about 300 km now and it continues to run perfectly. Will be checking fuel consumption to compare to previous levels. 

I would really appreciate input from others that may have any ideas. 
 

I sent the injectors from my '97 out to be cleaned, turned out they were *very* dirty, so much so that I had to remap the entire fuel curve because it went rich. iirc the left injector was down 6% and the right down 10%. So yes, the injectors can, and over time certainly will, lean the mixture. On modern auto, the system accomodates injector change by increasing the pulse width to keep the O2 sensor happy. On ours, well, I don't know when or if the factory started running the fuel from the O2 sensor. My first V11 is still on the bench with the stock ECU so I'm sure I'll be revisiting some of these questions in the coming months. 

[Lucky Phil]

3 hours ago, PhillipLarsen said:

Update. I did not hear anything back from HMB after I advised them that the cam chain tensioner does not fit my 2004 Ballabio. 
Wanting to take advantage of the riding season I went ahead with using the HMB tensioner wear pad and spring on my original tensioner base. The pad is near identical and the spring as well The HMB spring had a little more resistance than the original, likely because it is new. They look identical. 
I reassembled the bike, using new metal gasket on timing case, hoping to again have an oil tight bike. 
Ran the bike, checked spark scatter at idle and the 1750 to 2000 rpm range. Very slightly less scatter but maybe 20% less.
Took bike for a test ride. Same issue of popping back into air box at that rpm range whether riding or in my stand. 
I am now convinced this is not the issue causing misfire / popping into air box.
I set everything back to Decent tuneup setting 157mv, balanced TBs, CO =0, air screws 1 turn out, idle 1250. 
Extensive test in stand ( use my Hartzel dyno cooling fan) and riding showed missing and popping back into air box in the 1500 to 2800 rpm range (larger range than previous), plugs showing white / very lean indication. 
Also ran test in stand on left cylinder only and right cylinder only. Same problem both sides. 
There are no leaks on intake or exhaust. 
All sensors are new, plugs, etc. 
In desperation I decided to see if increase TPS setting would help.

i did it initially in large increments to see if changed. Without going through all the steps which was spread out over 2 days I found as I increased the TPS setting the range of rpm where missing and popping got tighter until it was only at 1950 RPM. One more increase and it was gone. I then worked back down until it started and went up in small increments until it stopped. Took numerous rides attempting to get it to pop or miss. It doesn’t now, no matter what I try. 
The end setting that makes it run so nice  with as low as I can set it with out inducing popping is 

TPS 285 mv, balanced TBs, air screws 1/2 out, idle 1250 RPM. Plugs show medium tan at various rpm runs. 
It doesn’t make sense to me that this works. 
Could it be fuel pump pressure? Or injector condition?

I am very pleased to have it running so fine, and not worrying it may pop and stall when making a left turn across traffic at low rpm, but would really like to understand if something is not correct  

I have put on about 300 km now and it continues to run perfectly. Will be checking fuel consumption to compare to previous levels. 

I would really appreciate input from others that may have any ideas. 
 

You'd be better off just adjusting the CO as a quick and dirty way to control the popping rather than the Tps sensor. The CO setting affects the whole range but is most effective at the bottom. 

Phil