Pushrod tubes . A wee heads up .

[desmo2]

Hi , after a sudden rush of blood to the head I decided to stop being so tight and buy new stainless pushrod tubes rather than make them .
Tubes duly arrived from a well known supplier and suspicions were immediately raised as the business end of the tubes remained unmachined and obviously out of round .
Long story short , the tubes I removed measured .699" . The new tubes measured .704" A full .005" up on original .
Anybody who knows anything about limits and fits will tell you a .005" interference on such a small diameter is nigh on impossible .
Tubes were all machined to original size and pressed into place . It's ok for me I guess but what about anybody without the facility to correct them ?
I'm more than sure pushrod tube fitting has been covered hundreds of times but thought it worth sharing my experience .
Be careful ..... very careful .

 

[Northern Monkey]

I got stainless ones - didn't measure, they were frozen for 2 days, heads heated in oven and we're still tight! Got em in tho


Sent by magic

 

[nick.ct]

The name of the well known supplier would be useful to prevent the same happening to others....................... I dont have the machining facilities

 

[Rob Farmer]

Have you measured the ID yet? some of them catch the pushrods

 

[B Murr]

I got stainless ones - didn't measure, they were frozen for 2 days, heads heated in oven and we're still tight! Got em in tho


Sent by magic

But what will happen if you ever have to replace them, will it be possible even with heating the head to get the hot tubes out of a hot head ?

 

[Northern Monkey]

But what will happen if you ever have to replace them, will it be possible even with heating the head to get the hot tubes out of a hot head ?

Dunno

Well they won't rust so hopefully won't need to replace em anytime soon

 

[cookie]

Hi , after a sudden rush of blood to the head I decided to stop being so tight and buy new stainless pushrod tubes rather than make them .
Tubes duly arrived from a well known supplier and suspicions were immediately raised as the business end of the tubes remained unmachined and obviously out of round .
Long story short , the tubes I removed measured .699" . The new tubes measured .704" A full .005" up on original .
Anybody who knows anything about limits and fits will tell you a .005" interference on such a small diameter is nigh on impossible .
Tubes were all machined to original size and pressed into place . It's ok for me I guess but what about anybody without the facility to correct them ?
I'm more than sure pushrod tube fitting has been covered hundreds of times but thought it worth sharing my experience .
Be careful ..... very careful .

this has been an issue for years.

had a right game getting a set fitted in my bike. heating the head helps, but freezing the tubes was a waste of time as they heat up too quickly, even if filled loosely with ice.

 

[nick.ct]

this has been an issue for years.

had a right game getting a set fitted in my bike. heating the head helps, but freezing the tubes was a waste of time as they heat up too quickly, even if filled loosely with ice.

Maybe some of that pipe freezer spray that plumbers use would help keep them cold enough

 

[(RIP) Arkwright]

The name of the well known supplier would be useful to prevent the same happening to others....................... I dont have the machining facilities

Maybe not, but you know a man that can!

 

[(RIP) Arkwright]

But what will happen if you ever have to replace them, will it be possible even with heating the head to get the hot tubes out of a hot head ?

They just knock out with a mandrel.

 

[byron]

I started a thread at the end of Jan about tubes on my r90s. Several suppliers sent me tubes of various inaccurate diameters and in the end I bought the sets from Shaw Stainless. There was also a thread on Adventure Rider about diameters and how far to insert them.

 

[dr nosh]

Are you saying that the Shaws ones are machined to the correct diameter?

 

[desmo2]

You're absolutely correct cookie . The moment the chilled tube touches the heated head , the game's over .
It's absolutely imperative that the tubes are the correct dia. to start with .

I'd rather not name the supplier of my tubes , if that's ok , but it is definately worth asking what the finished dia. is at the business end of any aftermarket tubes you decide to buy .

 

[byron]

The Shaw tubes are first class and mine only varied 0.02mm in size, but more importantly they are the correct size to shrink fit. Motorbins tubes were too large and they varied a lot. However they refunded me immediately.

 

[Kenny]

The Shaw tubes are first class and mine only varied 0.02mm in size, but more importantly they are the correct size to shrink fit. Motorbins tubes were too large and they varied a lot. However they refunded me immediately.

This is what we all wanted to know.

 

[desmo2]

Mine weren't Motobins .
I did however receive two extra long helicoils to repair stripped crankcase studs post-haste from them .
Just saying .

 

[Beemerboff]

The fit depends on the size of the hole in your barrels, something no one seams to have measured.
They vary and tubes seem to be made to fit even the largest holes.
If you have tight holes he barrels are relatively soft alloy and it takes a second or two to clean them up with a flap wheel in a power drill.
Polish the ends of the tubes too, use the proper mandrel,freeze the tubes and even the largest tubes go straight in faster than it takes to bad mouth a supplier.

 

[ChasF]

The fit depends on the size of the hole in your barrels, something no one seams to have measured.
They vary and tubes seem to be made to fit even the largest holes.
If you have tight holes he barrels are relatively soft alloy and it takes a second or two to clean them up with a flap wheel in a power drill.
Polish the ends of the tubes too, use the proper mandrel,freeze the tubes and even the largest tubes go straight in faster than it takes to bad mouth a supplier.

I think that previous threads on here and on advrider tells us that it's not as simple as that. I've had similar problems fitting incorrectly sized valve guides into a Triumph Bonneville head and my main concern forcing in oversized tubes would be the risk of damaging the barrel casting itself.

 

[mikeyboy]

I think that previous threads on here and on advrider tells us that it's not as simple as that. I've had similar problems fitting incorrectly sized valve guides into a Triumph Bonneville head and my main concern forcing in oversized tubes would be the risk of damaging the barrel casting itself.

What part of beemerboff,s thread didn't you read ?
Measure the hole,measure the fitting,adjust to suit

 

[ChasF]

What part of beemerboff,s thread didn't you read ?
Measure the hole,measure the fitting,adjust to suit

That is not what he said. He suggested that polishing the end of the tube would allow it to fit.

I accept that it would be best to measure the hole and adjust the tubes to fit although comparing the new tube to the one removed should suffice, but it seems most people have been supplied oversized, out of round tubes and just knocking them in with the mandrel may result in damaging the alloy casting.