Topic: CB750: Aware of cheap parts -tensioner rubber cracked in 2- Carb boots cracking

[Wobbly]

I would doubt Honda would source crap.

I'm inclined to think the same thing.

Same here. The parts are still available from Honda and the part numbers are unchanged. I don't think Honda changed a thing.

[HondaMan]

Is there any chance PartsnMore are selling genuine Honda parts in their own bags? I would doubt Honda would source crap.

I'm inclined to think that both Honda and the [vendor who sells these parts out of Taiwan] are getting these parts from the same place. It's not like there are 10 vendors out there who make cam chain tensioners?

[madmtnmotors]

I'm inclined to think that both Honda and the [vendor who sells these parts out of Taiwan] are getting these parts from the same place.

Please stop saying that. I have to believe that Honda is making their own and not sourcing from the same manufacturer whose parts are self destructing. If they are indeed getting them from the same source, then I'll have to stop buying Honda parts altogether, sell off my SOHC stock, and go get a new Indian. 

[PeWe]

I have bags labeled Made in Japan. Must be OK?
Metal alternative too, Made in USA!  OK, right?

[AshimotoK0]

I asked the question of the repro idler rollers common to cb750 & CB350k that David Silvers sells. I even offered to have one analysed  chemically to see if it is the correct extended temperature grade nitrile rubber & hardness . however he told me the tech info was  proprietary to the manufacturer so  was not forthcoming with the information. he could only offer that they have sold lots of them and never had any complaints. I have two of his repro rollers so I may just go ahead, take a sliver of rubber from a non contacting area and have it analysed by my mate at the local Uni.

[grcamna2]

I asked the question of the repro idler rollers common to cb750 & CB350k that David Silvers sells. I even offered to have one analysed  chemically to see if it is the correct extended temperature grade nitrile rubber & hardness . however he told me the tech info was  proprietary to the manufacturer so  was not forthcoming with the information. he could only offer that they have sold lots of them and never had any complaints. I have two of his repro rollers so I may just go ahead, take a sliver of rubber from a non contacting area and have it analysed by my mate at the local Uni.

I hope you do that Ash,have the rubber analyzed from the Taiwan roller and then also take a small sliver from an NOS Honda OEM rubber roller to have analyzed along with it. Good plan,this way we will Know.

[PeWe]

My unopened Honda labeled bags ordered from David Silver UK beginning of December 2015.

[Davidov]

After talking to a few other members about this issue, I decided to investigate.

Removed the tensioner plunger assembly from the rear of the cylinders.  I first felt with my finger for the top rubber wheel. I could spin it, but then felt where it was in fact......SPLIT IN HALF!   

I used a borescope to look through the tensioner opening, and confirmed that the rubber was barely on the metal section of the roller.
Pictured below, you can see the bare metal of the tensioner wheel where the rubber is coming off.

I am contacting VintageCB750 over email and demanding a refund. I did see the product was removed from their site, thanks to other members alerting them of the situation.
I feel like they also owe me a gasket set, since the one I just installed about 1,000 miles will be ruined on disassembly.
With a company name like "Vintage CB750", I think they should be held to higher standards than most online parts suppliers. They are serving a very specific group of enthusiasts, and have now betrayed the trust of several individuals.

So I should use the Honda parts? I don't have a proper riveting tool to install the PolyA or metal rollers.
I sunk a good deal of time and money into this engine build, and this is making my blood boil.

[madmtnmotors]

After talking to a few other members about this issue, I decided to investigate.

Removed the tensioner plunger assembly from the rear of the cylinders.  I first felt with my finger for the top rubber wheel. I could spin it, but then felt where it was in fact......SPLIT IN HALF!   

I used a borescope to look through the tensioner opening, and confirmed that the rubber was barely on the metal section of the roller.

So I should use the Honda parts?

Wise move. I'm glad that mine had not started coming apart yet (but was not far from it).

As PeWe indicated, the Honda parts bag indicates "made in Japan" so that's what I'm hanging my hat on. I may get a bore scope and monitor the condition of the factory parts just to be sure.

[grcamna2]

After talking to a few other members about this issue, I decided to investigate.

Removed the tensioner plunger assembly from the rear of the cylinders.  I first felt with my finger for the top rubber wheel. I could spin it, but then felt where it was in fact......SPLIT IN HALF!   

I used a borescope to look through the tensioner opening, and confirmed that the rubber was barely on the metal section of the roller.
Pictured below, you can see the bare metal of the tensioner wheel where the rubber is coming off.

I am contacting VintageCB750 over email and demanding a refund. I did see the product was removed from their site, thanks to other members alerting them of the situation.
I feel like they also owe me a gasket set, since the one I just installed about 1,000 miles will be ruined on disassembly.
With a company name like "Vintage CB750", I think they should be held to higher standards than most online parts suppliers. They are serving a very specific group of enthusiasts, and have now betrayed the trust of several individuals.

So I should use the Honda parts? I don't have a proper riveting tool to install the PolyA or metal rollers.
I sunk a good deal of time and money into this engine build, and this is making my blood boil.

I think a way to correctly rivet that top roller shouldn't be too much of an issue;the steel roller kit that PeWe is getting has clear instructions.

[madmtnmotors]

After talking to a few other members about this issue, I decided to investigate.

Removed the tensioner plunger assembly from the rear of the cylinders.  I first felt with my finger for the top rubber wheel. I could spin it, but then felt where it was in fact......SPLIT IN HALF!   

I used a borescope to look through the tensioner opening, and confirmed that the rubber was barely on the metal section of the roller.
Pictured below, you can see the bare metal of the tensioner wheel where the rubber is coming off.

I am contacting VintageCB750 over email and demanding a refund. I did see the product was removed from their site, thanks to other members alerting them of the situation.
I feel like they also owe me a gasket set, since the one I just installed about 1,000 miles will be ruined on disassembly.
With a company name like "Vintage CB750", I think they should be held to higher standards than most online parts suppliers. They are serving a very specific group of enthusiasts, and have now betrayed the trust of several individuals.

So I should use the Honda parts? I don't have a proper riveting tool to install the PolyA or metal rollers.
I sunk a good deal of time and money into this engine build, and this is making my blood boil.

I think a way to correctly rivet that top roller shouldn't be too much of an issue;the steel roller kit that PeWe is getting has clear instructions.

I like the shock absorbing qualities of the rubber rollers. I would want to have a heavy duty cam chain to use the steel rollers, but I am not ready to split the lower cases yet.

[flybox1]

Sorry to see this Davidov....thanks for the PM.  Its a painful realization.
Feck.  The DSS rollers are temp out of stock   
The only other vendor i'd trust for this is Yamiya750. 
$135 for the set of Genuine Honda Parts.

[grcamna2]

Wilbur,
I think keeping a close eye on the cam chain adjustment until the new chain has fully stretched and the steel rollers have seated-in(possibly 1000miles,which should always be done anyway)and then just setting the cam chain adjuster regularly will keep the chain taut enough w/ no worries on a little extra whirring sound from the steel rollers.  imo

[flybox1]

Is the Tsubaki/Camelia cam chain considered HD enough for these steel rollers?

[madmtnmotors]

Wilbur,
I think keeping a close eye on the cam chain adjustment until the new chain has fully stretched and the steel rollers have seated-in(possibly 1000miles,which should always be done anyway)and then just setting the cam chain adjuster regularly will keep the chain taut enough w/ no worries on a little extra whirring sound from the steel rollers.  imo

I would agree. I have not changed my timing chain though, and am still running the 40 year old chain that has about 20,000 miles.

Is the Tsubaki/Camelia cam chain considered HD enough for these steel rollers?

I would think so. Anything has got to be better than the 40 year old stock chain. 

Of course, I would have thought that about the tensioner components too... 

[Wobbly]

The only other vendor i'd trust for this is Yamiya750.
$135 for the set of Genuine Honda Parts.

Why not Honda?

http://www.discounthondaparts.com/fiche_section_detail.asp?section=2451854&category=Motorcycles&make=Honda&year=1977&fveh=131105

[madmtnmotors]

The only other vendor i'd trust for this is Yamiya750.
$135 for the set of Genuine Honda Parts.

Why not Honda?

http://www.discounthondaparts.com/fiche_section_detail.asp?section=2451854&category=Motorcycles&make=Honda&year=1977&fveh=131105

+1

I ordered mine through Honda Parts Nation. Sad thing is they were only a couple buck more than what I paid for the Taiwanese parts! 


http://www.hondapartsnation.com/oemparts/a/hon/506b8caaf870023420a1e919/cam-chain-tensioner

[flybox1]

Yamiya had "Genuine HONDA Part" in the listings, that's all. . .

I was just about to purchase new struts and lowering springs for my Volvo V70.
Guess that's shelved until this fix gets completed 

List to self of items also needed:
Head gaskets, copper crush washers, exhaust gaskets,

[bwaller]

I think it's really wise to at least pull the oil pan to look for debris. That kind of particle could end up anywhere. If you find bits in the pan it's up to the individual how far to keep checking. Gearbox shaft oiling holes, you name it. Bad deal guys.

[Eydugstr]

This sucks.  I used a kit from CB750Supply.com, am assuming it's the same manufacturer as VintageCB750.com's.  At some point will run a camera in through the tensioner opening and see if I can find any damage like you guys are finding.

With this going on I'm not suprised DSS sold out of the steel rollers.  Anyone had a bad experience with Cycle Exchange's redone tensioners with the white material?  Or are they strictly for racing motors only? http://www.cyclexchange.net/camshaftpage.html

[madmtnmotors]

This sucks.  I used a kit from CB750Supply.com, am assuming it's the same manufacturer as VintageCB750.com's.  At some point will run a camera in through the tensioner opening and see if I can find any damage like you guys are finding.

With this going on I'm not suprised DSS sold out of the steel rollers.  Anyone had a bad experience with Cycle Exchange's redone tensioners with the white material?  Or are they strictly for racing motors only? http://www.cyclexchange.net/camshaftpage.html

Mixed reviews on the CycleX part:

http://forums.sohc4.net/index.php/topic,150140.msg1714039.html#msg1714039

[Eydugstr]

I emailed CB750supply.com, and asked them if they had any complaints about their tensioner kits...This is the response I got...

Doug,


We do not use the same suppliers as Vintage CB750.  We have not had any problems with any of the kits that we have sold.  We appreciate the information that you have shared with us.


Thank you,


CB750 Supply

[flybox1]

Vintagecb750 = PartsnMore...out of Ontario, Canada.

Cb750supply is a different outfit in Florida

[Eydugstr]

Vintagecb750 = PartsnMore...out of Ontario, Canada.

Cb750supply is a different outfit in Florida

It's understood they're different businesses, but how many suppliers of these cam chain tensioners can there be?  The parts I received came in a plain brown box, no manufacturers logo on anything.

[scottly]

I like the shock absorbing qualities of the rubber rollers. I would want to have a heavy duty cam chain to use the steel rollers, but I am not ready to split the lower cases yet.

I think the round steel rollers available would focus a lot of pressure on the chain rollers over a narrow line across the rollers. I think they should be proper sprockets, which cup the chain rollers and distribute the load over a much greater area?

Here is a zoomed in version of one of Mark's pics of the OEM rubber roller, which shows the logo at about 2:00.