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 Honda CB350 Racers Promotion
 CB350: The Saga!

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T O P I C    R E V I E W
Ben Posted - 25 Mar 2004 : 10:51:01 AM
Hi all,

I have read about fitting early XL250/350 triple clamps/stem and forks to a CB350. Has anyone done this with any degree of success? It seems to be pretty much a straight swap as it is roumoured that the clamps and stem fit perfectly and the axle is the correct size. My bike has a T500 front drum with standard forks and I'm hoping this could be an easy and cheap way to strengthen up the front end while maintaing the existing brake.

Any Thoughts?

Thanks and Cheers,
Ben.
30   L A T E S T    R E P L I E S    (Newest First)
matcho mick Posted - 26 Mar 2014 : 8:22:21 PM
don't think welding the r/h piston was such a good idea ,let go over Lukey island classic ,small bits of oil ring in the sump plug ,oops,oh well back into hibination
keith campbell Posted - 19 May 2013 : 4:56:30 PM
Good to hear Mick. :)
New clothes also eh ......bike won't know itself.

Now for that Matchy eh?????
acotrel Posted - 18 May 2013 : 07:24:01 AM
I am jealous. I spoke to Allan Greening just before he died, and we discussed the likelihood that we'd both ride the Seeley 850 at the next old farts meeting. These days, I am pretty skint however we would have made the effort. I'm now looking for another job so I can pay for my vices .
matcho mick Posted - 17 May 2013 : 9:32:37 PM
it lives (again ),3 year hibernation,4 new valves,weld/remachined the r/h piston,dragged it off to Mt gambier old farts last weekend,upped the c/shaft to 15,(broady gearing )adjusted valve clearances after sat races,that was it,all good again,actually it's got new clothes,my young bloke did rising sun in blue/white combo,tres cool,good to be back,
racer7 Posted - 13 May 2012 : 11:31:15 AM
Well I got tired of adjusting the points ...... so bought a PAMCO total loss system from the USA. About A$115 delivered. Much better then the points and condenser! Fits really well, and the downloadable fitting instructions relatively foolproof!
racer7
OldKwak Posted - 02 Sep 2011 : 07:07:04 AM
Had a look at Pazon but didn't suit my bike. Seem to be a remake of the Boyer Ignitions
conker Posted - 01 Sep 2011 : 10:29:03 PM
Ben, about the twin pull twist grip - I think you can still back order some TZ350 parts through your local Yamaha agent. I've had two twist grips from that source for a long time, but I recently bought a ccouple of bodywork items which are still available. The twist grips come with three individual part numbers which make up the complete assembly. So you need to make sure you find them all when you are ordering.
racer7 Posted - 01 Sep 2011 : 4:08:14 PM
Thanks for that. One of the bikes up here has a Boretech, two have PVL, and mine points total loss - again.
There's a PAZON System, now made in N.Z. I think the owner/ manufacturer relocated from the U.K. a couple of years ago?
Anyone have any experience with these units?
regards
racer7
OldKwak Posted - 28 Aug 2011 : 10:26:25 AM
Why not have a look here at ignition systems http://www.ignitech.cz/english/aindex.htm I am sure you will find them very interesting. I am using this in preference to dyna on my Kwak and think they are the bees knees. Totally programmable and reliable and reasonably priced considering what they are. A bit difficult to install due to communication issues (Czech Emglish is even worse than the old Japanese English)but their stuff works and Ducati people love them. They even reply to emails if you can understand them. Have a look I am happy to help where I can.
racer7 Posted - 28 Aug 2011 : 06:57:47 AM

Not much happening lately huh?
Well here's some stuff from me. My CR93 (but 350cc) Replica has been running total loss points/ Condenser ignition. Got hold of a Newtronic K4 system from the UK. BUT ..... it has to be the most expensive piece of plastic junk imaginable! Good to see that they're now 'Under Development' on the existing unit. Perhaps using a bit more metal?
Back to points then. So far the two CB350's up here, regularly running 12,000 RPM, using different Cam profiles on needle bearings, are showing no sign of problems, related to machining the cams themselves to suit. Touch wood! There are another couple joining us soon, so there should be 4 CB350's on the track
Cheers
racer7
GD66 Posted - 05 Jan 2011 : 7:42:16 PM
Maybe at the Island Classic, I will be over doing commentary.
Ben Posted - 04 Jan 2011 : 12:08:41 PM
Haa haa. Yep, it is really me Glenn!

I have been keeping a low profile - will be back around the pits as soon as possible!

Will be good to see James' bike out on the track!

I was at the S/C for a couple of hours helping a mate, but did not find you in the pits. Hopefully catch up at the next one!

Cheers, Ben.


GD66 Posted - 23 Dec 2010 : 5:46:58 PM
Ben !! Is it really you, mate ? Didn't spot you at the nats or Southern Classic, so figured you must have parked The Saga up and turned into a human. Be warned, mate, it won't last....
There's a bloke on the other thread looking for an engine builder in Melb for his CB350, maybe you can point him at a tame whizkid in your area.
Did you hear, James Dwight (jvdairlie )has sold his lovely CB350 racer (sob) but happily Ron Angel bought it, so we can expect to see it back out there soon...unfortunately, it'll probably have some hotshot like Rod Tingate or similar aboard...

Hope to see your smiling face at the races again soon, mate.
Regards GD
Ben Posted - 23 Dec 2010 : 12:47:45 PM
The rebuild is still dragging on..... but have all the parts required and rebored cylinders ready to go!! The bike is on the back burner for now (life takes over sometimes eh?) but is always ticking along where possible.



matcho mick Posted - 06 Aug 2010 : 9:53:42 PM
geezas dec 09,how time flies ,so whos 350's up for the nats in 4 weeks??,i've entered the 350,just gotta rebuild the top end (again),Ben whats happening,are you & the saga going?,GD?,
Ben Posted - 09 Dec 2009 : 09:11:29 AM
Will do, thanks Jerry.

Does anyone have a good source for a decent twin pull fast action twist grip? Tommaselli/Magura or similar?



Jerry Posted - 09 Dec 2009 : 06:21:37 AM
Dear Ben, It will pay dividends if you deburr and polish the top faces of the valve springs which are in contact with the titanium retainers.This will reduce the wear on the retainers. Jerry Kooistra
Ben Posted - 08 Dec 2009 : 7:52:03 PM
Hi All,

CB72, the valves were APE from the states, one piece units. It was a shame to ruin them as they were lovely valves! I am going to try the needle roller ala GD in the new motor and see how it goes.

Getting there. My new cylinder head is ready with locally made one piece stainless valves and R&D springs w/titanium caps. I had these in the other motor but they did not get much of a run!!

CB72 Posted - 03 Dec 2009 : 4:03:03 PM
Those Henning pistons are pretty good. I had a pair, but of course they are 67.5mm for AHRMA regs which is slightly O/S but within reason. (not as big as a 44cc BSA 350 or 600cc Manx Norton in the 350 class).

The crown shape is pretty good and is remarkably close to what we run in our CB72, but ours has less of a bump and we machine more off the head and barrel to make it all work.

I like the ring pack that Todd specified. It is the best available.

Omega pistons have a great reputation in the UK, but I have no experience with them.

Stock springs and 12,000 rpm are a disaster waiting to happen. It's only a matter of time.
GD66 Posted - 03 Dec 2009 : 10:13:48 AM
Time will tell.I've got them, so I'm interested in using them. The poms swear by them, and they still have a fairly hot CB350 series going. Guy Martin said they're even using seven-speed boxes in some of the hotrods they have running at the TT and Sothern 100 ! But the CAT racing bike went ok and seemed reliable enough, that was a few years back when Alan Oversby was the pilot. I'll be looking to use that gear when I finally build a metho motor for my old girl, jury's still out on what pistons to use though. Eddie Lauder has had good results with Omega pistons in Keith's bike, there's a set in there that has apparently suffered a couple of blowups and are still in ok nick. J&E will make pistons to suit, some have used Todd Henning/Buff Harsh stuff but had appalling after-sales backup which has limited appeal, so I'm still dithering....need to get it done though, because all tracks still seem to have straights !! The valve springs I have in it have been in so long I can't remember where I sourced them, they're heavier than stock but not by much. Those who use stock don't seem to have any dramas, but as you say, there's always a missed shift waiting out there somewhere...
CB72 Posted - 03 Dec 2009 : 05:45:34 AM
G'day GD.

It's been a while since I checked the seat pressures, but I'd ask your engineer what seat pressure he thinks those valves need and compare that to the actual values. Someone there must have a spring tester and you already may have measured the installed height.

On problem I have is that I pull valves back into the head (pocketing) to get the compression I'm after, so I have to be careful there with all the inherent compromises that entails. That leaves the valve stems taller than stock so I frequently have to use shims or spacers under the springs.

Springs are just another area of compromise. Too soft and valves float. Too hard and it wipes out cams and followers. high lift cams create even higher pressure under load but you don't want to have the seat pressure too low.

If you ever plotted a cam and looked at the acceleration rates you will see that most cams are brutal on valves and seats and they need quite a lot more pressure than a modern 4 valve motor with its light valve gear.

I have used springs from just about every manufacturer over the years and in time they all float and all break - some are worse than others.

That all said, the issue here may be that he thinks that there's too much pressure for a light Titanium valve which has considerably less inertia than a stock or lightened steel valve. In which case it may be possible to cut the spring seats slightly to lower the seat pressure.

Or ask R&D what they recommend for Ti valves.

If your engineer has a spring he likes with enough seat pressure, not too much pressure at full lift and good damping between the coils I'd use that. My favorites were Norris triple wound with a flat damper between the two springs. I have no idea who made them for Norris, but now I use R&D and they work fine.

It all comes down to how hard you rev it and how often you miss gears.
If you short shift an never miss a shift, you can probably use softer springs. I tend to make the motor compensate for my lack of riding skills and work them hard, so I need a little more pressure to hold things together. Stuff wears out so that isn't an issue, but breaking is costly.

I'd be interested to hear your engineer's recommendations or suggestions.

GD66 Posted - 02 Dec 2009 : 7:15:01 PM
Wecome aboard, CB72. Do you not find the R and D springs are too high a poundage ? I got a set awhile ago from CAT racing, with some titanium valves, but my engineering guru is reluctant to use them for fear that they'll tulip the valve heads due to their high rate. Your thoughts ?
CB72 Posted - 02 Dec 2009 : 08:35:28 AM
That valve looks like it snapped off at the spot where the head is welded to the stem. Was it a one piece valve or Honda supplied two part valve?

We run our CB160 based racers up to very high revs and have been luck until last summer when the rider tried to chase down a CB350 up the long main straight. I heard the slight miss at the very top end that's a sure sign of valve bounce, and sure as God made little green apples, the head came off on the way to turn five at full tilt in 4th.

Ruined the head, crank, barrels etc etc.

Cam failure was probably caused in this case by the force of smashing the valve through the piston.

Those cams are old and break easily especially with lots of valve lift or if the valves start to float. In fact Megacycle snapped a CB92 cam of mine trying to straighten it to replicate the grind.

Needle rollers or bronze bushes are better at containing whip that ball bearings.

Essentials on a K4 are good valve springs - we use R&D with Titanium top caps and set the spring pressures. Next are good one piece valves and preferably with undercut stems and lightened heads - and replace them often - especially if you miss a shift or over rev it until the valves bounce.
Ben Posted - 04 Aug 2009 : 09:28:53 AM
Hi All,

Has been a while and will be a while yet (other life priorities draining bike funds!!....), but I am hoping to have the saga back to life by early 2010. I received my long awaited Joy Cam last week and now just need get the new valves and a rebore sorted - the put it all back togther of course.

Not as easy as it sounds at the moment but I remain committed!!

Cheers,
Ben.
GD66 Posted - 13 May 2009 : 10:13:39 PM
Not on a CB350 twin, they didn't ! Pay no heed. R7, and whack your disc back on. I have a drum (GT750 Suzuki), because when I first built the bike for the 1987 season, I was adamant that it had to "look period". And it does look good, and it stops like hell (right, Sir Al ?). But it still has linings from that time in it, which are so politically-incorrect and carcinogenic they should feature in an X Files episode.....it's a great brake, but for lightness, simplicity and performance, you can't beat a disc.
And for what it's worth, CB350 Hondas now are capable of lapping the Island at over 100 mph....and they're all fitted with discs...
racer7 Posted - 12 May 2009 : 6:51:27 PM
Hi All
Re-reading the topic from first to last, we started off with brakes. Whilst re=spoking my disc braked 350 front wheel, a casual visitor to my shed asked why I didn't have the drum brake fitted. After a lengthy explanation, my (now)non friend visitor, just said "Well they used to lap the Isle Of Man at over 100 mph decades ago. And used drum brakes!
I don't like him anymore. 'Cause now I'm putting the 'Drum' back! So many experts, so little time!
peen0_0 Posted - 01 Apr 2009 : 5:12:07 PM
Ben, I won't be at the Historics after all, but will keep those parts aside for when we might be able to catch up.
Chjeers, Tony.
Ben Posted - 01 Apr 2009 : 09:58:42 AM
Hi All,

Does anyone have a race profile cam that they are not using/is gathering the dusts of time that they would be willing to sell to me for the saga rebuild? Any top end parts also considered if you have some (basically need everthing)...

Thanks.
Ben Posted - 16 Mar 2009 : 09:31:13 AM
Good thought Mick, that was what I thought initially, then talked myself out of it as the cam was reprofiled by a reputable cam grinder and surely they would not leave a cam too brittle after welding.....

matcho mick Posted - 15 Mar 2009 : 10:27:46 PM
wonder if it's anything to do with reground cams,mine is factory RSC,is actually a "fat" cam,with centres i ground down for lightness,concidering,#1 i've locked the motor with bent valves through ingested pit gravel,#2 engaged 2nd instead of 4th at (my) max revs (no tacho,change when sensing valve bounce approaching ),& cam has survived all this mistreatment for quite some time,god knows how many years before i inherited it too,soo can we find out if these cams that broke were indeed regrinds??,i know yours was Ben,how about Adrians?,Old Kwak any thoughts??,cheers Mick

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