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New Shadow motor now what do I do?

Ducdude

Well Known and Active Forum Website User
VOC Member
Hi all I would like your input on how to proceed regarding the above bike's set up.

1952 Shadow freshly rebuilt motor and trans from the crank up
8:1 low expansion pistons
105 cams

NEW style 32mm MK1 Amals
#3 side
106 needle jet
250 main jet
17thou air jet behind the air screw

Burgess muffler (silencer)
Stock gearing
BTH
No air filters
160 miles since rebuild
Fresh plugs, filter, oils, valve adjust, head torque to 30ft/lbs at 100miles
Nice steady idle

The issues are as follows:
Pick up feels good in 1st gear but seems flat accelerating though 2nd.

On the motor way she runs strongly up to 85mph or so, at 75% throttle. It is an effort to get her up to 95mph at WFO and once there that is all she seems to want to do no matter if the mains at 210 or 250....She does a bit better getting to 95 with the 250s but not much.

Plugs are dry and slightly sooty around the electrode but the electrodes them selves are reasonably clean...

Finally the bike just does not feel lively my seat o meter says that there is only 30-35 hp at the rear wheel but all this lot is subjective.

All comments and suggestions are welcomed and encouraged..

Thanks much!

Cheers,
Eric
 

rapcom

Well Known and Active Forum Website User
VOC Member
You are already trying full throttle with only 160 miles since rebuild? I am very old-fashioned, but that sounds foolhardy to me. I would wait for at least 1000 miles of gradually increasing demand before trying it. Besides, you have only just assembled the rest of the bike as well. High speed running is not the time to discover you didn't tighten this important nut, or that vital banjo bolt. Take it steady, your bike will live longer.
 

Ducdude

Well Known and Active Forum Website User
VOC Member
You are already trying full throttle with only 160 miles since rebuild? I am very old-fashioned, but that sounds foolhardy to me. I would wait for at least 1000 miles of gradually increasing demand before trying it. Besides, you have only just assembled the rest of the bike as well. High speed running is not the time to discover you didn't tighten this important nut, or that vital banjo bolt. Take it steady, your bike will live longer.



Thanks much for you input!
The first 100 miles were back road hills with speed changes and a lot of shifting and stops to check this and adjust that... I never got her into 4th gear and my speeds were 40-60mph. The motorway allowed for an avg of 70mph in 4th once up to temp with short climes to max (for a mile or so) and then back down. Each of these runs is only a total of 20-30 miles with cool down periods of hours after. I do not want to baby the motor to much as I intend to run her hard and it my hope that this regime will uncover her failings with the least amount of prolonged stress to the bike and motor.

The correct way to run in a motor differs depending on who you ask. I have done the gentle easy way and had an oil burning beast for years (Ducati) I have also done a hard but considerate run in and had a strong clean running joy for 100's of thousands of miles (different Ducati). Truth be told I also did a very careful slow run in on an old Honda twin that never used a drop of oil ever.. So, what to do?

I am trying a mix of philosophies. Will it work, we shall see. At least for now I know there is an issue with something...Probably my head..LOL

Cheers and much appreciated,

Eric
PS I did in fact lose a headlight bolt and a crash bar on of the test runs so that did indeed motivate a full on bolt snugness check..:)
 

chankly bore

Well Known and Active Forum Website User
Non-VOC Member
What fuel are you using and what ignition advance? Most of this modern crap burns hotter and needs less advance. I nipped up a Comet probably due to crap fuel. Since using 98 octane, no further problems. Personally, I wouldn't do more than an unstressed 70 m.p.h. for the first 1000 miles. after this mileage maybe start mucking around. One thing at a time, first the silencer, then needle position, then slide cutaway if that does no good. One used to do a "plug chop" at full throttle under load and then work back through carburettor setting; but modern fuel makes plugs hard to read. Handy to know someone with a rolling road and an exhaust gas analyser, I suppose!
 

Monkeypants

Well Known and Active Forum Website User
VOC Member
You might try a Spiral baffle muffler(club), they have been shown to give good power on the twins.
Other than that, have you played with ignition timing or valve timing? Perhaps those are not spot on.
Also, what valve springs were used? The club ones are very cheap and made from a form of soft cheese that has had some FE powder added to make a metal like substance.
The good ones are made by R&D in the US, cost a bundle and are available thru Terry Prince. I have been told that they can add 20 mph to the top end, or rather that the cheesy ones can subtract 20 mph from the top.

Glen
 

Ducdude

Well Known and Active Forum Website User
VOC Member
What fuel are you using and what ignition advance? Most of this modern crap burns hotter and needs less advance. I nipped up a Comet probably due to crap fuel. Since using 98 octane, no further problems. Personally, I wouldn't do more than an unstressed 70 m.p.h. for the first 1000 miles. after this mileage maybe start mucking around. One thing at a time, first the silencer, then needle position, then slide cutaway if that does no good. One used to do a "plug chop" at full throttle under load and then work back through carburettor setting; but modern fuel makes plugs hard to read. Handy to know someone with a rolling road and an exhaust gas analyser, I suppose!


Thanks for the reply.

I am using 89 octain and 35-36deg BTDC .. I will try a silencerless run in the morning late morning after church//:)
and fresh 98 octain in about 50 miles..:)

Cheers,
Eric
 
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Ducdude

Well Known and Active Forum Website User
VOC Member
You might try a Spiral baffle muffler(club), they have been shown to give good power on the twins.
Other than that, have you played with ignition timing or valve timing? Perhaps those are not spot on.
Also, what valve springs were used? The club ones are very cheap and made from a form of soft cheese that has had some FE powder added to make a metal like substance.
The good ones are made by R&D in the US, cost a bundle and are available thru Terry Prince. I have been told that they can add 20 mph to the top end, or rather that the cheesy ones can subtract 20 mph from the top.


Appreciate the data and the cheese humor:

Last I checked they were out of Spiral baffle mufflers but I will try again on Monday...I will have a go checking the timing in the morning after I check my notes and confirm where it was set.. Not sure on the springs but my builder is known for quality work producing fast motors and he is very attentive of the details. I doubt he would use bits he was not sure would make a good motor..

Cheers,
Eric
 
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Monkeypants

Well Known and Active Forum Website User
VOC Member
The spring thing is not universally known.
It was noted by John Mcdougall some years ago that his customer's rebuilt bikes were not performing as they ought to. On checking valve spring pressures it was found that they were dramatically below spec. Dan Smith was already using the R&D springs, so John replaced the club springs with those. Thebike in question gained about 20 mph top end with just this one change. Im not sure if Terry was already onto this, or found out from Dan or John. In any case, by the time I got involved with Vincents in 2004, Terry was stocking the R&D racing valve spring kits. Cost is about $400 vs less than $100 for the others, but the quality is there.

Glen
 
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