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Discussion Starter · #1 ·
My little brother is building a 500cc triumph and wants to know the best bang for your buck engine mods. the kid is 23 and this is his second build. his first was a sweet sporty. this one just needs a bit more snot to keep him interested:) any suggestions on what he can do to get his bike moving?
he has a few more things to do, 21 front, slimmer seat fork covers etc. this is just the first mock up.
 

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Reminds me of years ago and the T100R I had. Regretfully all the performance mods were added before I purchaced it, so can't help you there. My 500 was really quick zero to sixty. :) I agree with Trent ejoy it like it is.

Chance...

PS. kewl bike. Wish I could still find 500.00 dollar basket cases. But don't we all. :)
 

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Keep in mind that T100s were the race bikes through the '60s and regularly spanked Harley's KRs. There is a ton of factory info on tuning and lots of hot-rod parts existed for them.
They will become fragile though, so be aware of what you are after!
Robbie
In 1965 this TR5RH went 134MPH on Daytona's track for time trials. It started out as a street bike.
 

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Megacycle do some cams for 500 units ,do a web search for their site . Also page 157 of Triumph Racing motorcycles in America by Lindsay Brooke has Jack Wilson's tuning tips for 500cc unit for classic racing .I am not able access a scanner at the moment ,but if no-one can come up with a scan this weekend I can do one during the week.
Cheers R
 

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Discussion Starter · #8 ·
Thanks for all of your advice. Some good tips here. I'll search the web for the cams and the tuning tips. Thanks for the positive comments too. He will be stoked
 

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Adding another tooth or two to the front sprocket (or using a smaller rear) will lower the rpm at highway speeds and make for a happier, longer living engine. With the greatly reduced weight of the kid's bike it doesn't need the short gearing of the stocker. If he does some performance mods, he'll definitely want taller gearing.

Cases have to be split for cams, so he might be better off with some mild head work, a careful valve job (that is, not like those done by your local auto machine shop!), and maybe a slightly larger carb. A thinner head gasket will bump up the compression a bit, but be sure to check the piston/head clearance. They make "R" followers for the 650s, if he can find something like that for the 500 he probably won't need to bother with new cams.

Try to convince him that mild is better than wild.
 

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These little bikes are pretty hot.You won't need to change engine parts to keep up with most other british bikes.Just put it together properly,and massage a few parts in the process.

The cams are equivalent to 3134 cams,but in the short stroke engine they work 1000 rpm higher.You can change cams without splitting the cases.You don't even need to remove the head from the barrel to do it.You need to lift the barrel enough to fit re-ground tappets,if you change cams.Cut the base gasket in 1/2 (if you use one) along the frame centreline,and join it back with Loctite 518.

The tappets are "R" radius,but lighter than 650/750 tappets and have a cup to fit the pushrod aluminium end (no steel cup at the bottom of the pushrod).

There was a similar topic at Britbike recently :http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=387793

Do a perfect valve job. Leave the seats in the head 3/32" wide and 0.020"-0.030" smaller diameter that the O.D. of the valve-head and back-grind the intake valves at 35 degrees to get 1/16" wide contact.
Make sure you have at least 0.002" intake guide clearance (right through the guide,especially at the centre),and 0.0025" exhaust guide clearance.

You can lighten the top valve spring collars a little,by squaring them.It doesn't hurt to grind some weight off the extreme ends of the rockers,around the adjuster and the pushrod ball.You don't want valve-float at 9000 rpm.Measure the fitted (seated) valve spring load with scales.

Don't be tempted to use big exhaust pipes.The 1-1/4 pipe is about right at 6000 rpm. 1-3/8" would be OK when you get to 7500 rpm.

12" intake length (from valve to bell-mouth) is good at 7500 rpm and also gives a torque boost a little over 5500.If it's shorter,you need more rpm to make it work.
If the exhaust length came in at 6500,you'd have a happy engine.

Weigh the pistons and make them the same.Radius any sharp corners around the valve-pockets and polish the crowns,1/8" radius where possible.

If there are any scratches/nicks in the conrods,polish them out vertically with #180 grit paper.Hold a rag underneath to catch any grit.

Check the cam timing,but don't bother with 0.020" tappet lift figures.Check it at 0.080" lift or so,and calculate the lobe centre,before you change anything.You can adjust it in 4.8 degree increments,using alternative camwheel keyways.

There must be something I've forgotten,but it's mostly just careful assembly.
 

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Discussion Starter · #14 ·
there are some seriously clued up cats on the journal. i knew i was looking in the right place. thanks again. if he can't get that thing running sweet with all the help given, theres no helping the boy!:D
 

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I rode Ryan's (Gepetto) 500 and it was pretty fast. It's dialed in for sure. Power felt 2 stroke style with that little high revver.

It wanted to be revved out for sure. Power kept coming fast at high RPMs. I think they're very capable of beating down a 650 Triumph if they're set up right.
 

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Plus, they look light enough to pick up and walk around with.

Hang on a second...
If a 500 could beat a Triumph 650...

I think they're very capable of beating down a 650 Triumph if they're set up right.
and a 650 is quicker than an Ironhead...

It's been almost a year since I've been on my Ironhead, but I have to say that I think my Triumph is quicker.
and finally, when things are right, an Ironhead can pull in front of a Busa...

...in an impromptu from the light streetrace a good runnin ironhead ridden with skill will jump a Hayabusa from the hole dam near everytime.
Than that 500 Triumph could, under the right circumstances, beat a Hayabusa!!

:D
 

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Plus, they look light enough to pick up and walk around with.

Hang on a second...
If a 500 could beat a Triumph 650...

and a 650 is quicker than an Ironhead...

and finally, when things are right, an Ironhead can pull in front of a Busa...

Than that 500 Triumph could, under the right circumstances, beat a Hayabusa!!

:D
Hahaha! That's some specious reasoning.

I was with you until the Ironhead/'Busa battle... that's is bit of a stretch.

I'd love to see the ironhead that could do it, though. I think if the hyabusa doesn't get a good launch, that's on the rider.
 

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Benway, you are right about picking them up and walking around with them! After the years of Crfyou talking shit about my "little" 500, I let him take it for a spin and told him not to be afraid of the rpm's. He thrashed it pretty hard, I could hear him about a half mile away at 8000 rpm! Properly set up with some "tricks" done to the engine, they will give most 650's a run for their money. I'm not a small guy and mine will fry the rear tire in first and second, or carry the front through first into second and comfortably cruise at 75 all day long. When I got my 80" shovel, I was expecting it to go pretty hard, but nothing makes me smile more than my t100. Maybe that's why I have 4 of them and no 650's!
 
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