Forum

[Andy C]

Does anyone have experience of “performance” cams against “fast road” cams in a Bullet – preferably a 612?

As some of you know I bought my old 612 Bullet back last year after selling it in 2013

When I sold it, it still had the standard Indian cams in it, when I bought it back I found that it had been fitted with “performance” cams.

From memory with the original Indian cams fitted it felt like it had a lot more bottom end, the performance cams don’t have the same bottom end performance as the Indian cams – they work better the harder you ride it, which I guess is pretty much what you would expect.

Guess that the fast road cams will further decrease bottom end performance but give a little more at the higher end of the rev range - or do they give a better spread of power?

Think that I can also gear it up a little as I am running a 19t gearbox sprocket – it feels like it could take 1 maybe 2 teeth more on the gearbox sprocket for more relaxed cruising, and less hurried up shifts in the lower gears.

Interested in the thoughts of the forum.

[stinkwheel]

Presumably the ones in a 612cc kit are the "fast road" you are refewrring to? (90023)

I can't compare like with like but I've got the 612 kit fitted and it pulls like a train from most parts of the rev range although I would say it does appreciate being revved higher, if it's going to knock, it does it when the engine is labouring.

I took pictures of the standard and kit cams next to one another when I did the build if that's any help?

Exhuaust:


Inlet:


The general ethos seems to be opening sooner, wider and for longer. Less of a point than I'd have expected making for a smoother transition from "opening" to "closing" and less chance if bounce I'd imagine?

21t is the de-facto maximum that will fit in there without fouling the inner chaincase. I've got 21t and a close ratio gear 4-speed in my 612 and it pulls 21t fine (effectively a "cruising gear", it'll still romp up to 70 in 3rd). You need to slip the clutch up to about 10mph on the close ratio box. Fine everywhere but on grass in a rally field where it's kind of a rev then coast with the clutch in kind of affair. I think it would be less happy with 21t on a standard ratio 4-speed box, it would be back to the old problem of sitting at too many revs in 3rd, not enough in 4th.

One metric ballhair of clearance with a 21t.

[Andy C]

Thanks for the reply - I have no idea of the duration of the "performance cams" , all I know is when I checked the lift they were the spec of those cams, I just wanted to check that it did in fact have different cams fitted as the vendor had said.

Like yours mine also pulls like a train, mine has a 5 speed box fitted and I find that with the 19 tooth sprocket it revs out pretty quickly between 1st & 2nd, if the overall gearing was a little taller then obviously I could take a little longer between gear changes and would also mean that the engine is not revving so hard at cruising speeds.

You are not the first to say that 21t is a good choice so perhaps my best option is to go for that.

[Blown265]

G'day Andy
I've used both #200180 and #90023 on the same long stroke engine.
No surprises here- the 90023 cams made for a faster bike, but required a higher rev range. These came on at 4000 rpm, and were done by 7000 rpm.
Conversely, the 200180 cams allowed for a lower usable rev range. They pulled from 2500rpm to 5500rpm, and were better suited for a mild cruiser.
Identify your riding style, modify the engine to suit, and then cam accordingly.
Both were used with a 5 speed and 22T sprocket (which required some case machining to clear).
Regards
Paul

[Andy C]

Paul.

Many thanks for that - looks like the cams I have - 200180 suit my riding style which is not sedate but still not totally "balls out".

22t sprocket looks to be the way to go - what do you need to machine? Primary case I guess?

Cheers.

[stinkwheel]

There is a flat circular recess in the back of the inner chaincase that the chain sits into. It's not immediately obvious in the picture I posted above but the chain on mine is almost touching the extreme edge of that recess. Any bigger than 21t and it would need to be milled out to a larger diameter.

You also need to make sure the back engine bolt is wound back flush with the head of the nuts on that side or it'll touch the chain pins.

[Andy C]

Thanks SW - I'll keep an eye out for all the protruburances when I go to 21teeth.

Probably will not be doing it for a few months as I currently have one of my other bikes on the bench, but it will get done before next spring.

Again thanks for the info.

[Blown265]

Hi Andy,
In addition to SW posts, the rear mounting point may need attention as well.
Before:

[Blown265]

After:

[Blown265]

And the other side of the sprocket, the back side of the inner primary case: