The Chopper Compendium

Trying to find out if it is necessary to rubber mount the newer (2003 +..?) Sportster engines. Since I probably won't have the donor bike, I won't be able to tell what the factory mounting was like. Or perhaps I'm just better off getting an older Sportster engine?

Any thoughts? Any transmission better than the other to mount in a Bobber?

Yeah, it's a new guy question.

Some one will answer, tho it may take a little time.

MaxTheGardener did a chop with Buell power.

Maybe try the XL Forum as well.

http://xlforum.net/vbportal/modules/Jig/index.php

Good luck &keep us posted.

Sorry I can not help never had a Harley yet.

But I am interested to know.

Boss9 wrote:Trying to find out if it is necessary to rubber mount the newer (2003 +..?) Sportster engines. Since I probably won't have the donor bike, I won't be able to tell what the factory mounting was like. Or perhaps I'm just better off getting an older Sportster engine?

Any thoughts? Any transmission better than the other to mount in a Bobber?

Yeah, it's a new guy question.

Unless you saw the factory transmission off the back of the cases there is little choice in a transmission but what the factory cast as part of the cases. Can't help with the particulars on the mounts they are way newer than anything I ever owned. But I can't see why you couldn't make any replacement mount you want to.
Dusty

Dusty-Dave wrote:

Boss9 wrote:Trying to find out if it is necessary to rubber mount the newer (2003 +..?) Sportster engines. Since I probably won't have the donor bike, I won't be able to tell what the factory mounting was like. Or perhaps I'm just better off getting an older Sportster engine?

Any thoughts? Any transmission better than the other to mount in a Bobber?

Yeah, it's a new guy question.

Unless you saw the factory transmission off the back of the cases there is little choice in a transmission but what the factory cast as part of the cases. Can't help with the particulars on the mounts they are way newer than anything I ever owned. But I can't see why you couldn't make any replacement mount you want to.
Dusty

Transmission wise I thought some were 4 speed, and some were 5 speed. I have an Buell XB9, which is of course a 5 speed. Older Sportsters were 4 speed ?

Looks like I just go with what I can find, and make it fit. Half the fun of it anyway. Was originally wondering how a vibration dampened engine did without vibration dampening.
Think I got a handle on it from the Sportster guys.

Since you're going to get a doner bike anyways I think it would be easier to just modify the stock frame and keep the stock mounts and tabs. That's most of the Sporty guys end up doing. So far from the feedback I get nobody yet is really happy with any of the frames they've built or bought from aftermarket suppliers. Biggest problem is that the Sporty motors just sit to high in the frame and then to get a nice looking 'stance' on the bike the frames end up being very very low in the rear and tend to scrape. Most die-hard builders just live with the problem. The best of the Paughco frames have 3.5" clearance and the stock bike has 7.5 to 8.25". I guess I forgot to ask if you were building a hardtail or a swingarm. No sense building a rubber mount hardtail so I guess you're doing a swingarm frame.

gww25 wrote:Since you're going to get a doner bike anyways I think it would be easier to just modify the stock frame and keep the stock mounts and tabs. That's most of the Sporty guys end up doing. So far from the feedback I get nobody yet is really happy with any of the frames they've built or bought from aftermarket suppliers. Biggest problem is that the Sporty motors just sit to high in the frame and then to get a nice looking 'stance' on the bike the frames end up being very very low in the rear and tend to scrape. Most die-hard builders just live with the problem. The best of the Paughco frames have 3.5" clearance and the stock bike has 7.5 to 8.25". I guess I forgot to ask if you were building a hardtail or a swingarm. No sense building a rubber mount hardtail so I guess you're doing a swingarm frame.

I'm building my own hardtail frame. I have the equipment and the space. I'm sure I'll learn what not to do on the first one, and maybe the second one will be better. Have a few ideas drawn up, but need the engine on hand to get them ironed out. I've looked at the aftermarket frames, and none fit my criteria.

Will probably just stay away from any rubber mounted engine stuff and make my life simpler. Sounds like a can of worms at this point.

had a 75 iron head sporty loved that bike regret selling that one only bad point was the super long brake arm was cheap pot metal . had to be super tight to not strip but it was a knife edge between tight and snap. it was the first year they switched the brake and shifter to the other side . dam thing ran like a top and I beat the hell out of it.

curt wrote:had a 75 iron head sporty loved that bike regret selling that one only bad point was the super long brake arm was cheap pot metal . had to be super tight to not strip but it was a knife edge between tight and snap. it was the first year they switched the brake and shifter to the other side . dam thing ran like a top and I beat the hell out of it.

I actually have a cad model of a 76 Iron Head sporty engine that I've been using for the frame mockup. It's a cool lookin motor !
Also have a 42 Panhead cad model, but doubt I really would go find a 42 Panhead to use in my first scratch built bike. The Iron Head is a possibility. Seen a few for sale.

wish I could afford a pan . ill bet you could do a much better job on the linkage than Harley did

would you be willing to share the cad models and some hard point measurements to make sure it is scaled right.

i'm sure you mean a 42 knucklehead or a 52 panhead, right?

as for the rubber mount sporty in a rigid frame without the rubber mounts, there are plenty of folks doing it over here. of course you'll feel a lot more vibration than you would in the original frame with rubber mounts, but then again if you were worried about vibration i doubt you'd be building a rigid frame, eh?

take care,
-dan

krymis wrote:would you be willing to share the cad models and some hard point measurements to make sure it is scaled right.

Sure I can share the Cad model, it's in Solidworks, and it's a big file. I'll get my Boss (wife) to put it up on our website in a few days, and send you the link

budoka wrote:i'm sure you mean a 42 knucklehead or a 52 panhead, right?

as for the rubber mount sporty in a rigid frame without the rubber mounts, there are plenty of folks doing it over here. of course you'll feel a lot more vibration than you would in the original frame with rubber mounts, but then again if you were worried about vibration i doubt you'd be building a rigid frame, eh?

take care,
-dan

Since I only have it as a CAD file, your probably right
I'm building a rigid, but having less vibration wouldn't hurt any either.
The design is coming along. Looks like I need to make a bit more room for an oil tank and battery, plus a few other changes. Still playing with the Girder frontend layout also.
Meantime starting on the frame jig. It's our busy time of the season now, so not much free time until later this fall.

krymis wrote:would you be willing to share the cad models and some hard point measurements to make sure it is scaled right.

I found where I had downloaded the engine cad file on the web. Here is the link https://grabcad.com/library/xlh1000-engine