Number of posts : 358 Registration date : 2007-12-23
Subject: todd cylinder heads Tue Feb 26, 2008 4:43 am
hi, can anyone tell me the difference between the todd heads and the standard heads on the 175cc engines. ive tried to buy one off ebay but they seem to be very popular and im not sure if their of any benifit. any information would be appreciated. thanks it also seems that these race bikes are not much good without the 3 speed cr boxes, which again seem pretty damd hard to come by. is there any other means of getting around this problem? has anyone found an alternative? thanks
mjpowell
Number of posts : 1074 Localisation : Lincoln England Registration date : 2006-12-09
Subject: Re: todd cylinder heads Sun Mar 02, 2008 3:34 am
Hi Ref Todd heads fins are thicker than std heads and there were 2 castings made part number on underside of head... GT 100 A for short reach plugs (1/2") GT 100 B for long reach plugs (3/4") Then they were machined to your spec i.e. 52mm (early D1),55mm (later D1 and all D3) or 60mm (all 175's) studs spacing. Also your compression ratio? I know at one time 10:1 road and 13:1 race ones were availble off the shelf so to speak...... However Pete Tibbitts is the only chap I think still using one?(I think) but he runs a iron barrell too!
nigel breeze
Number of posts : 358 Registration date : 2007-12-23
Subject: Re: todd cylinder heads Mon Mar 03, 2008 8:20 am
thanks for the todd info, much appreciated
Greenbat
Number of posts : 47 Registration date : 2008-03-11
I was going to post a new topic, but it might be more suitable to put it here. I have a Todd GT100 B head, for a 175. I am building up a D14/4 engine, and want to fit this head, and an iron barrel that has had the ports polished. The engine will go into a road bike, so whilst I want to increase performance a bit I don't want to lose too much reliability. Can anyone help? Thanks
cmurdoch
Number of posts : 3 Registration date : 2007-05-11
Subject: Re: todd cylinder heads Sun Apr 13, 2008 5:17 am
There was a Todd head fitted to a 175 barn find I got. Compression was mental, think I calculated 12.5:1. You have to advance the timing the bike by drilling and moving the stator plate. Anyway the bike flies- got it to 60 on the first run... bit silly as it then nipped up, but there was a hill, it was sunny... one thing leads to another.
However give it the beans quickly and it stutters and misfires, and it often needs a push when hot. Did have loads of overheating problems too. Pulls well up hills and pisses down everything the otherside.
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Tue Feb 26, 2008 4:43 am
it also seems that these race bikes are not much good without the 3 speed cr boxes, which again seem pretty damd hard to come by. is there any other means of getting around this problem? has anyone found an alternative? thanks
